A decision system and method for determining the reliability of OBU positioning results

Abstract

The application provides a kind of decision system and method for determining OBU positioning result reliability, comprising: obtaining the radio frequency signal transmitted by target OBU through array antenna;Convert multiple radio frequency signals into multiple digital signals;Calculate the amplitude of the multiple digital signals, and the average value and standard deviation of the amplitude, determine the amplitude difference coefficient corresponding to the target OBU according to the average value and standard deviation;Based on DBF algorithm, determine the positioning of the target OBU through the received multiple radio frequency signals, and obtain the power spectrum curve of the target OBU, and the first peak value and the second peak value of the power curve, determine the power spectrum peak value coefficient according to the first peak value and the second peak value;Compare the amplitude difference coefficient and the power spectrum peak value coefficient with the preset threshold value, to determine whether the positioning of the target OBU is reliable. Filter out the interference results from the blind area and through diffraction and reflection, solve the problem of ETC false alarm and error charge.

Description

Technical Field

[0001] This invention relates to the field of intelligent transportation technology, and specifically to a system and method for determining the reliability of OBU positioning results. Background Technology

[0002] In the ETC toll collection system, in order to solve the problems of adjacent lane interference and following vehicle interference and improve the transaction success rate, a radar positioning module is generally added to the RSU device to obtain the precise location of the OBU. The positioning results are used to guide the DSRC transaction module to avoid problems such as adjacent lane transactions and incorrect charges.

[0003] In practical applications, the maximum reliable reception range of the radar positioning module's array antenna is only within a 180° area in front; the area around and behind the antenna is a positioning blind spot. Currently, many provinces' ETC lanes use a dual-antenna mode, with one RSU installed at the front and one at the rear of each ETC lane. The front RSU is the primary RSU (front-end RSU), and the rear RSU is the backup RSU (rear-end RSU). If the front RSU fails to deduct the toll, the rear RSU is immediately activated to complete the transaction. When the rear RSU communicates with the OBU, because the OBU is located in the positioning blind spot of the front RSU, if the front RSU (especially the front RSU in the adjacent lane) receives the OBU's signal and performs positioning, the resulting positioning will be distorted. It is very likely that the OBU will be mistakenly identified as being within the legitimate transaction area, leading to a false alarm due to transaction failure. Another scenario is that when the adjacent lane RSU communicates with the OBU, due to obstructions such as toll booths and billboards, the signal from the adjacent lane OBU is diffracted and reflected to reach this lane. The RSU in this lane receives and locates the signal, but the location result is also incorrect. It is very likely that the adjacent lane OBU will be treated as the one in this lane and a normal transaction will be made, causing interference between adjacent lanes and incorrect charges.

[0004] Existing positioning technologies do not take into account the presence of large reflective surfaces nearby, interference from other devices, the OBU being located behind the RSU, or the signal transmission path being blocked. In these cases, the amplitude and phase of the signal reaching the array antenna via multipath can vary significantly, leading to incorrect positioning results and causing issues such as adjacent channel transactions and incorrect billing. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a system for determining the reliability of OBU positioning results, comprising: The array antenna, composed of multiple antenna elements, is used to receive radio frequency signals transmitted by the target OBU and send the multiple radio frequency signals to the downconversion receiving channel and the digital signal processing module respectively. The downconversion receiving channel is used to convert multiple received radio frequency signals into multiple low-frequency analog signals and send the multiple low-frequency analog signals to the AD conversion module; The AD conversion module is used to convert multiple received low-frequency analog signals into multiple digital signals, and send the multiple digital signals to the digital signal processing module; A digital signal processing module is used to calculate the amplitude of multiple received digital signals, as well as the average value and standard deviation of the amplitude. Based on the average value and standard deviation, it determines the amplitude difference coefficient corresponding to the target OBU. Based on the DBF algorithm, it determines the location of the target OBU through multiple received radio frequency signals and obtains the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power curve. Based on the first peak value and the second peak value, it determines the power spectrum peak coefficient. The amplitude difference coefficient and the power spectrum peak coefficient are compared with a preset threshold to determine whether the location of the target OBU is reliable.

