CN214795206U

CN214795206U - Laser radar

Info

Publication number: CN214795206U
Application number: CN202120703678.1U
Authority: CN
Inventors: 杨晋; 顾天长; 王重阳; 向少卿
Original assignee: Hesai Technology Co Ltd
Current assignee: Hesai Technology Co Ltd
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2021-11-19
Anticipated expiration: 2031-04-07

Abstract

The utility model provides a laser radar, include: the device comprises a laser emitting device, a control device, a detection device and a data processing device, wherein the control device is configured to generate a trigger signal based on a time sequence random number; the laser emitting device comprises at least one laser and a driver coupled with the laser, wherein the driver is configured to drive the laser to emit a laser pulse signal according to a trigger signal; the detection device is configured to receive an echo signal of the laser pulse signal reflected by the target object and convert the echo signal into an electric signal; and a data processing device for determining the distance information of the target object based on the time of transmitting the laser pulse signal and the time of receiving the echo signal. The utility model discloses a luminous scheme at random for interference point that disturbs laser radar does not have the space correlation, and the many pulse codes of recombination modulate chronogenesis and amplitude between the many pulses, judge whether echo code is the same with the transmission pulse sequence code, discernment echo signal further improves anti-interference effect.

Description

Laser radar

Technical Field

The present disclosure relates to the field of photoelectric detection, and more particularly, to a laser radar.

Background

In the point cloud generated by the laser radar, interference points are always a problem to be overcome as much as possible. Interference points are generated from a plurality of reasons, interference points generated by crosstalk between different laser radars is one important reason, and particularly, when the laser radars are widely applied to navigation of an automatic driving vehicle, the problem of crosstalk between the laser radars is particularly prominent. The detection light of the laser radar is concentrated in several commonly used wavelengths, so that the laser radar can easily receive laser or echo with the same wavelength sent by other radars, and cannot be filtered by means of light filtering and the like. Because the ranging principle of the laser radar is based on measuring the time of flight (tof) of the transmitted laser pulse, if each laser radar cannot judge whether the received laser pulse is sent by the laser radar, when pulses or echoes sent by other laser radars are received, the echo signal of the laser radar can be judged, and an interference point or even a test result is wrong.

The statements in this background section merely represent techniques known to the public and are not, of course, representative of the prior art.

SUMMERY OF THE UTILITY MODEL

In view of prior art's at least one defect, the utility model discloses a laser radar adopts the luminous scheme at random for interference point that disturbs laser radar does not have the space correlation, and the time sequence and the amplitude to between the multipulse are modulated in the recombination multipulse code, judge whether echo code is the same with the transmission pulse sequence code, and discernment echo signal further improves anti-interference effect.

The utility model provides a laser radar, include: laser emitting device, control device, detection device and data processing device, wherein,

the control device is configured to generate a trigger signal based on a timing random number;

the laser emitting device comprises at least one laser and a driver coupled with the laser, wherein the driver is configured to drive the laser to emit a laser pulse signal according to the trigger signal;

the detection device is configured to receive an echo signal of the laser pulse signal reflected by a target object and convert the echo signal into an electric signal; and

and the data processing device determines the distance information of the target object based on the time of transmitting the laser pulse signal and the time of receiving the echo signal.

According to an aspect of the present invention, the apparatus further comprises a random number generator configured to generate the timing random number, and the control device is coupled to the random number generator to receive the timing random number.

According to an aspect of the present invention, wherein the data processing apparatus is configured to calculate the correlation of the plurality of distance information, and filter the distance information of which the correlation is lower than a preset value as the interference signal.

According to an aspect of the invention, wherein the laser has a plurality of predetermined lighting moments, the control device is configured to: and selecting one light-emitting time from the plurality of preset light-emitting times as the trigger time of the driving signal according to the time sequence random number.

According to an aspect of the invention, wherein the laser has a predetermined lighting moment, the control device is configured to: and delaying or advancing the preset light-emitting time as the trigger time of the driving signal according to the time sequence random number.

According to an aspect of the present invention, wherein the laser is configured to emit a plurality of pulses, the control device is configured to adjust a time interval between the trigger signals corresponding to two adjacent pulses according to the timing random number.

According to an aspect of the present invention, wherein the laser transmitter includes a plurality of lasers and a plurality of drivers, which are the same in number, the laser radar includes a plurality of random number generators, which are the same in number as the lasers.

According to an aspect of the present invention, wherein the laser emitting device includes a plurality of lasers and a plurality of drivers coupled one by one to the lasers, the control device is coupled to the plurality of drivers, and the timing random number corresponds to a light emitting sequence of the plurality of lasers.

According to the utility model discloses an aspect, wherein laser emission device includes the multiunit laser instrument, every group laser instrument include a plurality of laser instruments and with a plurality of drivers that the laser instrument is coupled one by one, laser radar still include with a plurality of random number generators that the multiunit laser instrument corresponds, the chronogenesis random number that every random number generator produced and rather than the luminous order of a set of laser instrument that corresponds corresponding.

According to an aspect of the present invention, wherein the control device is further configured to control the driver to drive the laser to emit a laser pulse sequence having a multi-pulse code, the multi-pulse code comprising a timing code, an amplitude code and/or a pulse width code.

According to an aspect of the invention, wherein the random number generator is a pseudo-random number generator, the timing random number is generated by one or more of the following:

randomly extracting from a pre-stored random number table;

generating based on the clock phase;

generating based on the system temperature; and

generated by a linear feedback shift register.

The utility model also provides a laser radar, include: laser emitting device, control device, detection device and data processing device, wherein,

the data processing device determines the distance information of the target object based on the time of transmitting the laser pulse signal and the time of receiving the echo signal,

the laser pulse signal is a laser pulse sequence with multi-pulse coding, and the multi-pulse coding comprises time sequence coding, amplitude coding and/or pulse width coding.

