CN115236649A - Ultrasonic indoor three-dimensional positioning system and method - Google Patents

Abstract

The invention discloses an ultrasonic indoor three-dimensional positioning system and method. The ultrasonic indoor three-dimensional positioning system includes a central control module, a transmitting module and a receiving module, the central control module includes a central control unit, a sound velocity correction module and a wireless communication module, and the transmitting module includes a transmitting control unit, an ultrasonic transmitting module. and a wireless communication module, the receiving module includes a receiving processing unit, a wireless communication module and an ultrasonic receiving module; the ultrasonic transmitting module adopts a PMUT with a directivity of 180°, including one or more low-frequency ultrasonic transducers of different frequencies. The ultrasonic transducer is composed of a regional positioning ultrasonic transducer and a positional positioning ultrasonic transducer composed of more than 3 high-frequency ultrasonic transducers of different frequencies. The ultrasonic receiving module adopts a broadband microphone. The ultrasonic indoor three-dimensional positioning system can realize accurate three-dimensional positioning in a wide range of space, and the positioning accuracy reaches the millimeter level.

Description

Ultrasonic indoor three-dimensional positioning system and method

technical field

The invention belongs to the technical field of spatial positioning, and in particular relates to an ultrasonic indoor three-dimensional positioning system and method.

Background technique

Indoor positioning refers to the realization of position positioning in the indoor environment, mainly using wireless communication, base station positioning, inertial navigation positioning, motion capture and other technologies to integrate to form a set of indoor position positioning system, so as to realize the positioning of people and objects in indoor space. Location monitoring. Indoor positioning technology has broad application prospects, and can be combined with mobile Internet, cloud computing, big data, high-performance computers and other technologies to form new comprehensive applications, in space infrastructure services, disaster and emergency rescue, public safety, medical and health and elderly care services and other fields to expand the scope of application, and promote technological innovation and business model innovation.

At present, commonly used indoor positioning technologies include Wi-Fi, Bluetooth, infrared, RFID, ZigBee and ultrasonic positioning. Among them, ultrasonic positioning mainly adopts reflective ranging (after transmitting ultrasonic waves and receiving echoes generated by the measured object, the distance between the two is calculated according to the time difference between the echoes and the transmitted waves), and is determined by algorithms such as triangulation positioning. the position of the object. The ultrasonic positioning system consists of a main range finder and several electronic tags. The main range finder is placed in the space to be positioned, and each electronic tag is placed in a fixed position in the indoor space. First, the main range finder sends ultrasonic signals to each electronic tag. After the electronic tag receives the signal, it reflects and transmits it to the main range finder, so that the distance between each electronic tag and the main range finder can be determined, and the positioning coordinates can be obtained. The overall positioning accuracy of ultrasonic positioning is high, which can reach centimeter level. The disadvantage is that the ultrasonic wave is attenuated and interfered during the transmission process, which affects the effective range of its positioning and reduces the positioning accuracy.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an ultrasonic indoor three-dimensional positioning system, which solves the technical problems of limited positioning range, weak stability, and positioning accuracy easily affected by attenuation and interference in the ultrasonic positioning system. The system can achieve accurate three-dimensional positioning in a wide range of space, and the positioning accuracy can reach the millimeter level.

Another object of the present invention is to provide an indoor three-dimensional ultrasonic positioning method based on the ultrasonic indoor three-dimensional positioning system.

To achieve the above object, the present invention adopts the following technical solutions:

An ultrasonic indoor three-dimensional positioning system is characterized in that, comprising a central control module, a transmitting module and a receiving module, wherein:

The central control module includes a central control unit, a sound velocity correction module and a wireless communication module; the wireless communication module transmits a wireless signal to the area to be located, and communicates with the transmitting module and the receiving module, and the wireless signal includes a clock, a sound velocity And ultrasonic transducer coordinate information; Described central control unit includes micro control unit (Microcontroller Unit; MCU), clock source and storage unit, calculation and storage include information such as speed of sound, ultrasonic transducer space coordinates, etc., and control wireless communication ;