[0006] Furthermore, each antenna element of the array antenna is connected to a corresponding down-conversion receiving channel, and each down-conversion receiving channel is connected to a corresponding AD conversion module. The AD conversion module sends the signal to the digital signal processing module.

[0007] Furthermore, the downconversion receiving channel includes: a low-noise amplifier (LNA), a synchronous mixer, a filter, and an intermediate frequency amplifier.

[0008] Further, the amplitudes of the received multiple digital signals, as well as the average and standard deviation of the amplitudes, are calculated. Based on the average and standard deviation, the amplitude difference coefficient corresponding to the target OBU is determined, including: Assume the array antenna is a one-dimensional uniform linear array composed of N antenna elements, and the incident angle of the target OBU is... The spacing between the antenna elements is d, and the signals received by the array antenna are X1, X2, ..., X... N Obtain the amplitude of each signal as A1, A2, ..., A N Calculate the average M and standard deviation S of N amplitudes using the following formula: Define amplitude difference coefficient The standard deviation of the amplitude divided by the mean of the amplitude: .

[0009] Furthermore, based on the DBF algorithm, the location of the target OBU is determined by receiving multiple radio frequency signals, and the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power curve, are obtained. Based on the first peak value and the second peak value, the power spectrum peak coefficient is determined, including: The N signals received by the array antenna can be represented as set up yes The conjugate transpose of the given information gives the autocorrelation matrix of the array antenna as follows: The DBF algorithm performs a power spectrum scan on the autocorrelation matrix to obtain the power spectrum. The curve is as follows: in, The direction weighting coefficients are used to calculate the scanning angle range. ; Obtain the maximum peak value V1 and the second peak value V2 of the power spectrum curve; Define the peak power coefficient Divide the second peak by the first peak: .

[0010] Furthermore, the amplitude difference coefficient and power spectral peak coefficient are compared with preset thresholds to determine whether the location of the target OBU is reliable, including: Set amplitude difference coefficient threshold Set the power spectrum peak coefficient threshold When the amplitude difference coefficient Less than And the peak power spectral density Less than The DBF localization result was deemed reliable.

[0011] This invention also provides a method for determining the reliability of OBU positioning results, comprising: The radio frequency signal transmitted by the target OBU is acquired through the array antenna; Convert multiple radio frequency signals into multiple digital signals; Calculate the amplitude of the plurality of digital signals, as well as the average value and standard deviation of the amplitude, and determine the amplitude difference coefficient corresponding to the target OBU based on the average value and standard deviation; Based on the DBF algorithm, the location of the target OBU is determined by multiple received radio frequency signals, and the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power curve, are obtained. Based on the first peak value and the second peak value, the power spectrum peak coefficient is determined. The amplitude difference coefficient and the peak power spectrum coefficient are compared with preset thresholds to determine whether the location of the target OBU is reliable.

[0012] Further, the amplitudes of the multiple digital signals, as well as the average and standard deviation of the amplitudes, are calculated. Based on the average and standard deviation, the amplitude difference coefficient corresponding to the target OBU is determined, including: Assume the array antenna is a one-dimensional uniform linear array composed of N antenna elements, and the incident angle of the target OBU is... The spacing between the antenna elements is d, and the signals received by the array antenna are X1, X2, ..., X... N Obtain the amplitude of each signal as A1, A2, ..., A N Calculate the average M and standard deviation S of N amplitudes using the following formula: Define amplitude difference coefficient The standard deviation of the amplitude divided by the mean of the amplitude: .

[0013] Furthermore, based on the DBF algorithm, the location of the target OBU is determined by receiving multiple radio frequency signals, and the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power curve, are obtained. Based on the first peak value and the second peak value, the power spectrum peak coefficient is determined, including: The N signals received by the array antenna can be represented as set up yes The conjugate transpose of the given information gives the autocorrelation matrix of the array antenna as follows: The DBF algorithm performs a power spectrum scan on the autocorrelation matrix to obtain the power spectrum. The curve is as follows: in, The direction weighting coefficients are used to calculate the scanning angle range. ; Obtain the maximum peak value V1 and the second peak value V2 of the power spectrum curve; Define the peak power coefficient Divide the second peak by the first peak: .

