Radar calibration method based on total station
By obtaining the Gauss-Kruger coordinates of the radar installation point using a total station and converting them to WGS-84 coordinates, combined with trigonometric calculations, the problems of cumbersome road closures and low accuracy in existing millimeter-wave radar calibration methods are solved, achieving simple and efficient radar calibration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGZHOU RES INST OF XIAN UNIV OF ELECTRONIC SCI & TECH
- Filing Date
- 2022-10-10
- Publication Date
- 2026-06-19
AI Technical Summary
Existing millimeter-wave radar calibration methods require road closures, are cumbersome to operate, involve complex calculations, and have low calibration accuracy.
A total station was used to obtain the Gauss-Kruger coordinates of the roadside observation points and reference points where the radar was installed. The known points were used to establish the station. The Gauss-Kruger coordinates of the center point of the radar surface were measured and converted into WGS-84 coordinates. Combined with trigonometric operations, the northward deflection angle of the radar normal was obtained, thus achieving accurate radar calibration.
No road closures are required, the calibration operation is simple, the accuracy is high, and the calculation speed is fast, which improves calibration efficiency and safety.
Smart Images
Figure CN115712092B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of radar calibration technology, specifically relating to a radar calibration method based on a total station. Background Technology
[0002] Millimeter-wave radar is one of the front-end sensing technologies for smart highways. It enables real-time perception of vehicles, pedestrians, and traffic conditions at intersections, providing traffic managers and participants with a wider range of traffic environment conditions, improving road traffic efficiency, and reducing traffic congestion and accidents.
[0003] In existing technologies, the calibration methods used require road closures, are cumbersome to operate, involve complex calculations, have high time and cost, and have low calibration accuracy.
[0004] Therefore, we should continue to improve the calibration process in existing technologies to enhance calibration accuracy. Summary of the Invention
[0005] To address the aforementioned problems in the existing technology, this invention provides a radar calibration method based on a total station. The technical problem to be solved by this invention is achieved through the following technical solution:
[0006] Firstly, this application provides a radar calibration method based on a total station, comprising:
[0007] Obtain the roadside observation point and reference point of the radar installation, and obtain the Gauss-Kruger coordinates of the observation point and the Gauss-Kruger coordinates of the reference point;
[0008] Input the Gauss-Kruger coordinates of the observation point and the reference point into the total station to establish a station for the known point;
[0009] Use a total station to measure the center point of the radar surface and obtain the Gauss-Kruger coordinates of the center point of the radar surface.
[0010] Convert the Gauss-Kruger coordinates of the radar surface center point to WGS-84 coordinates to obtain the latitude and longitude of the radar surface center point.
[0011] Optionally, the center point of the radar surface can be measured multiple times using a total station, and the average value can be calculated as the Gauss-Kruger coordinates of the center point of the radar surface.
[0012] Optionally, it also includes: obtaining the radar normal north deflection angle;
[0013] Use a total station to measure the first and second measurement points on the radar surface, and obtain the Gauss-Kruger coordinates of the first and second measurement points.
[0014] Convert the Gauss-Krüger coordinates of the first and second measurement points to WGS-84 coordinates to obtain the latitude and longitude of the first and second measurement points.
[0015] Convert the latitude and longitude of the first measurement point and the latitude and longitude of the second measurement point into radians;
[0016] Based on the radians of the latitude and longitude of the first measurement point and the radians of the latitude and longitude of the second measurement point, the Earth radius and latitude circle radius corresponding to the latitude and longitude of the first measurement point, as well as the Earth radius and latitude circle radius corresponding to the latitude and longitude of the second measurement point, are obtained.
[0017] Perform trigonometric operations on the latitude and longitude of the first and second measurement points to obtain the angle between the vector formed by the first and second measurement points and the due north direction of the Earth, which is denoted as the first angle.
[0018] Determine the orientation of the radar normal and convert the first included angle into the north deflection angle of the radar normal.
[0019] Optionally, the process of converting the latitude and longitude of the first measurement point and the latitude and longitude of the second measurement point into radians includes:
[0020] The latitude and longitude of the first measurement point are (B) D ,L D H D The latitude and longitude of the second measurement point are (B). E ,L E H E );in,
[0021] Convert the latitude and longitude of the first measurement point to radians, that is:
[0022]
[0023] Among them, B D _Rad represents the latitude in radians of the first measurement point, L D _Rad represents the longitude in radians of the first measurement point, and PI is a constant;
[0024] Convert the latitude and longitude coordinates of the second measurement point to radians, that is:
[0025]
[0026] Among them, B E _Rad represents the latitude in radians at the second measurement point, L E _Rad represents the longitude in radians of the second measurement point, and PI is a constant.
