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WO2022206501A1 - 基于雷达的距离检测方法、装置、雷达及终端 - Google Patents

基于雷达的距离检测方法、装置、雷达及终端 Download PDF

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Publication number
WO2022206501A1
WO2022206501A1 PCT/CN2022/082440 CN2022082440W WO2022206501A1 WO 2022206501 A1 WO2022206501 A1 WO 2022206501A1 CN 2022082440 W CN2022082440 W CN 2022082440W WO 2022206501 A1 WO2022206501 A1 WO 2022206501A1
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Prior art keywords
flight time
radar
time
flight
frame
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PCT/CN2022/082440
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English (en)
French (fr)
Inventor
王超
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华为技术有限公司
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Publication of WO2022206501A1 publication Critical patent/WO2022206501A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • G01S17/14—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves wherein a voltage or current pulse is initiated and terminated in accordance with the pulse transmission and echo reception respectively, e.g. using counters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/4802—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G01S7/4863—Detector arrays, e.g. charge-transfer gates
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak

Definitions

  • the present application relates to the field of radar technology, and in particular, to a radar-based distance detection method, device, radar and terminal.
  • lidar By sending out emission signals to the environment, receiving echo signals reflected from target objects in the environment, and analyzing the echo signals, lidar can determine the distance and other information of the target objects in the environment.
  • the laser radar has a ranging range
  • the laser radar of the prior art has a range limit on the analysis and processing of the echo signal.
  • the echo signal is reflected by the target object within the ranging range of the lidar, and the distance information of the target object determined according to the echo signal analysis is within the ranging range.
  • the lidar when there is a target object with high reflectivity or ultra-high reflectivity (1000%) in the environment outside the ranging range, since the intensity of the reflected echo signal is strong enough, it can also be received by the lidar.
  • the methods proposed in the prior art have some aspects that need to be improved in terms of ensuring no loss of ranging capability, computational complexity and computational power requirements, and most of them are suitable for laser radars and even millimeter-wave radars based on pulse ranging and analog signal output.
  • the solid-state lidar based on the principle of single-photon detection is a kind of digital radar, and it is necessary to combine the characteristics of the principle of single-photon detection to study the solution to the distance ambiguity suitable for the lidar of this system.
  • the distance detection method of the embodiments of the present application can realize the resolution of the distance ambiguity problem of the radar, and improve the detection ability and detection accuracy of the target distance.
  • an embodiment of the present application provides a radar-based distance detection method, the method comprising:
  • the first flight time eliminate part of the flight time in the second flight time to obtain a third flight time, and the part of the flight time corresponds to the flight time of the target outside the ranging range;
  • the distance information of the target is determined
  • the radar turns off transmission in multiple transmission periods, and in the second measurement time corresponding to the second frame, the radar transmits in each transmission period.
  • the radar turns off the transmission in multiple transmission periods, so that at least one of the echo data of the first frame has the transmission turned off.
  • the echo data received in multiple transmission cycles has nothing to do with the target in the ranging range.
  • the flight time of the target outside the ranging range in the first flight time can be determined without being affected by the target. Interference of targets within the ranging range; so that when the first flight time is used to determine the target distance information, the distance information of the targets outside the ranging range can be obtained according to the flight time of the targets outside the ranging range, and the ability of target distance detection can be improved.
  • the radar transmits in each transmission period, so that the echo data of at least one second frame is related to both the targets within the ranging range and the targets outside the ranging range. Therefore, according to the echo data of at least one second frame, the determined second flight time includes the flight time of the target outside the ranging range and the flight time of the target within the ranging range; combined with the first flight time, the second flight time can be removed The false flight time corresponding to the flight time of the target outside the ranging range is obtained, and the third flight time is obtained.
  • the third flight time does not include the flight time of the target outside the ranging range, so using the third flight time can determine the distance information of the target within the ranging range without interference from the target outside the ranging range, which can improve the accuracy of target distance detection.
  • Spend According to the radar-based distance detection method according to the embodiment of the present application, the finally obtained distance information of the target is more comprehensive, and the obtained distance information of the target does not have distance ambiguity, and the accuracy is high.
  • the method further includes:
  • the radar is controlled to enter one or more off cycles, and each off cycle includes multiple emission cycles;
  • the radar is sequentially controlled to close the transmission for h transmission periods, open for 1 transmission period, and then close for a transmission period, where h and a are positive integers;
  • the first echo data of the first frame is received in the a transmission cycles, and the first echo data is used to determine the flight time of the target outside the ranging range of the radar.
  • the radar can prepare for the transmission of pulses within 1 transmission period.
  • the first echo data of the first frame received in the period has nothing to do with the target within the ranging range, so that the first echo data of the first frame can be used to determine the target outside the ranging range in the first flight time flight time without interference from targets in the ranging range.
  • the method further includes:
  • the second echo data of the first frame is received in the one transmission cycle, the second echo data is used to determine the fourth flight time, the first flight time includes the fourth flight time, and the The fourth flight time represents the flight time of the target within the ranging range.
  • the radar By controlling the radar to start transmitting in a transmitting period after each closing period, the first echo data of the first frame received in the one transmitting period is not interfered by the target outside the ranging range, and is consistent with the first frame. Therefore, the fourth time-of-flight determined according to the first echo data of the first frame can represent the target that cannot be detected in the entire off period of the first frame. Flight time to target in range.
  • the processor can determine the distance information of the target within the ranging range according to the fourth flight time and the third flight time in the first flight time. In this way, the missed detection of the target by the radar can be avoided, so that the obtained distance information of the target within the ranging range is more accurate.
  • the radar receives echoes through one or more single-photon detectors photons, and the echo data is determined based on the count of received echo photons.
  • the radar can determine the distance information of the target outside the ranging range and the distance information of the target within the ranging range according to the echo data.
  • determining the first flight time according to echo data of at least one first frame received by the radar includes:
  • the flight time of the target outside the ranging range of the radar in the first flight time is determined, wherein each photon count histogram includes one peak position .
  • the time of flight of the target outside the ranging range in each emission period in the entire shutdown period can be determined, so as to determine the target time out of the ranging range of the radar in the first flight time.
  • the time-of-flight enables the processor to further determine the distance information of targets outside the radar's ranging range.
  • the method of determining a photon count histogram can be applied to a fast moving scene, which makes the method of target distance detection more targeted, and can ensure the accuracy of the distance information determined by the distance detection.
  • determining the first flight time according to echo data of at least one first frame received by the radar includes:
  • the flight time of the target outside the ranging range of the radar in the first flight time is determined, where e is a positive integer less than or equal to a.
  • the flight time of the target outside the ranging range of the radar in the first flight time can be determined, so that the processor can further determine the distance information of the target outside the ranging range of the radar.
  • the method of determining a photon count histogram can be applied to a moving scene where the radar is in a slow speed, or when the radar is in a stationary scene, which makes the method of target distance detection more targeted and can ensure the accuracy of the distance information determined by the distance detection. And it is determined that the data processing cost of one photon count histogram is low, which can save the data processing cost of the processor and improve the data processing efficiency.
  • the method further includes:
  • the fourth flight time in the first flight time is determined according to the flight time corresponding to at least one peak position in the multiple flight time intervals in the one photon count histogram, and the multiple flight time intervals are based on the radar
  • the time-of-flight of targets outside the ranging range is determined.
  • the fourth flight time interval is determined according to the flight time of the target outside the ranging range of the radar, and the fourth flight time interval is determined according to the flight time corresponding to at least one peak position in the multiple flight time interval in a photon count histogram. time, so that the flight time of the target within the ranging range close to the flight time of the target outside the ranging range can be detected, that is, the fourth flight time. In this way, the missed detection caused by the flight time of the target in the ranging range during the entire off period of the first frame can be avoided, and the ranging capability of the radar can be improved.
  • the power of the transmission pulse within one transmission period of the start transmission is higher than that of the second measurement transmit pulse power over time.
  • the purpose of increasing the transmit pulse power is to capture the photons of the echo pulses of the targets at longer distances. In this way, the ranging capability of the radar system can be improved.
  • an embodiment of the present application provides a distance detection device, the device comprising:
  • a first determining module for determining a first flight time according to echo data of at least one first frame received by the radar, where the first flight time includes the flight time of a target outside the ranging range of the radar;
  • the second determining module determines the second flight time according to the echo data of at least one second frame received by the radar
  • the third determination module eliminates part of the flight time in the second flight time to obtain a third flight time, and the part of the flight time corresponds to the flight time of the target outside the ranging range;
  • the fourth determination module according to the first flight time and the third flight time, to determine the distance information of the target
  • the radar turns off transmission in multiple transmission periods, and in the second measurement time corresponding to the second frame, the radar transmits in each transmission period.
  • the device further includes:
  • the first control module controls the radar to enter one or more shutdown periods, and each shutdown period includes multiple emission periods;
  • the second control module in each off cycle, sequentially controls the radar to turn off the transmission for h firing cycles, turn on the firing for 1 firing cycle, and then turn off the firing for a firing cycle, where h and a are positive integers;
  • the first echo data of the first frame is received in the a transmission cycles, and the first echo data is used to determine the flight time of the target outside the ranging range of the radar.
  • the apparatus further includes:
  • the third control module controls the radar to start transmitting in a transmitting period after each closing period ends;
  • the second echo data of the first frame is received in the one transmission cycle, the second echo data is used to determine the fourth flight time, the first flight time includes the fourth flight time, and the The fourth flight time represents the flight time of the target within the ranging range.
  • the radar receives echoes through one or more single-photon detectors photons, and the echo data is determined based on the count of received echo photons.
  • the first determining module includes:
  • the first determination sub-module determines a photon count histograms according to the counts of echo photons received in the a emission periods in all the off periods of the first frame, wherein each photon count histogram is based on In all off periods, the counts of echo photons of emission periods in the same order are determined;
  • the second determination sub-module determines the time of flight of a target outside the ranging range of the radar in the first time of flight according to the time of flight corresponding to the a peak positions of the a photon count histograms, wherein each photon count histogram
  • the graph includes 1 peak position.
  • the first determining module includes:
  • the third determination sub-module determines a photon count histogram according to the counts of echo photons received in the a emission period in all the off periods of the first frame;
  • the fourth determination sub-module determines the flight time of the target outside the ranging range of the radar in the first flight time, wherein e is less than or equal to a positive integer of .
  • the apparatus further includes:
  • the fifth determination module according to the count of the echo photons in an emission period after each said shutdown period ends, to determine a photon count histogram
  • the sixth determination module determines the fourth flight time in the first flight time, the multiple flight time intervals.
  • the flight time interval is determined according to the flight time of the target outside the ranging range of the radar.
  • the power of the transmit pulse within one transmit period of the start-to-transmit is higher than that of the second measurement transmit pulse power over time.
  • a distance detection device including:
  • memory for storing processor-executable instructions
  • the processor is configured to implement the first aspect or one or more of the distance detection methods in multiple possible implementation manners of the first aspect when executing the instruction.
  • embodiments of the present application provide a non-volatile computer-readable storage medium on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the above-mentioned first aspect or the first aspect is implemented One or more of the various possible implementations of the distance detection method.
  • embodiments of the present application provide a computer program product, comprising computer-readable codes, or a non-volatile computer-readable storage medium carrying computer-readable codes, when the computer-readable codes are stored in an electronic
  • the processor in the electronic device executes the first aspect or one or more of the distance detection methods in the multiple possible implementation manners of the first aspect.
  • an embodiment of the present application provides a radar, including the second aspect or a distance detection device of one or more of the multiple possible implementations of the second aspect, or including the above-mentioned third aspect. distance detection device.
  • an embodiment of the present application provides a terminal, including the radar of the sixth aspect.
  • FIG. 1 shows a schematic structural diagram of a direct time-of-flight radar system.
  • FIG. 2 shows an exemplary schematic diagram of how a direct time-of-flight radar system works when transmitting in each transmission cycle.
  • FIG. 3 shows an exemplary schematic diagram of how the distance detection method according to an embodiment of the present application works within the first frame measurement time.
  • Fig. 4 shows an exemplary schematic diagram of determining the first flight time in a fast motion scene according to the distance detection method according to an embodiment of the present application.
  • FIG. 5 shows an exemplary schematic diagram of determining the first flight time in a slow moving scene or a static scene by the distance detection method according to an embodiment of the present application.
  • FIG. 6 shows an exemplary structural diagram of a distance detection apparatus according to an embodiment of the present application.
  • LiDAR light detection and ranging, LiDAR
  • a radar that uses a laser as a radiation source. Its working principle is to detect the corresponding target object by transmitting the detection signal through the laser and receiving the echo signal reflected by the target object.
  • Maximum ranging distance or the maximum detection distance, which is a parameter related to the configuration of the radar itself (factory-set parameters or related to factory-set parameters). For example, the maximum ranging distance of long-range adaptive cruise control (ACC) radar is 250m, and the maximum ranging distance of medium-range radar is 70-100m.
  • ACC adaptive cruise control
  • Distance ambiguity means that when the distance between the target and the lidar is greater than the maximum ranging distance, the echo signal reflected by the target does not fall within the ranging time period corresponding to the transmitted signal, and the measured target distance at this time is unreal. distance, this phenomenon is called distance blurring.
  • Dynamic range an important parameter of a photodetector, which indicates the detection capability of the photodetector, which can be expressed by the number of incident photons that the photodetector can respond to at the same time.
  • a detector array is used for simultaneous data acquisition, and the detector array may include multiple photodetectors. The greater the number of incident photons that can respond at the same time, the greater the dynamic range of the detector array. If the dynamic range of the photodetector is insufficient, it will greatly limit the accuracy and range of the detection system. Among them, the photodetector is used to capture photons and output a current pulse signal when the photons are captured.
  • the dynamic range of the detector array is "occupied" by photons of ambient light from the moment the photons are captured, and it will take some time to recover to the state where photons can be captured. Therefore, when the ambient light is strong, the number of photodetectors in the detector array that can capture effective signal photons will decrease, resulting in the inability to read out effective signals and reducing the accuracy of the overall system.
  • Range blur is a common problem with lidars.
  • the first strategy is to balance the ratio of the laser emission pulse period to the ranging range of the system, and to increase the ranging corresponding to two adjacent emission pulses as much as possible.
  • the interval of the window time, the number of pulses received in one ranging window time will inevitably decrease, which limits the ranging performance of the radar to a certain extent, especially for long-distance lidar and other radar systems with high performance requirements are more unfavorable .
  • the second common strategy is to optimize through various post-processing algorithms. The basic idea is to identify false signals and filter them out. The implementation methods and costs of system algorithms with different architectures are different, such as the "pulse-cut" method.
  • the third strategy is to use transmit power modulation to change or reduce the pulse peak power of the laser to reduce the probability of the system detecting photon signals beyond the ambiguous distance. This method may increase the complexity of hardware adjustment.
  • the fourth strategy is to perform pulse code modulation at the transmitter, but doing so may lose system performance and increase the complexity of hardware circuit control.
  • the existing methods have some aspects that need to be improved in terms of ensuring no loss of ranging capability, computational complexity and computational power requirements, and most of them are suitable for lidar based on pulse ranging and analog signal output.
  • the solid-state lidar based on the principle of single-photon detection is a kind of digital radar, and it is necessary to combine the characteristics of the principle of single-photon detection to study the solution to the distance ambiguity suitable for the lidar of this system.
  • the present application provides a radar-based distance detection method.
  • the distance detection method of the embodiments of the present application can achieve the resolution of the radar's distance ambiguity problem and improve the detection capability and detection accuracy of target distance.
  • FIG. 1 shows a schematic structural diagram of a direct time-of-flight radar system.
  • the distance detection method of the embodiment of the present application can be applied to, for example (but not limited to) the processor of the radar system shown in FIG. 1 .
  • the transmitting end of the direct time-of-flight radar system may include a laser, for example, a vertical cavity surface emitting laser (Vcsel), an electroluminescence display (ELD) or a pulsed laser Diodes (pulsed laser diodes, PLDs) can be used to provide optical signals.
  • a laser for example, a vertical cavity surface emitting laser (Vcsel), an electroluminescence display (ELD) or a pulsed laser Diodes (pulsed laser diodes, PLDs) can be used to provide optical signals.
  • the optical signal emitted by the laser is used as the emission signal, which is emitted into the environment by the emission optical system, and is reflected by the target object in the environment to obtain an echo pulse, that is, the echo signal, which is received by the receiving optical system.
