A sonic outdoor positioning and correction system and method

Abstract

Specifically, the present invention is an acoustic wave outdoor positioning and correction system and method, comprising: an acoustic wave transmitting and receiving module, comprising multiple acoustic wave base stations and at least one working tag, for obtaining the original distance data from the working tag to each acoustic wave base station; at least one reference tag with a known position, for providing a benchmark for changes in environmental parameters; a data processing module, for performing the following steps: a. calculating the measured position coordinates of the reference tag and the measured position coordinates of the working tag based on the original distance data; b. calculating the three-dimensional space deviation proportional coefficient based on the actual position coordinates of the reference tag and its measured position coordinates; c. correcting the measured position coordinates of the working tag using the deviation proportional coefficient to obtain the corrected coordinates; and a positioning output module, configured to output the corrected position coordinates of the working tag as the coordinate positioning result. The advantages of the present invention are: significantly improving the accuracy and reliability of acoustic wave positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic wave positioning, in particular to an acoustic wave outdoor positioning and correction system and method. Background Art

[0002] Due to its low cost and ease of implementation, acoustic positioning technology has been widely used in indoor positioning, robotic navigation, smart warehousing, and other fields. Its basic principle is to calculate the distance based on the propagation time difference of the acoustic signal between the tag and the base station, and then combine it with a positioning algorithm to determine the target's location.

[0003] However, acoustic positioning technology faces significant challenges in practical application. Acoustic signals are susceptible to interference from environmental factors. For example, ambient noise can cause signal distortion. Changes in parameters like temperature, humidity, and wind speed can affect the speed of sound waves (the theoretical speed of sound is approximately 344 meters per second, but actual environmental influences can lead to deviations), which can lead to distance calculation errors. Furthermore, multipath (the reflection and refraction of sound waves along multiple propagation paths) can cause time differences and confusion in the signals received by the base station, further reducing positioning accuracy.

[0004] Existing acoustic positioning systems often use a single positioning algorithm, such as triangulation, that relies solely on raw distance data to directly calculate position. These algorithms lack dynamic compensation for environmental parameters and error correction mechanisms. In complex environments, such as open outdoor spaces, these interference factors can significantly amplify positioning errors. Traditional positioning technologies often only achieve decimeter or even meter-level accuracy, making them difficult to meet the high-precision positioning requirements of centimeter-level accuracy, such as those required in industrial scenarios.

[0005] Therefore, how to effectively suppress environmental interference and dynamically compensate for sound wave propagation errors, thereby improving the accuracy and reliability of sound wave positioning, has become a technical problem that needs to be urgently solved in this field. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an acoustic wave outdoor positioning correction system and method to effectively suppress environmental interference and dynamically compensate for acoustic wave propagation errors, thereby improving the accuracy and reliability of acoustic wave positioning.

[0007] In order to achieve the above objectives, an acoustic wave outdoor positioning and correction system is designed, comprising: an acoustic wave transmitting and receiving module, comprising multiple acoustic wave base stations and at least one working tag, for obtaining original distance data from the working tag to each acoustic wave base station; at least one reference tag with a known position, for providing a benchmark for changes in environmental parameters; a data processing module, for performing the following steps: a. calculating the measured position coordinates (x0′, y0′, z0′) of the reference tag and the measured position coordinates (x0′, y0′, z0′) of the working tag based on the original distance data; b. calculating the measured position coordinates (x0′, y0′, z0′) of the reference tag and the measured position coordinates (x0′, y0′, z0′) of the working tag based on the original distance data; c. calculating the measured position coordinates (x0′, y0′, z0′) of the reference tag and the measured position coordinates (x0′, y0′, z0′) of the working tag based on the original distance data; a ′,y a ′,za '); b. Calculate the three-dimensional space deviation proportional coefficient according to the actual position coordinates (x0, y0, z0) of the reference tag and its measured position coordinates (x0', y0', z0') using the following formula: x =x0 / x0′,a y =y0 / y0′,a z =z0 / z0′,a x 、a y 、a z Indicates the deviation proportional coefficient, where x0, y0, z0 are not equal to zero; c. Using the deviation proportional coefficient to correct the measured position coordinates of the working tag, the corrected coordinates are obtained (x a ,y a , z a ), where x a =a x *x a ′,y a =a y *y a ′,z a =a z *z a '; Positioning output module, configured to output the corrected position coordinates (x a ,y a , z a ) as the coordinate positioning result.

[0008] Preferably, the present invention also includes: the data processing module includes an error compensation unit, which is specifically used to: dynamically correct the sound speed according to temperature, humidity and wind speed parameters, and generate an environmental error compensation coefficient based on the deviation between the measured distance and theoretical distance of the reference tag.