By the random light emitting of the laser, interference points interfering the laser radar do not have spatial correlation, so that the interference points can be judged as isolated points to be filtered, and the interference points are reduced. Furthermore, the time sequence interval and amplitude between the multiple pulses are modulated by combining the multiple pulse codes, and the echo signals are identified by judging whether the echo codes are the same as the transmitted pulse sequence codes, so that the anti-interference effect is further improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure. In the drawings:

FIG. 1a is a schematic diagram showing a three-dimensional effect of information points which emit non-random light;

FIG. 1b shows a schematic diagram of a two-dimensional effect of information dots emitting non-randomly;

FIG. 2 shows a lidar module diagram of an embodiment of the invention;

FIG. 3a is a schematic diagram showing a three-dimensional effect of information points randomly luminous;

FIG. 3b shows a schematic diagram of a two-dimensional effect of randomly emitted information dots;

FIG. 4 shows a timing diagram of a random light emitting time of an embodiment of the present invention;

fig. 5 shows a timing diagram of random light-emitting delay according to the second embodiment of the present invention;

FIG. 6a shows a schematic diagram of the interference when lasers are sequentially fired;

fig. 6b shows a schematic diagram of interference caused by random three-light-emitting sequence according to an embodiment of the present invention;

FIG. 7 shows a schematic of a multiple laser arrangement;

fig. 8 shows a laser radar module diagram according to a fourth embodiment of the present invention;

fig. 9 shows a laser radar module diagram according to a fifth embodiment of the present invention;

fig. 10 shows a laser radar module diagram according to a sixth embodiment of the present invention;

fig. 11 shows a timing diagram of the random combination of multiple pulse codes at the lighting time according to the seventh embodiment of the present invention;

fig. 12 is a timing chart of the random combination of the light emission delay and the multi-pulse code according to the eighth embodiment of the present invention;

FIG. 13 shows a schematic diagram of a multi-pulse coded driver architecture;

FIG. 14 shows a timing diagram of a multi-pulse encoded switch control signal and switch trigger signal;

FIG. 15 shows a schematic diagram of another multi-pulse coded driver architecture;

fig. 16 shows a flow chart of a ranging method of the present invention; and

fig. 17 shows a lidar module diagram according to an embodiment of the invention.

Detailed Description

In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the description of the present invention, it should be noted that unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection, either mechanically, electrically, or in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. In order to simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or reference letters in the various examples, which have been repeated for purposes of simplicity and clarity and do not in themselves dictate a relationship between the various embodiments and/or arrangements discussed. In addition, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

The multi-line laser radar comprises a plurality of lasers and a plurality of detectors, wherein the lasers can be arranged according to a specified direction (such as the vertical direction of the laser radar); the detectors and the lasers have corresponding relations, after one laser emits detection light, the detector corresponding to the laser receives light signals, and after the detector receives the light signals, the light flight time can be calculated through the time when the corresponding laser emits the detection light and the time when the detector receives the signals, so that the target object distance information can be obtained. After one transmission and reception is completed, the next laser emits probe light.

The laser radar rotates along an axis at a certain rotating speed in the working process, and data acquisition is carried out after the laser radar rotates for a certain angle every time according to the set sampling frequency, so that information around the radar is acquired in the rotating process, the sensing of the surrounding environment is realized, and all data points obtained after the radar rotates for a circle form a frame of point cloud. Taking a conventional mechanical rotary radar as an example, a plurality of detectors are arranged along the vertical direction of the radar, and different detectors are used for receiving echo signals with different vertical angles, so that data points measured by different detectors can acquire the corresponding vertical angles according to the positions of the detectors. The radar can rotate in the horizontal direction of 360 degrees, when the radar rotates to a certain horizontal angle, the plurality of lasers sequentially and circularly emit detection light, and the detector detects an optical signal after emitting the detection light by the corresponding lasers. After all detectors complete the round trip, detection information corresponding to the radar vertical Field of View (FOV) at that horizontal angle is obtained. After the detection at one horizontal angle is finished, the radar rotates to another horizontal angle, and the next round of detection is carried out. Therefore, the horizontal angle difference corresponding to two adjacent signal detections by the same detector can be expressed as the horizontal angle resolution of the radar.

In actual detection, the optical signal received by the detector not only includes an echo signal of the detection light reflected by the target object, but also may contain an interference signal, especially the detection light or the reflected light emitted by other laser radars, to form an interference point. Interference points can be simply divided into two categories: a single noise point (which may also be considered a solitary point) and multiple, even consecutive, noise points. The method for filtering the interference points is based on that the interference generated by signals of other laser radars or other interference sources is random and sporadic, namely, a point cloud is a spatial isolated point, and the isolated point can be identified and filtered by judging the correlation between the data point and other adjacent data points, so that the interference points are reduced.

However, when the interference point is from other laser radars, especially when the other laser radars are also used for the round-robin light emission detection of multiple lasers and detectors, multiple detectors of the laser radar may receive interference signals, and multiple interference points are obtained by detection at the same horizontal angle, so that the interference points have certain correlation.

Fig. 1a and 1b respectively show schematic diagrams of three-dimensional and two-dimensional effects of non-random light-emitting information points, which illustrate data points obtained by a laser radar detecting two plate-shaped targets separated by a certain distance, in fig. 1a, a Y axis corresponds to a detection horizontal angle of the laser radar, a Z axis corresponds to a detection vertical angle of the laser radar, and an X axis corresponds to a target distance obtained by detection, and the radar can obtain three-dimensional point cloud shown in fig. 1a according to real-time detection angles and target distance information of a laser and a corresponding detector. FIG. 1b is an X-Y two-dimensional graph of FIG. 1 a. The non-random light emission means that a plurality of lasers of the laser radar sequentially emit probe light at predetermined time intervals, and the light emission time intervals of two adjacent lasers are generally equal. Under the condition that the laser radar is not moved, the distance between the laser radar and the target object is not changed, a plurality of data points measured by a plurality of detectors at a plurality of horizontal angles correspond to the same distance value, and the point cloud is a dot matrix which is regularly arranged. As shown in fig. 1a, the open circles represent data points (illustrating real points) measured by real echoes of probe light reflected by the target object, and the star points represent interference points.

