PDOA-based three-antenna direction finding method, system and device, and storage medium

Abstract

The invention discloses a PDOA-based three-antenna direction finding method, system and device and a storage medium, and relates to the technical field of radio positioning, and the method comprises the steps: setting three antennas, and placing the three antennas according to a set included angle; receiving data and carrying out data preprocessing calculation; filtering the preprocessed data for the first time through a first filtering method; filtering the data filtered for the first time for the second time through a second filtering method; performing three-antenna angle adjustment on the data filtered for the second time according to a first compensation method; designing a buffer for third filtering; and performing fourth filtering according to a third filtering result, and confirming a final angle. According to the method, errors caused by a multi-path effect or environmental interference are reduced, the robustness is enhanced, the effective working angle range is expanded, the accuracy of results can be further improved through the multi-stage verification and screening process, and a more complex angle measurement algorithm is supported.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio positioning, and particularly relates to a three-antenna direction finding method, system, device, and storage medium based on PDOA. Background Art

[0002] The PDOA (Phase-Difference-of-Arrival) direction finding technology is a unique positioning technology of UWB. It determines the direction of a signal by using the phase difference of the signal arriving at two antennas. The direction of the signal source can be calculated through computation. In the existing direction finding technologies of single and dual antennas, due to environmental differences, the angle estimation accuracy will be lost, resulting in limitations in the angle measurement accuracy and reliability. Specifically, the following points are included: 1. Limited angle measurement accuracy: When the signal source is on the extension line of the connection between two antennas, ambiguity problems may occur. If the antenna spacing is too large, it may exceed the range of the signal wavelength, resulting in a phase difference exceeding 360 degrees and phase ambiguity; if the spacing is too small, it is difficult to distinguish subtle angle changes, reducing the angle resolution. 2. Insufficient robustness: If one of the antennas is interfered with or blocked, the performance of the entire system will decrease significantly because only one reference point remains. Facing multipath effects and environmental noise interference, the adaptability and correction ability of the dual-antenna system are limited. 3. Weak coverage and angle verification mechanism: Due to the small number of data points of single and dual antennas, the ability to handle complex reflection paths and occlusion problems is weak. The signal undergoes reflection, refraction, etc., forming multiple propagation paths. This will cause the received signal to contain components with multiple different phases and amplitudes, thus affecting the accuracy of PDOA. 4. Limited redundancy and fault tolerance: When one antenna fails, the other antenna working alone will cause a significant reduction in accuracy or even complete loss of direction finding ability. At the same time, the dual-antenna system lacks sufficient redundancy to cope with sudden environmental changes or hardware failures. Summary of the Invention

[0003] In view of the above existing problems, the present invention is proposed.

[0004] Therefore, the technical problem solved by the present invention is: to solve the problem of inaccurate angle measurement in the existing single and dual antenna direction finding systems. For single and dual antennas, affected by the environment, the angle jitters severely. By introducing a three-antenna direction finding algorithm based on PDOA (Phase Difference of Arrival), the angle measurement accuracy of the system is improved.

[0005] The optimal interval and angle for placing three antennas, improper placement will cause phase ambiguity problems. Due to wavelength limitations, the phase difference repeats, making it difficult to determine the true signal arrival angle. If the antenna spacing is not properly selected, it is easily affected by multipath effects in a complex environment, thereby reducing the direction finding accuracy.

[0006] The present invention adopts a three - antenna direction - finding technology, places three antennas at a specific included angle, and designs a signal - processing algorithm. By receiving the measurement values of the three antennas and processing them through the algorithm, this system can ultimately be used for more complex angle - measurement tasks.

[0007] Design a three - antenna layout, where one antenna is placed horizontally, and the other two antennas are placed at an included angle of 50° with the horizontal direction, and achieve a signal coverage of 120° in the forward direction while ensuring its accuracy and reliability.

