A GNSS-assisted circular arc synthetic aperture radar orientation device and orientation method

Abstract

The application provides a GNSS-aided arc synthetic aperture radar orientation device and method, the orientation device comprising a radar main body structure, a rotating shaft arranged on the radar main body structure, a forced centering device mounted on the rotating shaft, and a GNSS antenna mounted on the forced centering device. The north direction is set as the positive direction of the x-axis, the east direction is set as the positive direction of the y-axis, and the GNSS antenna at the center of the circle continuously collects coordinate values at an interval of Δt. The coordinate value of the rotating starting position of the radar swing arm is set as P1, and the radar swing arm is paused at N positions during rotation to obtain P i positions. m coordinate data are collected at any one P i position. GNSS coordinate corrections of the center of the circle and the P i positions are calculated. The coordinate correction value of the center of the circle and the correction coordinate value of any one P i position are calculated based on the GNSS coordinate corrections. The initial azimuth of the radar is calculated based on the coordinate correction value of the center of the circle and the coordinate correction value of any one P i position.

Description

Technical Field

[0001] This invention belongs to the fields of surveying and mapping and safety monitoring technology, specifically relating to a GNSS-assisted circular arc synthetic aperture radar orientation device and orientation method. Background Technology

[0002] Synthetic aperture deformation monitoring radar can overlay deformation monitoring area data with three-dimensional terrain to more intuitively display the deformation area and degree of deformation. In the overlay process, the initial azimuth angle of the radar must first be determined.

[0003] In existing technologies, such as the technical solution disclosed in Chinese patent document CN202211541111.4, the azimuth angle is determined by image matching through the setting of corner reflectors. However, when applying the technical solution disclosed in this patent document to achieve radar orientation, there are situations where corner reflectors cannot be deployed if the monitored object is considered to pose a certain danger.

[0004] Therefore, a contactless method for determining the initial azimuth is required. Furthermore, since radars are sometimes deployed in mountainous areas, it's necessary to minimize the additional equipment needed for orientation to reduce costs. To achieve radar timing, its own GNSS device can be fully utilized. Summary of the Invention

[0005] The purpose of this invention is to provide a GNSS-assisted circular arc synthetic aperture radar orientation device and orientation method to obtain the initial azimuth angle of the radar, and then to perform subsequent superposition of the radar deformation field and terrain.

[0006] The present invention provides a GNSS-assisted circular arc synthetic aperture radar orientation device, including a radar main structure, a rotating shaft disposed on the radar main structure, a forced centering device mounted on the rotating shaft, and a GNSS antenna mounted on the forced centering device;

[0007] The radar main structure includes a standard cuboid-shaped radar arm and a radar antenna that is connected to the radar arm via a connecting structure; the radar arm rotates horizontally around a pivot, and a forced centering device is installed at the point where the radar arm connects to the pivot.

[0008] The center of the GNSS antenna is set to coincide with the central axis of the rotating shaft.

[0009] Optionally, when using the GNSS-assisted circular synthetic aperture radar directional device to determine the radar azimuth angle, the number of GNSS antennas is set to at least one.

[0010] Optionally, when using a GNSS antenna to determine the radar azimuth, the specific process is as follows:

[0011] The GNSS antenna is mounted on a forced alignment device, and data is collected from the coordinates of the current location using the GNSS antenna.

[0012] After removing the GNSS antenna from the forced alignment device, it is installed on the end of the radar arm closest to the radar antenna; and the coordinates of the current position are collected through the GNSS antenna.

[0013] Optionally, when using two GNSS antennas to determine the radar azimuth, the specific process is as follows:

[0014] One of the GNSS antennas is placed on the forced alignment device, and the other GNSS antenna is placed on the radar arm near the radar antenna.

[0015] Two GNSS antennas collect data from the coordinates of their current location.

[0016] Optionally, the GNSS antenna uses RTK measurement to perform the measurement, and during the measurement process, a base station can be set up near the radar or differential calculation can be performed.

[0017] Optionally, the radar arm is driven by a high-precision stepper motor.

[0018] This invention also provides a GNSS-assisted circular arc synthetic aperture radar direction finding method, comprising the following steps:

[0019] Step 1: Install the GNSS-assisted circular synthetic aperture radar direction finding device as described above;

[0020] Based on the Cartesian plane rectangular coordinate system, let the north direction be the positive x-axis and the east direction be the positive y-axis, and set a GNSS antenna at the center C to continuously collect coordinate values ​​(x,y) at intervals Δt.

