A three-dimensional fusion positioning method and system based on angle of arrival and RSSI value

Abstract

This invention discloses a three-dimensional fusion positioning method and system based on angle of arrival (AHA) and RSSI (Reference Signal Indicator Score). The method includes: a direction-finding device acquiring the AHA (angle of arrival, pitch angle, azimuth angle) and RSSI value of a signal and removing outliers; based on the initial altitude, AHA, and direction-finding device position information, combined with the pitch and azimuth direction-finding accuracy, determining the target's location range on the Z0 plane and assigning weights, with the center of the region with the largest cumulative weight on the Z0 plane used as the target's estimated position (X0, Y0); combining the pitch direction-finding accuracy, determining the target's location range on the (X0, Y0) line and assigning weights, with the center of the region with the largest cumulative weight on the (X0, Y0) line used as the target's estimated position Z1; and obtaining the target's three-dimensional estimated position (X0, Y0, Z1) through iterative convergence. This invention features improved positioning accuracy and reduced algorithm complexity through three-dimensional region weighted search, which is beneficial for supporting the construction of low-altitude economic space target control systems.

Description

Technical Field

[0001] This invention relates to the field of space target orientation and positioning technology, and in particular to a three-dimensional fusion positioning method and system based on the Angle of Arrival (AOA) and Received Signal Strength Indication (RSSI) values. It is particularly suitable for monitoring active broadcast signals and calculating the spatial position of low-altitude airspace aircraft (such as UAVs), and can be widely applied to the construction of space target positioning and tracking systems in scenarios such as low-altitude economy, urban air traffic management, and UAV supervision. Background Technology

[0002] During flight, unmanned aerial vehicles (UAVs) should automatically broadcast identification information via Wi-Fi or Bluetooth. UAVs periodically radiate signals such as radio image transmission, remote control, and broadcast messages; however, current AOA positioning systems suffer from issues with positioning accuracy, algorithm complexity, and 3D positioning capabilities.

[0003] This invention addresses the aforementioned problems by utilizing observational information such as the location information of the direction-finding device, the target's angle of arrival (elevation and azimuth), and RSSI values. Combined with the accuracy of elevation and azimuth direction finding, it determines the area where the target exists on the Z0 plane and assigns weights to it. The center of the area with the largest cumulative weight on the Z0 plane is obtained as the target position estimate (X0, Y0), and the center of the area with the largest cumulative weight on the (X0, Y0) line is determined as the target position estimate Z1. Through iterative convergence, the target's three-dimensional position estimate (X0, Y0, Z1) is obtained, thus forming a three-dimensional fusion positioning method based on angle of arrival and RSSI values. Compared to existing positioning methods, this method improves positioning accuracy and reduces algorithm complexity through a three-dimensional region weighted search. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a three-dimensional fusion positioning method and system based on angle of arrival and RSSI value. It has the technical characteristics of improving positioning accuracy and reducing algorithm complexity through three-dimensional region weighted search, which is conducive to supporting the construction of low-altitude economic space target control system.

[0005] To achieve the aforementioned objectives of the invention, the technical solution adopted to solve its technical problems is as follows:

[0006] This invention discloses a three-dimensional fusion positioning method based on angle of arrival and RSSI value, comprising the following steps:

[0007] Step S1: Deploy at least two direction-finding devices with spatiotemporal synchronization capabilities within the detection area, observe the radio signals actively emitted by the target, and obtain the signal angle of arrival and RSSI value observed by each direction-finding device, wherein the angle of arrival includes the pitch angle. Azimuth ;

[0008] Outlier values ​​are removed from the observation data of each direction finding device based on the RSSI value, and the initial target height Z0 is set according to the target prior information.

