Foundation arc synthetic aperture radar initial orientation device and orientation method

Abstract

The application provides a foundation arc synthetic aperture radar initial orientation device and orientation method, which comprises an orientation auxiliary assembly, a guide rail structure, a radar main body structure and a rotating shaft; the radar main body structure comprises a radar swing arm and a radar antenna which is connected with the radar swing arm through a connecting structure, and the radar swing arm is installed on a second base and rotates in a horizontal direction with the rotating shaft as the center. The orientation method comprises the following steps: starting G1 to collect continuous coordinate values (x, y) with an interval Δt; setting the coordinate value of the starting position of the rotation of G2 as P1; driving the radar swing arm to rotate to drive G2 to rotate, and selecting N positions in the rotation process of the radar swing arm to pause, obtaining P i positions which are uniformly distributed on the rotating track of G2; collecting m coordinate data at any one P i position respectively; calculating the real and accurate coordinate value of any one P i position and the real and accurate coordinate value of the center C to obtain the coordinate adjustment value of the center C and the coordinate adjustment value of any one P i position, and calculating the radar initial azimuth angle α.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of surveying and mapping and the technical field of safety monitoring, and particularly relates to a ground-based circular arc synthetic aperture radar initial orientation device and an orientation method. BACKGROUND

[0002] The swing arm of the circular arc synthetic aperture radar forms a synthetic aperture in space through rotation and circular arc running track. In order to improve the resolution capability of the monitoring surface, the running range of the accumulation angle is expanded in the starting and ending stages in the focusing process. This process focuses the echo signals of the radar accumulation angle to provide high-definition scatter diagrams for subsequent analysis. At the same time, in order to more intuitively display the deformation area and deformation degree, the common practice is to superimpose the radar deformation map with the terrain. In order to accurately superimpose, the common practice is to use a total station to orient, but this method needs to transfer the reference point, which is time-consuming and laborious. Considering that the radar itself has a certain resolution, the orientation accuracy does not need to reach the millimeter level. Therefore, GNSS orientation can be considered. At the same time, the radar is sometimes deployed in mountainous areas and the like, and it is necessary to reduce the additional equipment required for orientation as much as possible to reduce the cost. In order to realize radar time service, the radar itself has a GNSS device that can be fully utilized. SUMMARY

[0003] The application aims to provide a ground-based circular arc synthetic aperture radar initial orientation device and an orientation method to obtain the initial azimuth angle of the radar and then perform the superposition of the radar deformation field and the terrain.

[0004] The application provides a ground-based circular arc synthetic aperture radar initial orientation device, which comprises a directional auxiliary assembly, a guide rail structure, a radar main body structure and a rotating shaft.

[0005] The guide rail structure comprises a first sliding rail, a second sliding rail, a first base and a second base. The first sliding rail and the second sliding rail are arranged side by side on the directional auxiliary assembly. The first base is in sliding connection with the first sliding rail and the second sliding rail. The second base is in mutual fixation with the first sliding rail and the second sliding rail. The GNSS antenna mounted on the second base is G1, and the GNSS antenna mounted on the first base is G2.

[0006] The radar main body structure is clamped at one end of the directional auxiliary assembly away from the guide rail structure. The radar main body structure comprises a radar swing arm and a radar antenna connected to the radar swing arm through a connecting structure. The radar swing arm is installed on the second base and rotates in the horizontal direction with the rotating shaft as the center.

[0007] The rotating shaft is installed on the radar swing arm, and the central axis of the rotating shaft and the central axis of the second base perpendicular to the sliding direction are arranged to coincide with each other.

[0008] Optionally, scale lines are also provided on both the first and second slide rails. The scale lines are set sequentially at intervals of 0.5 mm, with the central axis parallel to the width side of the second base and the orientation auxiliary component as the origin, and extending from the second base to the first base.

[0009] Optionally, a forced centering device is also provided at the center of both the first base and the second base. The GNSS antenna is mounted on the first base and the second base through the forced centering device. The distance between the forced centering device on the first base and the forced centering device on the second base is obtained by reading the scale line value at the location of the first base.