From the ranging mode analysis of the laser radar, a laser of the radar emits a detection beam, and a detector is activated to receive an echo signal within a certain time. The certain time can be determined by a predetermined detection distance of the laser radar, for example, the farthest detection distance of the laser radar is 200m, the laser emits a detection beam to start timing and activate the detector, the detector is deactivated after the time (200m × 2/light speed) (that is, the detection beam flies to a 200m target object and is reflected, and an echo signal reaches the laser radar), and the detection is finished. During the activation time of the detector, once the optical signal exceeding the noise threshold is received, the system judges that the detection light beam is the echo reflected by the target object, and the flight time obtained by subtracting the emission time of the detection light from the echo receiving time is used for calculating the distance of the target object. If an interference signal exceeding a noise threshold value is received within the activation time of the detector, a target object distance, namely an interference point, is calculated according to the receiving time of the interference signal.

If an interference radar exists, the laser radar emits a detection beam with a similar rule and time interval to the laser radar, then during the first detection, the first detector receives an interference signal within the activation time, and an interference point is generated during the first detection. During the second detection, the second detector is also likely to receive an interference signal caused by the next detection light of the interference radar during the activation time, and an interference point is also generated during the detection of the second detector. For the same reason, the third, fourth, and other multiple detectors adjacent to the first and second detectors may all receive interference signals caused by detection light sequentially emitted by the interference radar, and there are interference points in detection results of the multiple detectors. The distances corresponding to the interference points are related to the time intervals of the detection light emitted by the interference radar, if the emission time intervals of the multiple laser devices of the laser radar are fixed in a round-robin manner, and the time intervals of the multiple laser devices of the interference radar in a round-robin manner are also fixed, the receiving time of the interference signal is regular, and the calculated target object distance also has certain regularity, so that the interference points have spatial correlation.

With reference to fig. 1b, when the radar is at a certain horizontal angle (corresponding to the same Y-axis coordinate), the illustrated 5 detectors all receive the interference signal, and generate continuous interference points corresponding to the same horizontal angle and vertical angle, the distance information corresponding to these interference points has a small difference, and have strong spatial correlation with each other, and the interference points cannot be identified by using a spatial isolated point discrimination method, so as to generate noise points in the point cloud.

Based on the analysis, the utility model discloses a laser radar adopts the luminous scheme at random for interference point space correlation of interference laser radar reduces, reaches the degree that the algorithm can discern, and then regards it as the interfering signal filtering.

The utility model discloses a random lighting, including multiple mode: randomly jittering the emission time of the detection light beams emitted by each laser; the light emitting sequence of the lasers is randomly selected from the plurality of lasers, namely, the lasers are not sequentially emitted from the 1 st to the Nth according to the installation sequence, but one laser is randomly selected from the N lasers to emit light, and one laser is randomly selected from the rest N-1 lasers to emit light next time, or a random sequence is set for the N lasers, and the corresponding lasers are sequentially emitted according to the random sequence (N is a positive integer and represents the number of the lasers which are installed adjacently); one probe beam emitted by each laser comprises a plurality of pulses, and a plurality of pulses contained in the probe beams emitted by different lasers have random time intervals; a combination of two or more of the above-mentioned several random ways.

Combine above-mentioned non-random light emitting scheme, analysis the utility model discloses the technological effect of random light emitting scheme. The multiple detectors of the laser radar are supposed to receive the same number of interference signals, because the emission of the interference radar has regularity, compared with non-random light emission, the actual receiving time of the interference signals is unchanged, but the emission of detection light beams of the laser radar has randomness, so that two adjacent detectors cannot receive the interference signals at the same time, the horizontal angles and/or the vertical angles corresponding to the multiple interference points are not adjacent, and the spatial distance of the interference points is increased; even if two adjacent detectors still receive the interference signals at the same time, the emitting time of the laser radar is random, and the distance of the target object calculated according to the interference signals is random, so that the space distance of the interference points can be increased. Therefore, the detection angle of the interference point in the point cloud and/or the distance corresponding to the interference point also generate randomness, the spatial correlation of the interference point is reduced and exposed, and a spatial isolated point discrimination algorithm can identify the interference point and filter the interference point.

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are presented herein only to illustrate and explain the present invention, and not to limit the present invention.

The utility model provides a laser radar 10, as shown in fig. 2, including laser emission device 11, controlling means 12, detecting device 13 and data processing device 14.

The laser emitting device 11 includes a laser 111 and a driver 112 coupled thereto, and is configured to emit a laser pulse signal. The laser emitting device 11 comprises at least one laser 111 and a driver 112 corresponding to the laser 111, in the embodiment of fig. 2, a schematic diagram of an embodiment in which the laser emitting device 11 comprises one laser 111, one driver 112 and one random number generator 15 is shown, and an embodiment in which the laser emitting device 11 comprises a plurality of lasers 111, a plurality of drivers 112 and a plurality of random number generators 15 will be described in detail below. The laser 111 may be, for example, a Laser Diode (LD), an Edge-emitting laser (EEL), or a Vertical-cavity surface-emitting laser (VCSEL). The driver 112 may comprise, for example, a switch and a voltage source or energy storage device. The control device transmits a trigger signal to the switch to enable the switch to be conducted, and the voltage source or the energy storage device discharges the laser, so that the laser is driven to emit laser pulses.

The control device 12 is coupled to a driver 112, configured to generate a trigger signal based on the timing random number, and the driver 112 receives the trigger signal from the control device 12 and drives the coupled laser 111 to emit a laser pulse signal L. The timing random number may be a random integer or a random floating point number, and may correspond to a number or a time value in a time domain, and the control device 12 generates a trigger signal according to the timing random number and controls the laser 111 to emit light randomly through the driver 112 to reduce interference. For each laser emitting device 11, it may have one or more preset emission times, in the present invention, the control device 12 randomly adjusts or selects the emission time of the laser emitting device 11 according to the timing random number.

The laser pulse signal L is diffusely reflected on the target object, part of the echo signal L ' is returned to the laser radar 10, and the detection device 13 is configured to receive the echo signal L ' of the laser pulse signal L reflected by the target object and convert the echo signal L ' into an electrical signal. The detecting device 13 may include an Avalanche Photodiode (APD), a single photon avalanche photodiode (SPAD), or other types of photodetectors, and may convert the echo signals into current signals, voltage signals, or digital signals.