[0008] To solve the above - mentioned technical problems, the present invention provides the following technical solutions: A three - antenna direction - finding method based on PDOA, including: setting three antennas and placing them at a set included - angle; receiving data and performing data pre - processing calculations; filtering the pre - processed data for the first time through a first filtering method; filtering the data passed through the first filtering for the second time through a second filtering method; adjusting the angles of the three antennas for the data passed through the second filtering according to a first compensation method; designing a buffer counter for the third filtering; and performing a fourth filtering according to the result of the third filtering to confirm the final angle.

[0009] As a preferred solution of the three - antenna direction - finding method based on PDOA according to the present invention, wherein: the data pre - processing includes extracting PDOA, TDOA, and RSSI from the received data and calculating the overall average values of PDOA, TDOA, and RSSI; converting the original phase difference into an angle, calculating AOA through a first calculation method, and at the same time, combining the obtained AOA result with a preset calibration factor value of 0.95 to perform AOA angle conversion to obtain a new AOA value; where PDOA is the original phase difference, TDOA is the time difference, RSSI is the signal strength, and AOA is the angle of arrival.

[0010] As a preferred solution of the three - antenna direction - finding method based on PDOA according to the present invention, wherein: the first filtering includes setting a first threshold range; filtering the new AOA value through a first filtering method; the new AOA values exceeding the first threshold range will be considered inaccurate measurements and discarded; the new AOA values not discarded are input into the second filtering.

[0011] As a preferred solution of the three - antenna direction - finding method based on PDOA according to the present invention, wherein: the second filtering includes evaluating the sum of squared residuals and checking the signal strength of the new AOA value passed through the first filtering through a second filtering method to obtain valid measurement data.

[0012] As a preferred embodiment of the three-antenna direction finding method based on PDOA according to the present invention, wherein: the angle adjustment includes adjusting the angle obtained from the effective measurement data according to the actual installation angles of three antennas, namely antenna A, antenna B, and antenna C. The angle of antenna A is increased by 50°, the angle of antenna B is decreased by 50°, and the angle of antenna C remains unchanged. At the same time, the buffer counter corresponding to each antenna is updated.

[0013] As a preferred embodiment of the three-antenna direction finding method based on PDOA according to the present invention, wherein: the third filtering includes setting two buffer counters; the first buffer counter tracks the number of times the three antennas continuously receive valid signals. When any one of the antennas continuously receives valid signals, the count of the first buffer counter of the current antenna is incremented. When the remaining antennas receive signals, the count of the first buffer counter is decremented. After counting, different weights are selected for each antenna; the second buffer counter performs the weight selection for each antenna and records the number of times the antenna is finally selected. Each time the value corresponding to the antenna is selected, the count of the second buffer counter is incremented for additional filtering. When the results detected by the same antenna for 5 consecutive times are the same, the results are adopted; the antenna combination selection includes single-antenna selection, combination selection, C-antenna priority, and backup selection.

[0014] As a preferred embodiment of the three-antenna direction finding method based on PDOA according to the present invention, wherein: the third filtering further includes that when any one of the antennas meets the specified first condition, single-antenna selection is performed, and it is considered that the measurement result of the current antenna is reliable, and the angle of the current antenna is selected and the corresponding weight is increased; if none of the antennas meets the first condition, combination selection is performed, and the three antennas are combined to determine whether the second condition is met. When the selected combination meets the second condition, the angle with the smaller absolute value of AOA among the two antennas is selected and the corresponding weight is increased; when the selected combination does not meet the second condition, antenna C is selected, and if the third condition is met, the corresponding weight of antenna C is increased; when all conditions are not met, the antenna that meets the fourth condition is selected from antenna A or antenna C, and the corresponding weight is increased.

[0015] As a preferred embodiment of the three-antenna direction finding method based on PDOA according to the present invention, wherein: the fourth filtering includes selecting the antenna with the largest weight according to the result of the third filtering, incrementing the value of the second buffer counter of this antenna, and decrementing the values of the second buffer counters of the remaining two antennas; when the consecutive measurement data results from the same antenna meet the specified quantity, the average value and standard deviation of the consecutive measurement data are calculated; when the standard deviation is less than or equal to the second threshold, the average value is subjected to angle conversion.