[0010] Optionally, both G1 and G2 are measured using RTK measurement. During the measurement process, a base station can be set up near the radar or CORS can be used to perform differential calculations.

[0011] Optionally, the orientation assist component includes a first pillar, a second pillar, a third pillar, a fourth pillar, and a frame; one end of the first pillar, the second pillar, the third pillar, and the fourth pillar are respectively fixed to each other with the frame and perpendicular to the plane of the frame, and the other end of the first pillar, the second pillar, the third pillar, and the fourth pillar extends downward along the height direction.

[0012] The present invention also provides an initial orientation method for ground-based circular arc synthetic aperture radar, comprising the following steps:

[0013] Step 1: Install the ground-based circular arc synthetic aperture radar initial orientation device as described above;

[0014] Start G1 to continuously collect coordinate values ​​(x,y) at intervals Δt;

[0015] Set the coordinates of the starting position of rotation of G2 to P1;

[0016] The radar arm is driven to rotate, causing G2 to rotate. During the rotation, the radar arm pauses at N positions, resulting in P evenly distributed along the rotation trajectory of G2. 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 any point P. i Collect coordinates at the location;

[0017] Step 2: Calculate any P based on the distance between G1 and G2. i The true and accurate coordinates of the location And the true and accurate coordinates of the center C

[0018] The coordinate correction of the center C of the circle is calculated using the least squares method and denoted as (Δx). C ,Δy C ) and any P i The coordinate correction for the position is (Δx) i ,Δy i The final calculated value is the adjusted coordinate value of the center C of the circle. And any P i Adjusted coordinates of location

[0019] Step 3: Adjustment of coordinates based on the center C of the circle And any P i Adjusted coordinates of location Calculate the initial azimuth angle α of the radar.

[0020] Optionally, in step two, any P is calculated. i Adjusted coordinates of location and the adjusted coordinates of the center C The specific process is as follows:

[0021] Based on the Cartesian Cartesian coordinate system, let the north direction be the positive x-axis and the east direction be the positive y-axis;

[0022] Selecting G1 at the center C of the circle, continuously acquires m coordinate values ​​at a sampling frequency Δt.

[0023] For any P i m coordinate data points were collected at each location to obtain coordinate values.

[0024] Let L′ be the distance between G1 and G2. Taking L′ as the true value, based on the constraint condition, i.e., line segment P... i The distance C is equal to L′, and theoretically, we should have:

[0025]

[0026] Where: 1≤k≤m, k represents the kth coordinate value collected; 1≤k≤m, i represents the coordinate value at position P. i Coordinates collected at the location; For P i The true and accurate coordinates These are the true and accurate coordinates of the center C of the circle.

[0027] Optionally, the coordinate adjustment value of the circle center C can be obtained using estimation methods such as the least squares method. And any P i Adjusted coordinates of location The specific process is as follows:

[0028] Substitute the measured coordinate values into , we get:

[0029]

[0030] where: is the error between the true value and the measured value;

[0031] Linearize the above equation using Taylor's formula, and ignore the quadratic and higher order terms, so we have:

[0032]

[0033]

[0034] Let the number of rows of the unknown vector group be 2*N+2 and the number of columns be 1, then the unknown vector matrix X is:

[0035] X = [Δx C , Δy C , Δx 1 , Δy 1 , Δx 2 , Δy 2 , …, Δx N , Δy N ] T ;

[0036] Let , we get the error equation:

[0037]

[0038] where: represents the difference between the observed value calculated by substituting the kth measured value of at position P i into the formula and its approximate value;

[0039] Let the number of rows of the parameter matrix B be m*N and the number of columns be 2*N+2, according to the error equation, then the parameter matrix B is expressed as:

[0040]

[0041] Let the number of rows of the matrix L be 2*N+2 and the number of columns be 1, then it is expressed as:

[0042]

[0043] According to the principle of least squares, the unknown vector group X satisfies: T v = min; According to the principle of indirect adjustment, we have:

[0044] X = (BT B) -1 B T L;

[0045] That is, the correction number Δx C ,Δy C ,Δx 1 ,Δy 1 ,Δx 2 ,Δy 2 ,…Δx N ,Δy N ;

[0046] For the center C, the coordinate correction value is:

[0047]

[0048]

[0049] For P i , the corrected coordinate value is:

[0050]

[0051]

[0052] Optionally, the specific process of calculating the initial azimuth angle α of the radar in the third step is:

[0053] Calculate the quadrant angle Rcp between the center C and the point P1:

[0054]

[0055] According to the coordinate increment, the relationship between the quadrant angle Rcp and the azimuth angle α is determined:

[0056] ① When , it is determined that the quadrant angle Rcp and the azimuth angle α are in the first quadrant, that is, α=Rcp;

[0057] ② When , it is determined that the quadrant angle Rcp and the azimuth angle α are in the second quadrant, that is, α=Rcp+90°;

[0058] ③ When , it is determined that the quadrant angle Rcp and the azimuth angle α are in the third quadrant, that is, α=Rcp+180°;

[0059] ④ When , it is determined that the quadrant angle Rcp and the azimuth angle α are in the fourth quadrant, that is, α=Rcp+360°.

[0060] Compared with the prior art, the present application has the following beneficial effects:

[0061] The application provides an initial orientation device for a ground-based circular arc synthetic aperture radar. i The application fully utilizes the constraint condition of fixed baseline length and the characteristic of distribution on a circumference, obtains corrected coordinate values of each coordinate point after adjustment through measurement and adjustment means and GNSS technology, and obtains an initial azimuth angle of the radar through an azimuth angle calculation formula, so that the application has the advantages of accurate calculation, no need of an angle reflector, fast and convenient calculation, and the like, and a GNSS antenna is configured on the radar, and only one GNSS antenna needs to be carried, so that the burden of on-site personnel is reduced. i The application can freely set the number of baselines, and set the collection mode (dynamic or static observation) and data solving mode (RTK or precise baseline solving) of the position.

[0062] In addition to the purposes, characteristics and advantages described above, the application has other purposes, characteristics and advantages. The application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0063] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated herein for explanation by reference. In the drawings:

[0064] Figure 1 is a structure schematic view of mutual connection of a directional auxiliary assembly and a guide rail structure in an initial orientation device for a ground-based circular arc synthetic aperture radar in an embodiment of the application;

[0065] Figure 2 is a structure schematic view of mutual connection of a radar main body structure and a rotating shaft in an initial orientation device for a ground-based circular arc synthetic aperture radar in an embodiment of the application;

[0066] Figure 3 is a distribution schematic view of a radar swing arm starting position and a pause position in an initial orientation method for a ground-based circular arc synthetic aperture radar in an embodiment of the application.

[0067] Wherein:

[0068] 1. The directional auxiliary assembly, 11, a first support column, 12, a second support column, 13, a third support column, 14, a fourth support column, 15, a rectangular frame;

[0069] 2. The guide rail structure, 21, a first sliding rail, 22, a second sliding rail, 23, a first base, 24, a second base;

[0070] 3, radar main body structure, 31, radar swing arm, 32, antenna, 33, connecting structure;

[0071] 4, rotating shaft. DETAILED DESCRIPTION

[0072] Embodiment:

[0073] The application provides a ground base arc synthetic aperture radar initial orientation device, which comprises an orientation auxiliary assembly 1, a guide rail structure 2, a radar main body structure 3 and a rotating shaft 4, and details are shown in the following Figure 1 and Figure 2 .