  • the radar receiver may include a detector, such as a single photon avalanche diode (SPAD) or a digital silicon photomultiplier (SIPM), which has single-photon sensitivity and can capture photons of reflected echo pulses , when the detector captures the first photon, a current pulse signal is generated, which is output to the time-to-digital converter (TDC), and the time-of-flight is generated and recorded by the time-to-digital converter.
  • a detector such as a single photon avalanche diode (SPAD) or a digital silicon photomultiplier (SIPM), which has single-photon sensitivity and can capture photons of reflected echo pulses , when the detector captures the first photon, a current pulse signal is generated, which is output to the time-to-digital converter (TDC), and the time-of-flight is generated and recorded by the time-to-digital converter.
  • TDC time-to-digital converter
  • the ranging window time of the radar system can be determined.
  • the transmitting end of the radar transmits the transmit pulse, reaches the maximum ranging distance specified by the range, and then returns to the receiving end of the radar from the maximum ranging distance, which is the ranging window time.
  • the ranging window time may be equal to, for example, 1 microsecond (ranging range*2/speed of light).
  • the ranging window time can be set to be less than or equal to the transmit period.
  • the time-to-digital converter reports the delay to the processor, which is the difference between the current pulse signal input by the detector to the time-to-digital converter within the ranging window after each transmit pulse is transmitted relative to the transmit pulse. Delay, the processor stores the delay, that is, records a flight time.
  • the processor may perform histogram statistics on the stored times of the same flight time based on time-correlated single photon counting (TCSPC), and obtain a histogram with the abscissa as the flight time and the ordinate as the number. By detecting the peak position of the histogram, the flight time with the highest number of times can be found, and the distance information of the target object can be determined according to the flight time.
  • TCSPC time-correlated single photon counting
  • the target distance R 0 corresponding to the echo pulse can be calculated according to formula (1):
  • c is the speed of light
  • t 0 is the flight time with the highest number of times determined according to the histogram in the current scene.
  • the formula (1) is applicable to the case where the detector only receives the echo pulses reflected by the target within the ranging range.
  • the distance information of the target object determined by the processor will appear distance blurred.
  • the processor gets a flight time, which is a fake flight time. If the false flight time is brought into formula (1), the obtained distance information is wrong distance information, that is, distance ambiguity occurs.
  • the frame data collected by the receiving end can be divided into detection frame data and non-detection frame data, and the detection frame data can be used to calculate the real distance of the target object outside the ranging range. information, and then use the detection frame data and non-detection frame data to calculate the real distance information of the target object within the ranging range to achieve distance blur removal.
  • the first frame may be used to represent the detection frame
  • the second frame may be used to represent the non-detection frame.
  • the radar-based distance detection method includes:
  • the first flight time is determined according to the echo data of at least one first frame received by the radar, and the first flight time includes the flight time of the target outside the ranging range of the radar; according to the echo data of at least one second frame received by the radar
  • the data determines the second flight time; according to the first flight time, eliminate part of the flight time in the second flight time to obtain the third flight time, and the part of the flight time corresponds to the flight time of the target outside the ranging range;
  • the distance information of the target is determined, wherein, in the first measurement time corresponding to the first frame, the radar turns off the transmission in multiple transmission cycles, and in the second During the second measurement time corresponding to the frame, the radar transmits in each transmission period.
  • the radar turns off the transmission in multiple transmission periods, so that at least one of the echo data of the first frame has the transmission turned off.
  • the echo data received in multiple transmission cycles has nothing to do with the target in the ranging range.
  • the flight time of the target outside the ranging range in the first flight time can be determined without being affected by the target. Interference of targets within the ranging range; so that when the first flight time is used to determine the target distance information, the distance information of the targets outside the ranging range can be obtained according to the flight time of the targets outside the ranging range, and the ability of target distance detection can be improved.
  • the radar transmits in each transmission period, so that the echo data of at least one second frame is related to both the targets within the ranging range and the targets outside the ranging range. Therefore, according to the echo data of at least one second frame, the determined second flight time includes the flight time of the target outside the ranging range and the flight time of the target within the ranging range; combined with the first flight time, the second flight time can be removed The false flight time corresponding to the flight time of the target outside the ranging range is obtained, and the third flight time is obtained.
  • the third flight time does not include the flight time of the target outside the ranging range, so using the third flight time can determine the distance information of the target within the ranging range without interference from the target outside the ranging range, which can improve the accuracy of target distance detection.
  • Spend According to the radar-based distance detection method according to the embodiment of the present application, the finally obtained distance information of the target is more comprehensive, and the obtained distance information of the target does not have distance ambiguity, and the accuracy is high.
  • the radar-based distance detection method according to the embodiment of the present application will be described in detail below.
  • the radar receives echo photons through one or more single-photon detectors, and determines echo data according to the counts of the received echo photons.
  • the radar can determine the distance information of the target outside the ranging range and the distance information of the target within the ranging range according to the echo data.
  • the radar-based distance detection method can be aimed at a lidar using a single-photon device as a detector and based on time-correlated single-photon counting, and can calculate the target distance through direct flight time.
  • the transmitter of the lidar is preferably a laser with a higher center frequency, and the form of the laser at the transmitter is not limited, such as a vertical cavity surface emitting laser, an electroluminescent display, or a pulsed laser diode; the form of the lidar is not limited, such as mechanical, solid-state, Hybrid solid-state or other types; the detector at the receiving end can be, for example, a single-photon avalanche diode, a digital silicon photomultiplier tube, etc.; the working mode of the lidar is not limited to electrical scanning, floodlighting, line scanning or two-dimensional scanning devices. Dot matrix scanning, etc.
  • the center frequency is also called the point frequency.
  • the center frequency of the vertical cavity surface emitting laser Due to structural reasons, the center frequency of the vertical cavity surface emitting laser has no upper limit, which is usually 500KHz-1MHz, and can even be several GHz or even tens of GHz.
  • the center frequency of electroluminescent displays and pulsed laser diodes is usually 100KHz-300KHz. There is a heat dissipation problem in the actual radar system, so it can be considered to choose a laser with a narrower pulse width.
  • the fast response capability of the vertical cavity surface emitting laser itself is relatively high, so it is easy to realize narrow pulse width emission.
  • the measurement angle, working frame rate, repetition period of the transmission pulse (referred to as the transmission period) and measurement time (such as the first measurement time and the second measurement time) of the radar system can be preset. Wait.
  • the measurement angle can be set according to the actual scene;
  • the working frame rate can be set according to the actual scene, the high frame rate can be set in the scene with high precision requirement, and the low frame rate can be set in the scene with low precision requirement; It can be set to a value greater than or equal to the ranging window time.
  • the measurement time is the time to complete a frame of data collection when the lidar system collects data in units of frames.
  • the measurement time is much longer than the emission period and ranging time.
  • the radar may send out hundreds or even thousands of transmit pulses.
  • the first measurement time may be equal to the second measurement time, for example.
  • the working frame rate is related to the actual application scenario.
  • the working frame rate is defined as f.
  • the working frame rate can be set to more than 25 frames/second.
  • the working frame rate can be set from 10 frames/sec to 15 frames/sec.
  • the working frame rate can also be set to other values, which are not limited in this application.
  • the repetition period of the transmission pulse (transmission period for short) is set as t
  • the ranging window time is T
  • T0>>t ⁇ T the value of the ranging window time T can be determined according to the speed of light and the ranging range of the system.
  • the ranging range is 150 meters
  • the ranging window time may be equal to, for example, 1 microsecond.
  • the radar can also obtain the flight time t3 of the photons of the echo pulse 3 of the first transmitted pulse reflected by the target outside the ranging range.
  • the radar may eg be able to receive N+M frames of echo data.
  • the echo data of the N first frames received by the radar may be set as N frame detection frame data for processing to determine the first flight time.
  • the echo data of M second frames received by the radar are set as M frames of non-detected frame data for processing to determine the second flight time.
  • a part of the second flight time determined according to the echo data of the M second frames is the unreal flight time of the target outside the ranging range, which can be obtained according to the echo data of the N first frames
  • the flight time of the target outside the ranging range corresponding to the first flight time in the second flight time determined by the echo data of the M second frames is excluded to obtain the third flight time.
  • the first time of flight can determine the distance information of the target outside the ranging range, and the distance information of the target within the ranging range can be determined according to the third time of flight.
  • the echo data of the first frame is processed, and finally the distance information of the targets within the ranging range and outside the ranging range is obtained.
  • the echo data of the N first frames received by the radar can be set to have a flag bit, and the processor can distinguish whether the received data is the echo data of the first frame or the echo data of the second frame based on this.
  • the radar can be set to continuously receive echo data of N first frames as detection frame data.
  • the radar can be set to continuously receive N first frames
  • the echo data is used as the detection frame data, and it can also be set to receive the echo data of N discontinuous first frames as the detection frame data. This application does not limit this.
  • the received echo data of N consecutive first frames have correlation.
  • the radar system receives 25 frames of data (including echo data of the first frame and echo data of the second frame) per second.
  • the processor Since after receiving the echo data of the N first frames, the processor also needs to perform operations on the received echo data of the N first frames, so theoretically, in every second when the radar system performs distance detection, The earlier the echo data of the N first frames is received, the better.
  • data verification can be performed before the radar system is used for distance detection. Through the verification, the accuracy of the distance information obtained by processing the echo data of the N first frames can be improved.
  • the detection frame the first frame
  • 6-25 frames can be selected. as a non-detected frame (second frame).
  • the second second when the radar system performs distance detection several consecutive frames (such as 6-10 frames) in the 25 frames can be selected as the detection frame (the first frame), and 1-5 and 11-25 frames are taken as non-detection frames. frame (second frame).
  • the present application does not limit the specific selection manner of the detection frame (the first frame).
  • the radar system of the embodiment of the present application may include multiple radars arranged at different positions of the vehicle.
  • it may include a first radar suitable for distance detection in a fast moving scene and a second radar suitable for distance detection in a slow moving scene or a stationary scene.
  • a suitable radar can be selected for distance detection according to the speed of the vehicle to reduce the cost of data processing; the first radar and the second radar can also be used at the same time to improve the detection accuracy.
  • the radar system of the embodiment of the present application may further include more radars, which is not limited in the present application.
  • the distance information (including within and outside the ranging range) can be calculated and obtained, and within the second second of the radar system's operation, the vehicle It can work according to the distance information obtained in the first second when the radar system is working.
  • the vehicle can work according to the distance information obtained in the second second when the radar system is working, so that terminals such as vehicles can work.
  • the distance information on which the vehicle is based is kept up-to-date, thereby improving the safety of autonomous driving of the vehicle.
  • M and N may also be set so that the lidar completes the reception of N echo data of the first frame and the reception of M echo data of the second frame at other times. For example, it can be ensured that at least N echo data of the first frame can be received every 2 seconds or every 0.5 seconds. This application does not limit this.
  • the data received within the ranging window corresponding to each transmission period may include the echo photon count and ranging of the target within the ranging range. Echo photon counts for out-of-range targets.
  • the pulse transmission mode in the first measurement time can be set, so that the echo data of the first frame received in a fixed time period in each first measurement time only includes the echo data outside the ranging range. The echo photon count of the target. Based on this, the flight time of the target outside the ranging range can be determined according to the echo data of the first frame received in this time period.
  • the distance detection method of the embodiment of the present application further includes:
  • the radar is controlled to enter one or more off cycles, and each off cycle includes multiple emission cycles; in each off cycle, the radar is sequentially controlled to turn off and transmit for h firing cycles, turn on One transmit cycle is transmitted, and then a transmit cycle is turned off, where h and a are positive integers; wherein, the first echo data of the first frame is received in the a transmit cycle, and the first echo data is Used to determine the time of flight of targets outside the radar's range.
  • the radar can prepare for the transmission of pulses within 1 transmission period.
  • the first echo data of the first frame received in the period has nothing to do with the target within the ranging range, so that the first echo data of the first frame can be used to determine the target outside the ranging range in the first flight time flight time without interference from targets in the ranging range.
  • the start time tt of the first closing period of each first frame can be preset, so that the start time tt corresponding to any first frame is reached and the preset time tt elapses, the The first off period of the frame. It can be defined that the time corresponding to one off period is equal to the time corresponding to a+h+1 emission periods, where h ⁇ 1 and an integer, and a ⁇ 1 and an integer.
  • the processor controls the laser to turn off the pulse emission during the time corresponding to the first firing cycle to the h-th firing cycle in the first off cycle. (defined as pre-off emission); within the time corresponding to the h+1th emission period, the processor controls the laser to start pulse emission (defined as detection emission); the h+2th emission period to the a+h+1th emission During the time corresponding to the period, the processor controls the laser to turn off pulse emission (defined as continuous turn-off emission).
  • the power of the transmission pulse within one transmission period (detection transmission) when the transmission is turned on is higher than the transmission pulse power in the second measurement time.
  • the purpose of increasing the power of the transmitted pulse when detecting the emission is to capture the photons of the echo pulse of the target at a longer distance. In this way, the ranging capability of the radar system can be improved.
  • the purpose of setting the pre-shutdown emission is to charge the laser in advance within the time corresponding to the pre-shutdown emission, so that a transmission pulse that increases the transmission power can be emitted when the emission is detected.
  • the purpose of continuously shutting down the transmission is to make the data information received by the radar system come from the echo pulses of the targets outside the range within a period corresponding to a transmission period of the continuous shut-down transmission, so that the data can be received according to the data in the continuous shut-down transmission time.
  • the information (the first echo data of the first frame) calculates the distance information of the target outside the range.
  • the value of h can be preset according to the power of the emission pulse within one emission period (detection emission) when the emission is turned on, and the time required for the laser to be charged to be able to emit the emission pulse of this power, and the value of a can be determined according to Ranging requirements, adjust before ranging. For example, if the center frequency is 500kHz, and the ranging range is 300 meters, the transmission period is 2 microseconds (1/center frequency), and the ranging window time T is also 2 microseconds (measurement range). Distance range*2/speed of light).
  • the real flight time of the pulsed photon can be equal to 10 microseconds (1500m*2/speed of light). And 10 microseconds is equal to 5 emission periods, and the emission period is equal to the ranging window time, that is to say, for the pulses emitted in the first emission period, the echo pulse photons reflected by the target have a flight time equal to five emission periods. , captured by the detector within the sixth emission cycle at the latest.
  • the first flight time determined by the radar system includes the flight time of the target outside the ranging range of the radar determined in a transmission cycle of each shutdown period, so that the flight time of the target outside the ranging range of the radar can be determined according to the flight time of the target outside the ranging range of the radar. time, to determine the real flight time of the echo pulse photons of the target outside the ranging range, so as to determine the real distance information of the target object outside the ranging range.
  • a specific encoding method can be used to constrain the start time tt of the first off period of any first frame and the number of periods b of the time interval between two off periods to form specificity feature.
  • b can take one value or multiple values, for example, it can take one value b 0 , and the time interval between any two off periods of the first frame is equal and equal to b 0 *t ; If multiple values b 1 , b 2 , b 3 ??b c-1 are taken, the time intervals of the two off periods of the first frame are respectively b 1 *t, b 2 *t, b 3 *t ...b c-1 *t.
  • the value of the interval time of the off period of each first frame may be different, that is, the value of b of each first frame may be different.
  • the radar system receives 25 frames of data in 1 second.
  • the first off period is entered.
  • the detection emission is completed, for example, the laser pulse emission is turned on for one emission period, and the power of the emission pulse is increased.
  • the anti-jamming capability of the radar system can be improved, thereby improving the accuracy of the finally obtained distance information.
  • the time interval between any two off periods of any first frame and the start time of the first off period of any first frame can be selected in various ways, as long as the measurement can be satisfied This is not limited in this application.
  • the echo data of the first frame is also used to determine the flight time of the target within the ranging range
  • the distance detection method of the embodiment of the present application further includes:
  • the radar In a transmission period after each shutdown period, the radar is controlled to start transmitting; wherein, the second echo data of the first frame is received in the one transmission period, and the second echo data is used to determine the fourth flight time,
  • the first flight time includes the fourth flight time, and the fourth flight time represents the flight time of the target within the ranging range.