[0014] Furthermore, the amplitude difference coefficient and power spectral peak coefficient are compared with preset thresholds to determine whether the location of the target OBU is reliable, including: Set amplitude difference coefficient threshold Set the power spectrum peak coefficient threshold When the amplitude difference coefficient Less than And the peak power spectral density Less than The DBF localization result was deemed reliable.

[0015] This invention provides a system and method for determining the reliability of OBU positioning results. It calculates the peak power spectrum coefficient using the power spectrum curve of the DBF positioning algorithm and the amplitude difference coefficient using the signal strength of each antenna element of the array antenna. The system combines the peak power spectrum coefficient and the amplitude difference coefficient to determine whether the positioning result is reliable, filtering out interference results from blind zones and those caused by diffraction and reflection, thus solving the problems of false alarms and incorrect charges in ETC. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a determination system for determining the reliability of OBU positioning results according to an embodiment of the present invention; Figure 2 This is a flowchart of the system involved in the embodiments of the present invention; Figure 3 This is a schematic diagram of an array antenna receiving OBU signals according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the power spectrum curve involved in an embodiment of the present invention; Figure 5 This is a flowchart illustrating a method for determining the reliability of OBU positioning results according to an embodiment of the present invention. Figure 6 This is a schematic diagram of a one-dimensional array antenna arrangement according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a two-dimensional array antenna arrangement according to an embodiment of the present invention. Detailed Implementation

[0017] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0018] like Figure 1 As shown, the present invention provides a determination system for assessing the reliability of OBU positioning results, comprising: The array antenna, composed of multiple antenna elements, is used to receive radio frequency signals transmitted by the target OBU and send the multiple radio frequency signals to the downconversion receiving channel and the digital signal processing module respectively. The downconversion receiving channel is used to convert multiple received radio frequency signals into multiple low-frequency analog signals and send the multiple low-frequency analog signals to the AD conversion module; The AD conversion module is used to convert multiple received low-frequency analog signals into multiple digital signals, and send the multiple digital signals to the digital signal processing module; A digital signal processing module is used to calculate the amplitude of multiple received digital signals, as well as the average value and standard deviation of the amplitude. Based on the average value and standard deviation, it determines the amplitude difference coefficient corresponding to the target OBU. Based on the DBF algorithm, it determines the location of the target OBU through multiple received radio frequency signals and obtains the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power curve. Based on the first peak value and the second peak value, it determines the power spectrum peak coefficient. The amplitude difference coefficient and the power spectrum peak coefficient are compared with a preset threshold to determine whether the location of the target OBU is reliable.

[0019] Each antenna element of the array antenna is connected to a corresponding down-conversion receiving channel, and each down-conversion receiving channel is connected to a corresponding AD conversion module. The AD conversion module sends the signal to the digital signal processing module.

[0020] The downconversion receiving channel includes: a low-noise amplifier (LNA), a synchronous mixer, a filter, and an intermediate frequency amplifier.

[0021] The system's workflow is shown in Figure 2. Assume the array antenna is a one-dimensional uniform linear array composed of N antenna elements, and the incident angle of the target OBU is... The spacing between antenna elements is d. A schematic diagram of the array antenna receiving OBU signals is shown below. Figure 3 As shown.

[0022] The signals received by the array antenna are X1, X2, ..., X N Obtain the amplitude of each signal as A1, A2, ..., A N Calculate the average M and standard deviation S of N amplitudes using the following formula: Define amplitude difference coefficient The standard deviation of the amplitude divided by the mean of the amplitude: .