[0009] Preferably, the present invention also includes: the sound wave transmitting and receiving module adopts a dual-wave time difference anti-interference algorithm, specifically including: sending electromagnetic wave signals through the active radio frequency identification tag sensor RFID tag, and synchronously sending sound wave signals through the ultrasonic identification tag sensor USID tag, and respectively calculating the time T when the electromagnetic waves reach the base station rfid The time T when the sound wave reaches the base station usid , obtain the time difference ΔT between the arrival time of the sound wave and the arrival time of the electromagnetic wave, ΔT=T usid -T rfid The acoustic wave transmitting and receiving module also includes: performing 20kHz±2kHz bandpass filtering on the received acoustic wave signal to filter out non-matching signals.

[0010] Preferably, the present invention also includes: the positioning output module also includes a correction verification module, which is specifically used to verify whether the error between the coordinates of the corrected working tag and the actual position is less than the target error threshold. If it exceeds the limit, the signal acquisition and calculation process is re-triggered.

[0011] Preferably, the present invention further includes: the number of the acoustic wave base stations is 4, which are respectively arranged at different coordinate points in three-dimensional space to achieve spatial positioning of the object.

[0012] The present invention also provides an acoustic wave outdoor positioning and correction method, which uses the acoustic wave outdoor positioning and correction system, including the following steps: Step 1: Setting a reference tag, a working tag, and a base station, wherein each reference tag and the working tag is provided with an acoustic wave tag USID tag and an active radio frequency tag RFID tag, wherein the acoustic wave tag USID tag periodically transmits an acoustic wave signal containing a unique identification information ID, and the active radio frequency tag RFID tag simultaneously transmits a synchronous electromagnetic wave signal; Step 2: After the base station receives the acoustic wave signal and the electromagnetic wave signal respectively, it filters out the interference signal and records the arrival time difference ΔT between the electromagnetic wave and the acoustic wave, ΔT=T usid -T rfid , T usid is the time it takes for the sound wave to reach the base station, T rfid is the time it takes for the electromagnetic wave to reach the base station, and the USID code of the sound wave signal is extracted; Step 3: Calculate the actual distance S1′ from the working tag to the base station using the formula S=V*T, where S is the distance from the tag to the base station, V is the speed of the sound wave propagating in the medium, and T is the time it takes for the sound wave to reach the base station from the tag; Step 4: Calculate the deviation proportional coefficient a by using the actual position coordinates (x0, y0, z0) of the reference tag and the measured position coordinates (x0′, y0′, z0′) of the reference tag x =x0 / x0′,a y =y0 / y0′,a z =z0 / z0′, where x0, y0, and z0 are not equal to zero; Step 5: Substitute the deviation proportional coefficient into the measured position coordinates of the working tag (x a ′,y a ′,z a ′), through x a =a x *x a ′,y a =a y *y a ′,z a =a z *z a ′Correct the actual position coordinates of the working tag (x a ,y a , z a ).

[0013] Preferably, the present invention further comprises: the step 3 is specifically as follows: calculating the actual propagation speed V2′ of the sound wave emitted from the working tag, which is expressed as follows: V2′=V2*S2′ / S2; wherein, the expression is obtained based on the formula S=V*T transformed into T2=S2 / S2′=V2 / V2′; T2 is the time it takes for the sound wave to reach the base station from the reference tag, and T2 is calculated as follows: T2=S2 / S2′=V2 / V2′=ΔT2-T t -T r -T q , where ΔT2 is the time difference between the electromagnetic wave and the acoustic wave from the reference tag to the base, T t is the tag transmission delay, T r is the base station receiving delay, T q is the signal queuing time in seconds; V2 is the ideal sound speed, take V2=V s , V s is the theoretical speed of sound, V s =344 m / s; S2 is the signal measurement distance from the reference tag to the base station, calculated by S2=V2*T2; S2′ is the actual distance from the reference tag to the base station, obtained through actual measurement; the impact value ΔV is calculated based on the actual sound speed V2′, as follows: ΔV=V2′-V s =S2′*V2 / S2-V s ; Among them, this expression is based on V2′=V s +ΔV transformation, V2′ represents the actual propagation speed of the sound wave of the working tag, V s =344 m / s, ΔV represents the impact of environmental factors on the speed of sound waves, in m / s; the actual distance S1′ is calculated based on the impact value ΔV, and the expression is as follows: S1′=S1*V1′ / V1; where this expression is based on the formula S=V*T and is transformed into S1 / S1′=V1 / V1′=T1; where T1 is the time it takes for the sound wave to reach the base station from the working tag, in seconds; S1 is the signal measured distance from the working tag to the base station; S1′ is the actual distance from the working tag to the base station; V1 is the ideal sound speed, and V1=V s , V s is the theoretical speed of sound, V s =344 m / s; V1′ is the actual speed of sound, in m / s; the expression for the actual speed of sound V1′ is: V1′=V s +ΔV; the signal measurement distance value S1 is calculated by S1=V1*T1; the expression of time T1 is as follows: T1=T1=ΔT1-T t -T r -T q , where ΔT1 is the time difference between the electromagnetic wave and the acoustic wave from the reference tag to the base, T t is the tag transmission delay, Tr is the base station receiving delay, T q Queue time for the signal.