[0021] Set the coordinates of the starting position of the radar arm's rotation to P1;

[0022] The radar arm is driven to rotate, thereby rotating the GNSS antenna. During the rotation, the radar arm pauses at N positions, resulting in P. i Each position; and at any P i m coordinate data points are collected at each location; where 1 ≤ i ≤ N, and i represents the coordinates at location P. i Collect coordinates at the location;

[0023] Step 2: Based on the two line segments CP connecting the center C of the circle to any two points where the radar arm stops, i and CP j Calculate the center C and P of the circle. iGNSS coordinate corrections for the location;

[0024] Step 3: Calculate the coordinate correction value of the center C based on the GNSS coordinate correction values. and And any P i Corrected coordinates of position and

[0025] Step 4: Coordinate correction based on center C and And any P i Position coordinate correction value and Calculate the initial azimuth angle α of the radar.

[0026] Optionally, the specific process for calculating the GNSS coordinate correction in step two is as follows:

[0027] S2.1 Select a GNSS antenna at the center C and continuously collect m coordinate values ​​at intervals Δt. For any P i m coordinate data points were collected at each location to obtain coordinate values.

[0028] S2.2. Let the two line segments connecting the center C of the circle to any two points where the radar arm stops be CP. i and CP j For line segment CP respectively i and line segment CP j vector sum vector After analysis, we get:

[0029]

[0030]

[0031] Where: j represents the position P j The coordinates are collected at the location where i ≠ j;

[0032] S2.3, when At that time, we have (x i -x C )*(x j -x C )+(y i -y C )*(y j -y C ) = 0;

[0033] Let the function f = (x i -xC )*(x j -x C )+(y i -y C )*(y j -y C Its first-order partial derivative is:

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040] S2.4 For the function f, at the approximate value Performing a first-order Taylor expansion at f, we obtain an approximate value for the function f:

[0041]

[0042] That is, the GNSS coordinate correction is

[0043] Optionally, in step three, the coordinate correction value of the center C is calculated. and And any P i Position coordinate correction value and The specific process is as follows:

[0044] S3.1. Let i = 3, and based on the indirect adjustment method, let the unknown vector matrix X be:

[0045] X=[Δx C ,Δy C ,Δx1,Δy1,Δx2,Δy2,Δx3,Δy3,Δx4,Δy4]

[0046] Where Δx1, Δy1 are the corrections to the GNSS coordinate measurements of point P1, and Δx2, Δy2, Δx3, Δy3, Δx4, Δy4 are the corrections to any P1 coordinate measurement. i Correction to the GNSS coordinate measurement of a point;

[0047] Let parameter matrix B have 4*m rows and 10 columns; for Given this condition, matrix B1 from row 1 to row m is:

[0048]

[0049] Let matrix L1 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0050]

[0051] Right now

[0052] for Given this condition, the matrix B2 consisting of rows m+1 to 2m is:

[0053]

[0054] Let matrix L2 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0055]

[0056] Right now

[0057] for Given this condition, row 2m+1 to row 3m is matrix B3 as follows:

[0058]

[0059] Let matrix L3 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0060]

[0061] Right now

[0062] for Given this condition, row 3m+1 to row 4m, matrix B4 is:

[0063]

[0064] Let matrix L4 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0065]

[0066] Right now

[0067] That is, we get:

[0068] B = [B1 B2 B3 B4] T ;

[0069] L = [L1 L2 L3 L4] T That is, matrix L has 4*m rows and 1 column;

[0070] S3.2 Normalize the parameter matrix B:

[0071] normalized_B=(B-min(B)) / (max(B)-min(B));

[0072] Normalize matrix L:

[0073] normalized_L=(L-min(L)) / (max(L)-min(L));

[0074] Use the least squares method to find the optimal estimate of the unknown vector set X. * :

[0075] X * =argmin||normalized_B*X-normalized_L|| ^2 ;

[0076] The optimal estimate of the unknown vector set X. * After performing inverse normalization, we have:

[0077] X * =X*(max(L)-min(L))+min(L);