The data processing device 14 is configured to determine distance information of the target object based on the time at which the laser pulse signal L is emitted and the time at which the echo signal L' is received. The data processing device 14 is coupled to the detection device 13, for example, so that the reception time of the echo can be calculated from the electrical signal. The data processing device 14 is coupled to the control device 12, so that the triggering time of the triggering signal can be obtained as the emission time of the laser pulse signal. Additionally or alternatively, the data processing device 14 may be coupled to the laser emitting device 11, so as to obtain a more precise emitting time of the laser pulse signal, which is within the scope of the present invention. The data processing device 14 may comprise one or more of an analog-to-digital converter ADC, a time-to-digital converter TDC, a microprocessor.

The utility model discloses in, controlling means 12 random adjustment or select laser emission device 11's emission time, data processing apparatus can acquire this emission time to combine the detector to receive echo signal's time to calculate the flight time of light-emitting, thereby obtain accurate target object distance information. The transmitting time of the interference signal does not have the same randomness, so that the time difference between the receiving time of the interference signal and the random transmitting time of the laser radar is randomly changed, the time difference of a plurality of interference signals and the distance information corresponding to the interference points do not have spatial correlation any more, and the interference signals are easy to identify.

Fig. 3a and 3b are schematic diagrams illustrating a three-dimensional/two-dimensional effect of randomly-luminous information points, and similarly, data points obtained by detecting two plate-shaped targets at a certain distance by using a laser radar, in fig. 3a, a Y axis corresponds to a detection horizontal angle of the laser radar, a Z axis corresponds to a detection vertical angle of the laser radar, and an X axis corresponds to a target distance obtained by detection, and the laser radar can obtain a three-dimensional point cloud shown in fig. 3a according to real-time detection angles and target distance information of a laser and a corresponding detector. Figure 3b is an X-Y two-dimensional graph of figure 3 a. After the random light emitting scheme is adopted, the interference points received by the plurality of detectors do not have spatial correlation, as shown in fig. 3a, the random light emitting laser radar detects two flat plate-shaped targets to obtain partial information points, wherein the hollow circles on the connecting line represent data points (shown as real points) measured by real echoes of the detection light reflected by the targets, and the star points represent the interference points. Under the condition that the laser radar is not moved, the distance between the laser radar and a target object is not changed, a plurality of data points measured by a plurality of detectors at a plurality of horizontal angles correspond to the same distance value, and a dot matrix which is regularly arranged is arranged on a point cloud, as shown by real points in the figure; with reference to fig. 3b, the laser radar receives the interference signals at a certain horizontal angle (corresponding to the same Y-axis coordinate), and because other laser radars do not use the same random light emission strategy, the distance values obtained by the interference point calculation form divergent interference points at the horizontal angle and the vertical angle, and the distance information corresponding to these interference points have a large difference and do not have spatial correlation with each other, so that the interference points can be identified as spatial isolated points for filtering. Therefore, the random light-emitting scheme is adopted, so that the interference points interfering the laser radar do not have spatial correlation, and can be filtered out as interference signals through calculation and identification.

With continued reference to fig. 2, in accordance with a preferred embodiment of the present invention, lidar 10 further includes a random number generator 15 configured to generate time-sequential random numbers, and control device 12 is coupled to random number generator 15 to receive the time-sequential random numbers. The random number generator 15 is a pseudo-random number generator that generates time-sequential random numbers by one or more of the following: 1) a table look-up method, which randomly extracts from a group of random number tables stored in advance; 2) after the control device 12 sends out the trigger signal, the random number generator 15 samples the phase of the system clock, and converts the clock phase into a time value as a time sequence random number; 3) the random number generator 15 reads the system temperature, and generates a time sequence random number by using the temperature decimal place as a random number seed; 4) the random number sequence is generated by a Linear Feedback Shift Register (LFSR). It can be understood by those skilled in the art that the generation method is only briefly listed here, and the timing random number can also be generated by other methods, all of which are within the protection scope of the present invention.

In addition, in the embodiment of fig. 2, the control device 12 and the random number generator 15 are shown as separate components, but the present invention is not limited thereto, and it is also conceivable that the random number generator 15 is integrated into the control device 12, or that the random number generator 15 is not a component of the laser radar 10, but is located outside the laser radar 10, which are within the scope of the present invention.

Further, the data processing device 14 is further configured to calculate a correlation of the plurality of data points, and filter the distance information having a correlation lower than a preset value as the interference signal. Therefore, the random light-emitting scheme is to make the interference point interfering the laser radar have no spatial correlation, so that the interference point and the real point are more easily distinguished, which is the first step of reducing interference, and then the data processing device 14 calculates and identifies the interference point, filters the interference point as an interference signal, and finally reduces interference. The correlation of the distance information includes, for example, a distance between each point and a neighboring point in the point cloud or an average value of distances between each point and a plurality of neighboring points. In the basis the utility model discloses in laser radar's the point cloud that obtains, because the point that interference source and produce is great with the distance of adjacent point usually, comparatively dispersion, consequently through setting up the distance threshold value, can eliminate or reduce the quantity of interference point to a very big extent.

The modules of lidar 10 are described above, and the implementation of the random light emission scheme is described in detail below by way of a preferred embodiment.

The utility model discloses in, be that laser radar 10's data processing apparatus 14 can learn laser instrument 111's actual luminous moment through the anti-jamming principle of random lighting, receive the moment of echo and subtract actual luminous moment, the flight time (time of flight, tof) that can obtain promptly, and then the conversion obtains the distance information of target object, does not receive the influence of luminous moment random variation. For the interference source (other laser radars), because the laser pulse transmission time is a determined time value, or a fixed transmission interval and no time delay exists, or because the randomness of the time delay adopted by the laser radar 10 is different from that of the interference source, the laser pulse transmitted by the interference source, or the reflected echo of the interference source laser pulse by the same target object is received by the detection device 13 of the laser radar 10, and then the corresponding transmission time is subtracted to obtain a flight time tof value, and further the converted distance information has no correlation in space, so that the distance information can be filtered as an interference point.