[0016] Another object of the present invention is to provide a three-antenna direction-finding system based on PDOA. The present invention aims to accurately measure and determine the direction angle of a signal source through a series of steps of data reception, preprocessing, filtering, and angle adjustment. The system improves the measurement accuracy and reliability through multiple filtering and calibration means and is applicable to application scenarios that require high-precision direction detection.

[0017] To solve the above technical problems, the present invention provides the following technical solutions: A three-antenna direction-finding system based on PDOA, comprising: a data processing module, setting three antennas and placing them at a set included angle, receiving data and performing data preprocessing calculations; a first filtering module, filtering the preprocessed data through a first filtering method for the first time; a second filtering module, filtering the data passed through the first filtering through a second filtering method for the second time; an angle adjustment module, adjusting the angle of the data after the second filtering according to a first compensation method; a third filtering module, designing a buffer counter for the third filtering; a fourth filtering module, performing a fourth filtering according to the result of the third filtering to confirm the final angle.

[0018] A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that when the processor executes the computer program, it implements the steps of a method configured by a three-antenna direction-finding method based on PDOA.

[0019] A computer-readable storage medium, having a computer program stored thereon, characterized in that when the computer program is executed by a processor, it implements the steps of a method configured by a three-antenna direction-finding method based on PDOA.

[0020] Advantages of the present invention: The present invention uses three antennas to provide more data points, which helps to more accurately determine the direction of the signal source. By comparing the angles of arrival (AOA) from three different positions, errors caused by multipath effects or environmental interference can be reduced, improving the angle measurement accuracy; The three-antenna system can better handle problems such as signal strength changes, reflections, and occlusions. If the signal received by one antenna is interfered with, the data from the other two antennas can help correct errors or fill in information gaps, enhancing robustness; In some cases, the signal in a specific direction may be weak for one antenna but strong for other antennas. The three-antenna setup ensures that even when the performance of one antenna is poor, reliable data can still be obtained from the other two antennas, thus expanding the effective working angle range and achieving better coverage; The three-antenna scheme includes complex filtering logic to determine which antenna provides the most reliable data and decides the final angle through weight assignment. This multi-level verification and screening process can further improve the accuracy of the results; When one antenna fails, the remaining two antennas can still continue to work and maintain basic functions without complete failure. In addition, a self-check function can be implemented at the software level to detect and exclude problematic antenna readings; With the additional dimensional information provided by the third antenna, more complex and advanced algorithms can be used for position calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, where:

[0022] Figure 1 It is the overall flowchart of a PDOA three-antenna direction finding method provided by the first embodiment of the present invention.

[0023] Figure 2 It is the antenna layout diagram of a PDOA three-antenna direction finding method provided by the first embodiment of the present invention.

[0024] Figure 3 It is the module diagram of a PDOA three-antenna direction finding system provided by the second embodiment of the present invention.

[0025] Figure 4 It is the experimental data point diagram of a single-antenna of a PDOA three-antenna direction finding method provided by the fourth embodiment of the present invention.

[0026] Figure 5The final angle data distribution diagram of a PDOA three - antenna direction finding method provided for the fourth embodiment of the present invention. Detailed implementation manners

[0027] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention with reference to the accompanying drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0029] Embodiment 1, referring to Figure 1 - Figure 2 , which is the first embodiment of the present invention. This embodiment provides a PDOA three - antenna direction finding method, including:

[0030] Step S1: Set three antennas and place them at a set included - angle. Place the antennas with reference to Figure 2 the antenna layout diagram.

[0031] Step S2: Receive data and perform data pre - processing calculations.

[0032] ① Receive and pre - process data: Extract the original phase difference (PDOA), time difference (TDOA), and signal strength (RSSI) from the received data.