The transmitting module includes a transmitting control unit, an ultrasonic transmitting module and a wireless communication module; the ultrasonic transmitting module includes a regional positioning ultrasonic transducer and a position positioning ultrasonic transducer arranged in the space to be located. The ultrasonic transducer is composed of one or more low-frequency ultrasonic transducers of different frequencies, and the position positioning ultrasonic transducer is composed of more than 3 high-frequency ultrasonic transducers of different frequencies; the emission control unit It includes a micro control unit (MCU), a clock source, a storage unit and an ultrasonic transducer drive module, which drives the regional positioning or position positioning ultrasonic transducer to transmit ultrasonic waves to the space to be positioned, and the wireless communication module communicates with the central control module ;

The receiving module includes a receiving processing unit, a wireless communication module and an ultrasonic receiving module, the ultrasonic receiving module is a broadband microphone, and receives the ultrasonic signal from the transmitting module, and the wireless communication module receives the wireless signal from the central control module; the The receiving and processing unit includes a signal processing module, an MCU and a storage unit, and the data processing and operation procedures executed include determining the starting point of the ultrasonic emission time through wireless signals, and amplifying, filtering, collecting, and performing time-frequency conversion processing and processing on the received ultrasonic signals. Take envelope processing, extract the time of flight (TOF, Time of flight) of ultrasonic waves from transmission to reception from the processed time domain signals, determine the ultrasonic transducers involved in positioning from the frequency domain signals, and obtain them from wireless signals For the coordinate information of the ultrasonic transducer, the current area is determined by the area positioning ultrasonic transducer, and the position of the receiving module is calculated using the time-of-flight and the coordinate information of the position-positioning ultrasonic transducer.

The sound velocity correction module includes a temperature and humidity measuring unit and a pressure measuring unit, which are used to measure the ambient temperature, humidity and atmospheric pressure, so as to correct the atmospheric sound velocity of the space to be positioned.

The area positioning ultrasonic transducer can be selected according to the size of the space to be positioned, in particular, the area positioning ultrasonic transducer can be omitted when the space to be positioned is small and there is no need to divide the area; and when the space to be positioned is large , a combination of multiple low-frequency ultrasonic transducers of different frequencies can be selected as the regional positioning ultrasonic transducer, and the low-frequency ultrasonic transducers of different combinations correspond to different spatial regions delimited in the space to be positioned. In a certain spatial area, more than two groups of the same area positioning ultrasonic transducers can also be arranged at different positions, so as to ensure that the area positioning signal can completely cover the area.

Preferably, the frequency range of the low-frequency ultrasonic transducer is usually 20KHz-50KHz, and as an area positioning transducer, its propagation distance is usually greater than 10 meters. The frequency range of the high-frequency ultrasonic transducer is usually 50K-100KHz, and as a position positioning transducer, its propagation distance is usually greater than 5 meters.

Preferably, the low-frequency or high-frequency ultrasonic transducer is a piezoelectric micro-machined ultrasonic transducer (Piezoelectric Micro-machined Ultrasonic Transducer, PMUT). The directivity of the PMUT can usually reach 180°, thus covering the entire space or area to be positioned.

In the present invention, an omnidirectional broadband microphone is used in the ultrasonic receiving module, and its directivity is 180°. The frequency range of the broadband microphone can at least cover the frequency range of the low-frequency or high-frequency ultrasonic transducer. Preferably, there are more than two broadband microphones, which are arranged in different positions of the receiving module.

Further, the wireless communication modules of the central control module, the transmitting module and the receiving module may be composed of radio broadcasting, Wi-Fi, ZigBee, Bluetooth and the like.

Based on the ultrasonic indoor three-dimensional positioning system, the present invention also provides an indoor three-dimensional ultrasonic positioning method, comprising: the central control module, the central control unit, drives the sound speed correction module to collect and calculate the sound speed correction information, and drives the wireless communication module to transmit wireless signals, It includes clock, speed of sound and ultrasonic transducer coordinate information; after the transmitting module receives the wireless signal containing the transmitting instruction from the central control module, the transmitting control unit drives the area positioning ultrasonic transducer and the position positioning ultrasonic transducer to the undetermined The ultrasonic signal is transmitted from the bit space; the receiving module receives the ultrasonic signal from the transmitting module through the broadband microphone, and receives the wireless signal from the central control module through the wireless communication module. Position information; the receiving and processing unit determines the starting point of the ultrasonic transmission time through wireless signals, processes the ultrasonic signal received by the broadband microphone, and extracts the time of flight (TOF, Time of flight) of the ultrasonic wave from transmission to reception from the processed time domain signal. , from the frequency domain signal to determine the regional positioning ultrasonic transducer and position positioning ultrasonic transducer involved in the positioning, and obtain its position coordinate information from the wireless signal, according to the ultrasonic propagation TOF and the position coordinate of the ultrasonic transducer, calculate Receive the location information of the module.