Fig. 4 shows a timing chart of random lighting time in the first embodiment of the present invention. For the laser of the laser emitting device 11, for example, a plurality of light emitting times, such as a plurality of preset light emitting times t1, t2, … …, tn shown in fig. 4, may be stored in the control device 12 in advance, after the control device 12 receives the timing random number from the random number generator 15, one light emitting time tx is selected from the plurality of preset light emitting times t1, t2, … …, tn according to the timing random number as the light emitting time of the laser, the control device 12 sends a trigger signal at the light emitting time tx, and the driver 112 receives the trigger signal and drives the laser 111 coupled thereto to send a laser pulse signal. For the laser 111, the time of emitting a single laser pulse is random, and the time of emitting a laser pulse is a certain time value, so that when the detection device 13 receives two pulse signals, an interference point generated by the interference signal can be easily identified, thereby reducing interference. Preferably, the time-series random number is an integer between 1 and n. Alternatively, the random number generator 15 stores a plurality of preset light emission times t1, t2, … …, tn in advance, generates a random integer x between 1 and n, and then selects and outputs the preset light emission time tx to the control device 12.

Alternatively, the timing random number output by the random number generator 15 is a specific time value. For each laser 111 whose light emission timing varies between 0 and tmax, the random number generator 15 is configured to generate a random floating point number between 0 and tmax as the timing random number. After receiving the random floating point number, the control device 12 sends a trigger signal at a time corresponding to the random floating point number to drive the laser 111 to send a laser pulse signal.

Further, tmax is determined based on the maximum time interval during which one laser emission/detector is active to receive a corresponding one detection. For example, the flight time corresponding to the maximum detection distance of 200m is 1.33 μ s, and assuming that the time interval allocated by two adjacent detections is 1.5 μ s, the tmax does not exceed 0.17 μ s, so as to ensure the normal operation of the next detection. The time interval between two adjacent detections may be assigned according to the frame rate, the rotation speed, the number of lines or the resolution of the lidar.

In addition, only a single pulse signal is shown in FIG. 4, i.e., one probe beam contains only one pulse; those skilled in the art will readily appreciate that the laser pulse signal emitted by the laser may be multi-pulsed, i.e., one probe beam comprising a plurality of pulses. The plurality of preset light emission times t1, t2, … …, tn shown in fig. 4 are the light emission times of the first pulse emitted by each laser.

Fig. 5 shows a timing diagram of random light emission time delay according to the embodiment of the present invention, and for the laser of the laser emitting device 11, each time the laser detection pulse is emitted, the timing diagram has a preset light emission time. The utility model discloses in, random number generator 15 generates random light emission time delay tau, and controlling means 12 regards tau as the time delay of the luminous moment of laser instrument to change the actual luminous moment of laser instrument. In the embodiment shown in fig. 5, the laser emits two probe pulses, for example, p1 and p1', for example, for each time the laser 111-1 performs a time-of-flight measurement, and the preset light emission timings of the probe pulses p1 and p1' are t1 and t1', respectively, as shown by the probe pulses shown by the solid line in the emission waveform diagram of the laser 111-1 in fig. 5. For the probe pulse p1, the control device 12 delays the light emission time t1 by a random light emission delay τ 1 generated by the random number generator 15, the delay τ 1 shown in the figure being a negative value, and thus actually advancing the light emission time t 1; similarly, the control device 12 delays the light emission time t1 'based on the random light emission delay τ 1' generated by the random number generator 15, and since the delay τ 1 'shown in the figure is a positive value, the light emission time t1' is actually delayed. For laser 111-1, the emission moments of its two detection pulses are advanced and delayed differently, respectively, according to another embodiment of the present invention, the same laser can also have the same delay of multiple detection pulses, i.e. have the same sign, and have the same absolute value, in one time of flight time measurement.

Or alternatively, the control device 12 may also prestore n different delay amounts τ 1, τ 2, … …, τ n, which may include positive and negative different delay amounts, the random number generator 15 generates a random integer x in the range of 1-n and outputs the random integer x to the control device, the control device selects the delay amount τ x according to the random integer x, sends a trigger signal after adding the delay τ 1 to a preset light-emitting time, and the corresponding driver 112 receives the trigger signal and drives the laser 111-1 to send a laser pulse signal, thereby implementing randomness of the light-emitting time by a light-emitting delay random scheme. Further, the laser transmitter 11 includes a plurality of lasers 111, a laser 111-1, a laser 111-2, a laser 111-3 … …, and a laser 111-n, wherein each laser 111 has a predetermined light emitting time. The random number generator 15 generates a random light emission delay τ or a random integer x, from which the control device 12 determines the delay of the light emission timing of each laser 111. Corresponding to the laser 111-1, the control device 12 sends a trigger signal after adding a delay τ 1 to a preset light-emitting time, and the corresponding driver 112 receives the trigger signal and drives the laser 111-1 coupled with the trigger signal to send a laser pulse signal; corresponding to the laser 111-2, the control device 12 sends a trigger signal after adding a delay τ 2 to a preset light-emitting time, and the corresponding driver 112 receives the trigger signal and drives the laser 111-2 coupled with the trigger signal to send a laser pulse signal; corresponding to the laser 111-3, the control device 12 sends a trigger signal after adding a delay τ 3 to a preset light-emitting time, and the corresponding driver 112 receives the trigger signal and drives the laser 111-3 coupled with the trigger signal to send a laser pulse signal; and so on. The above operations are repeated for the next time of flight measurement for each laser. As shown in fig. 5, the solid line pulse is a preset light-emitting time, and a delay τ is added to the preset light-emitting time, so that the actual light-emitting time of each laser is random. The value of τ may be positive or negative, for example, a positive value indicates that the actual light emitting time is delayed from the preset light emitting time, as shown by the first laser pulse of laser 111-3 and laser 111-n in fig. 5, and the actual light emitting time indicated by the dashed line pulse is later than the preset light emitting time indicated by the solid line pulse; a negative value indicates that the actual light emission timing is advanced from the preset light emission timing, such as the first laser pulse of laser 111-1 and laser 111-2 in fig. 5, and the actual light emission timing indicated by the dashed line pulse is advanced from the preset light emission timing indicated by the solid line pulse.

Further, the time delay τ decreases the spatial correlation of the interference point, and it is expected that the larger the value (absolute value) of the time delay τ, the lower the spatial correlation of the interference point. In a lone point discrimination algorithm, the distance between each point and an adjacent point or the average value of the distances between each point and a plurality of adjacent points in a point cloud can be calculated, a correlation distance threshold value is set, and if the distance between a certain point and the adjacent point is greater than the threshold value, the point is judged as an interference point and filtered. Therefore, the correlation distance threshold should be greater than the distance between the real data points and less than the possible distance between the interference points, and the larger the value of τ is, the larger the spatial distance between the interference points is, and the corresponding correlation distance threshold may be increased accordingly.