  • the radar By controlling the radar to start transmitting in a transmitting period after each closing period, the first echo data of the first frame received in the one transmitting period is not interfered by the target outside the ranging range, and is consistent with the first frame. Therefore, the fourth time-of-flight determined according to the first echo data of the first frame can represent the target that cannot be detected in the entire off period of the first frame. Flight time to target in range.
  • the processor can determine the distance information of the target within the ranging range according to the fourth flight time and the third flight time in the first flight time. In this way, the missed detection of the target by the radar can be avoided, so that the obtained distance information of the target within the ranging range is more accurate.
  • the processor may control the laser to turn on and emit one firing period after each off period ends. Therefore, the second echo data of the first frame received in this one transmission period includes the count of echo pulse photons within the ranging range. Moreover, at the end of each shutdown period, the radar has not sent any pulses for a continuous transmission period. Therefore, it can be considered that the second echo data of the first frame received in this one transmission period does not include the out-of-ranging range. Counts of echo pulse photons. The second echo data of the first frame can be used to determine the fourth flight time. Therefore, the fourth flight time represents the flight time of the target within the ranging range, and the fourth flight time can be used to determine the distance information of the target within the ranging range.
  • the first flight time includes the flight time of the target outside the ranging range, and the flight time of the target within the ranging range, that is, the fourth flight time. Then, according to the first flight time and the third flight time, the distance information of the target is determined. It can be considered that according to the flight time of the target outside the ranging range in the first flight time, the distance information of the target outside the ranging range can be determined; The third flight time and the fourth flight time in the first flight time can determine the distance information of the target within the ranging range.
  • the processor may analyze and process the received data based on the time-correlated single-photon counting method to determine the first time of flight.
  • the principle of time-correlated single-photon counting is introduced first.
  • the time-to-digital converter can record n times (n ⁇ m) of the light flight time, and generate a photon count histogram of the flight time with respect to the number of counts.
  • n times n ⁇ m
  • the extreme value solving algorithm to detect the peak position of the photon count histogram can calculate the flight time value with the most occurrences, which is the final flight time. If multiple peak positions with different intensities are found when detecting peak positions, it can be considered that multiple flight times corresponding to multiple peak positions come from different targets, and the flight time values of multiple peak positions of the photon count histogram can be calculated, is the final flight time.
  • the detector can effectively remove the inherent noise of the device and ambient light noise under the condition that the incident single photon is captured, so that the number of counts caused by noise will be much lower than that caused by valid signals. , which can be easily identified from the photon count histogram.
  • the time-correlated single-photon counting technology performs repeated measurement of the target object's time of flight for multiple times, which can further improve the time resolution of the system.
  • determining the first flight time according to echo data of at least one first frame received by the radar includes:
  • each photon count histogram is based on the emission cycles in the same order in all off cycles is determined by the counts of the echo photons of ; according to the flight times corresponding to the a peak positions of the a photon count histograms, the flight time of the target outside the ranging range of the radar in the first flight time is determined, wherein each photon counts
  • the histogram includes 1 peak position.
  • the time of flight of the target outside the ranging range in each emission period in the entire shutdown period can be determined, so as to determine the target time out of the ranging range of the radar in the first flight time.
  • the time-of-flight enables the processor to further determine the distance information of targets outside the radar's ranging range.
  • the method of determining a photon count histogram can be applied to a fast moving scene, which makes the method of target distance detection more targeted, and can ensure the accuracy of the distance information determined by the distance detection.
  • the N first frames may include c1, c2, .
  • the device can determine the first photon count histogram (1Th) according to the single photon count of the received echo data within the time corresponding to the first emission period (1th) of the continuous shutdown emission of each shutdown period; In the time (2th) corresponding to the second emission period of continuous shutdown emission of one shutdown period, the single photon count of the received echo data determines the second photon count histogram (2Th); During the time (ath) of the a-th emission period of the continuous-off emission of one off period, the single-photon count of the received echo data determines the a-th photon count histogram (aTh). After obtaining a photon count histograms, peak positions can be detected for the a photon count histograms respectively.
  • the ordinate of the photon count histogram is the number of single photon counts. Therefore, the time information corresponding to the single photon with the largest number of times is the flight time of the target outside the ranging range determined by the radar system. Assuming that each photon count histogram detects a peak position, the flight times of targets outside the ranging range determined by the radar system are Tt1, Tt2...Tta, that is, the first flight time determined by the radar includes Tt1, Tt2... Tta.
  • the flight time of the target outside the ranging range determined by the radar system is Tt11, Tt12, Tt2...Tta.
  • Tt11 and Tt12 are both from the first photon count histogram. That is, the first flight time determined by the radar includes Tt11 , Tt12 , Tt2 . . . Tta.
  • the first flight time further includes a fourth flight time
  • the distance detection method in this embodiment of the present application further includes:
  • One photon count histogram is determined according to the count of echo photons in one emission period after each off period; according to the one photon count histogram, the flight corresponding to at least one peak position in multiple flight time intervals time, the fourth flight time in the first flight time is determined, and the multiple flight time intervals are determined according to the flight time of the target outside the ranging range of the radar.
  • the fourth flight time interval is determined according to the flight time of the target outside the ranging range of the radar, and the fourth flight time interval is determined according to the flight time corresponding to at least one peak position in the multiple flight time interval in a photon count histogram. time, so that the flight time of the target within the ranging range close to the flight time of the target outside the ranging range can be detected, that is, the fourth flight time. In this way, the missed detection caused by the flight time of the target in the ranging range during the entire off period of the first frame can be avoided, and the ranging capability of the radar can be improved.
  • the processor can obtain a histogram of photon counts according to the single-photon counts within one emission period immediately following each off period in the N first frames, and obtain a photon count histogram according to the above-mentioned method.
  • the flight time Tt1, Tt2...Tta of the target can determine a flight time interval.
  • a flight time interval [Tt1-P, Tt1+P] [Tt2-P can be determined according to the flight time Tt1, Tt2...Tta of the target outside the ranging range ,Tt2+P]...[Tta-P,Tta+P].
  • a flight time interval [Tt1-P, Tt1+P], [Tt2-P, Tt2+P]...[Tta-P, Tta+P] in the range of Part of the photon count histogram detects the peak position. If at least one peak position can be detected, it can be considered that the radar system has missed detection of the target within the ranging range during the entire off period of the N first frames. In this case, the flight time corresponding to the detected at least one peak position represents the flight time of the target in the ranging range that cannot be detected in the entire closing period of the first frame, and can be determined as the first flight time in the first flight time.
  • Four flight times For example, if three peak positions are detected in multiple flight time intervals, and the corresponding flight times are Tq1, Tq2, and Tq3, respectively, the determined fourth flight time includes Tq1, Tq2, and Tq3.
  • the flight time of the target outside the ranging range and the flight time of the target within the ranging range can be determined respectively, that is, the first flight time can be determined.
  • the distance information of the target outside the ranging range can be calculated according to the flight time of the target outside the ranging range, and the ranging capability of the radar is improved.
  • the processor may determine the distance information of the target outside the ranging range.
  • the flight time Tt1 corresponding to the peak position of the first photon count histogram (1Th) is in the first emission cycle when the emission is continuously turned off.
  • the time-of-flight determined by the echo photon count of the arriving echoes can be seen from the ranging principle of the direct time-of-flight radar system described above.
  • the radar system counts the emission time of the transmitted pulse corresponding to a ranging window time and counts the ranging window time.
  • the captured echo photons are counted, and the flight time is determined according to the count of the echo photons, that is to say, the flight time determined by the radar system must be less than or equal to the ranging window time T.
  • the echo photons captured by the radar system are actually the echo photons of the emission pulses detected and emitted before the continuous shutdown emission. Therefore, the actual flight time of the echo photons can be increased by one emission period t compared to the flight time determined by the radar system based on the counts of the captured echo photons. In this way, according to the flight time Tt1 corresponding to the peak position of the first photon count histogram (1Th), a flight time Tt1+t can be determined.
  • the flight time Tt2 corresponding to the peak position of the second photon count histogram (2Th) is the flight time Tt2 determined by the radar according to the captured echo photon counts in the second emission period of the continuous shutdown emission, and the flight time Tt2 of the continuous shutdown emission During the 2 emission periods, the echo photons captured by the radar system are actually the echo photons of the emission pulses that are continuously turned off before the emission is detected. Therefore, the actual flight time of the echo photons can be increased by 2 emission periods t compared to the flight time determined by the radar system based on the counts of captured echo photons. In this way, according to the flight time Tt2 corresponding to the peak position of the second photon count histogram (2Th), a flight time Tt2+2t can be determined.
  • the flight time Tta corresponding to the peak position of the a-th photon count histogram (aTh) is the flight time Tta determined by the radar according to the captured echo photon counts in the a-th emission cycle when the emission is continuously turned off.
  • the echo photons captured by the radar system are actually the echo photons of the emission pulses detected and emitted before the continuous shutdown emission. Therefore, the actual flight time of the echo photons can be increased by a transmission period t compared to the flight time determined by the radar system based on the counts of captured echo photons. In this way, according to the flight time Tta corresponding to the peak position of the a-th photon count histogram (aTh), a flight time Tta+at can be determined.
  • multiple peak positions are detected in the photon count histogram corresponding to the same emission period.
  • the flight time of the target outside the ranging range determined by the radar system is Tt11, Tt12, Tt2...Tta
  • Tt11 and Tt12 are the time of flight determined by the radar according to the captured echo photon counts in the first emission period of the continuous shutdown of the emission. It can be seen from the above description that, The actual flight time of the echo photons can be increased by one emission period t compared to the flight time determined by the radar system based on the counts of the captured echo photons.
  • flight times Tt11 and Tt12 corresponding to the peak position of the first photon count histogram two flight times Tt11+t and Tt12+t can be determined.
  • the flight times Tt11+t, Tt12+t, Tt2+2t...Tta+at can be obtained, and substituted into formula (1), so that t0 is equal to Tt11+t, Tt12+t, Tt2+2t...Tta+ at, the distance information of the out-of-range target can be calculated.
  • the processor may determine the distance information of the target within the ranging range.
  • the obtained first flight time may include, for example, the flight time Tt1 , Tt2 , . . . Tta of the target outside the ranging range.
  • the second flight time may be determined, and the second flight time may for example include Tt1, Tt2...Tta, Tk1, Tk2...Tks.
  • the flight time corresponding to the flight time of the out-of-range target in the second flight time can be removed first to obtain the third flight time, for example, the third flight time includes Tk1, Tk2...Tks.
  • the third flight time is the flight time of the target in the ranging range. Therefore, by substituting Tk1, Tk2...Tks into formula (1), so that t0 is equal to Tk1, Tk2...Tks, respectively, the distance information of the target in the range can be calculated. .
  • the processor can obtain the distance information of the target within the ranging range with higher accuracy.
  • the flight time Tq1 of the target within the ranging range can also be included.
  • the third flight time and the fourth flight time may be ORed to obtain, for example, Tq1, Tq2, Tq3, Tk1, Tk2...Tks.
  • the OR operation result of the third flight time and the fourth flight time is the flight time of the target within the ranging range.
  • Tq1, Tq2, Tq3, Tk1, Tk2...Tks can be substituted into formula (1), Make t0 equal to Tq1, Tq2, Tq3, Tk1, Tk2... Tks respectively, then the distance information of the target in the range can be calculated.
  • the distance information of the target within the range and the distance information of the target outside the range can be output as the point cloud depth map of the target within the range and the point cloud depth map of the target outside the range respectively, or It is integrated into a point cloud depth map including in-range targets and out-of-range targets and then output.
  • the distance detection method of the embodiment of the present application can obtain the distance information of the target outside the ranging range and the distance information of the target within the ranging range with high accuracy, and the acquisition of the two can be realized by calculation, and does not need to be in the radar. New hardware is added, so the ranging capability of the radar can be improved without increasing the hardware cost.
  • the detection window and the threshold of the peak position can be set, and all the peak positions and their flight times that exceed the threshold can be collected, and then the time information ( That is, the minimum and maximum values in the flight time of the peak position that exceeds the threshold) are used as the time information of the target. If the direction is the same, the minimum value is taken, and the maximum value is taken if the direction is opposite.
  • the relationship between the difference between the values and the speed of the vehicle is used to calculate the possible change law of the spatial distance relationship between the target and the lidar system over a period of time, and report the predicted law to the control system of the terminal.
  • the control system of the terminal can apply the pre-judgment rule to the echo data of the second frame received subsequently, such as predicting the possible distance information of the moving object within the second measurement time, so as to plan the driving according to the possible distance information of the moving object route etc.
  • determining the first flight time according to echo data of at least one first frame received by the radar includes:
  • a photon count histogram is determined; according to the flight times corresponding to e peak positions of a photon count histogram, the first photon count histogram is determined.
  • the flight time of the target outside the ranging range of the radar in the first flight time can be determined, so that the processor can further determine the distance information of the target outside the ranging range of the radar.
  • the method of determining a photon count histogram can be applied to a moving scene where the radar is in a slow speed, or when the radar is in a stationary scene, which makes the method of target distance detection more targeted and can ensure the accuracy of the distance information determined by the distance detection. And it is determined that the data processing cost of one photon count histogram is low, which can save the data processing cost of the processor and improve the data processing efficiency.
  • the N first frames may, for example, include c1, c2, .
  • the value of the number of off cycles c1, c2, . in this case, for N first frames, single-photon counts obtained for a emission period of continuous off-emission of all off periods can be combined into one photon count histogram (Th). Since the 1 photon count histogram (Th) is obtained during the continuous off emission time, there is no echo pulse photon of the target in the real range.
  • e By detecting the peak of the photon count histogram, e can be detected, for example. peak positions with different intensities, e ⁇ a.
  • the flight times corresponding to the strongest peak to the weakest peak are Tt1, Tt2...Tte. That is, the first flight time determined by the radar includes Tt1 , Tt2 . . . Tte.
  • the fourth flight time may be determined by referring to the fourth flight time in the fast motion scene above. The description of the determination method will not be repeated here.
  • the flight time of the target outside the ranging range and the flight time of the target within the ranging range can be determined respectively in a slow moving scene or a static scene.
  • the distance information of the target outside the ranging range can be calculated according to the flight time of the target outside the ranging range, and the ranging capability of the radar is improved.
  • the following introduces an exemplary method for determining the distance information of the target according to the first flight time and the third flight time in a slow moving scene or a static scene.
  • the processor may determine the distance information of the target outside the ranging range.
  • the flight times Tt1, Tt2... are different.
  • the flight time Tt1 corresponding to the strongest peak is the flight time determined by the radar according to the captured echo photon counts in the first emission cycle when the emission is continuously turned off.
  • the flight time Tt1 corresponding to the peak can be determined as a flight time Tt1+t.
  • the flight time Tt2 corresponding to the sub-strong peak is the flight time determined by the radar according to the captured echo photon counts in the second emission cycle when the emission is continuously turned off.
  • Tt2 a flight time Tt2+2t can be determined.
  • Tt1+t, Tt2+2t...Tte+et can be determined respectively, and substituted into formula (1), so that t0 is equal to Tt1+t, Tt2+2t...Tte+et, respectively, and the out-of-range target can be calculated. distance information.
  • the processor may determine the distance information of the target within the ranging range according to the third flight time, or according to the first flight time and the third flight time.
  • the processor may determine the distance information of the target within the ranging range according to the third flight time, or according to the first flight time and the third flight time.
  • the distance information of the target outside the ranging range and the distance information of the target within the ranging range can be obtained at the same time, thereby expanding the system performance.
  • the acquisition of the above distance information does not come at the expense of complex design and regulation.
  • the hardware control and implementation are relatively simple. Only the on and off of the laser pulse emission is designed, and the receiving end does not need to be modified, and the data can be collected normally.
  • the strategy of the embodiment of the present application does not require complex data post-processing, and only needs to perform the processing of the N first frames of echo data received during the corresponding continuous off-transmission time before obtaining a complete photon count histogram. The first echo data of one frame and the second echo data of N first frames received in the next first transmission period are stored and processed, and the complexity of the strategy and the implementation cost are small.