Specifically, the method for indoor three-dimensional ultrasonic positioning includes the following steps:

(1) The central control unit drives the sound speed correction module to collect atmospheric temperature, humidity and air pressure information, and corrects the sound speed, drives the wireless communication module to transmit wireless signals to the space to be located, and communicates with the transmitting module and the receiving module. It contains the atmospheric sound velocity in the space to be located, the clock driving the ultrasonic emission, and the coordinate information of the ultrasonic transducer;

(2) After the transmitting module receives the wireless signal containing the transmitting instruction from the central control module, the transmitting control unit drives the area positioning and position positioning ultrasonic transducer to transmit the ultrasonic signal to the space to be located;

(3) the receiving module receives the ultrasonic signal from the transmitting module through the broadband microphone, and receives the wireless signal from the central control module through the wireless communication module, and the wireless signal includes the same clock transmitted by the ultrasonic wave, the atmospheric sound speed and the position information of the ultrasonic transducer; The receiving and processing unit reads the atmospheric sound speed in the current space, the time starting point of ultrasonic transmission, and the position coordinate information of each ultrasonic transducer from the received wireless signal and stores it, and amplifies the ultrasonic signal received by the broadband microphone. Pass filtering, and finally sample and store;

(4) The receiving and processing unit transforms the ultrasonic time domain signal into a frequency domain signal by performing discrete Fourier transform on the digital signal obtained by sampling the ultrasonic signal; from the frequency domain signal, it is determined which frequency ultrasonic transducers are involved in this positioning. , and read the position coordinate information of the ultrasonic transducer in the storage unit, and then determine the current area by the regional positioning ultrasonic transducer; obtain the envelope of the time-domain signal through Hilbert transformation on the time-domain signal, The time-of-flight TOF of the ultrasonic waves emitted by the ultrasonic transducers from the transmission to the reception of the ultrasonic waves emitted by the positioning ultrasonic transducers at each position participating in this positioning is obtained through the envelope of the time-domain signal, and three values with smaller values (closest to the receiving module) are selected from the TOF time. Used to solve the position of the receiving module;

(5) Use the ultrasonic wave propagation TOF and the position coordinates of the position positioning transducer to calculate the position information of the receiving module, the formula is as follows:

In the formula: the coordinates of the receiving module are (x, y, z), and the three-dimensional coordinates of the three position positioning transducers are (x ₁ , y ₁ , z ₁ ), (x ₂ , y ₂ , z ₂ ), (x ₃ , y ₃ , z ₃ ), c is the speed of sound in the atmosphere, t ₁ , t ₂ , and t ₃ are the time-of-flight TOF of the ultrasonic waves emitted by the three position-location transducers from transmission to reception.

Beneficial effects: the present invention can achieve millimeter-level positioning at any position in the indoor space by using an omnidirectional ultrasonic transducer for transmission; using a broadband microphone for reception can simplify the ultrasonic receiving system and improve the versatility of the receiver; at the same time, The invention adopts the combination of the area positioning transducer and the position positioning transducer, which can realize accurate three-dimensional positioning in a large range; meanwhile, the invention can support an infinite number of receiving modules for positioning.

Description of drawings

Fig. 1 is the structural representation of the ultrasonic indoor three-dimensional positioning system of the present invention;

Figure 2 is a schematic diagram of indoor three-dimensional ultrasonic positioning;

Fig. 3 is the time domain signal schematic diagram of the ultrasonic signal received by the receiving module;

FIG. 4 is a schematic diagram of a frequency domain signal of an ultrasonic signal received by a receiving module.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described below are only used to explain the present invention, but not to limit the present invention. The protection scope of the present invention is not limited by the specific embodiments, but is determined by the claims.