In fig. 5, each laser emits two detection pulses in one time of flight measurement, but the present invention is not limited thereto, and may also emit one detection pulse, or emit three or more detection pulses, which are all within the scope of the present invention.

The control device 12 can adjust the emitting time of each detection pulse according to the timing random number, and can also directly adjust the time interval between double pulses in one detection beam, which is not described herein again.

According to another embodiment of the present invention, the control device 12 adjusts the light emitting sequence of the plurality of lasers according to the timing random number. Described in detail below with reference to fig. 6.

Fig. 6a shows a schematic representation of the sequential emission of lasers, in which the lidar 10 is detecting and has a lidar 10' as a source of interference in the vicinity. For convenience of introduction, the detection field of view is divided into a two-dimensional grid, wherein each square represents a sub-field of view, and the horizontal rows and vertical columns of the grid each comprise a plurality of sub-fields of view. For example, the laser emitting device 11 includes a row of 5 lasers 111, the detecting device 13 includes a row of 5 detectors corresponding to the 5 lasers 111, the 5 lasers 111 have a predetermined light emitting sequence, and the detectors corresponding thereto sequentially detect. When the laser radar 10 performs ranging, the lasers 111 in the same column emit light sequentially, as shown in the sequence 1-2-3-4-5 in fig. 6a, and the corresponding detectors receive light sequentially. If the interference source lidar 10' exists, the detection light emitted in the sequence of a-b-c-d-e, the sequence of the detection fields of the lidar 10 and the lidar 10' are consistent, and as shown in fig. 6a, echoes generated by the detection light emitted by the lidar 10' may be received by the detector of the lidar 10 in the same sequence, so that spatial correlations exist between a plurality of interference points and real points measured by the detector of the lidar 10, and the interference points are difficult to filter.

Fig. 6b shows a random interference diagram of the lighting sequence of the third embodiment of the present invention, when the laser radar 10 is in the ranging state, the multiple lasers 111 in the same column emit light in the order of 3-5-1-2-4, and the corresponding detectors receive light in the order of 3-5-1-2-4. If there is an interference source lidar 10', the detection light emitted in the order of a-b-c-d-e, or the reflected light generated at a target object, as shown in fig. 6b, may be received by the detector 131 in a different order, and there is no spatial correlation between the interference points measured by the detector 131 and it is easy to filter out the interference points.

Thus, for n lasers, the random number generator 15 may generate a random sequence of integers at a time, and the control means 12 then controls the n lasers to emit probe pulses in accordance with the random sequence of integers.

The random emission sequence, i.e. the random emission sequence of the plurality of lasers, corresponds to a larger delay in the emission time. For example, the interference sources emit light in the order of 1-2-3-4-5, the laser radar emits light in the order of 3-5-1-2-4, even if the interference signals are received on each detector, the 5 th detector of the laser radar receives the interference signals generated by the 2 nd light emission of the interference sources, the 4 th detector receives the interference signals generated by the 5 th light emission of the interference sources, the time intervals of the 2 nd light emission and the 5 th light emission of the interference sources are greatly different, the distances between two interference points caused by the interference signals received by the adjacent 4 th detector and the 5 th detector are also greatly different, and the two interference points are easily exposed to be space isolated points.

In summary, the random light-emitting scheme includes four schemes, i.e., random light-emitting time delay, random light-emitting sequence, and random light-emitting interval, and the four schemes can be combined for use, for example, the random light-emitting sequence and the random light-emitting time are combined, so that the spatial correlation of each interference point can be further reduced. It will be understood by those skilled in the art that the random light emitting scheme is described above by way of the preferred embodiment, and it is within the scope of the present invention to control the light emitting time of the laser based on the timing random number.

The description of the module configuration of the laser radar that realizes the above random light emission scheme is continued by the embodiment four/five/six.

Fig. 7 shows a schematic diagram of an arrangement of a plurality of lasers, and the laser emitting device 11 includes a plurality of lasers 111, as indicated by dots in fig. 7, and the plurality of lasers 111 are fixed on one or more circuit boards, and different line density distributions are obtained by the number of lasers mounted on the circuit boards and the mounting positions of the circuit boards. The random light emitting scheme of the utility model can be controlled independently for each row of lasers; it is also possible to have all lasers as a whole, each laser emitting light at a random time relative to the others.

Fig. 8 shows a schematic diagram of a lidar module according to a fourth embodiment of the present invention, wherein the laser transmitter 11 includes a plurality of lasers 111-1, 111-2, …, 111-n and drivers 112-1, 112-2, …, 112-n coupled in the same number as the lasers in one-to-one correspondence, and further, the lidar 10 includes random number generators 15-1, 15-2, …, 15-n in the same number as the lasers 111 in one-to-one correspondence. In the ranging state of the laser radar 10, the control device 12 generates a trigger signal based on a timing random number generated by a random number generator 15, the driver 112 corresponding thereto drives the coupled laser 111 to emit a laser pulse signal according to the trigger signal, and so on, and finally each random number generator 15 corresponds to one driver and one laser, so that random lighting time, random lighting delay and random lighting interval can be realized. Further, the control device 12 may also control the sequence of the plurality of trigger signals based on the plurality of timing random numbers, and then drive the coupled lasers 111 to emit light in a random sequence through the corresponding drivers 112, so as to implement a scheme of random light emitting sequence. To further reduce interference, multiple random lighting schemes may be used in combination.

Fig. 9 shows a schematic diagram of a laser radar module according to a fifth embodiment of the present invention, wherein the laser emitting device 11 includes a plurality of lasers 111-1, 111-2, …, 111-n and drivers 112-1, 112-2, …, 112-n coupled in the same number and in one-to-one correspondence with the lasers, and further, the laser radar 10 includes a random number generator 15. In the ranging state of the laser radar 10, the control device 12 generates a plurality of trigger signals based on a plurality of timing random numbers generated by the random number generator 15, and the plurality of drivers 112 drive the coupled lasers 111 to emit laser pulse signals according to the corresponding trigger signals, so that any one of four schemes of random light emitting time, random light emitting time delay, random light emitting interval and random light emitting sequence or a scheme of mutual combination can be realized.