[0074] The orientation auxiliary assembly 1 comprises a first support 11, a second support 12, a third support 13, a fourth support 14 and a rectangular frame 15, and details are shown in the following Figure 1 ; one end of the first support 11, the second support 12, the third support 13 and the fourth support 14 is respectively fixedly connected with four corners of the rectangular frame 15 and perpendicular to the plane where the rectangular frame 15 is located, and the other end of the first support 11, the second support 12, the third support 13 and the fourth support 14 respectively extends downward along the height direction. Here, preferably, the first support 11 and the second support 12 are arranged at one width side of the rectangular frame 15 with a spacing therebetween, and the spacing between the first support 11 and the second support 12 is preferably equal to the width of the radar swing arm 31; the third support 13 and the fourth support 14 are arranged at the other width side of the rectangular frame 15 with a spacing therebetween, and the spacing between the third support 13 and the fourth support 14 is preferably equal to the width of the radar swing arm 31; the spacing between the first support 11 and the third support 13 and the spacing between the second support 12 and the fourth support 14 are both preferably equal to or less than the length of the radar swing arm 31. The radar main body structure 3 is clamped between the first support 11, the second support 12, the third support 13 and the fourth support 14.

[0075] The guide rail structure 2 comprises a first sliding rail 21, a second sliding rail 22, a first base 23 and a second base 24, and details are shown in the following Figure 1; the first sliding rail 21 and the second sliding rail 22 are arranged side by side on the rectangular frame 15, and the first sliding rail 21 and the second sliding rail 22 are arranged at intervals along the width direction of the rectangular frame 15; the first base 23 is connected to the first sliding rail 21 and the second sliding rail 22 at the same time, and the first base 23 can slide horizontally along the first sliding rail 21 and the second sliding rail 22 (the sliding direction of the first base 23 is the length direction of the rectangular frame 15); the second base 24 is connected to the first sliding rail 21 and the second sliding rail 22 at the same time, and the second base 24 is arranged at intervals with the first base 23 and is fixedly connected to the first sliding rail 21 and the second sliding rail 22 by welding. The radar swing arm 31 is installed on the second base 24, and the rotating shaft 4 is installed on the radar swing arm 31, and the central axis of the rotating shaft 4 is arranged to coincide with the central axis of the second base 24 perpendicular to the sliding direction (that is, the central axis of the rotating shaft 4 is arranged to coincide with the central axis of the second base 24 parallel to the width side of the rectangular frame 15).

[0076] Optionally, the first sliding rail 21 and the second sliding rail 22 are preferably arranged symmetrically along the central axis of the width side of the rectangular frame 15, and the distance between the first sliding rail 21 and the second sliding rail 22 is preferably 5CM.

[0077] Optionally, the first sliding rail 21 and the second sliding rail 22 are also provided with scale lines, which are arranged at intervals of 0.5mm from the central axis of the second base 24 parallel to the width side of the rectangular frame 15 as the origin (that is, the central axis of the second base 24 parallel to the width side of the rectangular frame 15 is the 0 scale position) and in the direction extending from the second base 24 to the first base 23.

[0078] Optionally, a forced centering device is also arranged at the center of the first base 23 and the second base 24, and the GNSS antenna is installed on the first base 23 and the second base 24 through the forced centering device, and the distance between the forced centering device arranged on the first base 23 and the forced centering device arranged on the second base 24 (the distance between the two GNSS antenna centers) is obtained by reading the scale line value of the position of the first base 23.

[0079] The radar main body structure 3 includes a standard cuboid-shaped radar swing arm 31 and an antenna 32 connected to the radar swing arm 31 through a connecting structure 33, which will be described in detail in the following. Figure 2; the radar swing arm 31 rotates in the horizontal direction with the rotation shaft 4 as the center. Assuming that the GNSS antenna installed on the second base 24 is G1, and the GNSS antenna installed on the first base 23 is G2, since the center of G1 coincides with the central axis of the rotation shaft 4, the position corresponding to the center of G1 is the coordinate position of the center C on the plane; since G2 rotates with the radar swing arm 31, the rotation track of G2 is a circle.

[0080] Further, G1 and G2 both adopt the RTK (Real-Time Kinematic) measurement mode to realize measurement, and in the measurement process, a base station can be erected near the radar or CORS (Continuously Operating Reference Stations) is used to realize differential calculation.