[0078] The optimal estimate of X based on the unknown vector set X * The correction Δx of the GNSS coordinate measurement value is obtained. C Δy C , Δx1, Δy1, Δx2, Δy2, Δx3, Δy3, Δx4, Δy4;

[0079] Calculate the coordinate correction value of the center C of the circle based on the correction value of the GNSS coordinate measurement:

[0080]

[0081]

[0082] Calculate any P based on the correction value of GNSS coordinate measurement. i Position coordinate correction values:

[0083]

[0084]

[0085] Optionally, the specific process for calculating the initial radar azimuth angle α in step four is as follows:

[0086] S4.1 Calculate the quadrant angle Rcp between the center C and point P1:

[0087]

[0088] S4.2 Determine the relationship between the quadrant angle Rcp and the azimuth angle α based on the coordinate increment:

[0089] ①When When the quadrant angle Rcp and the azimuth angle α are in the first quadrant, α = Rcp;

[0090] ②When When the quadrant angle Rcp and the azimuth angle α are in quadrant II, α = Rcp + 90°;

[0091] ③When When the quadrant angle Rcp and the azimuth angle α are in quadrant III, α = Rcp + 180°;

[0092] ④ When When the quadrant angle Rcp and the azimuth angle α are in quadrant IV, α = Rcp + 360°.

[0093] Compared with the prior art, the present invention has the following beneficial effects:

[0094] The GNSS-assisted circular arc synthetic aperture radar (SAR) direction finding method proposed in this invention fully utilizes the rotation characteristic of SAR and the rule that the dot product of mutually perpendicular vectors is zero to achieve radar direction finding. This method offers advantages such as high computational accuracy, no need for corner reflectors, and fast and convenient calculation. In particular, by utilizing the radar's own GNSS antenna, it achieves radar direction finding without the need for additional equipment. For radar installations in remote mountainous areas and high-altitude plateau regions, this method reduces the load, saves expenses, and lowers costs.

[0095] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0096] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0097] Figure 1This is a schematic diagram of a GNSS-assisted circular arc synthetic aperture radar directional device according to an embodiment of the present invention;

[0098] Figure 2 yes Figure 1 A schematic diagram of the starting position and the paused position of the radar swing arm.

[0099] in:

[0100] 1. Forced centering device; 2. Radar main structure; 21. Radar swing arm; 22. Radar antenna; 23. Connecting structure; 3. Rotating shaft. Detailed Implementation

[0101] Example:

[0102] This invention provides a GNSS-assisted circular arc synthetic aperture radar direction finding device, see details. Figure 1 It includes a radar main structure 2, a rotating shaft 3 set on the radar main structure 2, a forced centering device 1 installed on the rotating shaft 3, and a GNSS antenna installed on the forced centering device 1.

[0103] The radar main structure 2 includes a standard rectangular radar arm 21 and a radar antenna 22 connected to the radar arm 21 via a connecting structure 23. The radar arm 21 rotates horizontally around a pivot 3, and a forced centering device 1 is installed at the point where the radar arm 21 connects to the pivot 3.

[0104] Furthermore, the radar arm 21 rotates around the pivot 3. Since the center of the GNSS antenna installed on the forced alignment device 1 coincides with the central axis of the pivot 3, the center position of the GNSS antenna is assumed to be the position of the center C coordinate on the horizontal plane.

[0105] Furthermore, when using this GNSS-assisted circular synthetic aperture radar (SAR) orientation device to determine the radar azimuth, the number of GNSS antennas is set to at least one. Specifically, one or two GNSS antennas can be used to determine the radar azimuth. When using one GNSS antenna to determine the radar azimuth, the specific process is as follows: first, the GNSS antenna is placed on the forced alignment device 1. After a period of observation and collection of sufficient coordinate point data, the GNSS antenna is then placed on the radar arm 21 near the radar antenna 22, ideally positioned at the center of the upper short side of the radar arm 21, before proceeding to subsequent steps. When using two GNSS antennas to determine the radar azimuth, the specific process is as follows: one GNSS antenna is placed on the forced alignment device 1, and the other GNSS antenna is placed on the radar arm 21 near the radar antenna 22, ideally positioned at the center of the upper short side of the radar arm 21, before proceeding to subsequent steps. Simultaneously, the data from both GNSS antennas is recorded. For details on the initial and paused positions during the swing of the radar arm 21, see [link to relevant documentation]. Figure 2 .