Fig. 10 shows a lidar module diagram according to a sixth embodiment of the present invention, and the laser transmitter 11 includes a plurality of lasers 111 and drivers 112 coupled in the same number as the lasers 111 in a one-to-one correspondence, and the plurality of lasers 111 and the drivers 112 are grouped, for example, into a group (shown as a group by a dashed box in fig. 7) according to a row of the lasers 111 shown in fig. 7 and the corresponding drivers 112, such as the first group, … and the nth group shown in fig. 10, where the correlation of the information points measured by the lasers 111 in each group is high, and thus the lasers in each group can be independently controlled. The laser radar 10 comprises a plurality of random number generators 15 corresponding to grouping numbers, timing random numbers generated by each random number generator 15 correspond to one group of lasers 111 and drivers 112, and any one or combination of four schemes of random light-emitting time, random light-emitting time delay, random light-emitting interval and random light-emitting sequence can be realized.

The scheme of random light emission is introduced through 6 preferred embodiments, so that interference points interfering with the laser radar do not have spatial correlation, and interference signals can be distinguished and filtered easily. In order to further improve the anti-interference effect, a random light-emitting scheme and a multi-pulse coding scheme can be combined, and the echo signals are identified by judging whether the codes of the echo signals are the same as the codes of the transmitted pulse sequences.

The description of the random light emitting scheme and the multi-pulse coding scheme is continued by examples seven and eight.

According to a preferred embodiment of the present invention, the control device 12 is further configured to control the driver 112 to drive the coupled laser 111 to emit a laser pulse sequence with multi-pulse coding, including timing coding, amplitude coding and/or pulse width coding.

Specifically, the detection light emitted by the laser 111 is a pulse sequence including N pulses, where N is an integer greater than or equal to 2, i.e., multiple pulses.

Fig. 11 shows a timing chart of random combination of light-emitting timings and multi-pulse coding according to embodiment seven of the present invention, in which, taking N ═ 2, that is, double pulses as an example, for the laser 111-1, the random number generator 15 generates two timing random numbers: t11 and t12, where t11 is the random light emission time of the first pulse and t12 is the random light emission time of the second pulse. t11 and t12 are both random numbers, so that the timing interval t12-t11 of the double pulse also has randomness. Similarly, the two pulse emitting time t21 of the laser 111-2 and the two pulse emitting time tn1 and tn2 of the t22 … … laser 111-n are random numbers, and the timing interval t12-t11 ≠ t22-t21 ≠ t32-t31 ≠ … … ≠ tn2-tn1 of the double pulse. When N > 2, the laser pulse train includes a plurality of laser pulses, for example, a first pulse, a second pulse, … …, and an nth pulse, and the light emission timings of the plurality of laser pulses are all based on a timing random number, and the timing intervals of the leading edges of the plurality of pulses are made random. Similarly, the timing intervals of a plurality of pulses can be directly set by adopting a scheme of random light-emitting intervals, and the same random effect can be realized. In contrast to the random approach of the emission instants alone, the data processing device 14 can recognize the echo signals from the time-sequence code.

Fig. 12 shows a timing chart of randomly combining the light-emitting delay with multi-pulse coding according to the eighth embodiment of the present invention, in a manner of adding a random event jitter to a fixed light-emitting interval, taking a double pulse as an example, setting the light-emitting time of two fixed pulses for each laser 111, and adding a random delay τ to both light-emitting time instants to make the pulse front edge of the first pulse random, i.e. randomize the light-emitting time; the leading edge intervals of the second pulse and the first pulse are also random, i.e., the pulse timing interval is encoded. This is another implementation of the time-sequential coding of the multi-pulse coding, from which the data processing device 14 can identify the echo signals.

The encoding is a sequence of laser pulses with time intervals, which may be referred to as time-sequential encoding. It may also be a pulse sequence that is pulse intensity modulated in time sequence, which may be called amplitude coding, or a combination of the two coding methods, that is, a pulse sequence that is pulse intensity modulated with a gap in time sequence. In addition, the pulse width can be changed based on the time sequence random number, and the pulse width coding can be realized. By combining these three kinds of encoding, it is possible to randomize the timing interval of the multiple pulses, the width of each pulse, and the amplitude of each pulse, and the data processing device 14 can recognize the echo signal more easily. Specifically, the laser emitting device 11 adopting multi-pulse coding takes the emitted pulse coding as a first coding, the detecting device 13 obtains a second coding of the echo pulse sequence after receiving the echo, the data processing device 14 judges whether the second coding is the same as the first coding, and when the second coding is the same as the first coding, the echo is taken as an echo signal of the coded pulse sequence. Because the transmitted pulse code has randomness, the echo pulse is easy to identify and filter interference, and the anti-interference effect is improved.

The amplitude encoding and pulse width encoding in multi-pulse encoding is mainly based on driver implementation, as further described below.

Fig. 13 shows a structural diagram of a multi-pulse coded driver, the driver includes a plurality of charging units and an energy storage device, when a switch TRIGGER signal (TRIGGER) controls a switch to be turned off, the charging units sequentially charge the energy storage device under the control of switch control signals (GATE1, GATE2, …, GATEN). After charging, the switch TRIGGER signal (TRIGGER) controls the switch to close, and the energy storage device starts to discharge, so that the laser emits laser pulses.

FIG. 14 illustrates a timing diagram of a multi-pulse encoded control signal and a switch TRIGGER signal, the switch TRIGGER signal (TRIGGER) being triggered at the end of the switch control signal (GATE1, GATE2, …, GATEN), such as the falling edge of the switch TRIGGER signal (TRIGGER) triggered by the falling edge of the timing sequence of the switch control signal (GATE1, GATE2, …, GATEN) illustrated in FIG. 14; if the switch TRIGGER signal (TRIGGER) end is the rising edge of the timing signal, the rising edge is used as the TRIGGER timing of the switch control signal to ensure that the emission process is started after the charging is finished, and the next charging-emission process can be started immediately after the previous charging and light-emitting process is finished.