  • An embodiment of the present application provides a distance detection device, see FIG. 6 , the device includes:
  • the first determination module 101 determines a first flight time according to echo data of at least one first frame received by the radar, where the first flight time includes the flight time of a target outside the ranging range of the radar;
  • the second determining module 102 determines the second flight time according to the echo data of at least one second frame received by the radar;
  • the third determination module 103 eliminates part of the flight time in the second flight time to obtain a third flight time, and the part of the flight time corresponds to the flight time of the target outside the ranging range;
  • the fourth determination module 104 determines the distance information of the target according to the first flight time and the third flight time,
  • the radar turns off transmission in multiple transmission periods, and in the second measurement time corresponding to the second frame, the radar transmits in each transmission period.
  • the apparatus further includes:
  • the first control module controls the radar to enter one or more shutdown periods, and each shutdown period includes multiple emission periods;
  • the second control module in each off cycle, sequentially controls the radar to turn off the transmission for h firing cycles, turn on the firing for 1 firing cycle, and then turn off the firing for a firing cycle, where h and a are positive integers;
  • the first echo data of the first frame is received in the a transmission cycles, and the first echo data is used to determine the flight time of the target outside the ranging range of the radar.
  • the apparatus further includes:
  • the third control module controls the radar to start transmitting in a transmitting period after each closing period ends;
  • the second echo data of the first frame is received in the one transmission cycle, the second echo data is used to determine the fourth flight time, the first flight time includes the fourth flight time, and the The fourth flight time represents the flight time of the target within the ranging range.
  • the radar receives echo photons through one or more single-photon detectors, and determines the echo data according to the count of the received echo photons.
  • the first determining module includes:
  • the first determination sub-module determines a photon count histograms according to the counts of echo photons received in the a emission periods in all the off periods of the first frame, wherein each photon count histogram is based on In all off periods, the counts of echo photons of emission periods in the same order are determined;
  • the second determination sub-module determines the time of flight of a target outside the ranging range of the radar in the first time of flight according to the time of flight corresponding to the a peak positions of the a photon count histograms, wherein each photon count histogram
  • the graph includes 1 peak position.
  • the first determining module includes:
  • the third determination sub-module determines a photon count histogram according to the counts of echo photons received in the a emission period in all the off periods of the first frame;
  • the fourth determination sub-module determines the flight time of the target outside the ranging range of the radar in the first flight time, wherein e is less than or equal to a positive integer of .
  • the apparatus further includes:
  • the fifth determination module according to the count of the echo photons in an emission period after each said shutdown period ends, to determine a photon count histogram
  • the sixth determination module determines the fourth flight time in the first flight time, the multiple flight time intervals.
  • the flight time interval is determined according to the flight time of the target outside the ranging range of the radar.
  • the power of the transmit pulse within one transmit period when the transmit is turned on is higher than the power of the transmit pulse within the second measurement time.
  • An embodiment of the present application provides a distance detection apparatus, comprising: a processor and a memory for storing instructions executable by the processor; wherein the processor is configured to implement the above method when executing the instructions.
  • Embodiments of the present application provide a radar, including the above distance detection device.
  • An embodiment of the present application provides a terminal including the above radar.
  • Embodiments of the present application provide a non-volatile computer-readable storage medium on which computer program instructions are stored, and when the computer program instructions are executed by a processor, implement the above method.
  • Embodiments of the present application provide a computer program product, including computer-readable codes, or a non-volatile computer-readable storage medium carrying computer-readable codes, when the computer-readable codes are stored in a processor of an electronic device When running in the electronic device, the processor in the electronic device executes the above method.
  • a computer-readable storage medium may be a tangible device that can hold and store instructions for use by the instruction execution device.
  • the computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing.
  • Non-exhaustive list of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read only memory (ROM), erasable type programmable read-only memory (electrically programmable read-only-memory, EPROM or flash memory), static random-access memory (static random-access memory, SRAM), portable compact disc read-only memory (compact disc read-only memory, CD - ROM), digital video discs (DVDs), memory sticks, floppy disks, mechanically encoded devices, such as punch cards or raised structures in grooves on which instructions are stored, and any suitable combination of the foregoing .
  • Computer readable program instructions or code described herein may be downloaded to various computing/processing devices from a computer readable storage medium, or to an external computer or external storage device over a network such as the Internet, a local area network, a wide area network and/or a wireless network.
  • the network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and/or edge servers.
  • a network adapter card or network interface in each computing/processing device receives computer-readable program instructions from a network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in each computing/processing device .
  • Computer program instructions for carrying out the operations of the present application may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or in one or more source or object code written in any combination of programming languages, including object-oriented programming languages such as Smalltalk, C++, etc., and conventional procedural programming languages such as the "C" language or similar programming languages.
  • the computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server implement.
  • the remote computer can be connected to the user's computer through any kind of network—including a local area network (LAN) or a wide area network (WAN)—or, can be connected to an external computer (e.g., use an internet service provider to connect via the internet).
  • electronic circuits such as programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (programmable logic arrays), are personalized by utilizing state information of computer-readable program instructions logic array, PLA), the electronic circuit can execute computer-readable program instructions to implement various aspects of the present application.
  • These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer or other programmable data processing apparatus to produce a machine that causes the instructions when executed by the processor of the computer or other programmable data processing apparatus , resulting in means for implementing the functions/acts specified in one or more blocks of the flowchart and/or block diagrams.