[0009] Step S2: For each direction finding device, based on its position information, the initial target height Z0, and the measured elevation angle... and azimuth and elevation angle direction finding error and azimuth direction finding error Determine the range of the two-dimensional confidence region where the target may exist on the plane at height Z0;

[0010] And according to the pitch angle And RSSI values, assigning a first weight to each sub-region within the two-dimensional confidence region. 1, where the first weight 1 is positively correlated with the pitch angle θ and also positively correlated with the RSSI value;

[0011] Step S3: Superimpose the confidence region ranges and first weights obtained by each direction finding device in the Z0 plane to obtain the cumulative weight distribution in the Z0 plane;

[0012] Select the region with the largest cumulative weight, and use the center of this region as the estimated horizontal position (X0, Y0) of the target in the Z0 plane;

[0013] Step S4: For each direction finding device, based on the horizontal position estimate (X0, Y0) obtained in step S3, the position of the direction finding device, and the measured elevation angle... and elevation angle direction finding error Determine the range of the one-dimensional confidence region where the target may exist on the (X0,Y0) line;

[0014] Based on the RSSI value, a second weight is assigned to each height sub-interval within the one-dimensional confidence region. 2, where the second weight 2 is positively correlated with the magnitude of RSSI values;

[0015] Step S5: Superimpose the one-dimensional confidence region range and its second weight obtained by all direction finding devices on the (X0,Y0) line to obtain the cumulative weight distribution on the (X0,Y0) line;

[0016] Select the region with the largest cumulative weight, and use the center of this region as the height estimate Z1 of the target on the (X0,Y0) line;

[0017] Step S6: Compare the deviation between the initial target height Z0 and the estimated height Z1, |Z0-Z1|, and set a threshold. ;

[0018] If the deviation is greater than the threshold, assign Z1 to Z0 and repeat S2~S5;

[0019] If the target does not exceed the threshold at least twice consecutively, output the estimated three-dimensional position of the target (X0, Y0, Z1).

[0020] Further, step S1:

[0021] The outlier removal based on RSSI values ​​specifically includes: each direction finding device maintaining a sliding window of historical RSSI values, calculating the mean and standard deviation of RSSI within the window; when a newly observed RSSI value deviates from the mean by more than a preset multiple of the standard deviation, it is determined to be an outlier, and the outlier will not participate in the subsequent positioning process; the preset multiple of the standard deviation is 2 to 4 times.

[0022] Further, step S2:

[0023] The direction-finding device is located at point (x, y, z) in the coordinate system. Based on the target height Z0 and its own height z, the height difference H of the working plane is determined, which is H = Z0 - z. Then, the position of the target on the Z0 plane (x + Hcosθ) is determined. / tan y+Hsin / tan );

[0024] Due to the existence of direction finding error , pitch angle at - ~ + The confidence level is high within the range, and the azimuth angle is within - ~ + The confidence level is relatively high within the range, thus determining the confidence region range corresponding to the target on the Z0 plane, i.e., (x + Hcos( - ) / tan( - ), y+Hsin( - ) / tan( - )), (x+Hcos( + ) / tan( - ), y+Hsin( + ) / tan( - )), (x+Hcos( - ) / tan( + ), y+Hsin( - ) / tan( + )), (x+Hcos( + ) / tan( + ), y+Hsin( + ) / tan( + The area enclosed by the four points forms a fan-shaped ring.

[0025] Specifically, the fan-shaped region is approximated as a rectangular region. The boundary of this rectangular region is determined by the minimum and maximum values ​​of the coordinates of the four boundary points, namely, the rectangular region enclosed by the four points (x_min, y_min), (x_min, y_max), (x_max, y_min), and (x_max, y_max), where x_min = min{x + Hcos( - ) / tan( - ), x+Hcos( + ) / tan( - ), x+Hcos( - ) / tan( + ), x+Hcos( + ) / tan( + )};x_max=max{x+Hcos( - ) / tan( - ), x+Hcos( + ) / tan( - ), x+Hcos( - ) / tan( + ), x+Hcos( + ) / tan( + )};y_min=min{y+Hsin( - ) / tan( - ), y+Hsin( + ) / tan( - ), y+Hsin( - ) / tan( + ), y+Hsin( + ) / tan( + )};y_max=max{y+Hsin( - ) / tan( - ), y+Hsin( + ) / tan( - ), y+Hsin( - ) / tan( + ), y+Hsin( + ) / tan( + )};

[0026] Specifically, the pitch angle confidence range can be set to - ~ + The azimuth confidence range can be set to - ~ + This can further improve the confidence level of the confidence region corresponding to the target on the Z0 plane, but it will increase the algorithm complexity.