[0023] The N signals received by the array antenna can be represented as set up yes The conjugate transpose of the given information gives the autocorrelation matrix of the array antenna as follows: The DBF algorithm employs the traditional beamforming-delay addition method to perform a power spectrum scan on the autocorrelation matrix to obtain the power spectrum. The curve is as follows Figure 4 As shown, it can be represented as: in, The direction weighting coefficients are used to calculate the scanning angle range. ; Obtain the maximum peak value V1 and the second peak value V2 of the power spectrum curve; Define the peak power coefficient Divide the second peak by the first peak: .

[0024] Figure 4 In the diagram, V1 is the maximum peak value of the power spectrum curve. Under conditions of no interference, the maximum peak value is the incident angle of the OBU. The corresponding power value; V2 is the second peak of the power spectrum curve, which is very small when there is no interference.

[0025] When the OBU transmits RF signals directly onto the array antenna from the RSU, due to the absence of multipath interference, the signal strength received by each antenna element on the array antenna is equal, and the signal phase depends only on the azimuth angle of the OBU. Consequently, the amplitude standard deviation S and the second peak value V2 of the power spectrum curve are very small (close to 0), resulting in an amplitude difference coefficient. T a and peak power spectral density T p is also very small.

[0026] When there is a large reflective surface nearby, interference from other equipment, the OBU is behind the RSU, or the signal transmission path is blocked, the signal reaching the array antenna through multipath interference will have significant differences in amplitude and phase, resulting in a very large amplitude standard deviation S and multiple peaks in the power spectrum curve, leading to an amplitude difference coefficient. and power spectral peak coefficient Larger.

[0027] Set amplitude difference coefficient threshold Set the power spectrum peak coefficient threshold When the amplitude difference coefficient Less than And the peak power spectral density Less than If the DBF positioning result is deemed reliable, it is considered unreliable and the positioning result is ignored.

[0028] Based on the same inventive concept, this invention also provides a method for determining the reliability of OBU positioning results, such as... Figure 5 As shown, it includes the following steps: Step S101: Acquire the radio frequency signal transmitted by the target OBU through the array antenna; Step S102: Convert multiple radio frequency signals into multiple digital signals; Step S103: Calculate the amplitude of the plurality of digital signals, as well as the average value and standard deviation of the amplitude, and determine the amplitude difference coefficient corresponding to the target OBU based on the average value and standard deviation; Step S104: Based on the DBF algorithm, the location of the target OBU is determined by multiple received radio frequency signals, and the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power curve, are obtained. Based on the first peak value and the second peak value, the power spectrum peak coefficient is determined. Step S105: Compare the amplitude difference coefficient and the power spectrum peak coefficient with a preset threshold to determine whether the location of the target OBU is reliable.

[0029] Assume the array antenna is a one-dimensional uniform linear array composed of N antenna elements, and the incident angle of the target OBU is... The spacing between the antenna elements is d, and the signals received by the array antenna are X1, X2, ..., X... N Obtain the amplitude of each signal as A1, A2, ..., A N Calculate the average M and standard deviation S of N amplitudes using the following formula: Define amplitude difference coefficient The standard deviation of the amplitude divided by the mean of the amplitude: .

[0030] The N signals received by the array antenna can be represented as set up yes The conjugate transpose of the given information gives the autocorrelation matrix of the array antenna as follows: The DBF algorithm performs a power spectrum scan on the autocorrelation matrix to obtain the power spectrum. The curve is as follows: in, The direction weighting coefficients are used to calculate the scanning angle range. ; Obtain the maximum peak value V1 and the second peak value V2 of the power spectrum curve; Define the peak power coefficient Divide the second peak by the first peak: .

[0031] Set amplitude difference coefficient threshold Set the power spectrum peak coefficient threshold When the amplitude difference coefficient Less than And the peak power spectral density Less than The DBF localization result was deemed reliable.

[0032] Specific Application Example 1: Reliability Determination of Positioning for One-Dimensional Array Antennas An array antenna is a one-dimensional linear array composed of four antenna elements, with an antenna spacing of d, such as... Figure 6 As shown.

[0033] The OBU transmits radio frequency signals, and the array antenna receives the signals as follows: , , , The corresponding amplitude is , , , Calculate the mean M and standard deviation S, and calculate the magnitude difference coefficient. .