[0027] Optionally, the Earth's radius and the radius of the latitude circle corresponding to the latitude and longitude of the first measurement point are respectively:
[0028]
[0029] Where D_Ec is the Earth's radius corresponding to the latitude and longitude of the first measurement point, D_Ed is the radius of the latitude circle corresponding to the latitude and longitude of the first measurement point, Rj is the Earth's equatorial radius, and Rc is the Earth's polar radius.
[0030] The Earth's radius and the radius of the latitude circle corresponding to the latitude and longitude of the second measurement point are as follows:
[0031]
[0032] Where E_Ec is the Earth's radius corresponding to the latitude and longitude information of the second measurement point, E_Ed is the radius of the latitude circle corresponding to the latitude and longitude information of the second measurement point, Rj is the Earth's equatorial radius, and Rc is the Earth's polar radius.
[0033] Optionally, the process of performing trigonometric operations on the latitude and longitude of the first and second measurement points to obtain the angle between the vector formed by the first and second measurement points and the Earth's true north direction includes:
[0034] Obtain the difference between the longitude of the first measurement point and the longitude of the second measurement point, and record it as the first difference. Obtain the difference between the latitude of the first measurement point and the latitude of the second measurement point, and record it as the second difference. Convert these values to the range of 0° to 360°.
[0035]
[0036] Where d_Lon is the difference between the longitude of the first measurement point and the longitude of the second measurement point, and d_Lat is the difference between the latitude of the first measurement point and the latitude of the second measurement point;
[0037] Based on the first difference and the second difference, the first included angle is obtained, that is:
[0038]
[0039] Where dx is the first variable generated in the process of obtaining the first included angle, dy is the second variable generated in the process of obtaining the first included angle, and angle is the first included angle;
[0040] Assuming the first measurement point is fixed at the origin, the north deflection angle between the first and second measurement points is determined based on the position of the second measurement point relative to the first measurement point on both axes in the four quadrants.
[0041]
[0042] Optionally, the vertical distance between the first measurement point and the second measurement point is the first distance, which is proportional to the first difference and / or the second difference.
[0043] The beneficial effects of this invention are:
[0044] This invention provides a radar calibration method based on a total station. By acquiring the latitude and longitude information of traffic participants, and using a GPS instrument to measure the Gauss-Kruger coordinates of the observation points and reference points on the roadside where the radar is installed, the method eliminates the need for road closures. It uses a total station to establish stations at known points and measures the Gauss-Kruger coordinates of the center point of the radar surface, directly converting them into latitude and longitude. This makes radar calibration easy to operate, highly accurate, and fast.
[0045] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0046] Figure 1 This is a flowchart of a radar calibration method based on a total station provided in an embodiment of the present invention;
[0047] Figure 2 This is a schematic diagram illustrating the positional relationship between the observation point, the reference point, and the center point of the radar surface provided in an embodiment of the present invention;
[0048] Figure 3 This is a schematic diagram of a radar surface provided in an embodiment of the present invention. Detailed Implementation
[0049] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.
[0050] Please see Figure 1 and Figure 2 As shown, Figure 1 This is a flowchart of a radar calibration method based on a total station provided in an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the positional relationship between the observation point, reference point, and radar surface center point provided in an embodiment of the present invention. The radar calibration method based on a total station provided in this application includes:
[0051] S101. Obtain the observation point and reference point of the radar installation on the roadside, and obtain the Gauss-Kruger coordinates of the observation point and the Gauss-Kruger coordinates of the reference point.
[0052] S102. Input the Gauss-Krüger coordinates of the observation point and the Gauss-Krüger coordinates of the reference point into the total station to establish a station for the known point.
[0053] S103. Use a total station to measure the center point of the radar surface and obtain the Gauss-Kruger coordinates of the center point of the radar surface.
[0054] S104. Convert the Gauss-Rüger coordinates of the radar surface center point to WGS-84 coordinates to obtain the latitude and longitude of the radar surface center point.
[0055] It should be noted that Gaussian coordinates are a type of Cartesian coordinate system, a type of projected coordinate system. This coordinate system is directly interchangeable with WGS-84 coordinates. Correspondingly, other projected coordinate systems that can be directly converted to WGS-84 coordinates can also be used.