[0014] Preferably, the present invention further comprises: the calculation of the measured position coordinates of the reference tag in step 4 includes: the coordinates of the four acoustic wave base stations are calculated using (x i ,y i , z i ) represents, where i=(1,2,3,4); based on the coordinates of the four acoustic base stations (x i ,y i , z i ), where i = (1, 2, 3, 4) and the actual distance S from the working tag to the base station calculated in step 3 i , establish a nonlinear system of equations:

[0015] ;

[0016] Where i = (1, 2, 3, 4), the quadratic term is eliminated by square difference, and the equation is converted into a linear system of equations Ax = b, Ay = b, Ax = b, and the least squares method is used to solve x = (A T A) −1 *A T b、y=(A T A) −1 *A T b、z=(A T A) −1 *A T b. Obtain the estimated coordinates (x, y, z) that minimize the sum of squared errors. This coordinate calculation method is used to calculate the measured position coordinates of the working tag and the measured position coordinates of the reference tag based on the measured distance.

[0017] Preferably, the present invention also includes: filtering out interference signals in step 2, specifically including: step 21: performing bandpass filtering on the received sound wave signal, retaining the signal within the frequency band of 20kHz±2kHz, the passband range is 18kHz to 22kHz, and the stopband attenuation is ≥30dB, which is used to suppress environmental noise and multipath interference signals and filter out noise outside the frequency band.

[0018] Preferably, the present invention further includes: ΔV is expressed as: ΔV=ΔV t +ΔV h +ΔV w , ΔV t is the effect of temperature on the speed of sound waves, ΔV h is the effect of humidity on the speed of sound waves, ΔV w is the effect of wind speed on the speed of sound waves.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This application significantly improves the accuracy and reliability of acoustic positioning through technical means such as dual-wave time difference anti-interference algorithm, multi-sensor data fusion, environmental parameter compensation and dynamic error correction; through dynamic compensation of environmental parameters such as temperature, humidity, wind speed and correction of the deviation ratio of reference tags, it effectively reduces the impact of environmental changes on positioning results; at the same time, the system adopts the spatial arrangement of multiple acoustic base stations and least squares calculation, with a simple structure and easy implementation, which is suitable for various scenarios such as indoor positioning, robot navigation, and intelligent warehousing. Verification data shows that the error between the corrected coordinates and the actual position can be controlled within 2 cm, meeting the needs of high-precision positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the signal containing the unique coded ID number emitted by the ultrasonic identification tag sensor USID tag;

[0022] Figure 2 This is a schematic diagram of the circuit structure of the sound wave transmitting and receiving module used for bandpass filtering;

[0023] Figure 3 This is the principle diagram of the bandpass filter signal processing of the sound wave transmission and reception module;

[0024] Figure 4 This is the effect diagram of the bandpass filter signal processing of the sound wave transmission and reception module;

[0025] Figure 5 This is a schematic diagram of a correction system with working tags as measurement points, reference tags as reference points, and multiple base stations forming a receiver plane;

[0026] Figure 6 This is a schematic diagram of the code implementation of proportional correction;

[0027] Figure 7 It is a schematic diagram of the correction system label and base station of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, principle and structure of the present invention more clear, it is further described below with reference to the accompanying drawings and specific embodiments.

[0029] refer to Figures 1 to 7 The acoustic wave outdoor positioning and correction system and algorithm described in this invention can be applied to scenarios requiring high-precision acoustic wave positioning, such as indoor positioning, robot navigation, and intelligent warehousing. The following describes the implementation of this invention in detail, using rail crane trolley positioning as an example, in conjunction with specific application scenarios.

[0030] Example 1: System composition and hardware deployment.

[0031] This system includes an acoustic wave transmitting and receiving module, a data processing module, a positioning calculation module, and a deviation correction calculation module. The specific hardware deployment is as follows.