As shown in Figure 1, an ultrasonic indoor three-dimensional positioning system includes a central control module, a transmitting module and a receiving module. Wherein, the central control module includes a central control unit, a sound velocity correction module and a wireless communication module; the central control unit includes a Microcontroller Unit (MCU), a clock source and a storage unit, which are used for sound velocity correction, ultrasonic transducers Calculation and storage of spatial coordinates and other information, and control the wireless communication module to achieve communication; the sound velocity correction module mainly includes temperature and humidity measurement units and pressure measurement units, which are used to measure ambient temperature, humidity and atmospheric pressure to correct the space to be positioned. Atmospheric sound speed; the wireless communication module transmits wireless signals including clock information, sound speed information and ultrasonic transducer coordinate information, which can be composed of radio broadcasting, Wi-Fi, ZigBee, Bluetooth, etc.

)个独立空间进行定位。The transmitting module includes a transmitting control unit, a wireless communication module and an ultrasonic transmitting module. The ultrasonic transmitting module is composed of a regional positioning ultrasonic transducer and a position positioning ultrasonic transducer; the regional positioning ultrasonic transducer is composed of one or multiple low-frequency ultrasonic transducers of different frequencies (T ₁ , T 1 , T ₂ , T3...), its frequency range can usually be selected in the range of 20KHz _- 50KHz. The number of ultrasonic transducers for regional positioning can be selected according to the size of the space to be positioned, especially when the space to be positioned is small, the ultrasonic transducers for regional positioning can be omitted; and when the space to be positioned is large, a number of different The combination of the low-frequency ultrasonic transducers of the frequencies is used as a regional positioning ultrasonic transducer; the low-frequency ultrasonic transducers of different combinations correspond to different spatial regions delimited in the space to be positioned. For example, when the ultrasonic transducers of every 3 frequencies of the 31 low-frequency ultrasonic transducers with frequencies of 20KHz, 21KHz, 22KHz, ..., 50KHz are selected as a group of regional positioning ultrasonic transducers, the 4495 (combined) number

) independent space for positioning.

The position positioning ultrasonic transducer is composed of a group of high-frequency ultrasonic transducers with different frequencies (S ₁ , S ₂ , S ₃ , S ₄ , S ₅ . selection within the range. The number is usually several to dozens, which are used for the positioning of specific locations in a certain area. According to the technical solution of the present invention, the combination of at least three position-positioning ultrasonic transducers that are not on the same straight line can determine the position of the receiving module in space.

The present invention distinguishes setting area positioning and position positioning ultrasonic transducers, and adopts two kinds of ultrasonic transducers with different frequencies, because low-frequency ultrasonic waves decay slowly in the air and have a larger effective range of propagation, and use low-frequency transducers as The regional positioning transducer can ensure that the receiving module in its area of action can receive the regional positioning ultrasonic signal; while the high-frequency ultrasonic wave attenuates faster in the air, and its scope of action is small, but the positioning accuracy is lower than that of the high-frequency ultrasonic transducer. higher.

The low-frequency or high-frequency ultrasonic transducer is recommended to be a piezoelectric microcomputer ultrasonic transducer (PMUT). In the field of ultrasonic positioning, the direction angle of conventional ultrasonic transducers is usually small, and there is a large blind spot during positioning. The directivity of PMUT can usually reach 180°, thus covering the entire space area to be positioned. PMUT can be selected according to frequency. Generally, the PMUT structure includes a substrate layer, a supporting layer and a structural layer, wherein the structural layer above the supporting layer is usually composed of a piezoelectric layer, an upper electrode, and a lower electrode. The supporting layer and the partially etched structural layer constitute a vibrating film, and the substrate layer After partial etching, a cavity structure corresponding to the vibrating membrane is formed under the support layer, and the vibrating membrane and its corresponding cavity structure constitute a PMUT oscillator. The PMUT vibrating element is driven by the circuit and emits ultrasonic waves of the corresponding frequency.

The emission control unit includes a Microcontroller Unit (MCU), a clock source, a storage unit, an ultrasonic transducer drive module, etc. The emission control unit drives the area or position-positioning ultrasonic transducer to emit ultrasonic waves to the space to be positioned.