  • These computer readable program instructions can also be stored in a computer readable storage medium, these instructions cause a computer, programmable data processing apparatus and/or other equipment to operate in a specific manner, so that the computer readable medium on which the instructions are stored includes An article of manufacture comprising instructions for implementing various aspects of the functions/acts specified in one or more blocks of the flowchart and/or block diagrams.
  • Computer readable program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other equipment to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other equipment to produce a computer-implemented process , thereby causing instructions executing on a computer, other programmable data processing apparatus, or other device to implement the functions/acts specified in one or more blocks of the flowcharts and/or block diagrams.
  • each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more functions for implementing the specified logical function(s) executable instructions.
  • the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.
  • each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations can be implemented in hardware (eg, a circuit or an ASIC (application) that performs the corresponding function or action. specific integrated circuit, application-specific integrated circuit)), or can be implemented with a combination of hardware and software, such as firmware, etc.
  • hardware eg, a circuit or an ASIC (application) that performs the corresponding function or action. specific integrated circuit, application-specific integrated circuit
  • firmware such as firmware, etc.

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Abstract

提供了一种基于雷达的距离检测方法、装置、雷达、终端、计算机可读存储介质及计算机程序产品，其中该距离检测方法包括：根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间；根据雷达接收的至少一个第二帧的回波数据确定第二飞行时间；根据第一飞行时间，消除第二飞行时间中的部分飞行时间，得到第三飞行时间；根据第一飞行时间和第三飞行时间，确定目标的距离信息，其中，在第一帧对应的第一测量时间内，雷达在多个发射周期内关闭发射，在第二帧对应的第二测量时间内，雷达在各发射周期进行发射。根据该方法的距离检测方法，能够实现解除雷达的距离模糊问题，提高目标距离的检测能力和检测准确度。

Description

基于雷达的距离检测方法、装置、雷达及终端
本申请要求于2021年4月2日提交中国专利局、申请号为202110361727.2、申请名称为“基于雷达的距离检测方法、装置、雷达及终端”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及雷达技术领域，尤其涉及一种基于雷达的距离检测方法、装置、雷达及终端。
背景技术
激光雷达通过向环境中发出发射信号，接收来自环境中的目标物体反射的回波信号，并对回波信号进行分析，可以确定环境中的目标物体的距离等信息。其中，激光雷达具有测距量程，现有技术的激光雷达，对回波信号的分析处理存在量程限制。理想情况下，回波信号是由激光雷达的测距量程内的目标物体反射的，根据回波信号分析确定的目标物体的距离信息在测距量程范围内。然而，在测距量程外的环境中存在高反射率或者超高反射率(1000％)的目标物体时，由于反射的回波信号的强度足够强，因此也能够被激光雷达接收到，激光雷达将测距量程外的目标反射的回波信号误作为测距量程内的目标的回波信号进行分析，造成分析得到的目标距离，与目标物体的真实距离出现偏差。这一现象称为距离模糊或者二义性距离折返。该现象可能会造成雷达误判触发虚警，传递出目标距离的错误信息，造成激光雷达应用于自动驾驶等安全性要求极高的场景时存在安全隐患。
现有技术提出的方法在保证测距能力不损失、计算复杂度和计算力要求等方面存在一些尚需完善的方面且大都适用于基于脉冲测距、模拟信号输出的激光雷达甚至毫米波雷达。基于单光子探测原理的固态激光雷达是一种数字雷达，需要结合单光子探测原理的特征研究适合该体制激光雷达的距离模糊的解决方法。
发明内容
有鉴于此，提出了一种基于雷达的距离检测方法、装置、雷达及终端，本申请实施例的距离检测方法能够实现解除雷达的距离模糊问题，提高目标距离的检测能力和检测准确度。
第一方面，本申请的实施例提供了一种基于雷达的距离检测方法，所述方法包括：
根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，所述第一飞行时间包括雷达的测距量程外的目标的飞行时间；
根据雷达接收的至少一个第二帧的回波数据确定第二飞行时间；
根据第一飞行时间，消除所述第二飞行时间中的部分飞行时间，得到第三飞行时间，所述部分飞行时间与测距量程外的目标的飞行时间相对应；
根据所述第一飞行时间和所述第三飞行时间，确定目标的距离信息，
其中，在第一帧对应的第一测量时间内，所述雷达在多个发射周期内关闭发射，在第二帧对应的第二测量时间内，所述雷达在各发射周期进行发射。
根据本申请实施例的基于雷达的距离检测方法，在第一帧对应的第一测量时间内，雷达 在多个发射周期内关闭发射，使得至少一个第一帧的回波数据中的关闭发射的多个发射周期内接收的回波数据，与测距量程内目标无关，通过接收第一帧的回波数据，可以确定第一飞行时间中的测距量程外的目标的飞行时间，而不受测距量程内目标的干扰；使得使用第一飞行时间确定目标距离信息时，可以根据测距量程外的目标的飞行时间得到测距量程外目标的距离信息，提升目标距离检测的能力。在第二帧对应的第二测量时间内，雷达在各发射周期内进行发射，使得至少一个第二帧的回波数据，与测距量程内目标和测距量程外目标都相关。因此，根据至少一个第二帧的回波数据，确定的第二飞行时间包括测距量程外目标的飞行时间和测距量程内目标的飞行时间；结合第一飞行时间，可以去除第二飞行时间中的测距量程外的目标的飞行时间对应的虚假飞行时间，得到第三飞行时间。并且第三飞行时间不包括测距量程外目标的飞行时间，因此使用第三飞行时间可以确定测距量程内目标的距离信息，而不受测距量程外目标干扰，可以提升目标距离检测的准确度。根据本申请实施例的基于雷达的距离检测方法，使得最终得到的目标的距离信息更全面，并且得到的目标的距离信息不会出现距离模糊，准确性较高。
根据第一方面，在所述距离检测方法的第一种可能的实现方式中，所述方法还包括：
在第一帧对应的第一测量时间内，控制雷达进入一个或多个关闭周期，每个关闭周期包括多个发射周期；
在每个关闭周期中，依次控制雷达关闭发射h个发射周期、开启发射1个发射周期、再关闭发射a个发射周期，其中h和a是正整数；
其中，在所述a个发射周期中接收第一帧的第一回波数据，所述第一回波数据用于确定雷达的测距量程外的目标的飞行时间。
通过控制雷达关闭发射h个发射周期，使得雷达可以为开启发射1个发射周期内脉冲的发射做准备；通过开启发射1个发射周期，再关闭发射a个发射周期，可以保证关闭发射a个发射周期内接收的第一帧的第一回波数据，与测距量程内目标无关，从而使得第一帧的第一回波数据，可以用于确定第一飞行时间中的测距量程外的目标的飞行时间，而不受测距量程内目标干扰。
根据第一方面的第一种可能的实现方式，在所述距离检测方法的第二种可能的实现方式中，所述方法还包括：
在每个所述关闭周期结束后的一个发射周期中，控制雷达开启发射；
其中，在该一个发射周期中接收第一帧的第二回波数据，所述第二回波数据用于确定第四飞行时间，所述第一飞行时间包括所述第四飞行时间，所述第四飞行时间表示测距量程内的目标的飞行时间。
通过在每个关闭周期结束后的一个发射周期中控制雷达开启发射，使得该一个发射周期中接收的第一帧的第一回波数据，不受测距量程外目标干扰，且与第一帧的全部关闭周期内出现在测距量程内的目标相关，因此，根据第一帧的第一回波数据确定的第四飞行时间，能够表示第一帧的全部关闭周期内没能检测到的测距量程内目标的飞行时间。使得处理器能够根据第一飞行时间中的第四飞行时间和第三飞行时间，确定测距量程内目标的距离信息。通过这种方式，可以避免雷达出现目标漏检，使得得到的测距量程内目标的距离信息准确度更高。
根据第一方面，以及以上第一方面的任意一种可能的实现方式，在所述距离检测方法的 第三种可能的实现方式中，所述雷达通过一个或多个单光子探测器接收回波光子，并根据接收的回波光子的计数，确定所述回波数据。
通过这种方式，使得雷达可以根据回波数据确定测距量程外目标的距离信息和测距量程内目标的距离信息。
根据第一方面的第三种可能的实现方式，在所述距离检测方法的第四种可能的实现方式中，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，包括：
根据所述第一帧的全部关闭周期的中的所述a个发射周期接收的回波光子的计数，确定a个光子计数直方图，其中每个光子计数直方图是根据全部关闭周期中，同一次序的发射周期的回波光子的计数确定的；
根据a个光子计数直方图的a个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间，其中，每个光子计数直方图包括1个峰位。
通过对a个光子计数直方图进行处理，可以确定全部关闭周期中的每个发射周期内的测距量程外的目标的飞行时间，从而确定第一飞行时间中雷达的测距量程外的目标的飞行时间，使得处理器可以进一步确定雷达的测距量程外的目标的距离信息。确定a个光子计数直方图的方法可以适用于速度较快的运动场景，使得进行目标距离检测的方式更具有针对性，能够保证距离检测确定的距离信息的准确度。
根据第一方面的第三种可能的实现方式，在所述距离检测方法的第五种可能的实现方式中，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，包括：
根据所述第一帧的全部关闭周期中的所述a个发射周期接收的回波光子的计数，确定1个光子计数直方图；
根据1个光子计数直方图的e个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间,其中e是小于或等于a的正整数。
通过这种方式，可以确定第一飞行时间中雷达的测距量程外的目标的飞行时间，使得处理器可以进一步确定雷达的测距量程外的目标的距离信息。确定1个光子计数直方图的方法可以适用于雷达处于速度较慢的运动场景、或者雷达处于静止场景时，使得进行目标距离检测的方式更具有针对性，能够保证距离检测确定的距离信息的准确度；并且确定1个光子计数直方图的数据处理成本较低，能够节约处理器的数据处理成本，提高数据处理效率。
根据第一方面的第三种可能的实现方式，在所述距离检测方法的第六种可能的实现方式中，所述方法还包括：
根据每个所述关闭周期结束后的一个发射周期中的所述回波光子的计数，确定1个光子计数直方图；
根据所述1个光子计数直方图中，多个飞行时间区间内的至少一个峰位对应的飞行时间，确定所述第一飞行时间中的第四飞行时间，所述多个飞行时间区间根据雷达的测距量程外的目标的飞行时间确定。
通过根据雷达的测距量程外的目标的飞行时间确定多个飞行时间区间，并根据1个光子计数直方图中，多个飞行时间区间内的至少一个峰位对应的飞行时间，确定第四飞行时间，使得可以检测到与测距量程外的目标的飞行时间接近的测距量程内目标的飞行时间，即第四飞行时间。通过这种方式，能够避免第一帧的全部关闭周期内，对测距量程内目标的飞行时间造成的漏检，可以提高雷达的测距能力。
根据第一方面的第一种可能的实现方式，在所述距离检测方法的第七种可能的实现方式中，所述开启发射1个发射周期内的发射脉冲的功率高于所述第二测量时间内的发射脉冲功率。
提高发射脉冲功率目的是捕获到更远距离的目标的回波脉冲的光子。通过这种方式，可以提升雷达系统的测距能力。
第二方面，本申请的实施例提供了一种距离检测装置，所述装置包括：
第一确定模块，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，所述第一飞行时间包括雷达的测距量程外的目标的飞行时间；
第二确定模块，根据雷达接收的至少一个第二帧的回波数据确定第二飞行时间；
第三确定模块，根据第一飞行时间，消除所述第二飞行时间中的部分飞行时间，得到第三飞行时间，所述部分飞行时间与测距量程外的目标的飞行时间相对应；
第四确定模块，根据所述第一飞行时间和所述第三飞行时间，确定目标的距离信息，
其中，在第一帧对应的第一测量时间内，所述雷达在多个发射周期内关闭发射，在第二帧对应的第二测量时间内，所述雷达在各发射周期进行发射。
根据第二方面，在所述距离检测装置的第一种可能的实现方式中，所述装置还包括：
第一控制模块，在第一帧对应的第一测量时间内，控制雷达进入一个或多个关闭周期，每个关闭周期包括多个发射周期；
第二控制模块，在每个关闭周期中，依次控制雷达关闭发射h个发射周期、开启发射1个发射周期、再关闭发射a个发射周期，其中h和a是正整数；
其中，在所述a个发射周期中接收第一帧的第一回波数据，所述第一回波数据用于确定雷达的测距量程外的目标的飞行时间。
根据第二方面的第一种可能的实现方式，在所述距离检测装置的第二种可能的实现方式中，所述装置还包括：
第三控制模块，在每个所述关闭周期结束后的一个发射周期中，控制雷达开启发射；
其中，在该一个发射周期中接收第一帧的第二回波数据，所述第二回波数据用于确定第四飞行时间，所述第一飞行时间包括所述第四飞行时间，所述第四飞行时间表示测距量程内的目标的飞行时间。
根据第二方面，以及以上第二方面的任意一种可能的实现方式，在所述距离检测装置的第三种可能的实现方式中，所述雷达通过一个或多个单光子探测器接收回波光子，并根据接收的回波光子的计数，确定所述回波数据。
根据第二方面的第三种可能的实现方式，在所述距离检测装置的第四种可能的实现方式中，第一确定模块包括：
第一确定子模块，根据所述第一帧的全部关闭周期的中的所述a个发射周期接收的回波光子的计数，确定a个光子计数直方图，其中每个光子计数直方图是根据全部关闭周期中，同一次序的发射周期的回波光子的计数确定的；
第二确定子模块，根据a个光子计数直方图的a个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间，其中，每个光子计数直方图包括1个峰位。
根据第二方面的第三种可能的实现方式，在所述距离检测装置的第五种可能的实现方式中，第一确定模块包括：
第三确定子模块，根据所述第一帧的全部关闭周期中的所述a个发射周期接收的回波光子的计数，确定1个光子计数直方图；
第四确定子模块，根据1个光子计数直方图的e个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间,其中e是小于或等于a的正整数。
根据第二方面的第三种可能的实现方式，在所述距离检测装置的第六种可能的实现方式中，所述装置还包括：
第五确定模块，根据每个所述关闭周期结束后的一个发射周期中的所述回波光子的计数，确定1个光子计数直方图；
第六确定模块，根据所述1个光子计数直方图中，多个飞行时间区间内的至少一个峰位对应的飞行时间，确定所述第一飞行时间中的第四飞行时间，所述多个飞行时间区间根据雷达的测距量程外的目标的飞行时间确定。
根据第二方面的第一种可能的实现方式，在所述距离检测装置的第七种可能的实现方式中，所述开启发射1个发射周期内的发射脉冲的功率高于所述第二测量时间内的发射脉冲功率。
第三方面，本申请的实施例提供了一种距离检测装置，包括：
处理器；
用于存储处理器可执行指令的存储器；
其中，所述处理器被配置为执行所述指令时实现上述第一方面或者第一方面的多种可能的实现方式中的一种或几种的距离检测方法。
第四方面，本申请的实施例提供了一种非易失性计算机可读存储介质，其上存储有计算机程序指令，所述计算机程序指令被处理器执行时实现上述第一方面或者第一方面的多种可能的实现方式中的一种或几种的距离检测方法。
第五方面，本申请的实施例提供了一种计算机程序产品，包括计算机可读代码，或者承载有计算机可读代码的非易失性计算机可读存储介质，当所述计算机可读代码在电子设备中运行时，所述电子设备中的处理器执行上述第一方面或者第一方面的多种可能的实现方式中的一种或几种的距离检测方法。
第六方面，本申请的实施例提供了一种雷达，包括上述第二方面或者第二方面的多种可能的实现方式中的一种或几种的距离检测装置，或者包括上述第三方面的距离检测装置。
第七方面，本申请的实施例提供了一种终端，包括上述第六方面的雷达。
本申请的这些和其他方面在以下(多个)实施例的描述中会更加简明易懂。
附图说明
包含在说明书中并且构成说明书的一部分的附图与说明书一起示出了本申请的示例性实施例、特征和方面，并且用于解释本申请的原理。
