CN203224625U - Positioning accuracy detection device of high-accuracy airborne laser radar system - Google Patents

Abstract

The utility model discloses a positioning accuracy detection device for a high-precision airborne laser radar system, which comprises a GPS receiver support frame, a GPS receiver, a detection rod side support frame, a first laser foot point detection rod, and a second laser foot point The detection rod and the central support frame of the detection rod, the GPS receiver is fixed on the GPS receiver support frame, the GPS receiver support frame is provided with a GPS receiver level adjustment mechanism, and the detection rod side support frame is a plurality of , a plurality of detection rod side support frames support the first laser foot detection rod and the second laser foot detection rod on a horizontal plane, one end of the first laser foot detection rod and the second laser foot detection rod One end is intersected on the central support frame of the detection rod, and the included angle between the first laser foot point detection rod and the second laser foot point detection rod is ≥90°. Therefore, the advantages of simple operation and small measurement error are realized, and at the same time, it is convenient for field use.

Description

Positioning accuracy detection device for high-precision airborne lidar system

technical field

The utility model relates to the field of laser radar positioning, in particular to a positioning accuracy detection device of a high-precision airborne laser radar system.

Background technique

At present, the LiDAR system is an active system that integrates laser ranging, global positioning system, inertial navigation system technology and high-resolution digital imaging technology to quickly obtain three-dimensional high spatial resolution of ground and ground targets. observation system. In the past ten years, airborne LiDAR technology has been widely accepted in developed countries in the world as a method of accurately and quickly obtaining 3D surface information, and has broad development prospects in many fields such as terrain monitoring, environmental monitoring, and 3D test modeling. Application requirements (Ackeman F, et al, Airborne laser scanning - present status and future expectation. ISPRS JPRS, 1999(54):64-67).

In actual engineering, the positioning accuracy of the laser radar system is generally judged by the DOM generated by the fusion of the laser point cloud and the digital image, or by finding the feature points of the ground object from the laser point cloud to judge the accuracy of the laser point cloud. The former method introduces the generation of DOM, so there are registration errors between the laser point cloud and the digital image and the pixel size error of the DOM image, so the positioning accuracy of the laser point cloud can only be roughly evaluated, and the error is at the decimeter level. The latter method also has errors in the accuracy of judging feature points due to the size of the feature and whether it is judged whether the surface or line is regular, the density of the laser point cloud, and the error between the laser foot point and the reflection point. The density of the point cloud or the task error when looking for feature points in the field is about 10cm.

Utility model content

The purpose of this utility model is to propose a positioning accuracy detection device for a high-precision airborne laser radar system to achieve the advantages of simple operation and small measurement error in view of the above problems.

For realizing above-mentioned object, the technical scheme that the utility model adopts is:

A positioning accuracy detection device for a high-precision airborne laser radar system, including a GPS receiver support frame, a GPS receiver, a detection rod side support frame, a first laser foot point detection rod, a second laser foot point detection rod and a detection rod The central support frame, the GPS receiver is fixed on the GPS receiver support frame, the GPS receiver horizontal adjustment mechanism is set on the GPS receiver support frame, the detection rod side support frame is multiple, and the multiple detection rods The side support frame supports the first laser foot point detection rod and the second laser foot point detection rod on a horizontal plane, and one end of the first laser foot point detection rod and one end of the second laser foot point detection rod are intersected on the detection rod On the central support frame, the included angle between the first laser foot point detection rod and the second laser foot point detection rod is ≥90°.

According to a preferred embodiment of the present utility model, the first laser foot point detection rod and the second laser foot point detection rod are fixed on the central support frame of the detection rod by positioning pins.

According to a preferred embodiment of the present utility model, the included angle between the first laser foot point detection rod and the second laser foot point detection rod is 90°.

According to a preferred embodiment of the present invention, the horizontal alignment point of the GPS receiver phase center of the GPS receiver support frame and the detection pole edge support frame is on the same vertical line.