The receiving module includes a receiving processing unit, a wireless communication module and an ultrasonic receiving module. As an ultrasonic signal receiver corresponding to the low-frequency or high-frequency ultrasonic transducer in the ultrasonic transmitting module, an omnidirectional broadband microphone is used in the ultrasonic receiving module of the present invention to receive ultrasonic signals of different frequencies from various directions. If a conventional ultrasonic transducer is used as the receiving unit, since the ultrasonic transducer usually has a small bandwidth, more receiving transducers are required to receive ultrasonic signals of a wider frequency band, thereby increasing the complexity and manufacturing of the receiving system. cost, and more receiving ultrasonic transducers will reduce the positioning accuracy. The frequency range of the omnidirectional broadband microphone can at least cover the frequency range of the low frequency or high frequency ultrasonic transducer, usually 20KHz-100KHz, and the directivity of the omnidirectional broadband microphone can usually reach 180°.

The receiving and processing unit includes a circuit, module or chip for amplifying, filtering, collecting and storing ultrasonic signals, an MCU and a storage unit for executing signal or data processing and operation programs. The receiving and processing unit determines the starting point of the transmission time of the ultrasonic transducer through the wireless signal, performs processing such as amplifying, filtering, collecting and time-frequency transformation on the ultrasonic signal, and extracts the flight of the ultrasonic wave from the transmission to the reception from the processed time domain signal. Time of flight (TOF, Time of flight), obtain the coordinate information of the regional positioning ultrasonic transducer and the position positioning ultrasonic transducer in space from the processed frequency domain signal, using the ultrasonic propagation time information and the position of the ultrasonic transducer The coordinate information calculates the position information of the receiving module.

Matching with the central control module, the wireless communication module in the transmitting module and the receiving module can be composed of radio broadcasting, Wi-Fi, ZigBee, Bluetooth and the like. Usually, the wireless communication between the central control module and the transmitting module is two-way communication; the central control module and the receiving module are one-way communication, that is, the wireless communication module in the receiving module is only used to receive wireless signals from the central control module .

Using the above-mentioned ultrasonic indoor three-dimensional positioning system, the method for indoor three-dimensional ultrasonic positioning according to the present invention includes:

The central control unit drives the sound speed correction module to collect and calculate the sound speed correction information, and drives the wireless communication module of the central control module to transmit wireless signals, including the clock, sound speed and ultrasonic transducer coordinate information; the transmission control unit receives the information from the central control module. After containing the wireless signal of the transmission command, the transmission control unit drives the area positioning ultrasonic transducer and the position positioning ultrasonic transducer to transmit the ultrasonic signal to the space to be positioned; the receiving module receives the ultrasonic signal from the transmitting module through the broadband microphone, and communicates wirelessly. The module receives the wireless signal from the central control module. The wireless signal includes the same clock of the ultrasonic transmission, the speed of atmospheric sound and the position information of the ultrasonic transducer. The signal is processed, and the time-of-flight (TOF, Time of flight) of the ultrasonic wave from transmission to reception is extracted from the processed time-domain signal, and the regional positioning ultrasonic transducer and Position the ultrasonic transducer, obtain its position coordinate information from the wireless signal, and calculate the position information of the receiving module according to the ultrasonic propagation TOF and the position coordinate of the ultrasonic transducer.

Specifically, the method for indoor three-dimensional ultrasonic positioning according to the present invention includes the following steps:

(1) The central control unit drives the sound speed correction module to collect information such as atmospheric temperature, humidity and air pressure, and corrects the sound speed. The central control unit drives the wireless communication module to transmit wireless signals to the positioning space, and communicates with the transmitting module and the receiving module. The wireless signal includes the atmospheric sound velocity information in the current positioning space, the clock information of the ultrasonic transmission, and the position information of the ultrasonic transducer. The central control module is installed in the positioning space, and it is necessary to ensure that each sensor of the sound speed correction module can work normally, and at the same time, it is necessary to ensure that the wireless signal is not blocked.