[0032] Acoustic wave transmitting and receiving module: Contains multiple acoustic wave tags (divided into reference tags and working tags) and 4 acoustic wave base stations. Among them, the reference tag is arranged at a short-distance fixed position. Taking this embodiment as an example, the reference tag is arranged in the middle of the trolley frame. The actual position of the reference tag (x0, y0, z0) is accurately measured and determined by a physical ruler. Since the reference tag is at a short-distance fixed position, its distance can be directly measured to ensure the accuracy of the coordinates. The working tag is arranged on the mobile device that needs to be monitored. Taking this embodiment as an example, the working tag is arranged on the left side of the trolley platform. Because long-distance track movement needs to be monitored, the track length is usually more than 10 meters. Its actual position cannot be directly measured by a physical ruler and needs to be calculated by the acoustic wave positioning system.

[0033] Each acoustic tag integrates an ultrasonic identification tag (USID) and an active radio frequency identification tag (RFID). The USID periodically transmits an acoustic signal containing a unique local ID code at a frequency of 20kHz±2kHz, while the RFID simultaneously transmits an electromagnetic wave signal. Because electromagnetic waves propagate much faster than acoustic waves, their arrival can be considered instantaneous.

[0034] Four acoustic wave base stations are located at different coordinate points in the three-dimensional space used for ranging. In this embodiment, the coordinates of the four acoustic wave base stations are (0, 0, 0), (1000, 0, 0), (0, 1000, 0), and (0, 0, 100). The x, y, and z axes represent the distance from any acoustic wave base station to the reference point (0, 0, 0) along the longitudinal, lateral, and vertical axes, respectively, in millimeters. The four acoustic wave base stations receive acoustic and electromagnetic wave signals and record their arrival times.

[0035] It is worth noting that when arranging reference labels, avoid setting them on the x, y, and z axes so that x0, y0, and z0 are not equal to zero.

[0036] Data processing module: includes data preprocessing unit, data fusion unit and error compensation unit.

[0037] The pre-processing unit performs a 20kHz±2kHz band-pass filter on the received sound wave signal, with a passband range of 18kHz-22kHz and a stopband attenuation of ≥30dB, to eliminate abnormal interference signals. Preferably, the pre-processing unit can be a multi-stage analog signal processing circuit based on the LM324 operational amplifier, comprising an input stage, a band-pass filter stage, a notch filter stage and a reference voltage module; the input stage adjusts the signal amplitude and isolates the signal source through a voltage divider circuit and a buffer op amp; the band-pass filter stage sets the center frequency of 1.0kHz and a quality factor of 10 through a resistor-capacitor network, allowing signals of a specific bandwidth to pass; the notch filter stage is designed for a frequency of 1.0kHz to suppress the frequency signal; the reference voltage provides a reference for the inverting terminal of the op amp to adjust the output DC bias; the overall signal buffering, band-pass filtering and notch filtering functions are realized, which is suitable for communication signal conditioning scenarios and can be flexibly adapted to different needs through parameter adjustment.

[0038] The data fusion unit performs weighted fusion on the distance data of multiple sensor base stations to improve data reliability.

[0039] The error compensation unit combines environmental parameters (temperature, humidity, wind speed) and the measured deviation of the reference tag to generate a dynamic error compensation coefficient.

[0040] Positioning calculation module: Based on the corrected distance data, the target position coordinates are calculated using triangulation positioning method or least squares method.

[0041] Deviation correction calculation module: Dynamically corrects the positioning result of the working tag by referring to the deviation ratio between the actual position of the reference tag and the position calculated by the system.

[0042] Example 2: Workflow and core algorithm of the correction method.

[0043] 1. Signal transmission and reception.

[0044] The acoustic tag periodically and synchronously transmits an acoustic signal (USID) and an electromagnetic wave signal (RFID). The acoustic tag includes a reference tag and a working tag. After the base station receives the two signals, it records the arrival time of the electromagnetic wave T rfid and the sound wave arrival time T usid , calculate the time difference ΔT=T usid -T rfid , where ΔT2 can be used to correspond to the reference label and ΔT1 to correspond to the working label.

[0045] 2. Data preprocessing.

[0046] Band-pass filtering is performed, and the received sound wave signal is processed by a 20kHz±2kHz band-pass filter, retaining only the signal within the frequency band of 30dB passband gain, suppressing environmental noise and multipath reflection interference, and eliminating the delayed signal formed by the sound wave reflected by the wall and equipment.

[0047] 3. Distance calculation and environmental error compensation.