In fig. 14, the switch control signals (GATE1, GATE2, …, GATEN) are of equal temporal width, thus ensuring that the pulse widths in the transmitted pulse train are substantially identical. In addition, control of the strength of the transmitted pulses may be achieved by controlling the width of the switch control signal in different pulse sequences. For example, if the switch control signal GATE1 and the switch control signal GATE2 have different signal durations, the amount of charge in the energy storage device, and thus the intensity of the single pulse emitted, will be different. According to different switch control signal durations, the control over the transmission pulse width can be controlled, the echo signals can be distinguished, and interference among different transmission signal sequences is avoided.

Fig. 15 shows another structural diagram of a multi-pulse coded driver, in which a plurality of energy storage devices are connected with a power supply, each energy storage device is connected with a control switch, and the control switches are responsible for controlling the on-off of the energy storage devices and the laser. When a control switch between one energy storage device and the laser is closed, the charge stored in the energy storage device drives the laser to emit laser pulses.

The unit switches in fig. 15 are independent of each other, and the control switches are independently controlled by the control unit, respectively, and at the same time in time sequence, the control unit can control the control switches to be independently opened or closed. When there are multiple control switches closed at the same time, the energy of the emitted laser pulse is the sum of the energies of several energy storage devices. By simultaneously closing a plurality of control switches at the same time to emit high energy pulses, detection of distant objects can be achieved. The pulse shape emitted in time sequence can be controlled by controlling the number and time points of the control switches closed in time sequence. For example, at a certain time, only 1 control switch is closed, and the intensity of the pulse emitted at that time is 1 unit, while at a subsequent time, N control switches are closed, and the intensity of the pulse emitted at the corresponding time is N units. The timing and intensity of the transmitted pulses can be controlled by the control unit controlling the number of switches closed at different times.

In summary, the timing, amplitude and pulse width of the laser pulses can be encoded by controlling the driver. The echo signal is identified by judging whether the echo code is the same as the code of the laser pulse sequence, so that the anti-interference effect is further improved.

The utility model also provides a range finding method 100, as shown in fig. 16, the method includes:

in step S101: generating a time sequence random number;

in step S102: controlling at least one driver of the laser emitting device to drive the coupled laser to emit a laser pulse signal based on the time sequence random number;

in step S103: receiving an echo signal of the laser pulse signal reflected by a target object; and

in step S104: and determining the distance information of the target object based on the emission time of the laser pulse signal and the time of receiving the echo signal.

According to an aspect of the utility model, still include: and calculating the correlation of the plurality of distance information, and judging the distance information with the correlation lower than a preset value as an interference signal.

According to an aspect of the present invention, wherein the step S102 includes: and controlling the emission time of the laser for emitting the laser pulse signal and/or controlling the time interval between adjacent laser pulses based on the time sequence random number.

According to an aspect of the present invention, wherein the step S102 includes: controlling a light emitting sequence of the plurality of lasers based on the timing random number.

According to an aspect of the present invention, wherein the step S102 includes generating the timing random number by:

randomly extracting from a pre-stored random number table;

generating based on the clock phase;

generating based on the system temperature; and

generated by a linear feedback shift register.

The utility model also provides a laser radar 20, as shown in FIG. 17, include: laser emitting means 21, control means 22, detection means 23 and data processing means 24, wherein,

the control device 22 is configured to generate a trigger signal based on a timing random number;

the laser emitting device 21 comprises at least one laser 211 and a driver 212 coupled to the laser 211, wherein the driver 212 is configured to drive the laser 211 to emit a laser pulse signal according to the trigger signal;

the detection device 23 is configured to receive an echo signal of the laser pulse signal reflected by the target object and convert the echo signal into an electrical signal; and

the data processing device 24 determines the distance information of the target object based on the time of transmitting the laser pulse signal and the time of receiving the echo signal,

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lidar comprising: laser emitting device, control device, detecting device and data processing device, characterized in that,

the data processing device is configured to determine distance information of the target object based on a time at which the laser pulse signal is emitted and a time at which the echo signal is received.

2. The lidar of claim 1, further comprising a random number generator configured to generate the timing random number, the control device coupled to the random number generator to receive the timing random number.

3. The lidar of claim 1, wherein the data processing apparatus is configured to calculate a correlation of a plurality of range information and filter range information having a correlation below a predetermined value as the interference signal.

4. The lidar of claim 2, wherein the laser has a plurality of preset firing moments, the control device configured to: and selecting one light-emitting time from the plurality of preset light-emitting times as the trigger time of the driving signal according to the time sequence random number.

5. The lidar of claim 2, wherein the laser has a predetermined firing time, the control device configured to: and delaying or advancing the preset light-emitting time as the trigger time of the driving signal according to the time sequence random number.

6. The lidar of claim 2, wherein the laser is configured to emit a plurality of pulses, and wherein the control device is configured to adjust a time interval between trigger signals corresponding to two adjacent pulses according to the timing random number.

7. The lidar of any of claims 2-6, wherein the laser emitting device comprises a same number of lasers and a plurality of drivers, the lidar comprising a same number of random number generators as the lasers.

8. The lidar of any of claims 2-6, wherein the laser emitting device comprises a plurality of lasers and a plurality of drivers coupled to the lasers one-to-one, the control device is coupled to the plurality of drivers, and the timing random number corresponds to a light emitting sequence of the plurality of lasers.

9. The lidar of any of claims 2-6, wherein the laser emitting device comprises a plurality of groups of lasers, each group of lasers comprising a plurality of lasers and a plurality of drivers coupled to the lasers one-to-one, the lidar further comprising a plurality of random number generators corresponding to the plurality of groups of lasers, each random number generator generating a timing random number corresponding to a lighting sequence of the group of lasers corresponding thereto.

10. The lidar of any of claims 2-6, wherein the control apparatus is further configured to control the driver to drive the laser to emit a sequence of laser pulses having multi-pulse coding including timing coding, amplitude coding, and/or pulse width coding.

11. The lidar of any of claims 2-6, wherein the random number generator is a pseudo-random number generator, the timing random number generated by one or more of: randomly extracting from a pre-stored random number table;

generating based on the clock phase;

generating based on the system temperature; and

generated by a linear feedback shift register.

12. A lidar comprising: laser emitting device, control device, detecting device and data processing device, characterized in that,