[0106] Furthermore, the GNSS antenna uses RTK (Real-time kinematic) measurement to perform measurements. During the measurement process, a base station can be set up near the radar or CORS (Continuously Operating Reference Stations) can be used to perform differential calculations.

[0107] Furthermore, the radar swing arm is driven by a high-precision stepper motor so that its rotation angle accuracy can reach 0.01°, which can be regarded as an accurate value.

[0108] This invention also provides a GNSS-assisted circular arc synthetic aperture radar orientation method to obtain the initial azimuth angle of the radar, and then perform subsequent superposition of the radar deformation field and terrain. The specific technical solution is as follows:

[0109] Step 1: Install the GNSS-assisted circular synthetic aperture radar direction finding device as described above;

[0110] Based on the Cartesian plane rectangular coordinate system, let the north direction be the positive x-axis and the east direction be the positive y-axis, and set a GNSS antenna at the center C to continuously collect coordinate values ​​(x,y) at intervals Δt.

[0111] Set the coordinates of the starting position of the radar arm's rotation to P1;

[0112] The radar arm is driven to rotate, thereby rotating the GNSS antenna. During the rotation, the radar arm pauses at N positions, resulting in P.i Each position; and at any P i m coordinate data points are collected at each location; where 1 ≤ i ≤ N, and i represents the coordinates at location P. i The i-th coordinate was collected at point i.

[0113] Step 2: Based on the two line segments CP connecting the center C of the circle to any two points where the radar arm stops, i and CP j Calculate the center C and P of the circle. i GNSS coordinate corrections for the location;

[0114] Step 3: Calculate the coordinate correction value of the center C based on the GNSS coordinate correction values. and And any P i Corrected coordinates of position and

[0115] Step 4: Correction values ​​based on the coordinates of the center C of the circle. and And any P i Corrected coordinates of position and Calculate the initial azimuth angle α of the radar.

[0116] Furthermore, the specific process for calculating the GNSS coordinate correction in step two is as follows:

[0117] S2.1 Select a GNSS antenna at the center C and continuously collect m coordinate values ​​at intervals Δt. For any P i m coordinate data points were collected at each location to obtain coordinate values.

[0118] S2.2. Let the two line segments connecting the center C of the circle to any two points where the radar arm stops be CP. i and CP j For line segment CP respectively i and line segment CP j vector sum vector After analysis, we get:

[0119]

[0120]

[0121] Where: j represents the position P j The coordinates are collected at the location where i ≠ j;

[0122] S2.3, when At that time, we have (x i -x C )*(x j -x C )+(y i -y C )*(y j -y C ) = 0;

[0123] Let the function f = (x i -x C )*(x j -x C )+(y i -y C )*(y j -y C Its first-order partial derivative is:

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] S2.4 For the function f, at the approximate value By performing a first-order Taylor expansion at f, we can obtain an approximate value for the function f:

[0131]

[0132] That is, the GNSS coordinate correction is

[0133] Furthermore, in step three, the coordinate correction value of the center C is calculated. and And any P i Position coordinate correction value and The specific process is as follows:

[0134] S3.1. Let i = 3, and based on the indirect adjustment method, let the unknown vector matrix X be:

[0135] X=[Δx C ,Δy C,Δx1,Δy1,Δx2,Δy2,Δx3,Δy3,Δx4,Δy4]

[0136] Where Δx1, Δy1 are the corrections to the GNSS coordinate measurements of point P1, and Δx2, Δy2, Δx3, Δy3, Δx4, Δy4 are the corrections to any P1 coordinate measurement. i Correction to the GNSS coordinate measurement of a point;

[0137] Let parameter matrix B have 4*m rows and 10 columns; for Given this condition, matrix B1 from row 1 to row m is:

[0138]

[0139] Let matrix L1 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0140]

[0141] Right now

[0142] for Given this condition, the matrix B2 consisting of rows m+1 to 2m is:

[0143]

[0144] Let matrix L2 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0145]

[0146] Right now

[0147] for Given this condition, row 2m+1 to row 3m is matrix B3 as follows:

[0148]

[0149] Let matrix L3 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0150]

[0151] Right now

[0152] for Given this condition, row 3m+1 to row 4m, matrix B4 is:

[0153]

[0154] Let matrix L4 have m columns and 1 row. Then the data in its k-th column (1≤k≤m) is:

[0155]

[0156] Right now

[0157] That is, we get:

[0158] B = [B1 B2 B3 B4] T ;

[0159] L = [L1 L2 L3 L4] T That is, matrix L has 4*m rows and 1 column;

[0160] S3.2 Normalize the parameter matrix B:

[0161] normalized_B=(B-min(B)) / (max(B)-min(B));

[0162] Normalize matrix L:

[0163] normalized_L=(L-min(L)) / (max(L)-min(L));

[0164] Use the least squares method to find the optimal estimate of the unknown vector set X. * :

[0165] X * =argmin||normalized_B*X-normalized_L|| ^2 ;

[0166] The optimal estimate of the unknown vector set X. * After performing inverse normalization, we have:

[0167] X * =X*(max(L)-min(L))+min(L);

[0168] The optimal estimate of X based on the unknown vector set X * The correction Δx of the GNSS coordinate measurement value is obtained. C Δy C , Δx1, Δy1, Δx2, Δy2, Δx3, Δy3, Δx4, Δy4;

[0169] Calculate the coordinate correction value of the center C of the circle based on the correction value of the GNSS coordinate measurement:

[0170]

[0171]

[0172] Calculate any P based on the correction value of GNSS coordinate measurement. i Position coordinate correction values:

[0173]

[0174]

[0175] Furthermore, the specific process for calculating the initial radar azimuth angle α in step four is as follows:

[0176] S4.1 Calculate the quadrant angle Rcp between the center C and point P1:

[0177]

[0178] S4.2 Determine the relationship between the quadrant angle Rcp and the azimuth angle α based on the coordinate increment:

[0179] ①When When the quadrant angle Rcp and the azimuth angle α are in the first quadrant, α = Rcp;

[0180] ②When When the quadrant angle Rcp and the azimuth angle α are in quadrant II, α = Rcp + 90°;

[0181] ③When When the quadrant angle Rcp and the azimuth angle α are in quadrant III, α = Rcp + 180°;

[0182] ④ When When the quadrant angle Rcp and the azimuth angle α are in quadrant IV, α = Rcp + 360°.

[0183] Alternatively, in addition to the methods described above, the center C and P of the circle can also be calculated. i After calculating the quadrant angle Rcp between two points (i.e., the quadrant angle Rcp between the center C and P2, or the quadrant angle Rcp between the center C and P3, or the quadrant angle Rcp between the center C and P4), the relationship between the quadrant angle Rcp and the azimuth angle α is determined based on the coordinate increment in order to finally calculate the initial azimuth angle α of the radar.

[0184] The experiment was conducted using the technical solution of this embodiment, specifically as follows:

[0185] Let the x-axis coordinates of the center C of the circle be: [0.0101, -0.0073, -0.0074, -0.0006, 0.0076, 0.0114, 0.0013, -0.0066, 0.0082, 0.0046];

[0186] The y-coordinates of the corresponding center C are: [-0.0036, 0.0085, 0.0027, 0.0143, -0.0013, -0.0033, -0.0151, 0.002, -0.0102, 0.0008];

[0187] The x-axis coordinates of P1 are: [0.9983, 1.0114, 0.9956, 0.9711, 0.9996, 1.0045, 0.9893, 1.0135, 0.9952, 0.9808];

[0188] The corresponding y-axis coordinates of P1 are: [0.0053, -0.0079, 0.0062, 0.0036, -0.0149, -0.0127, -0.0095, 0.0089, 0.0033, -0.0229];

[0189] The x-axis coordinates of P2 are: [-0.0049, -0.0058, -0.0057, 0.0026, 0.0086, 0.0178, 0.0093, -0.0031, 0.0063, -0.0006];

[0190] The corresponding y-axis coordinates of P2 are: [0.9953, 0.9917, 1.0063, 1.0166, 0.9832, 0.9925, 0.9987, 1.0102, 0.9862, 0.9945];

[0191] The x-axis coordinates of P3 are: [-0.9899, ​​-0.9913, -0.9889, -1.0006, -0.9877, -0.9966, -1.0036, -0.9933, -1.0068, -1.0081];

[0192] The corresponding y-axis coordinates of P3 are: [-0.0154, 0.0118, 0.0094, 0.0053, 0.0094, 0.0011, -0.0034, 0.0201, -0.0011, 0.0011];

[0193] The x-axis coordinates of P4 are: [0.0036, 0.0084, -0.0011, -0.0016, -0.0155, -0.0036, 0.0005, 0.005, -0.0085, -0.0106];

[0194] The corresponding y-axis coordinates of P4 are: [-0.988, -0.998, -0.9943, -0.9988, -1.0147, -0.999,

[0195] -0.9883, -1.0152, -1.0141, -0.9955).