[0033] Convert the PDOA value to the range of - 180° to 180°, and convert PDOA to an angle value PDOA deg :

[0034] PDOA deg =(PDOA / 2048)*(180 / π)

[0035] Calculate the remainder of, to obtain an angle in the range of 0 - 360°, and then subtract 180° to get an angle in the range of - 180° to 180°, to obtain a new angle value PDOA deg ':

[0036] PDOA deg '=(PDOA deg +540)mod(360° - 180°)

[0037] ② Calculate the average value: For a set of received data, calculate the average values of PDOA, TDOA, and RSSI.

[0038] Among them, 540.0f represents the floating-point value 540.0, and its function is to convert any original angle value into the standard range of -180° to 180° by adjusting the offset of the phase difference angle (PDOA).

[0039] It should be noted that the first calculation method can adopt the arcsine function calculation method, or the maximum likelihood estimation method, or the phase comparison method, etc. In an embodiment of the present invention, the first calculation method adopts the arcsine function to calculate AOA.

[0040] ③ Calculate AOA: Convert the average PDOA angle to radians:

[0041]

[0042] Use the arcsine function to calculate the angle of arrival (AOA), and divide the result by a calibration factor of 0.95:

[0043]

[0044] Finally, convert the AOA value back to the angular unit:

[0045]

[0046] Among them, PDOA avg represents the average value of 5 PDOAs, PDOA rad represents the PDOA radian value, AOA rad represents the AOA radian value, and AOA represents the AOA angle value.

[0047] Step S3: First filter the preprocessed data through the first filtering method.

[0048] Specifically, set the first threshold range. In an embodiment of the present invention, the first threshold range is set to -60° to 60°, that is, only the measurement results with the AOA value between -60° and 60° are retained.

[0049] It should be noted that the first filtering method can adopt the AOA range screening method, or the data consistency and signal strength verification method, or the AOA value change rate screening method, the signal strength screening method, the noise level screening method, the sliding window average screening, etc. In an embodiment of the present invention, the first filtering method adopts the AOA range screening method.

[0050] Filter the new AOA values through the AOA range screening.

[0051] New AOA values exceeding the first threshold range will be considered inaccurate measurements and discarded.

[0052] The new AOA values that have not been discarded are input into the second filtering.

[0053] Step S4: Filter the data that has passed the first filtering through a second filtering method.

[0054] The new AOA values after the first filtering are evaluated for the sum of squared residuals and signal strength checked through the second filtering method to obtain valid measurement data.

[0055] It should be noted that the second filtering method can adopt an AOA range screening method, or a data consistency and signal strength verification method, or an AOA value change rate screening method, a signal strength screening method, a noise level screening method, a moving window average screening method, etc. In an embodiment of the present invention, the second filtering method adopts a data consistency and signal strength verification method.

[0056] First, perform an evaluation of the sum of squared residuals. Calculate the sum of squared residuals of 10 consecutive data points, and only retain the data with a value less than 100 to ensure the consistency and reliability of the measurement:

[0057]

[0058] Among them, AOAWaveWeight is the standard deviation of the phase difference data, PDOA avg is the average value of 10 phase difference data in the window, PDOA duff is each phase difference data in the window, PDOA avg_cnt is the total number of phase difference data in the window, which is 10 in this embodiment, PDOA duff [i] is the i-th phase difference data, and i is the variable index.

[0059] Secondly, perform a signal strength check, and only retain the valid measurement data with a signal strength between -100 dBm and 0 dBm.

[0060] Step S5: Adjust the angles of the three antennas according to the first compensation method for the data after the second filtering.

[0061] The angle adjustment is the antenna position compensation. According to the angle of the antenna placement, the measured direction angle based on the antenna is converted into the direction angle based on the device.

[0062] Specifically: Adjust the angles obtained from the valid measurement data according to the actual installation angles of the three antennas (i.e., antenna A, antenna B, and antenna C). Antenna A is increased by 50°, antenna B is decreased by 50°, antenna C remains unchanged, and at the same time, update the buffer counter corresponding to each antenna.