[0027] Since the closer the target is to the direction finding device, the larger the elevation angle and the larger the RSSI value, the area confidence weight is designed based on the elevation angle and RSSI value. .

[0028] Further, step S3:

[0029] The weights of each direction finding device in the Z0 plane are superimposed to find the region with the largest cumulative weight in the Z0 plane. The center of this region is used as the estimated position (X0, Y0) of the target in the Z0 plane.

[0030] Further, step S4:

[0031] Based on the target's estimated position (X0, Y0) in the Z0 plane, the elevation angle, and the position of the direction finding device, the target position z+((X0-x) on the (X0, Y0) line is obtained. 2 +(Y0-y) 2 ) 1 / 2 tan ;

[0032] Due to the existence of direction finding error pitch angle at - ~ + The confidence level is high within the range, thus determining the possible range of the target area on the (X0,Y0) line, i.e., z+((X0-x)). 2 +(Y0-y) 2 ) 1 / 2 tan( - )~z+((X0-x) 2 +(Y0-y) 2 ) 1 / 2 tan( + );

[0033] Since the RSSI value increases as the target is closer to the direction finding device, the area confidence weight is designed based on the RSSI value. ;

[0034] Specifically, the pitch angle confidence range can be set to - ~ + This can further improve the confidence level of the confidence region corresponding to the target on the (X0,Y0) line, but it will increase the algorithm complexity.

[0035] Further, step S5:

[0036] The weights of the regions obtained by each direction finding device on the (X0,Y0) line are superimposed to obtain the region with the largest cumulative weight on the (X0,Y0) line. The center of this region is taken as the estimated position Z1 of the target on the (X0,Y0) line.

[0037] Further, step S6:

[0038] Compare the deviations |Z0-Z1| between Z0 and Z1, and set a threshold. ;

[0039] If the deviation is greater than the threshold Then assign Z1 to Z0, and repeat S2~S5;

[0040] If the threshold is not exceeded for three consecutive times Then (X0, Y0, Z1) will be used as the estimated value of the target position;

[0041] Use Z1 as the initial value for the subsequent target height Z0.

[0042] This invention discloses a three-dimensional fusion positioning system based on angle of arrival and RSSI value, comprising at least one observation target, at least two direction-finding devices, and at least one server, wherein:

[0043] The observation target is used to periodically radiate radio signals;

[0044] The direction-finding device possesses spatiotemporal synchronization capabilities, two-dimensional direction-finding capabilities, RSSI estimation capabilities, and outlier identification and removal capabilities; it is used to observe target signals and calculate the arrival and elevation angles of the signals. Azimuth The system estimates the RSSI value of the signal, extracts the signal spectrum characteristics, marks the receiving timestamp, and identifies abnormally large / small values ​​by combining the previously observed RSSI change trend of the same target. Abnormal observation values ​​are not included in the subsequent positioning process. The system also uploads the angle of arrival, RSSI, and spectrum characteristic observation data to the server.

[0045] The server receives observation data reported by each direction-finding device, classifies and correlates the observation data based on the electromagnetic and spatial characteristics of the observed target, sorts it by timestamp, and groups it by positioning time interval. Based on the grouped data, it performs 3D fusion positioning based on angle of arrival (AHA) and RSSI values. It initially sets the target height Z0 based on prior target information, determines the confidence region range corresponding to the target on the Z0 plane by combining the locations of each direction-finding device, and assigns confidence weights to the region based on the pitch angle and RSSI value. The weights of each direction finding device in the corresponding area of ​​the Z0 plane are superimposed to find the area with the largest cumulative weight in the Z0 plane, and the center of this area is used as the estimated position (X0, Y0) of the target in the Z0 plane.