(2) After the transmitting module receives the transmitting instruction contained in the wireless signal from the central control module, the transmitting control unit drives the area positioning and position positioning ultrasonic transducers to transmit ultrasonic signals to the space to be located, wherein the ultrasonic signals are composed of a plurality of different Frequency omnidirectional (180°) ultrasonic transducer generation.

In the specific implementation of the present invention, the transmission control unit and the wireless communication module in the transmission module can be assembled together, the assembled module and the ultrasonic transducer can be installed in the space to be positioned, and the ultrasonic transducer can be connected to the ultrasonic transducer through a wire. The ultrasonic drive port in the transmitting module is connected. During installation, it is necessary to ensure that the ultrasonic waves emitted by the ultrasonic transducer are not blocked, and the arrangement position of the ultrasonic transducer should ensure that the positioning activities outside the area are not affected. Make sure that any three position positioning ultrasound transducers are not on the same line.

A coordinate system is established with a certain point in space as the coordinate origin. Usually, the installation position of the emission control unit can be selected as the coordinate origin to determine the coordinate position of each ultrasonic transducer. Finally, the area information and position coordinate information of the installed ultrasonic transducer are recorded. in the central control module.

(3) The receiving module receives the ultrasonic signal from the transmitting module through the omnidirectional broadband microphone, and receives the wireless signal from the central control module through the wireless communication module. The receiving and processing unit reads and stores the atmospheric sound speed in the current space, the time starting point of ultrasonic transmission and the position coordinate information of each ultrasonic transducer from the received wireless signal. The receiving and processing unit amplifies and band-pass filters the ultrasonic signal received by the omnidirectional broadband microphone, and finally samples and stores it.

The receiving module can usually adopt an integrated design. In order to increase the reliability of positioning, two or more omnidirectional broadband microphones can be arranged in different positions in a receiving module as receiving units, so as to avoid the failure to receive ultrasonic signals due to occlusion. Happening.

(4) The receiving and processing unit transforms the ultrasonic time domain signal into a frequency domain signal by performing discrete Fourier transform on the digital signal obtained by sampling the ultrasonic signal, and determines which frequency ultrasonic transducers are involved in this positioning from the frequency domain signal. , and then determine the current area by the regional positioning ultrasonic transducer, and obtain the spatial coordinates of the above-mentioned ultrasonic transducer by searching the position coordinate information of the ultrasonic transducer in the storage unit, and obtain the time domain signal through Hilbert transform. The envelope of the time-domain signal, through the envelope of the time-domain signal, the time-of-flight TOF of the ultrasonic waves emitted by the ultrasonic transducers for positioning at each position participating in this positioning is obtained from the transmission to the reception, and the smaller value (distance) is selected from the TOF time. The three closest to the receiver module are used to solve for the position of the receiver module.

(5) The position information of the receiving module can be calculated by using the ultrasonic propagation time information and the position coordinate information of the position positioning transducer. The position calculation of the receiving module adopts the following formula:

In the formula: the coordinates of the receiving module are (x, y, z), and the three-dimensional coordinates of the three position positioning transducers are (x ₁ , y ₁ , z ₁ ), (x ₂ , y ₂ , z ₂ ), (x ₃ , y ₃ , z ₃ ), c is the speed of sound in the atmosphere, t ₁ , t ₂ , and t ₃ are the time-of-flight TOF of the ultrasonic waves emitted by the three position-location transducers from transmission to reception.

As shown in Fig. 2, a central control module C is arranged in the area to be located. At the same time, a large space is divided into several subspaces by _a plurality _of transmitting modules Z1, Z2, Z3, and there are ₂ groups in each subspace Area locating transducers (T ₁ T ₂ T ₃ , T ₁ T ₂ T ₄ , T ₁ T ₂ T ₅ , ...) and 8 position locating transducers (S ₁ , S ₂ , S ₃ , ... ) _S8 ). The receiving module R shown in FIG. 2 is located in the area (Z ₁ ) identified by the T ₁ T ₂ T ₃ transducer group, and the receiving module R receives the signals from the transducers T ₁ T ₂ T ₃ , S ₁ , S ₂ , S ₃ , S ₄ ultrasonic signals (Fig. 3), frequency domain signals can be obtained by performing discrete Fourier transform on the received ultrasonic time domain signals (Fig. 4). From the frequency domain signals, three low-frequency signals f ₁ , f ₂ , f ₃ emitted by the area localization ultrasonic transducers T ₁ , T ₂ , T ₃ , and the position localization ultrasonic transducers S ₁ , S ₂ can be obtained. The four high-frequency signals f _S1 , f _S2 , f _S3 , and f _S4 transmitted by , S ₃ and S ₄ , and then obtain the TOF information (TOF _S1 , TOF ) from the time domain signal from the position positioning ultrasonic transducer to the receiving module _S2 , TOF _S3 , TOF _S4 , ...), and finally, the position coordinates of the receiver can be obtained by using at least three coordinate information of the positioning ultrasonic transducer and the corresponding TOF information.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (10)