[0056] For details, please continue to see Figure 1 As shown in this embodiment, a radar calibration method based on a total station is provided. The purpose of calibration is to obtain the latitude and longitude of the radar's location in order to acquire the latitude and longitude information of traffic participants. A GPS instrument is used to measure the Gauss-Kruger coordinates of the observation point and reference point on the roadside where the radar is installed. No road closure is required. A total station is used to establish a station at the known points, and the Gauss-Kruger coordinates of the center point of the radar surface are measured and directly converted into latitude and longitude. This makes the radar calibration easy to operate, with high calibration accuracy and fast calculation speed.
[0057] It should be noted that a total station is a high-tech surveying instrument integrating optics, mechanics, and electronics. Among its functions, setting up a station at a known point is one of the commonly used functions of a total station in daily surveying work. The total station is used to set the coordinate data of the station point and the backsight point, thereby obtaining the coordinate data of the observation point. The total station calculates the coordinates of the observation point by measuring horizontal angles, distances (slope distance, horizontal distance), and elevation differences. Currently, the angle measurement accuracy of total stations can reach 0.5″ level, and the distance measurement accuracy is sub-millimeter level. The built-in program performs calculations, resulting in high coordinate measurement accuracy and fast processing speed.
[0058] It should be noted that the observation points and reference points are those with good observation conditions on the roadside GPS where the radar is installed, i.e., unobstructed and located in open spaces. The Gauss-Kruger coordinates of the observation points and reference points on the roadside where the radar is installed are converted into the latitude and longitude coordinates of the radar center. The method is simple and effective, improving the efficiency and safety of the calibration work. The Gauss-Kruger coordinates of the observation points and reference points can be obtained by GPS instrument RTK.
[0059] It should be noted that, Figure 2 The embodiments shown are only schematic representations of the positional relationship between the reference point and the observation point, and do not represent the actual positional relationship during the measurement process. Here, A can be a reference point or an observation point, B can be an observation point or a reference point, and this application does not limit it here. C is a schematic representation of the position of the center point of the radar surface. Figure 2 In the embodiment described, the rectangular pattern represents the road where the radar is installed.
[0060] In one alternative embodiment of this application, please refer to Figure 3 , Figure 3 This is a schematic diagram of a radar surface provided in an embodiment of the present invention. The center point of the radar surface is measured multiple times using a total station, and the average value is calculated as the Gauss-Kruger coordinates of the center point of the radar surface.
[0061] For details, please continue to see Figure 3 As shown, in this embodiment, the radar center can be selected as the geometric center of the radar housing surface, and marked on the radar surface as a cue point, such as... Figure 3 As shown, the center of the radar surface is point C. Due to human or instrumental errors during total station measurements, the radar center point can be measured multiple times to calculate the average coordinate value. The Gauss-Kruger coordinates of the radar surface center point are then converted to WGS-84 coordinates. The format of WGS-84 coordinates is 23.326807373055°N, 113.545784232222°E, where 23.326807373055°N is latitude and 113.545784232222°E is longitude, with N and E representing North latitude and East longitude, respectively.
[0062] It should be noted that, Figure 3 The illustrated embodiment is only schematically showing the shape of the radar surface and does not represent the actual situation.
[0063] In one optional embodiment of this application, the method further includes: obtaining the radar normal north deflection angle;
[0064] Use a total station to measure the first and second measurement points on the radar surface, and obtain the Gauss-Kruger coordinates of the first and second measurement points.
[0065] Convert the Gauss-Krüger coordinates of the first and second measurement points to WGS-84 coordinates to obtain the latitude and longitude of the first and second measurement points.
[0066] Convert the latitude and longitude of the first measurement point and the latitude and longitude of the second measurement point into radians;
[0067] Based on the radians of the latitude and longitude of the first measurement point and the radians of the latitude and longitude of the second measurement point, the Earth radius and latitude circle radius corresponding to the latitude and longitude of the first measurement point, as well as the Earth radius and latitude circle radius corresponding to the latitude and longitude of the second measurement point, are obtained.
[0068] Perform trigonometric operations on the latitude and longitude of the first and second measurement points to obtain the angle between the vector formed by the first and second measurement points and the due north direction of the Earth, which is denoted as the first angle.
[0069] Determine the orientation of the radar normal and convert the first included angle into the north deflection angle of the radar normal.