图1示出直接飞行时间雷达系统的结构示意图。
图2示出直接飞行时间雷达系统在各发射周期进行发射时的工作方式的示例性示意图。
图3示出根据本申请实施例的距离检测方法在第一帧测量时间内的工作方式的示例性示意图。
图4示出根据本申请实施例的距离检测方法在速度较快的运动场景下确定第一飞行时间 的示例性示意图。
图5示出根据本申请实施例的距离检测方法在速度较慢的运动场景或者静止场景下确定第一飞行时间的示例性示意图。
图6示出根据本申请实施例的距离检测装置的示例性结构图。
具体实施方式
以下将参考附图详细说明本申请的各种示例性实施例、特征和方面。附图中相同的附图标记表示功能相同或相似的元件。尽管在附图中示出了实施例的各种方面，但是除非特别指出，不必按比例绘制附图。
在这里专用的词“示例性”意为“用作例子、实施例或说明性”。这里作为“示例性”所说明的任何实施例不必解释为优于或好于其它实施例。
另外，为了更好的说明本申请，在下文的具体实施方式中给出了众多的具体细节。本领域技术人员应当理解，没有某些具体细节，本申请同样可以实施。在一些实例中，对于本领域技术人员熟知的方法、手段、元件和电路未作详细描述，以便于凸显本申请的主旨。
以下，对本申请实施例可能出现的术语进行解释。
激光雷达(light detection and ranging，LiDAR)：用激光器作为辐射源的雷达。其工作原理是通过激光器发射探测信号，并接收经过目标物体反射的回波信号，来探测相应的目标物体。
最大测距距离：或称最大探测距离，是与雷达自身配置有关的参数(出厂设置参数或与出厂设置参数相关)。例如，长距自适应巡航控制(adaptive cruise control，ACC)雷达的最大测距距离为250m，中距雷达的最大测距距离为70-100m。
距离模糊：距离模糊是指当目标离激光雷达的距离大于最大测距距离时，目标反射的回波信号不落在发射信号对应的测距时间段内，此时测得的目标距离为非真实距离，该现象称为距离模糊。
动态范围：光电探测器的一个重要参数，表示光探测器的探测能力，可以用光探测器同一时刻能响应的入射光子个数来表示。一些场景下使用探测器阵列同时进行数据采集，所述探测器阵列可包括多个光电探测器，同一时刻能响应的入射光子个数越多，探测器阵列的动态范围越大。如果光电探测器的动态范围不足，会很大程度上限制探测系统的准确性和使用范围。其中，光电探测器用于捕获光子并在捕获到光子时输出一次电流脉冲信号。如果光电探测器捕获到的是环境光的光子，那么从捕获到光子开始，探测器阵列的动态范围即被环境光的光子“占据”了一部分，而恢复到可以捕获光子的状态尚需要一定时间，因此，环境光较强时，探测器阵列中能够捕获有效信号光子的光电探测器个数会变少，导致其不能读出有效信号，降低了整体系统的准确性。
电学扫描：一种阵列光源发光顺序、由驱动电流的注入顺序和工作区域而决定的发光方式，无任何机械式的扫描部件。
距离模糊是激光雷达的一个常见问题。现有技术中，常用的距离模糊解决方案有以下几种：第一种策略是平衡激光器发射脉冲周期与系统的测距量程的比例，尽可能的拉大两次相邻发射脉冲对应的测距窗口时间的间隔，在一次测距窗口时间内接收到的脉冲数必然降低，一定程度上限制了雷达的测距性能，尤其对于远距离的激光雷达等对性能要求较高的雷达系 统更为不利。第二种常见的策略是通过各种后处理的算法优化，基本的思路是识别出虚假信号并做滤除，对于不同架构的系统算法的实现方式和代价不同，如“舍脉冲”法等。该种方法计算复杂度较大，对系统的计算能力要求较高。第三种策略是采用发射功率调制，改变或降低激光器的脉冲峰位功率，降低系统探测到模糊距离外的光子信号的概率，该种方法可能会增加硬件调节的复杂度。第四种策略是在发射端进行脉冲编码调制，但是这样做可能会损失系统性能，增加硬件电路控制的复杂度。
根据上文的描述，现有技术的方式在保证测距能力不损失、计算复杂度和计算力要求等方面存在一些尚需完善的方面且大都适用于基于脉冲测距、模拟信号输出的激光雷达甚至毫米波雷达。基于单光子探测原理的固态激光雷达是一种数字雷达，需要结合单光子探测原理的特征研究适合该体制激光雷达的距离模糊的解决方法。
为了解决上述技术问题，本申请提供了一种基于雷达的距离检测方法，本申请实施例的距离检测方法能够实现解除雷达的距离模糊问题，提高目标距离的检测能力和检测准确度。
图1示出直接飞行时间雷达系统的结构示意图。本申请实施例的距离检测方法可应用于例如(但不限于)图1所示的雷达系统的处理器中。
下面介绍基于单光子探测原理的直接飞行时间雷达系统的测距原理。如图1所示，直接飞行时间雷达系统的发射端可包括激光器，例如，可以是垂直腔表面发射激光器(vertical cavity surface emitting laser，Vcsel)、电致发光显示器(electroluminescence display，ELD)或者脉冲激光二极管(pulsed laser diode，PLD)，可用于提供光信号。激光器发射的光信号作为发射信号，由发射光学系统发射到环境中，并被环境中的目标物体进行反射得到回波脉冲，也即回波信号，并由接收光学系统接收。雷达接收端可包括探测器，例如单光子雪崩二极管(single photon avalanche diode，SPAD)或者数字硅光电倍增管(silicon photomultiplier，SIPM)，探测器具有单光子灵敏度，可以捕获反射的回波脉冲的光子，在探测器捕获到第一个光子时，即产生电流脉冲信号，并输出给时间数字转换器(time-to-digital converter，TDC)，由时间数字转换器产生飞行时间并记录。
根据雷达系统的测距量程，可以确定雷达系统的测距窗口时间。雷达的发射端将发射脉冲发射出去，到达量程规定的最大测距距离处，再由最大测距距离处返回到雷达的接收端的时间，即为测距窗口时间。举例来说，在测距量程是150米时，测距窗口时间可例如等于1微秒(测距量程*2/光速)。测距窗口时间可设置为小于或等于发射周期。时间数字转换器将延时上报至处理器，该延时是每个发射脉冲发射出去后、在测距窗口时间内由探测器输入至时间数字转换器的电流脉冲信号相对于该次发射脉冲的延时，处理器将该延时存储下来，即记录一次飞行时间。
在发射端发射多次发射脉冲后，在雷达的接收端可能记录有多次飞行时间。处理器可以基于时间相关单光子计数法(time-correlated single photon counting，TCSPC)对储存的相同飞行时间的次数进行直方图统计，得到横坐标为飞行时间、纵坐标为次数的直方图。通过对直方图检测峰位可以找到次数最高的飞行时间，根据该飞行时间即可确定一次目标物体的距离信息。
在不产生距离模糊的情况下，回波脉冲对应的目标距离R 0可以根据公式(1)计算：
R 0＝ct 0/2        公式(1)
其中，c为光速，t 0为当前场景中根据直方图确定的次数最高的飞行时间。
公式(1)适用于探测器仅接收到测距量程内的目标反射的回波脉冲的情况。而在测距量程外的目标反射的回波脉冲光子也被探测器捕获时，处理器确定的目标物体的距离信息就会出现距离模糊。原因在于，雷达的探测器捕获到回波脉冲光子时，雷达可能已经进入下一个甚至下下个发射脉冲对应的测距窗口时间内。在此情况下，处理器会得到一个飞行时间，这个飞行时间是虚假的飞行时间。如果将虚假的飞行时间带入公式(1)，得到的距离信息是错误的距离信息，即出现距离模糊。
在一种可能的实现方式中，本申请实施例可以通过将接收端采集到的帧数据区分为检测帧数据和非检测帧数据，并应用检测帧数据计算测距量程外的目标物体的真实距离信息，再应用检测帧数据和非检测帧数据计算测距量程内的目标物体的真实距离信息，实现距离模糊的去除。例如，可使用第一帧表示检测帧，使用第二帧表示非检测帧，本申请实施例的基于雷达的距离检测方法，包括：
根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，所述第一飞行时间包括雷达的测距量程外的目标的飞行时间；根据雷达接收的至少一个第二帧的回波数据确定第二飞行时间；根据第一飞行时间，消除所述第二飞行时间中的部分飞行时间，得到第三飞行时间，所述部分飞行时间与测距量程外的目标的飞行时间相对应；根据所述第一飞行时间和所述第三飞行时间，确定目标的距离信息，其中，在第一帧对应的第一测量时间内，所述雷达在多个发射周期内关闭发射，在第二帧对应的第二测量时间内，所述雷达在各发射周期进行发射。
根据本申请实施例的基于雷达的距离检测方法，在第一帧对应的第一测量时间内，雷达在多个发射周期内关闭发射，使得至少一个第一帧的回波数据中的关闭发射的多个发射周期内接收的回波数据，与测距量程内目标无关，通过接收第一帧的回波数据，可以确定第一飞行时间中的测距量程外的目标的飞行时间，而不受测距量程内目标的干扰；使得使用第一飞行时间确定目标距离信息时，可以根据测距量程外的目标的飞行时间得到测距量程外目标的距离信息，提升目标距离检测的能力。在第二帧对应的第二测量时间内，雷达在各发射周期内进行发射，使得至少一个第二帧的回波数据，与测距量程内目标和测距量程外目标都相关。因此，根据至少一个第二帧的回波数据，确定的第二飞行时间包括测距量程外目标的飞行时间和测距量程内目标的飞行时间；结合第一飞行时间，可以去除第二飞行时间中的测距量程外的目标的飞行时间对应的虚假飞行时间，得到第三飞行时间。并且第三飞行时间不包括测距量程外目标的飞行时间，因此使用第三飞行时间可以确定测距量程内目标的距离信息，而不受测距量程外目标干扰，可以提升目标距离检测的准确度。根据本申请实施例的基于雷达的距离检测方法，使得最终得到的目标的距离信息更全面，并且得到的目标的距离信息不会出现距离模糊，准确性较高。
下面对本申请实施例的基于雷达的距离检测方法进行详细描述。
在一种可能的实现方式中，雷达通过一个或多个单光子探测器接收回波光子，并根据接收的回波光子的计数，确定回波数据。
通过这种方式，使得雷达可以根据回波数据确定测距量程外目标的距离信息和测距量程内目标的距离信息。
举例来说，本申请实施例的基于雷达的距离检测方法可针对以单光子器件为探测器、基于时间相关单光子计数的激光雷达，能够实现通过直接飞行时间计算目标距离。激光雷达的 发射端优选中心频率较高的激光器，不限定发射端激光器的形态，例如垂直腔表面发射激光器、电致发光显示器或者脉冲激光二极管等；不限定激光雷达的形态如机械式、固态、混合固态或其他类型；接收端的探测器可例如是单光子雪崩二极管、数字硅光电倍增管等；不限定激光雷达的工作方式为电学扫描、泛光照明、线型扫描或利用二维扫描器件的点阵扫描等方式。
其中，中心频率也称点频，中心频率越高的激光器，其单位时间内能够发射的发射脉冲数量更多，意味着能接收到的回波脉冲也更多，使得雷达系统记录的飞行时间信息更充足，可以提升雷达系统的计算冗余度。由于结构原因，垂直腔表面发射激光器的中心频率是没有上限的，通常在500KHz-1MHz，甚至可以是几GHz乃至几十GHz。电致发光显示器和脉冲激光二极管的中心频率通常为100KHz-300KHz。在实际雷达系统中存在散热问题，因此可以考虑选择发射脉冲脉宽较窄的激光器。垂直腔表面发射激光器本身的快速响应能力比较高，因此容易实现窄脉宽发射。
根据雷达系统的测距量程以及测距需求，可以预先设置雷达系统的测量角度、工作帧率、发射脉冲的重复周期(简称发射周期)以及测量时间(例如第一测量时间和第二测量时间)等。其中，测量角度可以根据实际场景进行设置；工作帧率可以根据实际场景进行设置，在精度要求高的场景可以设置为高帧率，在精度要求不高的场景可以设置为低帧率；发射周期可设置为大于或等于测距窗口时间的值，测量时间是激光雷达系统以帧为单位采集数据时，完成一帧数据采集的时间，测量时间远大于发射周期和测距时间，在测量时间内，雷达可能会发出几百次甚至上千次发射脉冲。在本申请实施例中，第一测量时间可例如等于第二测量时间。
其中，工作帧率和实际应用场景有关，例如，定义工作帧率为f,在高速和中速的场景中，为了保证测距性能，工作帧率可设置为25帧/秒以上。在低速场景中，工作帧率可设置为10帧/秒-15帧/秒。根据实际场景和测距需求，工作帧率也可以设置为其他值，本申请对此不作限制。
如图2所示，设定发射脉冲的重复周期(简称发射周期)为t，测距窗口时间为T，测量时间T0等于m个发射周期的时间，T0＝m*t。其中，T0＞＞t≥T，测距窗口时间T的取值可以根据光速以及系统的测距量程确定。例如测距量程为150米，测距窗口时间可例如等于1微秒。假设在测距量程内有一个目标物体、测距量程外也有一个目标物体时，在第一个发射脉冲发出后的第一个测距窗口时间T1(T1＝T)内，测距量程内的目标物体反射得到的回波脉冲1的光子的飞行时间可为t1。在第二个发射脉冲发出后的第二个测距窗口时间T2(T2＝T)内，测距量程内的目标物体反射得到的回波脉冲2的光子的飞行时间可为t2。第二个测距窗口时间内雷达还可获得测距量程外的目标反射第一个发射脉冲的回波脉冲3的光子的飞行时间t3。直到第m个发射脉冲发出后的第m个测距窗口时间Tm(Tm＝T)内，雷达系统完成一帧数据的采集，可记录下多个飞行时间。
举例来说，在1秒内，雷达可例如能够接收N+M帧回波数据。可以设置雷达接收的N个第一帧的回波数据作为N帧检测帧数据，用于进行处理以确定第一飞行时间。相应地，设置雷达接收到的M个第二帧的回波数据，作为M帧非检测帧数据，用于进行处理以确定第二飞行时间。然而，其中根据M个第二帧的回波数据确定的第二飞行时间中，有一部分是测距量程外的目标的不真实的飞行时间，可以根据N个第一帧的回波数据得到的第一飞行时间，将 M个第二帧的回波数据确定的第二飞行时间中与第一飞行时间对应的测距量程外的目标的飞行时间排除，得到第三飞行时间，这样，根据第一飞行时间可以确定测距量程外的目标的距离信息，根据第三飞行时间可以确定测距量程内的目标的距离信息，由此，可通过对M个第二帧的回波数据和N个第一帧的回波数据进行处理，最终得到测距量程内和测距量程外的目标的距离信息。其中，雷达接收到的N个第一帧的回波数据可设置为具有标志位，处理器可以基于此分辨接收到的数据是第一帧的回波数据还是第二帧的回波数据。对于运动速度较快的场景，雷达可以设置为连续接收N个第一帧的回波数据作为检测帧数据，对于运动速度较慢的场景或者静止场景，雷达可以设置为连续接收N个第一帧的回波数据作为检测帧数据，也可以设置为接收不连续的N个第一帧的回波数据作为检测帧数据。本申请对此不作限制。
在一种可能的实现方式中，接收到的连续的N个第一帧的回波数据具有相关性。例如，在工作帧率为25帧/秒时，雷达系统每秒接收25帧数据(包括第一帧回波数据以及第二帧回波数据)。由于在接收到N个第一帧的回波数据后，处理器还要对接收的N个第一帧的回波数据进行运算，所以理论上，在雷达系统进行距离检测的每一秒内，N个第一帧的回波数据越早接收越好。在实际应用中，由于系统的硬件非理想性原因，以及数据传输过程中丢帧、丢包等原因，可在使用雷达系统进行距离检测前，先进行数据校验。通过校验，可以提高对N个第一帧的回波数据进行处理得到的距离信息的准确度。在校验通过后，可例如在雷达系统进行距离检测的第一秒内，任选25帧中的连续几帧(例如1-5帧)作为检测帧(第一帧)，取6-25帧作为非检测帧(第二帧)。在雷达系统进行距离检测的第二秒内，可以任选25帧中的连续几帧(例如6-10帧)作为检测帧(第一帧)，取1-5、11-25帧作为非检测帧(第二帧)。本申请对检测帧(第一帧)的具体选择方式不做限制。
在一种可能的实现方式中，本申请实施例的雷达系统可以包括设置在车辆的不同位置的多个雷达。例如，可以包括适合运动速度较快的场景下的距离检测的第一雷达和适合运动速度较慢的场景或者静止场景下的距离检测的第二雷达。在实际应用中，可以根据车辆的速度选择适合的雷达进行距离检测，以降低数据处理成本；第一雷达和第二雷达也可以同时使用，以提高检测精度。本申请实施例的雷达系统还可以包括更多雷达，本申请对此不作限制。
在一种可能的实现方式中，M可以根据工作帧率f预先设置。例如，在N＝5且f＝25帧/秒时，M可例如设置为等于20帧，使得每秒保证至少能够接收到5个第一帧的回波数据，来计算得到一次测距量程外的目标的距离信息，这样，在雷达系统工作的第1秒时间内，可以计算得到一次距离信息(包括测距量程内和测距量程外)，在雷达系统工作的第2秒时间内，车辆可以根据雷达系统工作的第1秒得到的距离信息进行工作，在雷达系统工作的第3秒时间内，车辆可以根据雷达系统工作的第2秒得到的距离信息进行工作，使得车辆等终端进行工作时依据的距离信息保持最新，从而提高车辆的自动驾驶安全性。
其中，M和N也可以设置为使得激光雷达在其他时间内完成N个第一帧的回波数据的接收和M个第二帧的回波数据的接收。例如，可以使得每2秒或者每0.5秒内保证至少能够接收到N个第一帧的回波数据。本申请对此不作限制。
在一种可能的实现方式中，雷达在各发射周期进行发射时，每个发射周期对应的测距窗口时间内接收到的数据中，可能包括测距量程内目标的回波光子计数和测距量程外目标的回波光子计数。本申请实施例可以通过对第一测量时间内的脉冲发射方式进行设置，使得每个第一测量时间内一个固定时间段接收到的第一帧的回波数据中，仅包括测距量程外的目标的 回波光子计数。基于此，可以根据该时间段接收到的第一帧的回波数据，确定测距量程外的目标的飞行时间。本申请实施例的距离检测方法还包括：
在第一帧对应的第一测量时间内，控制雷达进入一个或多个关闭周期，每个关闭周期包括多个发射周期；在每个关闭周期中，依次控制雷达关闭发射h个发射周期、开启发射1个发射周期、再关闭发射a个发射周期，其中h和a是正整数；其中，在所述a个发射周期中接收第一帧的第一回波数据，所述第一回波数据用于确定雷达的测距量程外的目标的飞行时间。
通过控制雷达关闭发射h个发射周期，使得雷达可以为开启发射1个发射周期内脉冲的发射做准备；通过开启发射1个发射周期，再关闭发射a个发射周期，可以保证关闭发射a个发射周期内接收的第一帧的第一回波数据，与测距量程内目标无关，从而使得第一帧的第一回波数据，可以用于确定第一飞行时间中的测距量程外的目标的飞行时间，而不受测距量程内目标干扰。
举例来说，参见图3，可以预设每个第一帧的第一个关闭周期的开始时间tt，使得到达任意一个第一帧对应的开始时间并经过预设时间tt后，进入该第一帧的第一个关闭周期。可定义一个关闭周期对应的时间等于a+h+1个发射周期对应的时间，其中h≥1且为整数，a≥1且为整数。
在每个关闭周期内，完成以下操作：以第一个关闭周期为例，第一个关闭周期内的第一个发射周期到第h个发射周期对应的时间内，处理器控制激光器关闭脉冲发射(定义为预关闭发射)；第h+1个发射周期对应的时间内，处理器控制激光器开启脉冲发射(定义为检测发射)；第h+2个发射周期到第a+h+1个发射周期对应的时间内，处理器控制激光器关闭脉冲发射(定义为连续关闭发射)。每个第一帧的数据接收时间(第一测量时间T0)内有若干个(c个)关闭周期，相邻两个关闭周期之间的时间间隔可以等于b个发射周期。
在一种可能的实现方式中，开启发射1个发射周期(检测发射)内的发射脉冲的功率高于第二测量时间内的发射脉冲功率。检测发射时提高发射脉冲功率目的是捕获到更远距离的目标的回波脉冲的光子。通过这种方式，可以提升雷达系统的测距能力。