[0046] Based on the target's estimated position (X0, Y0) in the Z0 plane, elevation angle, and direction finding device position, combined with direction finding error... This allows us to determine the potential area of ​​the target along the (X0, Y0) line, and assign confidence weights to the area based on the RSSI value. The weights of the regions obtained by each direction-finding device along the (X0,Y0) line are superimposed to obtain the region with the largest cumulative weight along the (X0,Y0) line. The center of this region is taken as the estimated position Z1 of the target on the (X0,Y0) line; a threshold is set. The deviation |Z0-Z1| between Z0 and Z1 is compared. If the deviation is greater than the threshold, the result is considered as follows: If Z1 is assigned to Z0, the 3D fusion localization process is repeated. If the result does not exceed the threshold three times consecutively... Then (X0, Y0, Z1) will be used as the estimated value of the target position, and Z1 will be used as the initial value of the target height Z0 for the next set of observation data.

[0047] By employing the above technical solutions, this invention has the following advantages and positive effects compared with the prior art:

[0048] 1. This invention conducts in-depth research on the radio direction finding three-dimensional fusion positioning method. By utilizing radio direction finding positioning technology, and through observation information such as the position information of the direction finding device, the target's angle of arrival (elevation angle, azimuth angle), and RSSI value, combined with the direction finding accuracy of the elevation angle and azimuth angle, the range of the area where the target exists is determined and weighted. Through iterative convergence, the estimated value of the target's three-dimensional position is obtained, thus forming a three-dimensional fusion positioning method based on the angle of arrival and RSSI value.

[0049] 2. This invention discloses a three-dimensional fusion positioning system based on angle of arrival and RSSI value, which has the technical characteristics of improving positioning accuracy and reducing algorithm complexity through three-dimensional region weighted search, and is conducive to supporting the construction of low-altitude economic space target control system. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0051] Figure 1This is a schematic diagram of the process of a three-dimensional fusion positioning method based on angle of arrival and RSSI value according to the present invention;

[0052] Figure 2 This is a block diagram of a three-dimensional fusion positioning system based on angle of arrival and RSSI value according to the present invention. Detailed Implementation

[0053] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Example 1

[0055] like Figure 1 As shown, this invention discloses a three-dimensional fusion positioning method based on angle of arrival and RSSI value, comprising the following steps:

[0056] Step S1: Deploy direction-finding devices within the detection area to observe the radio signals actively radiated by the target and obtain the signal's angle of arrival (elevation angle, azimuth angle) and RSSI value. Based on the RSSI value, outlier values ​​are removed from the observation data of each direction-finding device, and the initial target altitude Z0 is set according to prior information;

[0057] Step S2: Based on the initial altitude, angle of arrival, and direction finding device position information, combined with the elevation angle and azimuth angle direction finding accuracy, determine the possible range of the target on the Z0 plane, and assign weights to this range based on the elevation angle and RSSI value.

[0058] Step S3: Superimpose the area range weights obtained by each direction finding device in the Z0 plane to obtain the area with the largest cumulative weight, and use the center of this area as the estimated position (X0, Y0) of the target in the Z0 plane;

[0059] Step S4: Based on the target's estimated position (X0,Y0) in the Z0 plane, pitch angle, and direction finding device position, and combined with the pitch angle direction finding accuracy, determine the possible range of the target's area on the (X0,Y0) line, and assign weights to this range based on the RSSI value.

[0060] Step S5: Superimpose the weights of the regions obtained by each direction finding device on the (X0,Y0) line to obtain the region with the largest cumulative weight, and take the center of the region as the estimated position Z1 of the target on the (X0,Y0) line;

[0061] Step S6: Compare the deviation between Z0 and Z1. If the deviation is greater than the threshold, assign Z1 to Z0 and repeat S2~S5. If the deviation does not exceed the threshold for three consecutive times, then (X0, Y0, Z1) is used as the estimated value of the target position.