1. an ultrasonic indoor three-dimensional positioning system, is characterized in that, comprises central control module, transmitting module and receiving module, wherein: The central control module includes a central control unit, a sound velocity correction module and a wireless communication module; the wireless communication module transmits a wireless signal to the area to be located, and communicates with the transmitting module and the receiving module, and the wireless signal includes a clock, a sound velocity and ultrasonic transducer coordinate information; the central control unit includes a micro-control unit, a clock source and a storage unit, calculates and stores information including the speed of sound and the ultrasonic transducer space coordinates, and controls wireless communication; The transmitting module includes a transmitting control unit, an ultrasonic transmitting module and a wireless communication module; the ultrasonic transmitting module includes a regional positioning ultrasonic transducer and a position positioning ultrasonic transducer arranged in the space to be located. The ultrasonic transducer is composed of one or more low-frequency ultrasonic transducers of different frequencies, and the position positioning ultrasonic transducer is composed of more than 3 high-frequency ultrasonic transducers of different frequencies; the emission control unit It includes a micro-control unit, a clock source, a storage unit and an ultrasonic transducer drive module, which drives the regional positioning ultrasonic transducer or the position positioning ultrasonic transducer to transmit ultrasonic waves to the space to be positioned; the wireless communication module and the central control module carry out communication; The receiving module includes a receiving processing unit, a wireless communication module and an ultrasonic receiving module; the ultrasonic receiving module is a broadband microphone, receiving ultrasonic signals from the transmitting module, and the wireless communication module receives wireless signals from the central control module; the The receiving and processing unit includes a signal processing module, a micro-control unit and a storage unit, and the data processing and operation programs executed include: determining the starting point of the ultrasonic emission time through the received wireless signal, and amplifying, filtering, collecting and converting the ultrasonic signal in time and frequency. And take the envelope processing, extract the time-of-flight of the ultrasonic wave from transmission to reception from the processed time-domain signal, determine the ultrasonic transducer involved in positioning from the frequency-domain signal, and obtain the coordinates of the ultrasonic transducer from the wireless signal information, determine the current area according to the area positioning ultrasonic transducer, and use the time of flight and the coordinate information of the position positioning ultrasonic transducer to calculate the position of the receiving module. 2 . The ultrasonic indoor three-dimensional positioning system according to claim 1 , wherein the space to be positioned is not divided into space regions, and the region positioning ultrasonic transducer is omitted. 3 . 3. The ultrasonic indoor three-dimensional positioning system according to claim 1, wherein the regional positioning ultrasonic transducers are more than 2 groups of identical regional positioning ultrasonic transducers arranged at different positions in the delimited space region . 4. The ultrasonic indoor three-dimensional positioning system according to claim 1, wherein the frequency range of the low-frequency ultrasonic transducer is 20KHz-50KHz, and the frequency range of the high-frequency ultrasonic transducer is 50K- 100KHz. 5 . The ultrasonic indoor three-dimensional positioning system according to claim 1 , wherein the low-frequency or high-frequency ultrasonic transducer is a piezoelectric microcomputer ultrasonic transducer, and its directivity is 180°. 6 . 6 . The ultrasonic indoor three-dimensional positioning system according to claim 1 , wherein the frequency range of the broadband microphone is 20KHz～100KHz, and its directivity is 180°. 7 . 7 . The ultrasonic indoor three-dimensional positioning system according to claim 1 , wherein there are more than two broadband microphones, which are arranged in different positions of the receiving module. 8 . 8 . The ultrasonic indoor three-dimensional positioning system according to claim 1 , wherein the wireless communication modules of the central control module, the transmitting module and the receiving module are composed of radio broadcasting, Wi-Fi, ZigBee or Bluetooth. 9 . 