[0048] Correct the distance from the reference tag to the base station. The actual distance S2′ of the reference tag is known by measuring with a ruler. After the base station receives the signal from the reference tag, it calculates the time difference ΔT2 and combines it with the known tag transmission delay T t (fixed delay of the tag's internal circuit processing signal), base station reception delay T r (fixed delay for the base station to receive the signal and convert it into a digital signal), signal queuing time T q (queue waiting time when multi-tag signal transmission occurs), the sound wave propagation time T2=ΔT2-T t -T r -T q , in seconds.

[0049] Theoretical sound velocity is V S =344m / s, calculate the measured distance of the reference tag S2=V s ×T2. Due to environmental factors (temperature ΔV t , humidity ΔV h , wind speed ΔV w ) influence, the actual sound speed V2′=V s +ΔV, the expression of the environmental factor's influence on the speed of sound waves ΔV is ΔV=ΔV t +ΔV h +ΔV w , and the actual distance S2′=V2′×T2, so the actual sound speed correction formula can be derived: V2′=V s × S2′ / S2. The environmental impact value ΔV=V2′-V s , ΔV is obtained by calculation.

[0050] Finally, the distance from the working tag to the base station is corrected. The signal reception and processing process of the working tag is consistent with that of the reference tag. Through the time difference ΔT1 and the known delay T t 、T r 、T q , calculate the sound wave propagation time T1=ΔT1-T t -T r -T q , measure the distance S1=V s × T1. Combined with the ΔV calculated from the reference tag, the actual sound speed V1′=V s +ΔV, so the actual distance from the working tag to the base station after the correction is S1′=V1′×T1=S1×(V s +ΔV) / V s .

[0051] 4. Position calculation and correction.

[0052] Reference tag position calculation: The coordinates of the four base stations are known (x i ,y i , z i ), (i=1,2,3,4), based on the measured distance S2 from the corrected reference tag to each base station, a nonlinear equation group is established:

[0053] ;

[0054] Expanding the square root yields:

[0055] (xx i ) 2 +(yy i ) 2 + (zz i ) 2 =S 2i 2 ;

[0056] Specifically include:

[0057] Equation 1: (x-x1) 2 + (y-y1) 2 + (z-z1) 2 =S 21 2 ;

[0058] Equation 2: (x-x²) 2 + (y-y2) 2 + (z-z2) 2 =S 22 2 ;

[0059] Equation 3: (x-x3) 2 + (y-y3) 2 + (z-z3) 2 =S 23 2 ;

[0060] Equation 4: (x-x4) 2 + (y-y4) 2 + (z-z4) 2 =S 24 2 ;

[0061] In order to transform the nonlinear equation into a linear system for easy solution, the quadratic term x is eliminated by subtracting the two equations. 2 ,y 2 , z 2 , using equation S 21 2 and S22 2 For example:

[0062] S 21 2 -S 22 2 =(x-x1) 2 + (y-y1) 2 + (z-z1) 2 -(x-x2) 2 -(y-y2) 2 -(z-z2) 2 ;

[0063] Expand and simplify:

[0064] 2(x2-x1)x+2(y2-y1)y+2(z2-z1)z= S 21 -S 22 +x2 2 +y2 2 +z2 2 -x1 2 -y1 2 -z1 2 ;

[0065] Similarly, subtracting Equation 3 from Equation 1 and Equation 4 from Equation 1 yields two other linear equations.

[0066] Represent the linear equations in the form of a 3*3 matrix Ax′=b;

[0067] ;

[0068] ;

[0069] ;

[0070] Where A is the matrix coefficient, x′=(x, y, z), and b is the constant term vector.

[0071] Solve an overdetermined system of equations using the least squares method:

[0072] x=(A T A) −1 *A T b;

[0073] y=(A T A) −1 *A T b;

[0074] z=(A T A) −1 *A T b;

[0075] Among them A T is the transpose of matrix A, (A T A) −1 It is the inverse matrix (if invertible), and by minimizing the sum of squared errors, we obtain the system-estimated position coordinates (x0′, y0′, z0′) of the reference tag that is closest to the true value.

[0076] 5. Position calculation and correction of work labels:

[0077] Similarly, based on the corrected distance S1′ of the working tag, the equations are established and solved to obtain the system-calculated position of the working tag (x a ′,y a ′,z a ′).

[0078] The deviation ratio between the actual position of the reference tag (x0, y0, z0) and the system-calculated position of the reference tag (x0′, y0′, z0′) is:

[0079] a x =x0 / x0′,a y =y0 / y0′,a z =z0 / z0′; Since the reference label is set to avoid being coaxial with the x, y, and z axes, x0, y0, and z0 are not equal to zero, and the corresponding x0′, y0′, and z0′ are also not zero. x 、a y 、a z Are also not zero.