[0062] Further, step S1:

[0063] The target periodically emits signals such as radio image transmission, remote control, and broadcast messages;

[0064] There are at least two direction-finding devices deployed within the detection area; specifically, at least one when the height of the observed target is determined.

[0065] The direction finding device has the ability to synchronize in time and space, that is, the direction finding device operates under a unified spatial coordinate system and a unified clock.

[0066] The direction finding device has signal analysis capabilities and can extract spectral and spatial characteristic information from the signal;

[0067] The direction finding device has two-dimensional direction finding capability and calculates the angle of arrival (elevation angle) of the signal. Azimuth Estimate the RSSI value of the signal and mark the received timestamp;

[0068] The direction finding device has the ability to identify and eliminate outliers. By combining the previously observed RSSI change trend of the same target, it can identify abnormal large / small values. Outliers are not included in the subsequent positioning process.

[0069] The target height Z0 is initially set based on prior information about the target.

[0070] Further, step S2:

[0071] The direction-finding device is located at point (x, y, z) in the coordinate system. Based on the target height Z0 and its own height z, the height difference H of the working plane is determined, which is H = Z0 - z. Then, the position of the target on the Z0 plane (x + Hcosθ) is determined. / tan y+Hsin / tan );

[0072] Due to the existence of direction finding error , pitch angle at - ~ + The confidence level is high within the range, and the azimuth angle is within - ~ + The confidence level is relatively high within the range, thus determining the confidence region range corresponding to the target on the Z0 plane, i.e., (x + Hcos( - ) / tan( - ), y+Hsin( - ) / tan( - )), (x+Hcos( + ) / tan( - ), y+Hsin( + ) / tan( - )), (x+Hcos( - ) / tan( + ), y+Hsin( - ) / tan( + )), (x+Hcos( + ) / tan( + ), y+Hsin( + ) / tan( + The area enclosed by the four points forms a fan-shaped ring.

[0073] Specifically, the fan-shaped region is approximated as a rectangular region, that is, the rectangular region enclosed by the four points (x_min, y_min), (x_min, y_max), (x_max, y_min), and (x_max, y_max), where x_min = min{x + Hcos( - ) / tan( - ), x+Hcos( + ) / tan( - ), x+Hcos( - ) / tan( + ), x+Hcos( + ) / tan( + )};x_max=max{x+Hcos( - ) / tan( - ), x+Hcos( + ) / tan( - ), x+Hcos( - ) / tan( + ), x+Hcos( + ) / tan( + )};y_min=min{y+Hsin( - ) / tan( - ), y+Hsin( + ) / tan( - ), y+Hsin( - ) / tan( + ), y+Hsin( + ) / tan( + )};y_max=max{y+Hsin( - ) / tan( - ), y+Hsin( + ) / tan( - ), y+Hsin( - ) / tan( + ), y+Hsin( + ) / tan( + )};

[0074] Specifically, the pitch angle confidence range can be set to - ~ + The azimuth confidence range can be set to - ~ + This can further improve the confidence level of the confidence region corresponding to the target on the Z0 plane, but it will increase the algorithm complexity.

[0075] Since the closer the target is to the direction finding device, the larger the elevation angle and the larger the RSSI value, the area confidence weight is designed based on the elevation angle and RSSI value. .

[0076] Further, step S3:

[0077] The weights of each direction finding device in the Z0 plane are superimposed to find the region with the largest cumulative weight in the Z0 plane. The center of this region is used as the estimated position (X0, Y0) of the target in the Z0 plane.

[0078] Further, step S4:

[0079] Based on the target's estimated position (X0, Y0) in the Z0 plane, the elevation angle, and the position of the direction finding device, the target position z+((X0-x) on the (X0, Y0) line is obtained. 2 +(Y0-y) 2 ) 1 / 2 tan ;

[0080] Due to the existence of direction finding error pitch angle at - ~ + The confidence level is high within the range, thus determining the possible range of the target area on the (X0,Y0) line, i.e., z+((X0-x)). 2 +(Y0-y) 2 ) 1 / 2 tan( - )~z+((X0-x) 2 +(Y0-y) 2 ) 1 / 2 tan( + );

[0081] Since the RSSI value increases as the target is closer to the direction finding device, the area confidence weight is designed based on the RSSI value. ;

[0082] Specifically, the pitch angle confidence range can be set to - ~ + This can further improve the confidence level of the confidence region corresponding to the target on the (X0,Y0) line, but it will increase the algorithm complexity.