[0034] Calculate the autocorrelation matrix Scan the power spectrum to obtain the azimuth angle. and power spectrum curve .

[0035] The direction weighting coefficients are used to calculate the scanning angle range. .

[0036] According to the power spectrum curve Calculate the peak power coefficient .

[0037] Depend on and Determining the azimuth angle based on the relationship between the value and the set threshold Reliability.

[0038] Specific Application Example 2: Reliability Determination of Two-Dimensional Array Antenna Positioning An array antenna consists of two mutually perpendicular linear arrays composed of eight antenna elements, with a spacing of d between the linear array antennas, such as... Figure 7As shown.

[0039] The OBU transmits radio frequency signals, and the array antenna receives the signals as follows: , , , , , , , The corresponding amplitude is , , , , , , , Calculate the mean M and standard deviation S, and calculate the magnitude difference coefficient. .in The transverse array antenna consists of antenna elements 1-4. The received signal of the transverse array antenna is... Find the horizontal autocorrelation matrix By scanning the power spectrum, the lateral azimuth angle can be obtained. and transverse power spectrum curve .

[0040] The direction weighting coefficients are used to calculate the scanning angle range. .

[0041] Based on the transverse power spectrum curve Calculate the peak power coefficient of the transverse power spectrum .

[0042] The longitudinal array antenna consists of antenna elements 5-8. The received signal of the longitudinal array antenna is... Find the longitudinal autocorrelation matrix Scan the power spectrum to obtain the longitudinal azimuth angle. and longitudinal power spectrum curve .

[0043] The direction weighting coefficients are used to calculate the scanning angle range. .

[0044] Based on the longitudinal power spectrum curve Calculate the peak power coefficient of the longitudinal power spectrum .

[0045] Use lateral azimuth and longitudinal azimuth The coordinates of the OBU were calculated using the RSU installation parameters.

[0046] From the amplitude difference coefficient Transverse power spectral peak coefficient Longitudinal power spectral peak coefficient The values ​​of these three coefficients determine whether the OBU positioning result is reliable, and output a valid positioning result and a judgment result.

[0047] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0048] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0049] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0050] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A system for determining the reliability of OBU positioning results, characterized in that, include: The array antenna, composed of multiple antenna elements, is used to receive radio frequency signals transmitted by the target OBU and send the multiple radio frequency signals to the downconversion receiving channel and the digital signal processing module respectively. The downconversion receiving channel is used to convert multiple received radio frequency signals into multiple low-frequency analog signals and send the multiple low-frequency analog signals to the AD conversion module; The AD conversion module is used to convert multiple received low-frequency analog signals into multiple digital signals, and send the multiple digital signals to the digital signal processing module; A digital signal processing module is used to calculate the amplitude of multiple received digital signals, as well as the average and standard deviation of the amplitudes. Based on the average and standard deviation, it determines the amplitude difference coefficient corresponding to the target OBU. Based on the DBF algorithm, it determines the location of the target OBU through multiple received radio frequency signals and obtains the power spectrum curve of the target OBU, as well as the first peak and second peak of the power spectrum curve. Based on the first peak and second peak, it determines the power spectrum peak coefficient. The amplitude difference coefficient and the power spectrum peak coefficient are compared with a preset threshold to determine whether the location of the target OBU is reliable.

2. The system according to claim 1, characterized in that, Each antenna element of the array antenna is connected to a corresponding down-conversion receiving channel, and each down-conversion receiving channel is connected to a corresponding AD conversion module. The AD conversion module sends the signal to the digital signal processing module.

3. The system according to claim 1, characterized in that, The downconversion receiving channel includes: a low-noise amplifier (LNA), a synchronous mixer, a filter, and an intermediate frequency amplifier.