[0063] Each adjustment involves the same addition and subtraction changes.

[0064] Step S6: Design a buffer for the third filtering.

[0065] Set two buffer counters.

[0066] The first buffer counter is used to track the number of times the corresponding antennas (A, B, C) continuously receive valid signals. Their function is to record which antenna provides more stable or more frequent valid measurements; when any antenna continuously receives valid signals, the first buffer counter of the current antenna increases. Specifically: add 5 each time, add 1 if it is greater than 50 and less than 150, and do not add if it is greater than 150.

[0067] When the remaining antennas receive signals, the first buffer counter decreases by 2. After counting, each antenna selects a different weight; this helps to assign different weights to each antenna in subsequent logic.

[0068] The second buffer counter is used for weight selection of each antenna. Each time the value obtained by the corresponding antenna is selected, the count of the second buffer counter increases by 1 for the third filtering. When the results detected for the same antenna are the same for 5 consecutive times, the result is adopted.

[0069] The value obtained by the corresponding antenna refers to the valid measurement data after the antenna installation angle adjustment in step S5.

[0070] It should also be noted that the antenna combination selection includes single antenna selection, combination selection, C antenna priority, and standby selection.

[0071] When any antenna meets the specified first condition, single antenna selection is performed, and it is considered that the measurement result of the current antenna is reliable, and the angle of the current antenna is selected to increase the corresponding weight.

[0072] Among them, in an embodiment of the present invention, the first condition includes: ① The first buffer counter is greater than 100; ② The signal strength is higher than -80 dBm; ③ AOA * TDOA > 0 or |AOA| < 10°.

[0073] If no single antenna meets the first condition, combination selection is performed. The three antennas are combined and selected from the AC or BC combinations. It is judged whether the second condition is met. When the selected combination meets the second condition, the angle with the smaller absolute value of AOA among the two antennas is selected to increase the corresponding weight.

[0074] Among them, in one embodiment of the present invention, the second condition includes: ① The buffer counters of both the AC or BC antennas are greater than 20; ② The signal strength of one of the antennas is higher than that of the unselected antenna; ③ The angle difference of the selected combination + 20 offset is less than the angle difference of the other pair of combinations.

[0075] When the selected combination does not meet the second condition, then the C antenna is selected. If the third condition is met, then the corresponding weight of the C antenna is increased, and the weight is increased by 2.

[0076] Among them, in one embodiment of the present invention, the third condition includes: ① The angle of the C antenna is less than 30°; ② The first buffer counter is greater than 40; ③ AOA * TDOA > 0.

[0077] When all conditions are not met, select the antenna that meets the fourth condition from the A antenna or the C antenna, and increase the corresponding weight.

[0078] Among them, in one embodiment of the present invention, the fourth condition includes: ① The first buffer counter is greater than 40; ② The signal strength is at least 5 dBm higher than the other; ③ The angle of AOA * TDOA > 0 or |AOA| < 10°.

[0079] Step S7: Perform the fourth filtering based on the third filtering result to confirm the final angle.

[0080] According to the result of the third filtering, select the antenna with the largest weight, add 1 to the value of the second buffer counter of this antenna, and subtract 1 from the values of the second buffer counters of the remaining two antennas.

[0081] When the continuous measurement data results from the same antenna meet the specified quantity, that is, the value of the second buffer counter is greater than 5, then calculate the average value and standard deviation of the continuous measurement data.

[0082] When the standard deviation is less than or equal to the second threshold, where the second threshold is set to 0.5, then convert the average value into the final angle value within the range of 0° to 360°.

[0083] Embodiment 2, referring to Figure 3 , is an embodiment of the present invention. This embodiment provides a three-antenna direction finding system based on PDOA, including: a data processing module 100, a first filtering module 200, a second filtering module 300, an angle adjustment module 400, a third filtering module 500, and a fourth filtering module 600.