[0083] Further, step S5:

[0084] The weights of the regions obtained by each direction finding device on the (X0,Y0) line are superimposed to obtain the region with the largest cumulative weight on the (X0,Y0) line. The center of this region is taken as the estimated position Z1 of the target on the (X0,Y0) line.

[0085] Further, step S6:

[0086] Compare the deviations |Z0-Z1| between Z0 and Z1, and set a threshold. ;

[0087] If the deviation is greater than the threshold Then assign Z1 to Z0, and repeat S2~S5;

[0088] If the threshold is not exceeded for three consecutive times Then (X0, Y0, Z1) will be used as the estimated value of the target position;

[0089] Use Z1 as the initial value for the subsequent target height Z0.

[0090] Example 2

[0091] like Figure 2 As shown, this invention discloses a three-dimensional fusion positioning system based on angle of arrival and RSSI value, comprising at least one target, at least two direction-finding devices, and at least one server, wherein:

[0092] The observation target periodically radiates signals such as radio image transmission, remote control, and broadcast messages;

[0093] The direction-finding device uses satellite time synchronization, or optionally server time synchronization, and has differential positioning capabilities, enabling it to calculate the signal's angle of arrival (elevation angle). Azimuth The system estimates the RSSI value of the signal, extracts the signal spectrum characteristics, and marks the receiving timestamp. Combined with the previously observed RSSI change trend of the same target, it identifies abnormal large / small values. Abnormal observation values ​​are not included in the subsequent positioning process. The direction finding device uploads observation information such as angle of arrival, RSSI, and spectrum characteristics to the server.

[0094] The server receives observation data reported by each direction-finding device, classifies and correlates the observation data based on the electromagnetic and spatial characteristics of the observed target, sorts it by timestamp, and groups it by positioning time interval. Based on the grouped data, it performs 3D fusion positioning based on angle of arrival (AHA) and RSSI values. The target height Z0 is initially set according to prior target information. Combining the locations of each direction-finding device, the server determines the confidence region range corresponding to the target on the Z0 plane, and assigns confidence weights to the region based on the pitch angle and RSSI value. The weights of each direction finding device in the corresponding area of ​​the Z0 plane are superimposed to find the area with the largest cumulative weight in the Z0 plane, and the center of this area is used as the estimated position (X0, Y0) of the target in the Z0 plane.

[0095] Based on the target's estimated position (X0, Y0) in the Z0 plane, elevation angle, and direction finding device position, combined with direction finding error... This allows us to determine the potential area of ​​the target along the (X0, Y0) line, and assign confidence weights to the area based on the RSSI value. The weights of the regions obtained by each direction-finding device along the (X0,Y0) line are superimposed to obtain the region with the largest cumulative weight along the (X0,Y0) line. The center of this region is taken as the estimated position Z1 of the target on the (X0,Y0) line; a threshold is set. The deviation |Z0-Z1| between Z0 and Z1 is compared. If the deviation is greater than the threshold, the result is considered as follows: If Z1 is assigned to Z0, the 3D fusion localization process is repeated. If the result does not exceed the threshold three times consecutively... Then (X0, Y0, Z1) will be used as the estimated value of the target position, and Z1 will be used as the initial value of the target height Z0 for the next set of observation data.