其中，设置预关闭发射的目的是在预关闭发射对应的时间内，提前为激光器充能，使得检测发射时能够发射出提高发射功率的发射脉冲。连续关闭发射的目的是使得连续关闭发射的a个发射周期对应的时间内，雷达系统接收到的数据信息均来自量程外的目标的回波脉冲，从而能够根据接收的连续关闭发射时间内的数据信息(第一帧的第一回波数据)计算量程外的目标的距离信息。
举例来说，在图3的应用场景中，可设置h＝2，则第一个关闭周期内的第1-2个发射周期内，关闭激光器脉冲发射，即预关闭发射；第3个发射周期对应的时间内，开启激光器脉冲发射，即检测发射，检测发射时提高发射脉冲功率；可设置a＝6，则第4个发射周期到第9个发射周期对应的时间内，关闭激光器脉冲发射，即连续关闭发射。
其中，h的取值可以根据开启发射1个发射周期(检测发射)内的发射脉冲的功率，以及激光器充能到能够发出该功率的发射脉冲所需要的时间预先设置，a的取值可以根据测距需求，在测距前进行调整，例如，中心频率为500kHz，测距量程是300米，则发射周期是2微秒(1/中心频率)，测距窗口时间T也是2微秒(测距量程*2/光速)。如果想测量300米内的目标以及300米-1500米内的高反射率目标的距离信息，以1500米处存在高反射率目标为 例，则从雷达系统发出发射脉冲，到发射脉冲被该高反射率目标反射，再到回波脉冲回到雷达系统，脉冲光子真实飞行时间可等于10微秒(1500m*2/光速)。而10微秒等于5个发射周期，且发射周期等于测距窗口时间，也就是说，第一个发射周期内发出的脉冲，被目标反射的回波脉冲光子飞行时间等于五个发射周期的时间，最迟在第六个发射周期时间内被探测器捕获。在此情况下，只要使得一个关闭周期的连续关闭发射时间等于6个发射周期的时间即可(a＝6)。实际应用中，1500米已经是一个比较大的距离，因此，a的值不必预设的很大，通常设置在10以内即可。本申请对a的具体取值方式不作限制。
这样，雷达系统确定的第一飞行时间中，包括每个关闭周期的a个发射周期内确定的雷达的测距量程外的目标的飞行时间，从而能够根据雷达的测距量程外的目标的飞行时间，确定测距量程外的目标的回波脉冲光子的真实飞行时间，以确定测距量程外的目标物体的真实距离信息。
在一种可能的实现方式中，可以采用特定的编码方式对任意一个第一帧的第一个关闭周期的起始时刻tt和两个关闭周期的时间间隔的周期数b进行约束，形成特异性特征。对于任意一个第一帧，b可以取一个值，也可以取多个值，例如，可以取一个值b 0，该第一帧的任意两个关闭周期的时间间隔相等，且等于b 0*t；如果取多个值b 1，b 2，b 3……b c-1，则该第一帧的两个关闭周期的时间间隔分别是b 1*t，b 2*t，b 3*t……b c-1*t。对于N个第一帧，每个第一帧的关闭周期的间隔时间的取值可以不同，也即，每个第一帧的b的取值可以不同。
举例来说，雷达系统的工作帧率为25帧/秒，则1秒内，雷达系统接收25帧数据。可例如将第6至第10帧确定为第一帧(N＝5)。接收每个第一帧的回波数据的时间(第一测量时间T0)等于200(m＝200)个发射周期。可例如预设第一个第一帧(第6帧)的第一个关闭周期的开始时间tt为0.1s，且每间隔10(b＝10)个发射周期的时间，进入下一个关闭周期。例如，到达第一个第一帧开始时间并经过0.1s(tt＝0.1s)后，进入第一个关闭周期。在第一个关闭周期内，先完成预关闭发射，例如使激光器脉冲发射关闭两个发射周期的时间(h＝2)。然后，再完成检测发射，例如使激光器脉冲发射开启一个发射周期的时间，并提高发射脉冲的功率。然后，使激光器脉冲发射连续关闭三个发射周期的时间(a＝3)。第一个关闭周期结束。间隔10个发射周期的时间(b＝10)，进入第二个关闭周期。以次类推，直到到达第一个第一帧结束时间，完成第一个第一帧的回波数据的接收。
可例如预设第二个第一帧(第7帧)的第一个关闭周期的开始时间tt为0.2s(tt＝0.2s)，且每间隔8(b＝8)个发射周期的时间，进入下一个关闭周期。例如，到达第二个第一帧开始时间并经过0.2s后，进入第一个关闭周期。在第一个关闭周期内，先完成预关闭发射，例如使激光器脉冲发射关闭一个发射周期的时间(h＝1)。然后，再完成检测发射，例如使激光器脉冲发射开启一个发射周期的时间，并提高发射脉冲的功率。然后，使激光器脉冲发射连续关闭四个发射周期的时间(a＝4)。第一个关闭周期结束。间隔8个发射周期的时间(b＝8)，进入第二个关闭周期。以次类推，直到到达第二个第一帧结束时间，完成第二个第一帧的回波数据的接收。
通过这种方式，可以提高雷达系统的抗干扰能力，从而提升最终得到的距离信息的准确度。本领域技术人员应理解，任意一个第一帧的任意两个关闭周期之间的时间间隔，以及任意一个第一帧的第一个关闭周期的开始时间都可以有多种选择，只要能够满足测量需求即可，本申请对此不作限制。
在一种可能的实现方式中，第一帧的回波数据也用于确定测距量程内的目标的飞行时间，本申请实施例的距离检测方法还包括：
在每个关闭周期结束后的一个发射周期中，控制雷达开启发射；其中，在该一个发射周期中接收第一帧的第二回波数据，第二回波数据用于确定第四飞行时间，第一飞行时间包括第四飞行时间，第四飞行时间表示测距量程内的目标的飞行时间。
通过在每个关闭周期结束后的一个发射周期中控制雷达开启发射，使得该一个发射周期中接收的第一帧的第一回波数据，不受测距量程外目标干扰，且与第一帧的全部关闭周期内出现在测距量程内的目标相关，因此，根据第一帧的第一回波数据确定的第四飞行时间，能够表示第一帧的全部关闭周期内没能检测到的测距量程内目标的飞行时间。使得处理器能够根据第一飞行时间中的第四飞行时间和第三飞行时间，确定测距量程内目标的距离信息。通过这种方式，可以避免雷达出现目标漏检，使得得到的测距量程内目标的距离信息准确度更高。
举例来说，在每个关闭周期结束后的一个发射周期，处理器可控制激光器开启发射。因此，该一个发射周期中接收到的第一帧的第二回波数据中，包括测距量程内的回波脉冲光子的计数。并且，在每个关闭周期结束时，雷达已经连续a个发射周期没有脉冲发出，因此，可认为该一个发射周期中接收到的第一帧的第二回波数据中，不包括测距量程外的回波脉冲光子的计数。第一帧的第二回波数据可用于确定第四飞行时间，因此，第四飞行时间表示测距量程内的目标的飞行时间，第四飞行时间可用于确定测距量程内目标的距离信息。
基于此，第一飞行时间中，包括测距量程外目标的飞行时间，以及测距量程内的目标的飞行时间也即第四飞行时间。则根据第一飞行时间和第三飞行时间，确定目标的距离信息，可以认为，根据第一飞行时间中的测距量程外目标的飞行时间，可以确定测距量程外目标的距离信息；根据第三飞行时间和第一飞行时间中的第四飞行时间，可以确定测距量程内目标的距离信息。
下面介绍本申请实施例确定第一飞行时间的一种示例性方法。
在一种可能的实现方式中，在接收到N个第一帧的回波数据之后，处理器可以基于时间相关单光子计数方法，对接收到的数据进行分析处理，确定第一飞行时间。
在此先介绍时间相关单光子计数的原理。在测量时间T0内，可能有m次的脉冲发射与接收，时间数字转换器能够记录n次(n<m)光飞行时间，生成一个飞行时间关于计数次数的光子计数直方图。采用极值求解算法对光子计数直方图检测峰位可以计算出现次数最多的飞行时间值，即为最终确定的飞行时间。如果在检测峰位时，发现存在强度不同的多个峰位，可认为多个峰位对应的多个飞行时间来自不同的目标，可以计算光子计数直方图的多个峰位的飞行时间值，即为最终确定的飞行时间。通过运用时间相关单光子计数技术，在捕获到入射的单光子的条件下，探测器能够有效的去除器件固有噪声和环境光噪声，使得噪声引起的计数次数将远低于有效信号引起的计数次数，从光子计数直方图上能很容易甄别出来。同时时间相关单光子计数技术对目标物进行多次飞行时间的重复测量，可以进一步提高系统的时间分辨率。
在一种可能的实现方式中，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，包括：
根据第一帧的全部关闭周期的中的a个发射周期接收的回波光子的计数，确定a个光子 计数直方图，其中每个光子计数直方图是根据全部关闭周期中，同一次序的发射周期的回波光子的计数确定的；根据a个光子计数直方图的a个峰位对应的飞行时间，确定第一飞行时间中雷达的测距量程外的目标的飞行时间，其中，每个光子计数直方图包括1个峰位。
通过对a个光子计数直方图进行处理，可以确定全部关闭周期中的每个发射周期内的测距量程外的目标的飞行时间，从而确定第一飞行时间中雷达的测距量程外的目标的飞行时间，使得处理器可以进一步确定雷达的测距量程外的目标的距离信息。确定a个光子计数直方图的方法可以适用于速度较快的运动场景，使得进行目标距离检测的方式更具有针对性，能够保证距离检测确定的距离信息的准确度。
举例来说，对于任意一个第一帧，在每一个关闭周期的时间内，都完成一次连续关闭发射，且连续发射时间等于a个发射周期。在速度较快的运动场景，参见图4，N个第一帧(检测帧)中可例如分别包括c1、c2、……、cn个关闭周期，对于N个第一帧的回波数据，处理器可以根据每一个关闭周期的连续关闭发射的第一个发射周期对应的时间(1th)内，接收的回波数据的单光子计数，确定第一个光子计数直方图(1Th)；可以根据每一个关闭周期的连续关闭发射的第二个发射周期对应的时间(2th)内，接收的回波数据的单光子计数，确定第二个光子计数直方图(2Th)；以此类推，可以根据每一个关闭周期的连续关闭发射的第a个发射周期的时间(ath)内，接收的回波数据的单光子计数，确定第a个光子计数直方图(aTh)。在得到a个光子计数直方图后，可以对a个光子计数直方图分别检测峰位。由上文描述可知，光子计数直方图的纵坐标是单光子计数的次数，因此，次数最多的单光子对应的时间信息，即为雷达系统确定的测距量程外目标的飞行时间。假设每个光子计数直方图均检测到一个峰位，雷达系统确定的测距量程外目标的飞行时间分别是Tt1、Tt2……Tta，即，雷达确定的第一飞行时间包括Tt1、Tt2……Tta。
在一种可能的实现方式中，在同一个发射周期对应的时间内接收到来自不同的两个高反射率目标的回波脉冲时，该发射周期对应的光子计数直方图可以检测到多个峰位，例如雷达系统确定的测距量程外目标的飞行时间分别是Tt11，Tt12，Tt2……Tta。其中，Tt11和Tt12均来自第一个光子计数直方图。即，雷达确定的第一飞行时间包括Tt11，Tt12，Tt2……Tta。
在一种可能的实现方式中，第一飞行时间还包括第四飞行时间，本申请实施例的距离检测方法还包括：
根据每个关闭周期结束后的一个发射周期中的回波光子的计数，确定1个光子计数直方图；根据1个光子计数直方图中，多个飞行时间区间内的至少一个峰位对应的飞行时间，确定第一飞行时间中的第四飞行时间，多个飞行时间区间根据雷达的测距量程外的目标的飞行时间确定。
通过根据雷达的测距量程外的目标的飞行时间确定多个飞行时间区间，并根据1个光子计数直方图中，多个飞行时间区间内的至少一个峰位对应的飞行时间，确定第四飞行时间，使得可以检测到与测距量程外的目标的飞行时间接近的测距量程内目标的飞行时间，即第四飞行时间。通过这种方式，能够避免第一帧的全部关闭周期内，对测距量程内目标的飞行时间造成的漏检，可以提高雷达的测距能力。
举例来说，处理器可以根据N个第一帧中每一个关闭周期后紧跟的一个发射周期时间内的单光子计数，得到一张光子计数直方图，并根据上述方法获得的测距量程外的目标的飞行时间Tt1、Tt2……Tta，可以确定a个飞行时间区间。例如，在发射脉冲的脉宽为P时，根 据测距量程外的目标的飞行时间Tt1、Tt2……Tta，可以确定a个飞行时间区间[Tt1-P,Tt1+P]、[Tt2-P,Tt2+P]……[Tta-P,Tta+P]。
在一种可能的实现方式中，可以对a个飞行时间区间[Tt1-P,Tt1+P]、[Tt2-P,Tt2+P]……[Tta-P,Tta+P]的范围内的部分光子计数直方图检测峰位，如果能够检测到至少一个峰位，可以认为在N个第一帧的全部关闭周期内，雷达系统对测距量程内的目标存在漏检。在此情况下，检测到的至少一个峰位对应的飞行时间，表示第一帧的全部关闭周期内没能检测到的测距量程内目标的飞行时间，可以确定为第一飞行时间中的第四飞行时间。例如，多个飞行时间区间内共检测到三个峰位，对应的飞行时间分别是Tq1、Tq2、Tq3，则确定的第四飞行时间包括Tq1、Tq2、Tq3。
通过这种方式，可以在速度较快的运动场景下，分别确定测距量程外的目标的飞行时间以及测距量程内的目标的飞行时间，也即确定第一飞行时间。使得可以根据测距量程外的目标的飞行时间计算测距量程外的目标的距离信息，提高雷达的测距能力。
下面介绍根据第一飞行时间和第三飞行时间，确定目标的距离信息的一种示例性方法。
在一种可能的实现方式中，根据第一飞行时间，处理器可以确定测距量程外目标的距离信息。参见图4，举例来说，在速度较快的运动场景下，第1个光子计数直方图(1Th)峰位对应的飞行时间Tt1，是连续关闭发射的第1个发射周期内，雷达根据捕获到的回波光子计数确定的飞行时间，由上文描述的直接飞行时间雷达系统的测距原理可知，雷达系统针对一个测距窗口时间对应的发射脉冲的发射时间，统计该测距窗口时间内捕获到的回波光子计数，并根据回波光子的计数确定飞行时间，也就是说，雷达系统确定的飞行时间，一定是小于或等于测距窗口时间T的。而连续关闭发射的第1个发射周期内，雷达系统捕获的回波光子，实际上是连续关闭发射前的检测发射的发射脉冲的回波光子。因此，回波光子的实际飞行时间，比雷达系统根据捕获的回波光子计数确定的飞行时间，可增加1个发射周期t。这样，根据第1个光子计数直方图(1Th)峰位对应的飞行时间Tt1，可以确定一个飞行时间Tt1+t。
第2个光子计数直方图(2Th)峰位对应的飞行时间Tt2，是连续关闭发射的第2个发射周期内，雷达根据捕获到的回波光子计数确定的飞行时间，而连续关闭发射的第2个发射周期内，雷达系统捕获的回波光子，实际上是连续关闭发射前的检测发射的发射脉冲的回波光子。因此，回波光子的实际飞行时间，比雷达系统根据捕获的回波光子计数确定的飞行时间，可增加2个发射周期t。这样，根据第2个光子计数直方图(2Th)峰位对应的飞行时间Tt2，可以确定一个飞行时间Tt2+2t。
以此类推，第a个光子计数直方图(aTh)峰位对应的飞行时间Tta，是连续关闭发射的第a个发射周期内，雷达根据捕获到的回波光子计数确定的飞行时间，而连续关闭发射的第a个发射周期内，雷达系统捕获的回波光子，实际上是连续关闭发射前的检测发射的发射脉冲的回波光子。因此，回波光子的实际飞行时间，比雷达系统根据捕获的回波光子计数确定的飞行时间，可增加a个发射周期t。这样，根据第a个光子计数直方图(aTh)峰位对应的飞行时间Tta，可以确定一个飞行时间Tta+at。
基于此，根据Tt1+t、Tt2+2t……Tta+at，代入公式(1)，使得t 0分别等于Tt1+t、Tt2+2t……Tta+at，即可计算量程外目标的距离信息。
在一种可能的实现方式中，在同一个发射周期对应的光子计数直方图检测到多个峰位，例如雷达系统确定的测距量程外目标的飞行时间分别是Tt11，Tt12，Tt2……Tta，且Tt11 和Tt12来自第1个光子计数直方图时，Tt11和Tt12是连续关闭发射的第1个发射周期内，雷达根据捕获到的回波光子计数确定的飞行时间，由上文描述可知，回波光子的实际飞行时间，比雷达系统根据捕获的回波光子计数确定的飞行时间，可增加1个发射周期t。因此，根据第1个光子计数直方图峰位对应的飞行时间Tt11和Tt12，可以确定2个飞行时间Tt11+t、Tt12+t。以此类推，可得到飞行时间Tt11+t、Tt12+t、Tt2+2t……Tta+at，代入公式(1)，使得t0分别等于Tt11+t、Tt12+t、Tt2+2t……Tta+at，即可计算量程外目标的距离信息。
通过这种方式，即可获得测距量程外目标的距离信息。
在一种可能的实现方式中，根据第三飞行时间，处理器可以确定测距量程内目标的距离信息。
举例来说，根据上文描述的方法，获得的第一飞行时间中，可例如包括测距量程外目标的飞行时间Tt1、Tt2……Tta。并且，根据至少一个第二帧的回波数据，可确定第二飞行时间，第二飞行时间可例如包括Tt1、Tt2……Tta，Tk1、Tk2……Tks。在此情况下，可先去除第二飞行时间中，与测距量程外目标的飞行时间相对应的飞行时间，得到第三飞行时间，例如，第三飞行时间包括Tk1、Tk2……Tks。第三飞行时间是测距量程内目标的飞行时间，因此，将Tk1、Tk2……Tks，代入公式(1)，使得t0分别等于Tk1、Tk2……Tks，即可计算量程内目标的距离信息。
进一步地，根据第一飞行时间和第三飞行时间，处理器可以获得准确度更高的测距量程内目标的距离信息。
举例来说，根据上文描述的方法，获得的第一飞行时间中，除包括测距量程外目标的飞行时间Tt1、Tt2……Tta外，还可例如包括测距量程内目标的飞行时间Tq1、Tq2、Tq3(第四飞行时间)。第三飞行时间和第四飞行时间可进行或运算，例如得到Tq1、Tq2、Tq3，Tk1、Tk2……Tks。在此情况下，第三飞行时间和第四飞行时间的或运算结果是测距量程内目标的飞行时间，因此，可将Tq1、Tq2、Tq3，Tk1、Tk2……Tks代入公式(1)，使得t0分别等于Tq1、Tq2、Tq3，Tk1、Tk2……Tks，即可计算量程内目标的距离信息。
通过这种方式，可以获得准确度更高的测距量程内目标的距离信息。
在一种可能的实现方式中，测距量程内目标的距离信息和测距量程外目标的距离信息可以分别作为量程内目标的点云深度图、量程外目标的点云深度图输出，也可以整合成一张包括量程内目标和量程外目标的点云深度图后输出。
本申请实施例的距离检测方法，可以获得测距量程外目标的距离信息，以及准确度较高的测距量程内目标的距离信息，并且二者的获取可以通过计算实现，不需要在雷达中新增硬件，因此可以在不增加硬件成本的条件下，提高雷达的测距能力。
在一种可能的实现方式中，在速度较快的运动场景中，如果对a个光子计数直方图检测峰位时，发现任意一个光子计数直方图中，存在强度相近但是飞行时间分布大于发射脉冲的脉宽t的多个峰位，可以认为多个峰位是来自运动目标的回波脉冲的飞行时间而非噪声。在此情况下，可设置检测窗及峰位的阈值，将所有超出阈值的峰位及其飞行时间采集下来，后续根据目标的运动方向与车前进方向是否相同或不同，分别提取这些时间信息(即超出阈值的峰位的飞行时间)中的最小值和最大值作为目标的时间信息，如果方向相同则取最小值，如果方向相反则取最大值，并根据所有时间信息中的最大值与最小值之差和车速的关系，推算目标与激光雷达系统的空间距离关系在一段时间内的可能变化规律，并将预判的规律上报 终端的控制系统。使得终端的控制系统能够将预判的规律应用于后续接收的第二帧的回波数据，例如预测该运动目标在第二测量时间内的可能距离信息，以便根据运动目标的可能距离信息规划行驶路线等。
下面介绍本申请实施例确定第一飞行时间的另一种示例性方法。
在一种可能的实现方式中，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，包括：
根据第一帧的全部关闭周期中的a个发射周期接收的回波光子的计数，确定1个光子计数直方图；根据1个光子计数直方图的e个峰位对应的飞行时间，确定第一飞行时间中雷达的测距量程外的目标的飞行时间,其中e是小于或等于a的正整数。