[0081] The application also provides an initial orientation method of the ground-based circular arc synthetic aperture radar, so as to obtain the initial azimuth of the radar and then superimpose the subsequent radar deformation field and terrain. The specific technical scheme is as follows:

[0082] Step one, install the initial orientation device of the ground-based circular arc synthetic aperture radar, so that G1 collects coordinate values (x, y) at intervals of Δt without interruption; at the same time, G2 rotates with the radar swing arm, and the coordinate values corresponding to the positions where G2 is temporarily stopped during the rotation of the radar swing arm are collected, so that coordinate values P uniformly distributed on the rotation track of G2 are obtained i ; and the coordinate value of the starting position of the rotation of the radar swing arm is set as P1, which is described in detail in Figure 3 ; at any P i position, m coordinate data are collected (m is generally not less than 3, and in the application, m is preferably set as m=10). Wherein, Δt is generally not less than 1 second, 1≤i≤N, and N is generally not less than 3,

[0083] Step two, calculate the measurement value of GNSS

[0084] Assuming that the north direction is the positive direction of the x axis, and the east direction is the positive direction of the y axis;

[0085] Selecting G1 at the center C to collect coordinate values collected at a frequency of Δt without interruption Wherein, 1≤k≤m, and k represents the kth coordinate value collected;

[0086] At any position P i , m coordinate data are collected to obtain coordinate values Wherein, 1≤k≤m, and i represents the coordinate collected at the position P i ; and

[0087] Let the distance between G1 and G2 be L', and let L' be the true value, based on the constraint that the line segment P i The distance of C (i.e., the distance from any point to the center) should theoretically equal L', i.e., there is:

[0088]

[0089] wherein: is the true and accurate coordinate value of P i , and is the true and accurate coordinate value of C.

[0090] Based on the coordinate values obtained by uninterrupted collection at the collection frequency Δt of G1 at the center C and for any position P i The coordinate values obtained by collection of m coordinate data all have errors, and therefore, the coordinate adjustment value of each point is obtained by using the measurement adjustment method, and the coordinate adjustment value of the center C is represented as , and the coordinate correction number thereof is (Δx C , Δy C ); the coordinate adjustment value of P i is represented as , and the coordinate correction number thereof is (Δx i , Δy i ).

[0091] Substitute the measured coordinate values into equation 1), i.e., obtain:

[0092]

[0093] wherein: is the error between the true value and the measured value.

[0094] Linearize equation 2) using the Taylor formula, and omit the second and higher order terms, and thus there is:

[0095]

[0096]

[0097] wherein: is the distance calculated using the kth measured coordinate value at the position P i and the kth measured coordinate value at the center C.

[0098] Let the number of rows of the unknown vector group be 2*N+2, and the number of columns be 1, and then the unknown vector matrix X is:

[0099] X = [Δx C , Δy C , Δx 1 , Δy 1 , Δx2 , Δy 2 ,…, Δx N , Δy N ] T 5);

[0100] Let Thus, the error equation can be obtained from equation 3):

[0101]

[0102] wherein: represents the difference between the observation value calculated after substituting the kth measurement value of the pair at position P i into the formula and its approximate value.

[0103] Let the parameter matrix B have m*N rows and 2*N+2 columns, and according to the error equation, it can be expressed as:

[0104]

[0105] Let the matrix L have 2*N+2 rows and 1 column, and it can be expressed as:

[0106]

[0107] According to the least square method principle, the unknown vector group X is required to satisfy v T v = min. According to the indirect adjustment principle, we have:

[0108] X = (B T B) -1 B T L 9);

[0109] That is, the correction numbers Δx C , Δy C , Δx 1 , Δy 1 , Δx 2 , Δy 2 ,…, Δx N , Δy N can be obtained.