[0070] Specifically, the method for obtaining the north deflection angle of the radar normal provided in this embodiment requires first marking a first measurement point D and a second measurement point E on the radar surface. The greater the vertical distance between the first measurement point D and the second measurement point E, the better. Figure 3 The first measurement point D and the second measurement point E do not represent the absolute positions of the radar surface endpoints. For example, the first measurement point D and the second measurement point E could also be located diagonally opposite the center point of the radar surface. Due to human or instrumental errors during total station measurements, the radar center point can be measured multiple times to calculate the average coordinate value. The Gauss-Kruger coordinates of the two endpoints of the radar surface are converted to WGS-84 coordinates. The format of WGS-84 coordinates is 23.34680737°N, 113.5457842323°E, where 23.34680737°N is latitude and 113.5457842323°E is longitude, with N and E being North latitude and East longitude, respectively.
[0071] It should be noted that, Figure 3 The illustrated embodiment only schematically shows one positional relationship between the first observation point D and the second observation point E. Other positional relationships are also included, which are not limited here. That is, the greater the distance between the first observation point D and the second observation point E, the better.
[0072] In an optional embodiment of this application, the process of converting the latitude and longitude of the first measurement point and the latitude and longitude of the second measurement point into radians includes:
[0073] The latitude and longitude coordinates of the first measurement point are (B D ,L D H D The latitude and longitude coordinates of the second measurement point are (B). E ,L E H E );in,
[0074] Convert the latitude and longitude coordinates of the first measurement point to radians, that is:
[0075] B D _Rad=B D *PI / 180
[0076] L D _Rad=L D *PI / 180;
[0077] Among them, B D _Rad represents the latitude in radians of the first measurement point, L D _Rad represents the longitude in radians of the first measurement point, and PI is a constant;
[0078] Convert the latitude and longitude coordinates of the second measurement point to radians, that is:
[0079]
[0080] Among them, B E _Rad represents the latitude in radians at the second measurement point, L E _Rad represents the longitude in radians of the second measurement point, and PI is a constant.
[0081] In one optional embodiment of this application, the Earth's radius and the radius of the latitude circle corresponding to the latitude and longitude of the first measurement point are respectively:
[0082]
[0083] Where D_Ec is the Earth's radius corresponding to the latitude and longitude of the first measurement point, D_Ed is the radius of the latitude circle corresponding to the latitude and longitude of the first measurement point, Rj is the Earth's equatorial radius, and Rc is the Earth's polar radius.
[0084] The Earth's radius and the radius of the latitude circle corresponding to the latitude and longitude of the second measurement point are as follows:
[0085]
[0086] Where E_Ec is the Earth's radius corresponding to the latitude and longitude information of the second measurement point, E_Ed is the radius of the latitude circle corresponding to the latitude and longitude information of the second measurement point, Rj is the Earth's equatorial radius, and Rc is the Earth's polar radius.
[0087] In an optional embodiment of this application, the process of performing trigonometric operations on the latitude and longitude of the first measurement point and the second measurement point to obtain the angle between the vector formed by the first measurement point and the due north direction of the Earth includes:
[0088] Obtain the difference between the longitude of the first measurement point and the longitude of the second measurement point, and record it as the first difference. Obtain the difference between the latitude of the first measurement point and the latitude of the second measurement point, and record it as the second difference. Convert these values to the range of 0° to 360°.
[0089]
[0090] Where d_Lon is the difference between the longitude of the first measurement point and the longitude of the second measurement point, and d_Lat is the difference between the latitude of the first measurement point and the latitude of the second measurement point;
[0091] Based on the first difference and the second difference, the first included angle is obtained, that is:
[0092]
[0093] Where dx is the first variable generated in the process of obtaining the first included angle, dy is the second variable generated in the process of obtaining the first included angle, and angle is the first included angle;
[0094] Assuming the first measurement point is fixed at the origin, the north deflection angle between the first and second measurement points is determined based on the position of the second measurement point relative to the first measurement point on both axes in the four quadrants.
[0095]
[0096] Since there is a 90° difference between the angle between the first and second measurement points on the radar surface and the true north direction and the true north deflection angle of the radar normal, the true north deflection angle of the radar normal is calculated based on the orientation of the radar normal.
[0097] In one optional embodiment of this application, the vertical distance between the first measurement point and the second measurement point is a first distance, which is proportional to a first difference and / or a second difference.