9. The method for indoor three-dimensional ultrasonic positioning of the ultrasonic indoor three-dimensional positioning system according to any one of claims 1 to 8, comprising: the central control unit of the central control module drives the sound speed correction module to collect and calculate the sound speed correction information, and drives the wireless communication module. Transmit wireless signals, which include clock, speed of sound and ultrasonic transducer coordinate information; after the transmitting module receives the wireless signal containing the transmitting instruction from the central control module, the transmitting control unit drives the area positioning ultrasonic transducer and the position positioning ultrasonic transducer. The transmitter transmits ultrasonic signals to the space to be located; the receiving module receives the ultrasonic signals from the transmitting module through the broadband microphone, and receives the wireless signals from the central control module through the wireless communication module. The position information of the transducer; the receiving and processing unit determines the starting point of the ultrasonic transmission time through the wireless signal, processes the ultrasonic signal received by the broadband microphone, and extracts the flight time of the ultrasonic wave from transmission to reception from the processed time domain signal. Determine the area positioning ultrasonic transducer and position positioning ultrasonic transducer involved in the positioning in the domain signal, and obtain its position coordinate information from the wireless signal, and calculate the receiving module according to the ultrasonic propagation time of flight and the position coordinate of the ultrasonic transducer. location information. 10. The method for indoor three-dimensional ultrasonic positioning according to claim 9, characterized in that, comprising the steps of: (1) The central control unit drives the sound speed correction module to collect atmospheric temperature, humidity and air pressure information, and corrects the sound speed, drives the wireless communication module to transmit wireless signals to the space to be located, and communicates with the transmitting module and the receiving module. It contains the atmospheric sound speed in the current positioning space, the clock driving the ultrasonic emission, and the coordinate information of the ultrasonic transducer; (2) After the transmitting module receives the wireless signal containing the transmitting instruction from the central control module, the transmitting control unit drives the area positioning and position positioning ultrasonic transducer to transmit the ultrasonic signal to the space to be located; (3) The receiving module receives the ultrasonic signal from the transmitting module through the broadband microphone, and receives the wireless signal from the central control module through the wireless communication module, and the wireless signal includes the clock of the ultrasonic transmission, the speed of atmospheric sound and the position information of the ultrasonic transducer; The processing unit reads the atmospheric sound speed in the current space, the time starting point of ultrasonic transmission, and the position coordinate information of each ultrasonic transducer from the received wireless signal and stores it, and amplifies and bandpasses the ultrasonic signal received by the broadband microphone. Filter, finally sample and store; (4) The receiving and processing unit transforms the ultrasonic time domain signal into a frequency domain signal by performing discrete Fourier transform on the digital signal obtained by sampling the ultrasonic signal, and determines which frequency ultrasonic transducers are involved in this positioning from the frequency domain signal. , and read the position coordinate information of the ultrasonic transducer in the storage unit, and then determine the current area by the regional positioning ultrasonic transducer; obtain the envelope of the time-domain signal through Hilbert transformation on the time-domain signal, The time-of-flight TOF of the ultrasonic waves emitted by the ultrasonic transducers from each position positioning ultrasonic transducer participating in this positioning from transmission to reception is obtained through the envelope of the time-domain signal, and three smaller values are selected from the TOF time to solve the receiving module Location; (5) Calculate the position information of the receiving module using the time-of-flight TOF of ultrasonic propagation and the position coordinates of the position positioning transducer. The formula is as follows:

In the formula: the coordinates of the receiving module are (x, y, z), and the three-dimensional coordinates of the three position positioning transducers are (x ₁ , y ₁ , z ₁ ), (x ₂ , y ₂ , z ₂ ), (x ₃ , y ₃ , z ₃ ), c is the speed of sound in the atmosphere, t ₁ , t ₂ , and t ₃ are the time-of-flight TOF of the ultrasonic waves emitted by the three position-location transducers from transmission to reception.

Images