[0110] For the center C, the coordinate correction value is:

[0111]

[0112]

[0113] For P i , the corrected coordinate value is:

[0114]

[0115]

[0116] Step three, calculate the initial azimuth angle of radar α

[0117] Calculate the quadrant angle Rcp between the center C and P1 two points:

[0118]

[0119] According to the coordinate increment, the relationship between the quadrant angle Rcp and the radar azimuth angle α is judged:

[0120] ① When , it is judged that the quadrant angle Rcp and the azimuth angle α are in the first quadrant, that is, α=Rcp;

[0121] ② When , it is judged that the quadrant angle Rcp and the azimuth angle α are in the second quadrant, that is, α=Rcp+90°;

[0122] ③ When , it is judged that the quadrant angle Rcp and the azimuth angle α are in the third quadrant, that is, α=Rcp+180°;

[0123] ④ When , it is judged that the quadrant angle Rcp and the azimuth angle α are in the fourth quadrant, that is, α=Rcp+360°.

[0124] The technical scheme of the embodiment is applied to test, as follows:

[0125] In this experimental example, the local coordinate system is used, the distance L' between the two GNSS center positions is 1 meter, m is selected as 10, and n is selected as 2. That is, the following data is obtained:

[0126] The x-axis coordinates of the center C: [-0.0011 0.0014 -0.0031 -0.0122 0.0112 -0.0040 0.0106 0.0023 -0.0118 0.0161];

[0127] The corresponding y-axis coordinates of the center C: [-0.0068 0.0083 -0.0021 0.0099 -0.0085 -0.0156 -0.0158 0.0054 0.0020 -0.0027];

[0128] The x-axis coordinates of P1: [0.9871 0.9931 1.0056 1.0042 1.0023 0.9987 0.9989 1.0094 1.0029 1.0024];

[0129] Corresponding y-axis coordinates of P1 : [-0.0107 -0.0111 -0.0121 0.0126 -0.0109 -0.0015 -0.0022 -0.0033 0.0119 0.0103];

[0130] x-axis coordinates of P2: [0.0017 -0.0010 -0.0020 -0.0030 0.0023 -0.0012 -0.0109 0.0117 -0.0103 -0.0107];

[0131] Corresponding y-axis coordinates of P2: [1.0002 0.9978 0.9854 0.9976 0.9931 0.9918 0.9904 0.9956 0.9833 1.0080];

[0132] x-axis coordinates of P3: [-0.9887 -1.0038 -0.9929 -0.9972 -1.0046 -1.0087 -0.9907 -1.0105 -1.0055 -0.9994]

[0133] Corresponding y-axis coordinates of P3: [-0.0004 -0.0011 -0.0014 0.0032 0.0021 0.0004 -0.0016 -0.0011 -0.0002 0.0010];

[0134] x-axis coordinates of P4: [-0.0002 -0.0003 -0.0004 0.0000 0.0001 0.0010 0.0019 0.0006 -0.0003 0.0008]

[0135] Corresponding y-axis coordinates of P4: [-1.0015 -0.9914 -1.0079 -1.0026 -1.0011 -1.0043 -1.0022 -0.9922 -0.9986 -0.9988].

[0136] According to the above formula, the correction numbers can be calculated as:

[0137] [Δx C ,Δy C ,Δx 1 ,Δy 1 ,Δx 2 ,Δy 2 ,Δx 3 ,Δy 3 ,Δx 4 ,Δy 4 ]

[0138] = [-0.0217, -0.0218, -0.0711, -0.0147, -0.0292, -0.0740, 0.0063, -0.0291, -0.0147, 0.0096];

[0139] For the center C, the coordinate correction value is:

[0140]

[0141]

[0142] For the point P on the circumference i , the corrected coordinate value is:

[0143]

[0144]

[0145] According to the above steps, the initial azimuth of the radar is α:

[0146] Calculate the quadrant angle Rcp of the points C and P1:

[0147]

[0148]

[0149]

[0150] According to the coordinate increment, determine the relationship between the quadrant angle Rcp and the azimuth α:

[0151] ① When , it is determined that the quadrant angle Rcp and the azimuth α are in the first quadrant, i.e. α = Rcp;

[0152] ② When , it is determined that the quadrant angle Rcp and the azimuth α are in the second quadrant, i.e. α = Rcp + 90°;

[0153] ③ When , it is determined that the quadrant angle Rcp and the azimuth α are in the third quadrant, i.e. α = Rcp + 180°;

[0154] ④ When , it is determined that the quadrant angle Rcp and the azimuth α are in the fourth quadrant, i.e. α = Rcp + 360°.