通过这种方式，可以确定第一飞行时间中雷达的测距量程外的目标的飞行时间，使得处理器可以进一步确定雷达的测距量程外的目标的距离信息。确定1个光子计数直方图的方法可以适用于雷达处于速度较慢的运动场景、或者雷达处于静止场景时，使得进行目标距离检测的方式更具有针对性，能够保证距离检测确定的距离信息的准确度；并且确定1个光子计数直方图的数据处理成本较低，能够节约处理器的数据处理成本，提高数据处理效率。
举例来说，对于任意一个第一帧，在每一个关闭周期的时间内，都完成一次连续关闭发射，且连续发射时间等于a个发射周期。在雷达处于速度较慢的运动场景，参见图5，N个第一帧(检测帧)中可例如分别包括c1、c2、……、cn个关闭周期，第一帧帧数N和每个第一帧的关闭周期数c1、c2、……、cn的取值可能较小，根据每一个关闭周期的连续关闭发射的一个发射周期对应的时间内，接收的回波数据的单光子计数不够多，在此情况下，对于N个第一帧，可以将全部关闭周期的连续关闭发射的a个发射周期得到的单光子计数合并到一个光子计数直方图(Th)中。由于该1个光子计数直方图(Th)是在连续关闭发射时间内得到的，因此没有任何真实量程内的目标的回波脉冲光子，通过对光子计数直方图检测寻峰，可例如检测到e个强度不同的峰位，e≤a。最强峰位到最弱峰对应的飞行时间依次为Tt1、Tt2……Tte。即，雷达确定的第一飞行时间包括Tt1、Tt2……Tte。
在一种可能的实现方式中，在雷达处于速度较慢的运动场景、或者雷达处于静止场景时，第四飞行时间的确定方式可参照上文速度较快的运动场景下的第四飞行时间的确定方式的描述，在此不再赘述。
通过这种方式，可以在速度较慢的运动场景、或者静止场景下，分别确定测距量程外的目标的飞行时间以及测距量程内的目标的飞行时间，也即确定第一飞行时间。使得可以根据测距量程外的目标的飞行时间计算测距量程外的目标的距离信息，提高雷达的测距能力。
下面介绍速度较慢的运动场景、或者静止场景下，根据第一飞行时间和第三飞行时间，确定目标的距离信息的一种示例性方法。
在一种可能的实现方式中，根据第一飞行时间，处理器可以确定测距量程外目标的距离信息。参见图5，举例来说，一个光子计数直方图(Th)峰位对应的飞行时间Tt1、Tt2……Tte，分别是最强峰位到最弱峰的飞行时间，且e个峰位的强度均不同。在此情况下，可认为最强峰对应的飞行时间Tt1是连续关闭发射的第1个发射周期内，雷达根据捕获到的回波光子计数确定的飞行时间，由上文描述可知，根据最强峰对应的飞行时间Tt1，可以确定一个飞行时间Tt1+t。可认为次强峰对应的飞行时间Tt2是连续关闭发射的第2个发射周期内，雷达根据捕获到的回波光子计数确定的飞行时间，由上文描述可知，根据次强峰对应的飞行 时间Tt2，可以确定一个飞行时间Tt2+2t。以此类推，可以分别确定Tt1+t、Tt2+2t……Tte+et，代入公式(1)，使得t0分别等于Tt1+t、Tt2+2t……Tte+et，即可计算量程外目标的距离信息。
通过这种方式，即可获得测距量程外目标的距离信息。
在一种可能的实现方式中，根据第三飞行时间，或者，根据第一飞行时间以及第三飞行时间，处理器可以确定测距量程内目标的距离信息。其具体方式可以参照上文中速度较快的运动场景下，测距量程内目标的距离信息的确定方式的描述，在此不再赘述。
根据本申请实施例的距离检测方法，可以同时得到测距量程外目标的距离信息以及测距量程内目标距离信息，拓展了系统性能。并且，上述距离信息的获取并未以复杂的设计和调控为代价，硬件控制和实现方式上较为简单，仅设计激光器脉冲发射的开启和关闭，接收端无需做修改，正常采集数据即可。本申请实施例的策略不需要复杂的数据后处理，仅需要在得到完整的光子计数直方图前，对N个第一帧的回波数据中对应的连续关闭发射时间内接收到的N个第一帧的第一回波数据以及和其后的第一个发射周期内接收到的N个第一帧的第二回波数据进行保存并处理，策略的复杂度和实现的代价较小。
本申请的实施例提供了一种距离检测装置，参见图6，所述装置包括：
第一确定模块101，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，所述第一飞行时间包括雷达的测距量程外的目标的飞行时间；
第二确定模块102，根据雷达接收的至少一个第二帧的回波数据确定第二飞行时间；
第三确定模块103，根据第一飞行时间，消除所述第二飞行时间中的部分飞行时间，得到第三飞行时间，所述部分飞行时间与测距量程外的目标的飞行时间相对应；
第四确定模块104，根据所述第一飞行时间和所述第三飞行时间，确定目标的距离信息，
其中，在第一帧对应的第一测量时间内，所述雷达在多个发射周期内关闭发射，在第二帧对应的第二测量时间内，所述雷达在各发射周期进行发射。
在一种可能的实现方式中，所述装置还包括：
第一控制模块，在第一帧对应的第一测量时间内，控制雷达进入一个或多个关闭周期，每个关闭周期包括多个发射周期；
第二控制模块，在每个关闭周期中，依次控制雷达关闭发射h个发射周期、开启发射1个发射周期、再关闭发射a个发射周期，其中h和a是正整数；
其中，在所述a个发射周期中接收第一帧的第一回波数据，所述第一回波数据用于确定雷达的测距量程外的目标的飞行时间。
在一种可能的实现方式中，所述装置还包括：
第三控制模块，在每个所述关闭周期结束后的一个发射周期中，控制雷达开启发射；
其中，在该一个发射周期中接收第一帧的第二回波数据，所述第二回波数据用于确定第四飞行时间，所述第一飞行时间包括所述第四飞行时间，所述第四飞行时间表示测距量程内的目标的飞行时间。
在一种可能的实现方式中，所述雷达通过一个或多个单光子探测器接收回波光子，并根据接收的回波光子的计数，确定所述回波数据。
在一种可能的实现方式中，第一确定模块包括：
第一确定子模块，根据所述第一帧的全部关闭周期的中的所述a个发射周期接收的回波 光子的计数，确定a个光子计数直方图，其中每个光子计数直方图是根据全部关闭周期中，同一次序的发射周期的回波光子的计数确定的；
第二确定子模块，根据a个光子计数直方图的a个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间，其中，每个光子计数直方图包括1个峰位。
在一种可能的实现方式中，第一确定模块包括：
第三确定子模块，根据所述第一帧的全部关闭周期中的所述a个发射周期接收的回波光子的计数，确定1个光子计数直方图；
第四确定子模块，根据1个光子计数直方图的e个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间,其中e是小于或等于a的正整数。
在一种可能的实现方式中，所述装置还包括：
第五确定模块，根据每个所述关闭周期结束后的一个发射周期中的所述回波光子的计数，确定1个光子计数直方图；
第六确定模块，根据所述1个光子计数直方图中，多个飞行时间区间内的至少一个峰位对应的飞行时间，确定所述第一飞行时间中的第四飞行时间，所述多个飞行时间区间根据雷达的测距量程外的目标的飞行时间确定。
在一种可能的实现方式中，所述开启发射1个发射周期内的发射脉冲的功率高于所述第二测量时间内的发射脉冲功率。
本申请的实施例提供了一种距离检测装置，包括：处理器以及用于存储处理器可执行指令的存储器；其中，所述处理器被配置为执行所述指令时实现上述方法。
本申请的实施例提供了一种雷达，包括上述距离检测装置。
本申请的实施例提供了一种终端，包括上述雷达。
本申请的实施例提供了一种非易失性计算机可读存储介质，其上存储有计算机程序指令，所述计算机程序指令被处理器执行时实现上述方法。
本申请的实施例提供了一种计算机程序产品，包括计算机可读代码，或者承载有计算机可读代码的非易失性计算机可读存储介质，当所述计算机可读代码在电子设备的处理器中运行时，所述电子设备中的处理器执行上述方法。
以上各实施例的示例性说明可参见图1-图5及其相关说明，在此不再赘述。
计算机可读存储介质可以是可以保持和存储由指令执行设备使用的指令的有形设备。计算机可读存储介质例如可以是――但不限于――电存储设备、磁存储设备、光存储设备、电磁存储设备、半导体存储设备或者上述的任意合适的组合。计算机可读存储介质的更具体的例子(非穷举的列表)包括：便携式计算机盘、硬盘、随机存取存储器(random access memory，RAM)、只读存储器(read only memory，ROM)、可擦式可编程只读存储器(electrically programmable read-only-memory，EPROM或闪存)、静态随机存取存储器(static random-access memory，SRAM)、便携式压缩盘只读存储器(compact disc read-only memory，CD-ROM)、数字多功能盘(digital video disc，DVD)、记忆棒、软盘、机械编码设备、例如其上存储有指令的打孔卡或凹槽内凸起结构、以及上述的任意合适的组合。
这里所描述的计算机可读程序指令或代码可以从计算机可读存储介质下载到各个计算/处理设备，或者通过网络、例如因特网、局域网、广域网和/或无线网下载到外部计算机或外部存储设备。网络可以包括铜传输电缆、光纤传输、无线传输、路由器、防火墙、交换机、 网关计算机和/或边缘服务器。每个计算/处理设备中的网络适配卡或者网络接口从网络接收计算机可读程序指令，并转发该计算机可读程序指令，以供存储在各个计算/处理设备中的计算机可读存储介质中。
用于执行本申请操作的计算机程序指令可以是汇编指令、指令集架构(instruction set architecture，ISA)指令、机器指令、机器相关指令、微代码、固件指令、状态设置数据、或者以一种或多种编程语言的任意组合编写的源代码或目标代码，所述编程语言包括面向对象的编程语言—诸如Smalltalk、C++等，以及常规的过程式编程语言—诸如“C”语言或类似的编程语言。计算机可读程序指令可以完全地在用户计算机上执行、部分地在用户计算机上执行、作为一个独立的软件包执行、部分在用户计算机上部分在远程计算机上执行、或者完全在远程计算机或服务器上执行。在涉及远程计算机的情形中，远程计算机可以通过任意种类的网络—包括局域网(local area network，LAN)或广域网(wide area network，WAN)—连接到用户计算机，或者，可以连接到外部计算机(例如利用因特网服务提供商来通过因特网连接)。在一些实施例中，通过利用计算机可读程序指令的状态信息来个性化定制电子电路，例如可编程逻辑电路、现场可编程门阵列(field-programmable gate array，FPGA)或可编程逻辑阵列(programmable logic array，PLA)，该电子电路可以执行计算机可读程序指令，从而实现本申请的各个方面。
这里参照根据本申请实施例的方法、装置(系统)和计算机程序产品的流程图和/或框图描述了本申请的各个方面。应当理解，流程图和/或框图的每个方框以及流程图和/或框图中各方框的组合，都可以由计算机可读程序指令实现。
这些计算机可读程序指令可以提供给通用计算机、专用计算机或其它可编程数据处理装置的处理器，从而生产出一种机器，使得这些指令在通过计算机或其它可编程数据处理装置的处理器执行时，产生了实现流程图和/或框图中的一个或多个方框中规定的功能/动作的装置。也可以把这些计算机可读程序指令存储在计算机可读存储介质中，这些指令使得计算机、可编程数据处理装置和/或其他设备以特定方式工作，从而，存储有指令的计算机可读介质则包括一个制造品，其包括实现流程图和/或框图中的一个或多个方框中规定的功能/动作的各个方面的指令。
也可以把计算机可读程序指令加载到计算机、其它可编程数据处理装置、或其它设备上，使得在计算机、其它可编程数据处理装置或其它设备上执行一系列操作步骤，以产生计算机实现的过程，从而使得在计算机、其它可编程数据处理装置、或其它设备上执行的指令实现流程图和/或框图中的一个或多个方框中规定的功能/动作。
附图中的流程图和框图显示了根据本申请的多个实施例的装置、系统、方法和计算机程序产品的可能实现的体系架构、功能和操作。在这点上，流程图或框图中的每个方框可以代表一个模块、程序段或指令的一部分，所述模块、程序段或指令的一部分包含一个或多个用于实现规定的逻辑功能的可执行指令。在有些作为替换的实现中，方框中所标注的功能也可以以不同于附图中所标注的顺序发生。例如，两个连续的方框实际上可以基本并行地执行，它们有时也可以按相反的顺序执行，这依所涉及的功能而定。
也要注意的是，框图和/或流程图中的每个方框、以及框图和/或流程图中的方框的组合，可以用执行相应的功能或动作的硬件(例如电路或ASIC(application specific integrated circuit，专用集成电路))来实现，或者可以用硬件和软件的组合，如固件等来实现。
尽管在此结合各实施例对本发明进行了描述，然而，在实施所要求保护的本发明过程中，本领域技术人员通过查看所述附图、公开内容、以及所附权利要求书，可理解并实现所述公开实施例的其它变化。在权利要求中，“包括”(comprising)一词不排除其他组成部分或步骤，“一”或“一个”不排除多个的情况。单个处理器或其它单元可以实现权利要求中列举的若干项功能。相互不同的从属权利要求中记载了某些措施，但这并不表示这些措施不能组合起来产生良好的效果。
以上已经描述了本申请的各实施例，上述说明是示例性的，并非穷尽性的，并且也不限于所披露的各实施例。在不偏离所说明的各实施例的范围和精神的情况下，对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。本文中所用术语的选择，旨在最好地解释各实施例的原理、实际应用或对市场中的技术的改进，或者使本技术领域的其它普通技术人员能理解本文披露的各实施例。

Claims (14)

  1. 一种基于雷达的距离检测方法，其特征在于，所述方法包括：
    根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，所述第一飞行时间包括雷达的测距量程外的目标的飞行时间；
    根据雷达接收的至少一个第二帧的回波数据确定第二飞行时间；
    根据第一飞行时间，消除所述第二飞行时间中的部分飞行时间，得到第三飞行时间，所述部分飞行时间与测距量程外的目标的飞行时间相对应；
    根据所述第一飞行时间和所述第三飞行时间，确定目标的距离信息，
    其中，在第一帧对应的第一测量时间内，所述雷达在多个发射周期内关闭发射，在第二帧对应的第二测量时间内，所述雷达在各发射周期进行发射。
  2. 根据权利要求1所述的方法，其特征在于，所述方法还包括：
    在第一帧对应的第一测量时间内，控制雷达进入一个或多个关闭周期，每个关闭周期包括多个发射周期；
    在每个关闭周期中，依次控制雷达关闭发射h个发射周期、开启发射1个发射周期、再关闭发射a个发射周期，其中h和a是正整数；
    其中，在所述a个发射周期中接收第一帧的第一回波数据，所述第一回波数据用于确定雷达的测距量程外的目标的飞行时间。
  3. 根据权利要求2所述的方法，其特征在于，所述方法还包括：
    在每个所述关闭周期结束后的一个发射周期中，控制雷达开启发射；
    其中，在该一个发射周期中接收第一帧的第二回波数据，所述第二回波数据用于确定第四飞行时间，所述第一飞行时间包括所述第四飞行时间，所述第四飞行时间表示测距量程内的目标的飞行时间。
  4. 根据权利要求1-3中任一项所述的方法，其特征在于，所述雷达通过一个或多个单光子探测器接收回波光子，并根据接收的回波光子的计数，确定所述回波数据。
  5. 根据权利要求4所述的方法，其特征在于，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，包括：
    根据所述第一帧的全部关闭周期的中的所述a个发射周期接收的回波光子的计数，确定a个光子计数直方图，其中每个光子计数直方图是根据全部关闭周期中，同一次序的发射周 期的回波光子的计数确定的；
    根据a个光子计数直方图的a个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间，其中，每个光子计数直方图包括1个峰位。
  6. 根据权利要求4所述的方法，其特征在于，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，包括：
    根据所述第一帧的全部关闭周期中的所述a个发射周期接收的回波光子的计数，确定1个光子计数直方图；
    根据1个光子计数直方图的e个峰位对应的飞行时间，确定所述第一飞行时间中雷达的测距量程外的目标的飞行时间,其中e是小于或等于a的正整数。
  7. 根据权利要求4所述的方法，其特征在于，所述方法还包括：
    根据每个所述关闭周期结束后的一个发射周期中的所述回波光子的计数，确定1个光子计数直方图；
    根据所述1个光子计数直方图中，多个飞行时间区间内的至少一个峰位对应的飞行时间，确定所述第一飞行时间中的第四飞行时间，所述多个飞行时间区间根据雷达的测距量程外的目标的飞行时间确定。
  8. 根据权利要求2所述的方法，其特征在于，所述开启发射1个发射周期内的发射脉冲的功率高于所述第二测量时间内的发射脉冲功率。
  9. 一种距离检测装置，其特征在于，所述装置包括：
    第一确定模块，根据雷达接收的至少一个第一帧的回波数据确定第一飞行时间，所述第一飞行时间包括雷达的测距量程外的目标的飞行时间；
    第二确定模块，根据雷达接收的至少一个第二帧的回波数据确定第二飞行时间；
    第三确定模块，根据第一飞行时间，消除所述第二飞行时间中的部分飞行时间，得到第三飞行时间，所述部分飞行时间与测距量程外的目标的飞行时间相对应；
    第四确定模块，根据所述第一飞行时间和所述第三飞行时间，确定目标的距离信息，
    其中，在第一帧对应的第一测量时间内，所述雷达在多个发射周期内关闭发射，在第二帧对应的第二测量时间内，所述雷达在各发射周期进行发射。
  10. 一种距离检测装置，其特征在于，包括：
    处理器；
    用于存储处理器可执行指令的存储器；
    其中，所述处理器被配置为执行所述指令时实现权利要求1-8任意一项所述的方法。
  11. 一种非易失性计算机可读存储介质，其上存储有计算机程序指令，其特征在于，所述计算机程序指令被处理器执行时实现权利要求1-8中任意一项所述的方法。
  12. 一种计算机程序产品，其特征在于，包括计算机可读代码，或者承载有计算机可读代码的非易失性计算机可读存储介质，当所述计算机可读代码在电子设备中运行时，所述电子设备中的处理器执行权利要求1-8中任意一项所述的方法。
  13. 一种雷达，其特征在于，包括权利要求9-10中任一项所述的距离检测装置。
  14. 一种终端，其特征在于，包括权利要求13所述的雷达。
PCT/CN2022/082440 2021-04-02 2022-03-23 基于雷达的距离检测方法、装置、雷达及终端 WO2022206501A1 (zh)

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