[0084] The data processing module 100 sets three antennas and places them at the set included angle, receives data and performs data preprocessing calculations.

[0085] Specifically, three antennas (A, B, and C) are set and placed at a preset angle. Signal data from the three antennas are received, and the original phase difference (PDOA), time difference (TDOA), and received signal strength (RSSI) are extracted. The PDOA value is converted to the range of -180° to 180°, the average values of PDOA, TDOA, and RSSI are calculated, the angle of arrival (AOA) is calculated using the arcsine function, and calibration is performed.

[0086] Extract and preprocess the signal data to provide basic data for subsequent filtering and angle calculation.

[0087] The first filtering module 200 performs the first filtering on the preprocessed data through the first filtering method.

[0088] Specifically, the first threshold range of the AOA value is set to -60° to 60°. According to the set first threshold range, the data with AOA values within this range are selected, and the data outside the range are discarded.

[0089] Remove the data that may be inaccurate in the initial measurement to improve the accuracy and efficiency of subsequent processing.

[0090] The second filtering module 300 performs the second filtering on the data passed through the first filtering through the second filtering method.

[0091] Specifically, calculate the sum of the squares of the residuals of 10 consecutive data points, retain the data points less than 100, and only retain the data with signal strength between -100 dBm and 0 dBm.

[0092] Further ensure the reliability and consistency of the data and exclude outliers.

[0093] The angle adjustment module 400 adjusts the angle of the data after the second filtering according to the first compensation method.

[0094] Specifically, angle compensation: Adjust the angle obtained from the effective measurement data according to the actual installation angles of the three antennas.

[0095] Convert the direction angle based on the antenna to the direction angle based on the device to compensate for the deviation caused by the antenna placement.

[0096] The third filtering module 500 designs a buffer for the third filtering.

[0097] Specifically, set two buffer counters to track the effective signal reception of the antennas, assign different weights to each antenna according to the status of the buffer counters, and perform single-antenna selection, combined selection, or other selections according to different conditions.

[0098] Assign weights to different antennas or antenna combinations to select the most reliable antenna or combination for subsequent processing.

[0099] The fourth filtering module 600 performs a fourth filtering based on the result of the third filtering to confirm the final angle.

[0100] Specifically, according to the result of the third filtering, the antenna with the largest weight is selected, and the average value and standard deviation of its continuous measurement data are calculated. When the standard deviation is less than or equal to the second threshold, the average value is converted into the final angle value.

[0101] Determine the most accurate and reliable angle measurement result from the data that has undergone the previous filtering and weight assignment.

[0102] Embodiment 3, the third embodiment of the present invention, which is different from the previous two embodiments in that:

[0103] Specifically, if the method for direction finding using three antennas based on PDOA is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that makes a contribution to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0104] The computer program includes several instructions that can cause a computer device (such as a server, a personal computer, or other network devices) to execute the following steps:

[0105] Set three antennas A, B, and C and place them at a preset included angle; receive signal data, extract the original phase difference (PDOA), time difference (TDOA), and signal strength (RSSI), perform a range conversion on the PDOA value to make it between -180° and 180°, calculate the average values of PDOA, TDOA, and RSSI, convert the average PDOA into radians, and use the arcsine function to calculate the angle of arrival (AOA). Divide the calculated AOA value by the calibration factor 0.95 and convert it back to the angle unit.

[0106] Set the first threshold range to -60° to 60°. Through the AOA range screening method, retain the measurement results with AOA values between -60° and 60°, and discard the AOA values outside the first threshold range; evaluate the sum of squared residuals for the data after the first filtering, calculate the sum of squared residuals for 10 consecutive data points, and only retain the data with a value less than 100. Conduct a signal strength check and only retain the data with a signal strength between -100 dBm and 0 dBm.