[0196] For the center C, its coordinate correction value is:

[0197]

[0198]

[0199] For P i The corrected coordinates are:

[0200]

[0201]

[0202] The coordinates of P1 are (0.9249, -0.0187).

[0203] Based on the above steps, the initial azimuth angle of the radar can be calculated as α:

[0204] Calculate the quadrant angle Rcp between points C and P1:

[0205]

[0206]

[0207]

[0208] Based on the coordinate increment, determine the relationship between the quadrant angle Rcp and the azimuth angle α:

[0209] ①When When the quadrant angle Rcp and the azimuth angle α are in the first quadrant, α = Rcp;

[0210] ②When When the quadrant angle Rcp and the azimuth angle α are in quadrant II, α = Rcp + 90°;

[0211] ③When When the quadrant angle Rcp and the azimuth angle α are in quadrant III, α = Rcp + 180°;

[0212] ④ When When the quadrant angle Rcp and the azimuth angle α are in quadrant IV, α = Rcp + 360°.

[0213] Based on the above calculations, condition ① is satisfied, that is, the initial azimuth angle of the radar is finally obtained as α = 0.22°.

[0214] The GNSS-assisted circular arc synthetic aperture radar (SAR) orientation method proposed in this invention fully utilizes the rotational characteristic of the SAR and the high precision of its stepper motor. Furthermore, it leverages the principle that the dot product of mutually perpendicular vectors is zero to achieve radar orientation. This method offers advantages such as accurate calculation, no need for corner reflectors, and fast and convenient computation. In particular, by utilizing the radar's own GNSS antenna, it achieves radar orientation without requiring additional equipment. For radar installations in remote mountainous areas and high-altitude plateau regions, this method reduces the load, saves expenses, and lowers costs.

[0215] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A GNSS-assisted circular arc synthetic aperture radar direction finding method, characterized in that, Includes the following steps: Step 1: Install the GNSS-assisted circular synthetic aperture radar direction finding device; Based on the Cartesian plane rectangular coordinate system, let the north direction be... The positive direction of the axis is east. The positive direction of the axis, and the center of the circle. The GNSS antenna at the location has a sampling interval. Continuous collection of coordinate values ; Set the coordinates of the starting position of the radar arm's rotation to... ; The radar arm is driven to rotate, thereby rotating the GNSS antenna. During the rotation, the radar arm selects... Pause at each position to obtain Each position; and in any one of them All locations were collected 1 coordinate data; among which, , Indicated as in position Collect coordinates at the location; Step 2: Based on setting the center of the circle The two line segments connecting any two points to where the radar arm stops. and Calculate the center of the circle and GNSS coordinate corrections for the location; Step 3: Determine the center of the circle based on GNSS coordinate corrections. coordinate correction values and And any one Corrected coordinates of position and ; Step 4: Based on the center of the circle coordinate correction values and And any one Position coordinate correction value and Calculate the initial azimuth angle of the radar ; The specific process for calculating the GNSS coordinate correction in step two is as follows: S2.1 Select the center of the circle The GNSS antenna at the location has a sampling interval. Continuous collection coordinate values For any one All locations were collected From the coordinate data, obtain the coordinate values. ; S2.2, Set the center of the circle The two line segments connecting any two points where the radar arm stops are respectively and For line segments respectively and line segments vector sum vector After analysis, we get: ； ； in: Indicated as in position Coordinates were collected at the location and ; S2.3, when At that time, there was ; Let function Its first-order partial derivative is: ； ； ； ； ； ； S2.4, For functions In approximate value Performing a first-order Taylor expansion at the point, we obtain the function Approximate value: ； That is, the GNSS coordinate correction is , , , , , ; The GNSS-assisted circular arc synthetic aperture radar orientation device includes a radar main structure (2), a rotating shaft (3) set on the radar main structure (2), a forced centering device (1) installed on the rotating shaft (3), and a GNSS antenna installed on the forced centering device (1). The radar main structure (2) includes a standard rectangular radar arm (21) and a radar antenna (22) connected to the radar arm (21) via a connecting structure (23); the radar arm (21) rotates horizontally around the pivot (3), and a forced centering device (1) is installed at the point where the radar arm (21) is connected to the pivot (3). The center of the GNSS antenna is set to coincide with the central axis of the rotating shaft (3).