[0155] According to the above calculation, condition ① is satisfied, and finally the initial azimuth of the radar is α = 0.2°.

[0156] The application provides a device and a method for radar initial orientation, designs an orientation auxiliary device, fully utilizes the constraint condition of fixed baseline length and the characteristic of distribution on a circumference, obtains corrected coordinate values of each coordinate point after adjustment through adjustment and GNSS technology, and obtains the initial azimuth of the radar through an azimuth calculation formula. i The traditional baseline adjustment method often only uses one or several fixed baselines for calculation due to the condition limitation. The method of the application can freely set the number of baselines and set the baselines at P i The position acquisition mode (dynamic or static observation) and the data solution mode (RTK or precise baseline solution) are high in flexibility and can be adapted to different precision requirements.

[0157] The above merely describes the preferred embodiments of the application and is not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A ground-based circular arc synthetic aperture radar initial orientation device, characterized in that, It includes a directional auxiliary component (1), a guide rail structure (2), a radar main body structure (3), and a rotating shaft (4); The guide rail structure (2) includes a first slide rail (21), a second slide rail (22), a first base (23), and a second base (24). The first slide rail (21) and the second slide rail (22) are arranged side by side on the orientation auxiliary component (1). The first base (23) is slidably connected to both the first slide rail (21) and the second slide rail (22). The second base (24) is fixedly connected to both the first slide rail (21) and the second slide rail (22). The GNSS antenna installed on the second base (24) is G1, and the GNSS antenna installed on the first base (23) is G2. The radar main structure (3) is mounted on the end of the directional auxiliary component (1) away from the guide rail structure (2); and the radar main structure (3) includes a radar swing arm (31) and a radar antenna (32) connected to the radar swing arm (31) through a connecting structure (33). The radar swing arm (31) is mounted on the second base (24) and rotates horizontally about the pivot (4). The rotating shaft (4) is mounted on the radar swing arm (31), and the central axis of the rotating shaft (4) coincides with the central axis of the second base (24) perpendicular to the sliding direction. The orientation assist component (1) includes a first pillar (11), a second pillar (12), a third pillar (13), a fourth pillar (14), and a frame (15); one end of the first pillar (11), the second pillar (12), the third pillar (13), and the fourth pillar (14) are respectively fixed to the frame (15) and perpendicular to the plane of the frame (15), and the other end of the first pillar (11), the second pillar (12), the third pillar (13), and the fourth pillar (14) are respectively extended downward along the height direction.

2. The ground-based circular arc synthetic aperture radar initial orientation device according to claim 1, characterized in that, The first slide rail (21) and the second slide rail (22) are also provided with scale lines. The scale lines are set sequentially with the central axis parallel to the width side of the second base (24) and the orientation auxiliary component (1) as the origin, and in the direction extending from the second base (24) to the first base (23) at intervals of 0.5 mm.

3. The ground-based circular arc synthetic aperture radar initial orientation device according to claim 2, characterized in that, A forced centering device is provided at the center of both the first base (23) and the second base (24). The GNSS antenna is installed on the first base (23) and the second base (24) through the forced centering device. The distance between the forced centering device on the first base (23) and the forced centering device on the second base (24) is obtained by reading the scale line value at the location of the first base (23).

4. The ground-based circular arc synthetic aperture radar initial orientation device according to claim 1, characterized in that, Both G1 and G2 employ RTK measurement, and during the measurement process, a base station is set up near the radar or CORS is used to perform differential calculations.