[0080] The actual position of the working label is corrected by the deviation ratio:

[0081] x a =a x *x a ′,y a =a y *y a ′,z a =a z *z a ′.

[0082] By taking the measured position of the working label (x a ′,y a ′,z a ′) into the deviation ratio correction, the actual position of the corrected working label (x a ,y a , z a ).

[0083] It is worth noting that the actual position of the reference tag (x0, y0, z0) is a real and accurate value obtained through manual measurement. Due to its high accuracy, it can be used as a reference standard data; the system-calculated position of the reference tag (x0′, y0′, z0′) is obtained through system calculation; the calculated position of the working tag (x a ′,y a ′,z a ′) is obtained through system calculation; the actual position of the working label (x a ,y a , z a ) is calculated based on the deviation ratio correction. Taking the rail crane trolley positioning test as an example, the actual effect of this system and method is verified:

[0084] The test environment is as follows: a force 4 or force 5 wind environment, with the actual reference tag position coordinates (10, 10, 1000). The working tag needs to monitor the movement of the trolley on a 10-meter-long track. The unit of the tag position coordinates is millimeters.

[0085] The specific test process is as follows: the trolley moves to the preset mark point on the track, the system calculates the position of the working tag and corrects it, repeats the test 5 times, and compares the error between the actual position and the position after correction.

[0086] Test data:

[0087] The coordinates of the four base stations are (0, 0, 0), (1000, 0, 0), (0, 1000, 0), and (0, 0, 100).

[0088] The actual position coordinates of the reference tag are (10, 10, 1000); unit: mm.

[0089] Environment 1: Level 4 wind.

[0090] The distances from the reference tag to the four base stations are (1058, 1393, 1371, 961).

[0091] It can be concluded that the measured coordinates of the reference label are (90, 120, 1030);

[0092] Since the Z-axis distance can meet the requirements at the test site, we can get a z =1000 / 1030=0.97.

[0093] Use the existing triangulation method to calculate: the measured coordinates of the working tag;

[0094] The system and method of the present invention are used to calculate: the actual coordinates of the working tag after correction;

[0095] Obtain the actual position coordinates of the working tag through manual real measurement;

[0096] Calculate the distances from the three coordinates to the base station and perform error comparison, comparing the errors between the measured distance and the actual distance, and between the actual distance and the actual distance, respectively, to ensure that the error between the actual coordinates and the actual coordinates after the correction of the present invention is within the range of the target error threshold, and verify the accuracy of the system's correction measurement of the actual position of the working tag.

[0097] Table 1. The real position coordinates, calculated position coordinates, and Z-axis distances between the working tag and the four base stations after correction under level 4 wind.

[0098]

[0099] In a force 4 wind environment, the reference tag system calculates the position (90, 120, 1030), and the deviation ratio a z =1000 / 1030≈0.97; the error of the working tag after correction is ≤ the target error threshold of 2cm (for example, the distance from the actual position to the base station is 6270mm, the distance from the position to the base station calculated by the system is 6247mm, and the distance from the position to the base station after correction is 6250mm, the error is +30mm×0.97≈+29.1mm, and the final error is 5mm).

[0100] Environment 2: Level 5 wind.

[0101] The distances from the reference tag to the four base stations are (10689, 1386, 1407, 969) respectively; the calculated coordinates of the reference tag are (110, 81, 1065); and a z =1000 / 1065=0.94.

[0102] Use the existing triangulation method to calculate: the measured coordinates of the working tag;

[0103] The system and method of the present invention are used to calculate: the actual coordinates of the working tag after correction;

[0104] Obtain the actual position coordinates of the working tag through manual real measurement;

[0105] Calculate the distances from the three coordinates to the base station and perform error comparison, comparing the errors between the measured distance and the actual distance, and between the actual distance and the actual distance, respectively, to ensure that the error between the actual coordinates and the actual coordinates after the correction of the present invention is within the range of the target error threshold, and verify the accuracy of the system's correction measurement of the actual position of the working tag.

[0106] Table 2. The real position coordinates, calculated position coordinates, and Z-axis distances between the working tag and the four base stations after correction under level 5 wind.

[0107]

[0108] In a force 5 wind environment, the reference tag system calculates the position (110, 81, 1065), and the deviation ratio a z =1000 / 1065≈0.94; the error of the working tag after correction is ≤ the target error threshold of 5cm (for example, the distance from the actual position to the base station is 7070mm, the distance from the position to the base station calculated by the system is 7051mm, and the distance from the position to the base station after correction is 7040mm. The error is -20mm×0.94≈-18.8mm, and the final error is 2mm).