[0096] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A three-dimensional fusion positioning method based on angle of arrival and RSSI value, characterized in that, Includes the following steps: Step S1: Deploy at least two direction-finding devices with spatiotemporal synchronization capabilities within the detection area, observe the radio signals actively emitted by the target, and obtain the signal angle of arrival and RSSI value observed by each direction-finding device, wherein the angle of arrival includes the pitch angle. Azimuth ; Outlier values ​​are removed from the observation data of each direction finding device based on the RSSI value, and the initial target height Z0 is set according to the target prior information. Step S2: For each direction finding device, based on its position information, the initial target height Z0, and the measured elevation angle... and azimuth and elevation angle direction finding error and azimuth direction finding error Determine the range of the two-dimensional confidence region where the target may exist on the plane at height Z0; And according to the pitch angle And RSSI values, assigning a first weight to each sub-region within the two-dimensional confidence region. 1, where the first weight 1 is positively correlated with the pitch angle θ and also positively correlated with the RSSI value; Step S3: Superimpose the confidence region ranges and first weights obtained by each direction finding device in the Z0 plane to obtain the cumulative weight distribution in the Z0 plane; Select the region with the largest cumulative weight, and use the center of this region as the estimated horizontal position (X0, Y0) of the target in the Z0 plane; Step S4: For each direction finding device, based on the horizontal position estimate (X0, Y0) obtained in step S3, the position of the direction finding device, and the measured elevation angle... and elevation angle direction finding error Determine the range of the one-dimensional confidence region where the target may exist on the (X0,Y0) line; Based on the RSSI value, a second weight is assigned to each height sub-interval within the one-dimensional confidence region. 2, where the second weight 2 is positively correlated with the magnitude of RSSI values; Step S5: Superimpose the one-dimensional confidence region range and its second weight obtained by all direction finding devices on the (X0,Y0) line to obtain the cumulative weight distribution on the (X0,Y0) line; Select the region with the largest cumulative weight, and use the center of this region as the height estimate Z1 of the target on the (X0,Y0) line; Step S6: Compare the deviation between the initial target height Z0 and the estimated height Z1, |Z0-Z1|, and set a threshold. ; If the deviation is greater than the threshold, assign Z1 to Z0 and repeat S2~S5; If the target does not exceed the threshold at least twice consecutively, output the estimated three-dimensional position of the target (X0, Y0, Z1).

2. The three-dimensional fusion positioning method based on angle of arrival and RSSI value according to claim 1, characterized in that, The outlier removal based on RSSI values ​​in step S1 specifically includes: each direction finding device maintaining a sliding window of historical RSSI values, calculating the mean and standard deviation of RSSI within the window; when a newly observed RSSI value deviates from the mean by more than a preset multiple of the standard deviation, it is determined to be an outlier, and the outlier will not participate in the subsequent positioning process; the preset multiple of the standard deviation is 2 to 4 times.

3. The three-dimensional fusion positioning method based on angle of arrival and RSSI value according to claim 1, characterized in that, The step S2, determining the range of the two-dimensional confidence region where the target may exist on the Z0 plane, specifically includes: The direction-finding device is located at point (x, y, z) in the coordinate system. Based on the target height Z0 and its own height z, the height difference H of the working plane is determined, which is H = Z0 - z. Then, the position of the target on the Z0 plane (x + Hcosθ) is determined. / tan y+Hsin / tan ); Set the pitch angle confidence interval as - ~ + Within the range, the azimuth confidence interval is set to - ~ + Within the range; Determine the confidence region range corresponding to the target on the Z0 plane, i.e., (x + Hcos( - ) / tan( - ), y+Hsin( - ) / tan( - )), (x+Hcos( + ) / tan( - ), y+Hsin( + ) / tan( - )), (x+Hcos( - ) / tan( + ), y+Hsin( - ) / tan( + )), (x+Hcos( + ) / tan( + ), y+Hsin( + ) / tan( + The fan-shaped area formed by the four points.