5. A ground-based circular arc synthetic aperture radar initial orientation method, characterized in that, Includes the following steps: Step 1: Install the ground-based circular arc synthetic aperture radar initial orientation device as described in any one of claims 1-4; Start G1 to continuously collect coordinate values ​​(x,y) at intervals Δt; Set the coordinates of the starting position of rotation of G2 to P1; The radar arm is driven to rotate, causing G2 to rotate. During the rotation, the radar arm pauses at N positions, resulting in P evenly distributed along the rotation trajectory of G2. 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 any point P. i Collect coordinates at the location; Step 2: Calculate any P based on the distance between G1 and G2. i The true and accurate coordinates of the location And the true and accurate coordinates of the center C The coordinate correction of the center C of the circle is calculated using the least squares method and denoted as (Δx). C ,Δy C ) and any P i The coordinate correction for the position is (Δx) i ,Δy i The final calculated value is the adjusted coordinate value of the center C of the circle. And any P i Adjusted coordinates of location Step 3: Adjustment of coordinates based on the center C of the circle And any P i Adjusted coordinates of location Calculate the initial azimuth angle α of the radar.

6. The initial orientation method for ground-based circular arc synthetic aperture radar according to claim 5, characterized in that, In step two, any P is calculated. i Adjusted coordinates of location and the adjusted coordinates of the center C The specific process is as follows: Based on the Cartesian Cartesian coordinate system, let the north direction be the positive x-axis and the east direction be the positive y-axis; Selecting G1 at the center C of the circle, continuously acquires m coordinate values ​​at a sampling frequency Δt. For any P i m coordinate data points were collected at each location to obtain coordinate values. Let L′ be the distance between G1 and G2. Taking L′ as the true value, based on the constraint condition, i.e., line segment P... i The distance C is equal to L′, and theoretically, we should have: Where: 1≤k≤m, k represents the kth coordinate value collected; 1≤i≤m, i represents the coordinate value at position P. i Coordinates collected at the location; For P i The true and accurate coordinates These are the true and accurate coordinates of the center C of the circle.

7. The initial orientation method for ground-based circular arc synthetic aperture radar according to claim 6, characterized in that, The coordinate adjustment value of the center C of the circle was obtained using estimation methods such as the least squares method. And any P i Adjusted coordinates of location The specific process is as follows: Substitute the measured coordinate values In this way, we get: in: This represents the error between the true value and the measured value. Linearizing the above equation using Taylor's formula and neglecting terms of quadratic degree and above, we have: Let the number of rows of the unknown vector group be 2*N+2 and the number of columns be 1. Then its unknown vector matrix X is: X=[Δx C ,Δy C ,Δx 1 ,Δy 1 ,Δx 2 ,Δy 2 ,…,Δx N ,Δy N ] T ; make The error equation is then obtained: in: Represented as at position P i The difference between the observed value and its approximate value is calculated by substituting the k-th measurement value into the formula. Let parameter matrix B have m*N rows and 2*N+2 columns. According to the error equation, parameter matrix B can be expressed as: Given a matrix L with 2*N+2 rows and 1 column, it can be represented as: According to the principle of least squares, the unknown vector set X must satisfy v T v = min; According to the principle of indirect adjustment, we have: X=(B T B) -1 B T L; That is, calculate the corrections Δx C , Δy C , Δx 1 , Δy 1 , Δx 2 , Δy 2 , … Δx N , Δy N ; For the center C, its coordinate correction value is: For P i The corrected coordinates are:

8. The initial orientation method for ground-based circular arc synthetic aperture radar according to claim 7, characterized in that, The specific process for calculating the initial radar azimuth angle α in step three is as follows: Calculate the quadrant angle Rcp between the center C and point P1: Based on the coordinate increment, determine the relationship between the quadrant angle Rcp and the azimuth angle α: ①When When the quadrant angle Rcp and the azimuth angle α are in the first quadrant, α = Rcp; ②When When the quadrant angle Rcp and the azimuth angle α are in quadrant II, α = Rcp + 90°; ③When When the quadrant angle Rcp and the azimuth angle α are in quadrant III, α = Rcp + 180°; ④ When When the quadrant angle Rcp and the azimuth angle α are in quadrant IV, α = Rcp + 360°.

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