[0109] In summary, the present invention effectively suppresses environmental interference (such as wind speeds of 4-5) through dynamic compensation and deviation ratio correction of reference tags, correcting the original 100-centimeter positioning error to within 10 centimeters. After combining multi-tag gradient correction, the final accuracy can reach 5 centimeters, meeting the high-precision positioning requirements.

[0110] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent replacement or change made by any technician familiar with the technical field within the technical scope disclosed by the present invention based on the technical solution and novel concept of the present invention should be covered by the scope of protection of the present invention.

Claims

1. An acoustic wave outdoor positioning and correction system, characterized in that: include: The acoustic wave transmitting and receiving module includes multiple acoustic wave base stations and at least one working tag, and is used to obtain the original distance data from the working tag to each acoustic wave base station; At least one reference tag with a known position, used to provide a benchmark for changes in environmental parameters; a data processing module, used to perform the following steps: a. Calculate the measured position coordinates (x0′, y0′, z0′) of the reference tag and the measured position coordinates (x0′, y0′, z0′) of the working tag based on the original distance data; a ′,y a ′,z a ′); b. Calculate the three-dimensional space deviation proportional coefficient based on the actual position coordinates (x0, y0, z0) of the reference tag and its measured position coordinates (x0′, y0′, z0′) according to the following formula: a x =x0 / x0′,a y =y0 / y0′,a z =z0 / z0′,a x 、a y 、a z represents the deviation proportional coefficient, where x0, y0, and z0 are not equal to zero; c. Using the deviation proportional coefficient to correct the measured position coordinates of the working tag to obtain the corrected coordinates (x a ,y a , z a ), where x a =a x *x a ′,y a =a y *y a ′,z a =a z *z a '; Positioning output module, configured to output the corrected position coordinates (x a ,y a , z a ) as the coordinate positioning result.

2. The acoustic wave outdoor positioning and correction system according to claim 1, characterized in that: The data processing module includes an error compensation unit, which is specifically used to dynamically correct the sound speed according to temperature, humidity and wind speed parameters, and generate an environmental error compensation coefficient based on the deviation between the measured distance and the theoretical distance of the reference tag.

3. The acoustic wave outdoor positioning and correction system according to claim 1, characterized in that: The acoustic wave transmitting and receiving module adopts a dual-wave time difference anti-interference algorithm, specifically including: sending electromagnetic wave signals through the active radio frequency identification tag sensor RFID tag, and synchronously sending acoustic wave signals through the ultrasonic identification tag sensor USID tag, respectively calculating the time T when the electromagnetic wave reaches the base station rfid The time T when the sound wave reaches the base station usid , and obtain the time difference ΔT between the arrival time of the sound wave and the arrival time of the electromagnetic wave, ΔT=T usid -T rfid ; The sound wave transmitting and receiving module further includes: performing 20kHz±2kHz bandpass filtering on the received sound wave signal to filter out non-matching signals.

4. The acoustic wave outdoor positioning and correction system according to claim 1, characterized in that: The positioning output module also includes a correction verification module, which is specifically used to verify whether the error between the coordinates of the corrected working tag and the actual position is less than the target error threshold. If it exceeds the limit, the signal acquisition and calculation process is re-triggered.

5. The acoustic wave outdoor positioning and correction system according to claim 1, characterized in that: The number of the acoustic wave base stations is 4, which are respectively arranged at different coordinate points in three-dimensional space to achieve spatial positioning of the object.

6. A method for outdoor acoustic wave positioning and correction, characterized in that: Using the acoustic wave outdoor positioning and correction system as described in any one of claims 1 to 5, The method includes the following steps: Step 1: Set up a reference tag, a working tag, and a base station. Each reference tag and working tag is equipped with an acoustic tag (USID) and an active radio frequency tag (RFID). The acoustic tag (USID) periodically transmits an acoustic signal containing a unique identification information ID, while the active radio frequency tag (RFID) sends a synchronous electromagnetic wave signal. Step 2: After the base station receives the acoustic wave signal and the electromagnetic wave signal respectively, it filters out the interference signal and records the arrival time difference ΔT between the electromagnetic wave and the acoustic wave. ΔT=T usid -T rfid , T usid is the time it takes for the sound wave to reach the base station, T rfid is the time it takes for the electromagnetic wave to reach the base station, and the USID code of the acoustic wave signal is extracted; Step 3: Calculate the actual distance S1′ between the working tag and the base station using the formula S=V*T, where S is the distance from the tag to the base station, V is the speed of the acoustic wave in the medium, and T is the time it takes for the acoustic wave to reach the base station from the tag; Step 4: Calculate the deviation proportional coefficient a by using the actual position coordinates (x0, y0, z0) of the reference tag and the measured position coordinates (x0′, y0′, z0′) of the reference tag. x =x0 / x0′,a y =y0 / y0′,a z =z0 / z0′, where x0, y0, and z0 are not equal to zero; Step 5: Substitute the deviation proportional coefficient into the measured position coordinates of the working tag (x a ′,y a ′,z a ′), through x a =a x *x a ′,y a =a y *y a ′,z a =a z *z a ′Correct the actual position coordinates of the working tag (x a ,y a , z a ).