[0107] According to the actual installation angles of antennas A, B, and C, adjust the angles obtained from the valid measurement data. Increase the angle of antenna A by 50°, decrease the angle of antenna B by 50°, and keep the angle of antenna C unchanged. Update the buffer counters corresponding to each antenna; design a buffer, set the first buffer counter and the second buffer counter, track the number of times each antenna continuously receives valid signals, and adjust the first buffer counter. Make single-antenna selection, combined selection, C-antenna priority, and standby selection according to the set conditions, assign different weights to each antenna, and increase the corresponding weights; according to the results of the third filtering, select the antenna with the largest weight, calculate the average value and standard deviation of the continuous measurement data. When the standard deviation is less than or equal to the second threshold (set to 0.5), convert the average value to the final angle value within the range of 0° to 360°, and output the final angle value as the direction finding result.

[0108] The logic and / or steps represented in the flowchart or described otherwise herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0109] More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other appropriate processing as necessary, and then stored in a computer memory.

[0110] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits with logic gate circuits for implementing logical functions on data signals, application specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

[0111] The computer program of the present invention further supports real-time operations. For example, the computer program of the present invention should be able to receive signal data from three antennas in real time and perform real-time preprocessing, including extracting parameters such as PDOA, TDOA, and RSSI; adopting efficient computational algorithms such as fast Fourier transform (FFT) and matrix operations to reduce the computational time and ensure real-time performance; using multi-threaded or asynchronous processing techniques in program design so that operations such as data reception, preprocessing, filtering, and angle calculation can be performed in parallel to improve the processing speed; according to changes in the real-time environment, the program can dynamically adjust the threshold range and filtering conditions to adapt to different signal environments and measurement requirements.

[0112] Example 4, referring to Figure 4 - Figure 5 , which is an embodiment of the present invention, provides a three-antenna direction finding method based on PDOA. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0113] As Figure 4 are the experimental data of the single-eye antenna. It can be seen from the scatter plots of the experimental data of these single-eye antennas that the noise points are relatively obvious, indicating that the measurement accuracy of the single-eye antenna is insufficient.

[0114] According to the operation steps in Example 1, the final angle value is obtained by collecting the original data. As Figure 5 shown, it is the distribution diagram of the final angle data.

[0115] As shown in Table 1 are the original data of the three antennas.

[0116] Table 1 Original Antenna Data Table

[0117]

[0118]

[0119] The scores of the three antennas are calculated, as shown in Table 2.

[0120] Table 2 Antenna Score Table

[0121] Score Antenna A Antenna B Antenna C 1 -2 -2 5 2 -2 -2 5 3 -2 -2 5 4 -2 -2 5 5 -2 -2 5 ... ... ... ... 3663 -2 -2 5 3664 -2 -2 5 3665 -2 -2 5 3666 -2 -2 5 ... ... ... ... 8938 -2 -2 5 8939 -2 -2 5 8940 -2 -2 5 8941 -2 -2 5

[0122] The final calculation obtains the total scores of the three antennas, as shown in Table 3.

[0123] Table 3 Antenna Total Score Table

[0124]

[0125]

[0126] The obtained final data is shown in Table 4.

[0127] Table 4 Final Data Table

[0128]

[0129]

[0130] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A three-antenna direction finding method based on PDOA, characterized in that: Including, Set three antennas and place them at a set included angle. Receive data and perform data preprocessing calculations. First filter the preprocessed data through a first filtering method. Second filter the data passed through the first filter through a second filtering method. Adjust the angles of the three antennas according to the first compensation method for the data after the second filter. Design a buffer counter for the third filter. Perform a fourth filter based on the result of the third filter to confirm the final angle.

2. The PDOA three-antenna direction finding method according to claim 1, wherein: The data preprocessing includes, Extract PDOA, TDOA, and RSSI from the received data and calculate the overall average values of PDOA, TDOA, and RSSI. Convert the original phase difference into an angle, calculate AOA through a first calculation method, and at the same time, combine the obtained AOA result with a preset calibration factor value of 0.95 to perform AOA angle conversion to obtain a new AOA value. Wherein, PDOA is the original phase difference, TDOA is the time difference, RSSI is the signal strength, and AOA is the angle of arrival.