2. The GNSS-assisted circular arc synthetic aperture radar direction finding method according to claim 1, characterized in that, In step three, the center of the circle is determined. coordinate correction values and And any one Position coordinate correction value and The specific process is as follows: S3.1, Let Based on the use of the indirect adjustment method to set the unknown vector matrix for: ； in, for Correction to the GNSS coordinate measurement of the point. , , Each one Correction to the GNSS coordinate measurement value of a point; Let the parameter matrix be Its number of rows is The number of columns is 10; for This condition applies to rows 1 through 2. Row matrix for: ; Let matrix The number of columns is If the row number is 1, then its first row is... The data in the column is: ； in, ; Right now ; for This condition, then its first Arriving Behavior Matrix for: ； Let matrix The number of columns is If the row number is 1, then its first row is... The data in the column is: ； Right now ; for This condition, the first Arriving Behavior Matrix for: ； Let matrix The number of columns is If the row number is 1, then its first row is... The data in the column is: ； Right now ; for This condition, the first Arriving Behavior Matrix for: ； Let matrix The number of columns is If the row number is 1, then its first row is... The data in the column is: ； Right now ; That is, we get: ； , i.e., matrix The number of rows is The number of columns is 1; S3.2, Based on parameter matrix sum matrix Solving the unknown vector set using the least squares method The optimal estimate ; Based on unknown vector groups The optimal estimate Obtain the correction value of GNSS coordinate measurement. , , , , , , , , , ; Calculate the center of the circle based on the correction value of GNSS coordinate measurement. Coordinate correction values: ； ； Calculate any correction value based on GNSS coordinate measurement values. Position coordinate correction values: ； 。 3. The GNSS-assisted circular arc synthetic aperture radar direction finding method according to claim 2, characterized in that, Step four involves calculating the radar's initial azimuth angle. The specific process is as follows: S4.1 Calculate the center of the circle and Quadrant angle between two points : ； S4.2 Determine the quadrant angle based on the coordinate increment. With azimuth The relationship between them: ①When When, determine the quadrant angle. With azimuth The area between them is the first quadrant, i.e. ; ②When When, determine the quadrant angle. With azimuth The area between is the second quadrant, i.e. ; ③When When, determine the quadrant angle. With azimuth The area between is the third quadrant, i.e. ; ④ When When, determine the quadrant angle. With azimuth The area between is the fourth quadrant, i.e. .

4. The GNSS-assisted circular arc synthetic aperture radar direction finding method according to any one of claims 1-3, characterized in that, When using the GNSS-assisted circular synthetic aperture radar orientation device to determine the radar azimuth angle, the number of GNSS antennas is set to at least one.

5. The GNSS-assisted circular arc synthetic aperture radar direction finding method according to claim 4, characterized in that, When using a GNSS antenna to determine the radar azimuth angle, the specific process is as follows: The GNSS antenna is placed on the forced centering device (1), and the coordinates of the current position are collected through the GNSS antenna. After removing the GNSS antenna from the forced alignment device (1), it is installed on the end of the radar arm (21) near the radar antenna (22); and the coordinates of the current position are collected through the GNSS antenna.

6. The GNSS-assisted circular arc synthetic aperture radar direction finding method according to claim 4, characterized in that, When using two GNSS antennas to determine the radar azimuth angle, the specific process is as follows: One of the GNSS antennas is placed on the forced centering device (1), and the other GNSS antenna is placed on the radar arm (21) near the radar antenna (22). Two GNSS antennas collect data from the coordinates of their current location.

7. The GNSS-assisted circular arc synthetic aperture radar direction finding method according to claim 5 or 6, characterized in that, The GNSS antenna uses RTK measurement to perform the measurement, and a base station is set up near the radar during the measurement process.

8. The GNSS-assisted circular arc synthetic aperture radar direction finding method according to claim 7, characterized in that, The radar swing arm (21) is driven by a high-precision stepper motor.

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