[0098] Specifically, in this embodiment, the greater the distance between the first measurement point and the second measurement point, the better. This can also be understood as the greater the difference between the latitude and longitude of the first measurement point and the latitude and longitude of the second measurement point, the better, so that better calibration accuracy can be achieved during the radar calibration process.
[0099] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.
Claims
1. A total station based radar calibration method, characterized in that, include: Obtain the roadside observation point and reference point of the radar installation, and obtain the Gauss-Kruger coordinates of the observation point and the Gauss-Kruger coordinates of the reference point; Input the Gauss-Kruger coordinates of the observation point and the reference point into the total station to establish a station for the known point; Use a total station to measure the center point of the radar surface and obtain the Gauss-Kruger coordinates of the center point of the radar surface. Convert the Gauss-Rüg coordinates of the radar surface center point to WGS-84 coordinates to obtain the latitude and longitude of the radar surface center point. Obtain the radar normal north deflection angle; Use a total station to measure the first and second measurement points on the radar surface, and obtain the Gauss-Kruger coordinates of the first and second measurement points. Convert the Gauss-Krüger coordinates of the first and second measurement points to WGS-84 coordinates to obtain the latitude and longitude of the first and second measurement points. Convert the latitude and longitude of the first measurement point and the latitude and longitude of the second measurement point into radians; Based on the radians of the latitude and longitude of the first measurement point and the radians of the latitude and longitude of the second measurement point, the Earth radius and latitude circle radius corresponding to the latitude and longitude of the first measurement point, as well as the Earth radius and latitude circle radius corresponding to the latitude and longitude of the second measurement point are obtained. Perform trigonometric operations on the latitude and longitude of the first and second measurement points to obtain the angle between the vector formed by the first and second measurement points and the due north direction of the Earth, which is denoted as the first angle. Determine the orientation of the radar normal and convert the first included angle into the north deflection angle of the radar normal; The process of converting the latitude and longitude of the first measurement point and the latitude and longitude of the second measurement point into radians includes: The latitude and longitude of the first measuring point is , and the latitude and longitude of the second measuring point is ; wherein, Convert the latitude and longitude of the first measurement point to radians, that is: ； in, The value in radians represents the latitude of the first measurement point. The value in radians represents the longitude of the first measurement point. It is a constant; Convert the latitude and longitude coordinates of the second measurement point to radians, that is: ； in, The latitude of the second measurement point is expressed in radians. The value in radians represents the longitude of the second measurement point. It is a constant; The Earth's radius and the radius of the latitude circle corresponding to the latitude and longitude of the first measurement point are as follows: ； wherein, is a radius of the Earth corresponding to the latitude of the first measurement point, is a radius of the latitude circle corresponding to the latitude of the first measurement point, is an equatorial radius of the Earth, is a polar radius of the Earth; The Earth's radius and the radius of the latitude circle corresponding to the latitude and longitude of the second measurement point are as follows: ； in, The latitude and longitude information of the second measurement point corresponds to the Earth's radius. The latitude and longitude information of the second measurement point corresponds to the radius of the latitude circle. The equatorial radius of the Earth. The polar radius of the Earth; The process of performing trigonometric operations on the latitude and longitude of the first and second measurement points to obtain the angle between the vector formed by the first and second measurement points and the Earth's true north direction includes: Obtain the difference between the longitude of the first measurement point and the longitude of the second measurement point, denoted as the first difference; obtain the difference between the latitude of the first measurement point and the latitude of the second measurement point, denoted as the second difference, and convert them to the range of 0° to 360°. ； in, This is the difference between the longitude of the first measurement point and the longitude of the second measurement point. This is the difference between the latitude of the first measurement point and the latitude of the second measurement point; Based on the first difference and the second difference, the first included angle is obtained, that is: ； wherein, a first variable generated in the process of acquiring the first included angle, a second variable generated in the process of acquiring the first included angle, is the first included angle; Assuming the first measurement point is fixed at the origin, the north deflection angle between the first and second measurement points is determined based on the position of the second measurement point relative to the first measurement point on both axes in the four quadrants. ； wherein represents a positive north deflection angle.
2. The total station based radar calibration method of claim 1, wherein, The center point of the radar surface was measured multiple times using a total station, and the average value was calculated as the Gauss-Kruger coordinates of the radar surface center point.
3. The total station based radar calibration method of claim 1, wherein, The vertical distance between the first measurement point and the second measurement point is the first distance, which is proportional to the first difference and / or the second difference.