4. The three-dimensional fusion positioning method based on angle of arrival and RSSI value according to claim 3, characterized in that, The fan-shaped region is approximated as its circumscribed rectangular region. The boundary of this rectangular region is determined by the minimum and maximum values ​​of the coordinates of four boundary points: namely, the rectangular region enclosed by the four points (x_min, y_min), (x_min, y_max), (x_max, y_min), and (x_max, y_max), where x_min = min{x + Hcos( - ) / tan( - ), x+Hcos( + ) / tan( - ), x+Hcos( - ) / tan( + ), x+Hcos( + ) / tan( + )};x_max=max{x+Hcos( - ) / tan( - ), x+Hcos( + ) / tan( - ), x+Hcos( - ) / tan( + ), x+Hcos( + ) / tan( + )};y_min=min{y+Hsin( - ) / tan( - ), y+Hsin( + ) / tan( - ), y+Hsin( - ) / tan( + ), y+Hsin( + ) / tan( + )};y_max=max{y+Hsin( - ) / so( - ),y+Hsin( + ) / so( - ),y+Hsin( - ) / so( + ),y+Hsin( + ) / so( + )}。 5. A three-dimensional fusion positioning method based on angle of arrival and RSSI value according to claim 1, characterized in that, The specific steps for determining the range of the one-dimensional confidence region where the target may exist on the (X0,Y0) line in step S4 are as follows: Based on the target's estimated position (X0, Y0) in the Z0 plane, the elevation angle, and the position of the direction finding device, the target position z+((X0-x) on the (X0, Y0) line is obtained. 2 +(Y0-y) 2 ) 1 / 2 tan ; The possible range of the target on the line (X0, Y0) is determined as z + ((X0 - x)). 2 +(Y0-y) 2 ) 1 / 2 tan( - )~z+((X0-x) 2 +(Y0-y) 2 ) 1 / 2 tan( + ).

6. A three-dimensional fusion positioning system based on angle of arrival and RSSI value, used to implement the method according to any one of claims 1 to 5, characterized in that, It includes at least one observation target, at least two direction-finding devices, and at least one server, wherein: The observation target is used to periodically radiate radio signals; The direction-finding device possesses spatiotemporal synchronization capabilities, two-dimensional direction-finding capabilities, RSSI estimation capabilities, and outlier identification and removal capabilities; it is used to observe target signals and calculate the arrival and elevation angles of the signals. Azimuth The system estimates the RSSI value of the signal, extracts the signal spectrum characteristics, marks the receiving timestamp, and identifies abnormally large / small values ​​by combining the previously observed RSSI change trend of the same target. Abnormal observation values ​​are not included in the subsequent positioning process. The system also uploads the angle of arrival, RSSI, and spectrum characteristic observation data to the server. The server receives observation data reported by each direction-finding device, classifies and correlates the observation data based on the electromagnetic and spatial characteristics of the observed target, sorts it by timestamp, and groups it by positioning time interval. Based on the grouped data, it performs 3D fusion positioning based on angle of arrival (AHA) and RSSI values. It initially sets the target height Z0 based on prior target information, determines the confidence region range corresponding to the target on the Z0 plane by combining the locations of each direction-finding device, and assigns confidence weights to the region based on the pitch angle and RSSI value. The weights of each direction finding device in the corresponding area of ​​the Z0 plane are superimposed to find the area with the largest cumulative weight in the Z0 plane, and the center of this area is used as the estimated position (X0, Y0) of the target in the Z0 plane. Based on the target's estimated position (X0, Y0) in the Z0 plane, elevation angle, and direction finding device position, combined with direction finding error... This allows us to determine the potential area of ​​the target along the (X0, Y0) line, and assign confidence weights to the area based on the RSSI value. The weights of the regions obtained by each direction-finding device along the (X0,Y0) line are superimposed to obtain the region with the largest cumulative weight along the (X0,Y0) line. The center of this region is taken as the estimated position Z1 of the target on the (X0,Y0) line; a threshold is set. The deviation |Z0-Z1| between Z0 and Z1 is compared. If the deviation is greater than the threshold, the result is considered as follows: If Z1 is assigned to Z0, the 3D fusion localization process is repeated. If the result does not exceed the threshold three times consecutively... Then (X0, Y0, Z1) will be used as the estimated value of the target position, and Z1 will be used as the initial value of the target height Z0 for the next set of observation data.

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