3. The PDOA three - antenna direction - finding method according to claim 1, characterized in that: The first filter includes, Set a first threshold range. Filter the new AOA value through the first filtering method. The new AOA values outside the first threshold range will be considered inaccurate measurements and discarded. The new AOA values not discarded are input into the second filter.

4. The PDOA three-antenna direction finding method according to claim 3, characterized in that: The second filter includes, Evaluate the sum of squared residuals and check the signal strength of the new AOA value passed through the first filter through a second filtering method to obtain effective measurement data.

5. The PDOA three-antenna direction finding method according to claim 4, characterized in that: The angle adjustment includes, Adjust the angle obtained from the effective measurement data according to the actual installation angles of the three antennas, namely antenna A, antenna B, and antenna C. Antenna A increases by 50°, antenna B decreases by 50°, and antenna C remains unchanged. At the same time, update the buffer counter corresponding to each antenna.

6. The PDOA three-antenna direction finding method according to claim 5, wherein: The third filter includes, Set two buffer counters. The first buffer counter tracks the number of times the three antennas continuously receive effective signals. When any one antenna continuously receives an effective signal, the count of the first buffer counter of the current antenna increases. When the remaining antennas receive signals, the count of the first buffer counter of the current antenna decreases. After counting, different weights are selected for each antenna. The second buffer counter performs weight selection for each antenna, records the number of times the antenna is finally selected, and for each value of the angle adjustment obtained from the effective measurement data corresponding to the antenna, the count of the second buffer counter is incremented by 1, and the third filter is performed. When the results detected by the same antenna are the same for 5 consecutive times, the results are adopted. After the results are adopted, antenna combination selection is performed, where the combination selection includes single antenna selection, combination selection, C antenna priority, and standby selection.

7. The PDOA three-antenna direction finding method according to claim 6, wherein: The third filter also includes, When any one antenna meets the specified first condition, single antenna selection is performed, the measurement result of the current antenna is considered reliable, and the angle of the current antenna is selected to increase the corresponding weight. If none of the antennas satisfies the first condition, combination selection is performed. Three antennas are combined and it is determined whether the second condition is satisfied. When the selected combination satisfies the second condition, the angle with a smaller absolute value of AOA among the two antennas is selected and the corresponding weight is increased. When the selected combination does not satisfy the second condition, antenna C is selected. If the third condition is satisfied, the corresponding weight of antenna C is increased. When all conditions are not satisfied, an antenna that satisfies the fourth condition is selected from antenna A or antenna C, and the corresponding weight is increased.

8. The PDOA three-antenna direction finding method according to claim 7, wherein: The fourth filtering includes According to the result of the third filtering, the antenna with the largest weight is selected, the value of the second buffer counter is incremented by 1, and the values of the second buffer counters of the remaining two antennas are decremented by 1. When the consecutive measurement data results from the same antenna satisfy a specified number, the average value and standard deviation of the consecutive measurement data are calculated. When the standard deviation is less than or equal to the second threshold, the average value is subjected to angle conversion.

9. A three - antenna direction - finding system based on PDOA, characterized in that, including A data processing module (100) that sets three antennas and places them at a set included angle, receives data, and performs data preprocessing calculations. A first filtering module (200) that performs a first filtering on the preprocessed data by a first filtering method. A second filtering module (300) that performs a second filtering on the data passed through the first filtering by a second filtering method. An angle adjustment module (400) that adjusts the angle of the data passed through the second filtering according to a first compensation method. A third filtering module (500) that designs a buffer counter to perform a third filtering. A fourth filtering module (600) that performs a fourth filtering according to the result of the third filtering to confirm the final angle.

10. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, the steps of a PDOA three-antenna direction finding method according to any one of claims 1 to 8 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, the steps of a PDOA three-antenna direction finding method according to any one of claims 1 to 8 are implemented.

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