4. The system according to claim 1, characterized in that, Calculate the amplitude of multiple received digital signals, as well as the average and standard deviation of the amplitudes. Based on the average and standard deviation, determine the amplitude difference coefficient corresponding to the target OBU, including: Assume the array antenna is a one-dimensional uniform linear array composed of N antenna elements, and the incident angle of the target OBU is... The spacing between the antenna elements is d, and the signals received by the array antenna are X1, X2, ..., X... N Obtain the amplitude of each signal as A1, A2, ..., A N Calculate the average M and standard deviation S of N amplitudes using the following formula: Define amplitude difference coefficient The standard deviation of the amplitude divided by the mean of the amplitude: .

5. The system according to claim 1, characterized in that, Based on the DBF algorithm, the location of the target OBU is determined by receiving multiple radio frequency signals, and the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power spectrum curve, are obtained. Based on the first peak value and the second peak value, the power spectrum peak coefficient is determined, including: The N signals received by the array antenna can be represented as set up yes The conjugate transpose of the given information gives the autocorrelation matrix of the array antenna as follows: The DBF algorithm performs a power spectrum scan on the autocorrelation matrix to obtain the power spectrum. The curve is as follows: in, The direction weighting coefficients are used to calculate the scanning angle range. ; Obtain the maximum peak value V1 and the second peak value V2 of the power spectrum curve; Define the peak power coefficient Divide the second peak by the first peak: .

6. The system according to claim 1, characterized in that, The amplitude difference coefficient and the peak power spectrum coefficient are compared with preset thresholds to determine whether the location of the target OBU is reliable, including: Set amplitude difference coefficient threshold Set the power spectrum peak coefficient threshold When the amplitude difference coefficient Less than And the peak power spectral density Less than The DBF localization result was deemed reliable.

7. A method for determining the reliability of OBU positioning results, characterized in that, include: The radio frequency signal transmitted by the target OBU is acquired through the array antenna; Convert multiple radio frequency signals into multiple digital signals; Calculate the amplitude of the plurality of digital signals, as well as the average value and standard deviation of the amplitude, and determine the amplitude difference coefficient corresponding to the target OBU based on the average value and standard deviation; Based on the DBF algorithm, the location of the target OBU is determined by multiple received radio frequency signals, and the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power spectrum curve, are obtained. Based on the first peak value and the second peak value, the power spectrum peak coefficient is determined. The amplitude difference coefficient and the peak power spectrum coefficient are compared with preset thresholds to determine whether the location of the target OBU is reliable.

8. The method according to claim 7, characterized in that, Calculate the amplitude of the plurality of digital signals, as well as the average and standard deviation of the amplitudes. Based on the average and standard deviation, determine the amplitude difference coefficient corresponding to the target OBU, including: Assume the array antenna is a one-dimensional uniform linear array composed of N antenna elements, and the incident angle of the target OBU is... The spacing between the antenna elements is d, and the signals received by the array antenna are X1, X2, ..., X... N Obtain the amplitude of each signal as A1, A2, ..., A N Calculate the average M and standard deviation S of N amplitudes using the following formula: Define amplitude difference coefficient The standard deviation of the amplitude divided by the mean of the amplitude: .

9. The method according to claim 7, characterized in that, Based on the DBF algorithm, the location of the target OBU is determined by receiving multiple radio frequency signals, and the power spectrum curve of the target OBU, as well as the first peak value and the second peak value of the power spectrum curve, are obtained. Based on the first peak value and the second peak value, the power spectrum peak coefficient is determined, including: The N signals received by the array antenna can be represented as set up yes The conjugate transpose of the given information gives the autocorrelation matrix of the array antenna as follows: The DBF algorithm performs a power spectrum scan on the autocorrelation matrix to obtain the power spectrum. The curve is as follows: in, The direction weighting coefficients are used to calculate the scanning angle range. ; Obtain the maximum peak value V1 and the second peak value V2 of the power spectrum curve; Define the peak power coefficient Divide the second peak by the first peak: .

10. The method according to claim 7, characterized in that, The amplitude difference coefficient and the peak power spectrum coefficient are compared with preset thresholds to determine whether the location of the target OBU is reliable, including: Set amplitude difference coefficient threshold Set the power spectrum peak coefficient threshold When the amplitude difference coefficient Less than And the peak power spectral density Less than The DBF localization result was deemed reliable.

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