7. The method according to claim 6, characterized in that The step 3 is specifically as follows: Calculate the actual propagation speed V2′ of the sound wave emitted from the working tag, the expression is as follows: V2′=V2*S2′ / S2; The expression is obtained by transforming the formula S=V*T into T2=S2 / S2′=V2 / V2′; T2 is the time it takes for the sound wave to reach the base station from the reference tag, and T2 is calculated as: T2=S2 / S2′=V2 / V2′=ΔT2-T t -T r -T q , where ΔT2 is the time difference between the electromagnetic wave and the acoustic wave from the reference tag to the base, T t is the tag transmission delay, T r is the base station receiving delay, T q is the signal queuing time in seconds; V2 is the ideal sound speed, take V2=V s , V s is the theoretical speed of sound, V s =344 m / s; S2 is the signal measured distance from the reference tag to the base station, calculated by S2=V2*T2; S2′ is the actual distance from the reference tag to the base station, obtained through actual measurement; The impact value ΔV is calculated based on the actual sound velocity V2′, and the expression is as follows: ΔV=V2′-V s =S2′*V2 / S2-V s ; The expression is based on V2′=V s +ΔV transformation, V2′ represents the actual propagation speed of the sound wave of the working tag, V s =344 m / s, ΔV represents the impact of environmental factors on the speed of sound waves, in m / s; The actual distance S1′ is calculated based on the influence value ΔV, and the expression is as follows: S1′=S1*V1′ / V1; Among them, this expression is based on the formula S=V*T transformed into S1 / S1′=V1 / V1′=T1; Where T1 is the time it takes for the sound wave to reach the base station from the working tag, in seconds; S1 is the signal measured distance from the working tag to the base station; S1′ is the actual distance from the working tag to the base station; V1 is the ideal sound speed, and V1=V s , V s is the theoretical speed of sound, V s =344 m / s; V1′ is the actual speed of sound, in m / s; The expression of actual sound speed of V1′ is: V1′=V s +ΔV; The signal measurement distance value S1 is calculated by S1=V1*T1; the expression of time T1 is as follows: T1=ΔT1-T t -T r -T q , where ΔT1 is the time difference between the electromagnetic wave and the acoustic wave from the reference tag to the base, T t is the tag transmission delay, T r is the base station receiving delay, T q Queue time for the signal.

8. The method according to claim 7, characterized in that The calculation of the measured position coordinates of the reference tag in step 4 includes: The coordinates of the four acoustic base stations are expressed as (x i ,y i , z i ) represents, where i=(1,2,3,4); Based on the coordinates of the four acoustic base stations (x i ,y i , z i ), where i = (1, 2, 3, 4) and the actual distance S from the working tag to the base station calculated in step 3 i , establish a nonlinear system of equations: ； Where i = (1, 2, 3, 4), the quadratic term is eliminated by square difference, and the equation is converted into a linear system of equations Ax = b, Ay = b, Ax = b, and the least squares method is used to solve x = (A T A) −1 *A T b、y=(A T A) −1 *A T b、z=(A T A) −1 *A T b. Obtain the estimated coordinates (x, y, z) that minimize the sum of squared errors. The measured position coordinates are used to calculate the measured position coordinates of the working tag and the reference tag based on the measured distance.

9. The method according to claim 6, characterized in that The step 2 of filtering out interference signals specifically includes: Step 21: Perform bandpass filtering on the received acoustic wave signal to retain the signal within the 20kHz±2kHz frequency band. The passband range is 18kHz to 22kHz, and the stopband attenuation is ≥30dB. This is used to suppress environmental noise and multipath interference signals and filter out noise outside the frequency band.

10. The method according to claim 7, characterized in that The expression of ΔV is: ΔV=ΔV t +ΔV h +ΔV w , ΔV t is the effect of temperature on the speed of sound waves, ΔV h is the effect of humidity on the speed of sound waves, ΔV w is the effect of wind speed on the speed of sound waves.

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