At the same time, the technical solution of the utility model also discloses a detection method of a positioning accuracy detection device of a high-precision airborne laser radar system, including the following steps:

a. Set up multiple positioning accuracy detection devices of the above-mentioned high-precision airborne laser radar system in the measurement area. The device is a GPS static observation point;

B. Utilize the positioning accuracy detection device erected above to collect the GPS static observation data of the measurement area, and select the GPS static observation point collected by one of the above-mentioned multiple positioning accuracy detection devices as the reference point, and use the GPS static observation data of the above-mentioned collection to GPS static observation points have been set up for adjustment processing, and the coordinates of these GPS static observation points are obtained;

c. Taking the coordinates of the GPS static observation points obtained above as a reference, separate the laser point cloud data detected by the laser foot point detection rod, and store them in groups according to the detection method;

d. Calculate the precise coordinates of each GPS static observation point based on the above-mentioned laser point cloud data.

According to a preferred embodiment of the present utility model, the above-mentioned calculation of the precise coordinates of the GPS static observation point includes the following steps:

的值最小，公式中di是指激光脚点到直线方程Ax+By+cZ=0的距离； Select a set of laser point cloud data, use the straight line equation Ax+By+Cz=0 to fit the set of laser point cloud data, and find the coefficients A, B, and C in the equation so that the equation

The value of is the smallest, and di in the formula refers to the distance from the laser foot point to the straight line equation Ax+By+cZ=0;

Obtain the projection line equation ax+by=0 of the above linear equation Ax+By+Cz=0 on the XY plane, and then adjust the equation coefficients a and b to a1 and b1, so that the projection point of the above laser point cloud data on the XY plane The numbers distributed on both sides of the straight line a1x+b1y=0 are basically equal;

Obtain the fitting line equation A2x+B2y+C2Z=0 of another set of laser point clouds of the same detection point and its projection equation a2x+b2y=0 on the XY plane;

Solve the intersection point of the equation a1x+b1y=0 and the equation a2x+b2y=0 as the plane coordinate of the checkpoint;

The elevation coordinate of the GPS static observation point is obtained by measuring the height above the ground of the support frame on the side of the detection pole; the height difference obtained by subtracting the height coordinate of the static observation point coordinates of the GPS , which is the height coordinate of the GPS static observation point.

The beneficial effects of the utility model are: the technical solution of the utility model uses two cross-placed first laser foot point detection rods and second laser foot point detection rods with large slenderness ratio and high reflectivity as laser point cloud detection rods and The theoretical intersection point of the crossbar is used as the inspection point of the laser radar positioning accuracy. After the aircraft carries the laser radar to complete the project data collection, according to the two sets of laser point clouds measured by the two crossbars erected, the least square method is used to fit the two sets of point clouds respectively. Two straight line equations of two sets of laser point clouds, and then calculate the projection straight line equations of these two straight lines on the horizontal plane and obtain the coordinates of the intersection of these two projected straight lines as the plane coordinates of the laser radar positioning accuracy check point, while the laser radar positioning The height coordinates of the accuracy check point are obtained by measuring the height of the central support frame and the radius of the detection rod; then the error is obtained by comparing the coordinates of the synchronously observed GPS base station placed directly above the center support frame and the coordinates of the laser radar positioning accuracy check point. LiDAR positioning accuracy of points. Therefore, the advantages of simple operation and small measurement error are realized, and at the same time, it is convenient for field use.

The technical solutions of the present utility model will be further described in detail through the drawings and embodiments below.

Description of drawings

Fig. 1 is a schematic structural diagram of a positioning accuracy detection device of a high-precision airborne laser radar system described in an embodiment of the present invention;

FIG. 2 is an enlarged view of point C in the positioning accuracy detection device of the high-precision airborne lidar system shown in FIG. 1 .

In conjunction with the accompanying drawings, reference signs are as follows in the utility model embodiment:

1-GPS receiver support frame; 2-GPS receiver level adjustment mechanism; 3-GPS receiver; 4, 7, 11, 12-side support frame of the detection rod; 5-first laser foot point detection rod; 6-detection Rod center support frame; 8 - positioning pin; 9 - GPS receiver phase center horizontal alignment point; 10 - second laser foot point detection rod.

Detailed ways

The preferred embodiments of the present utility model are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present utility model, and are not intended to limit the present utility model.

As shown in Figure 1 and Figure 2, a positioning accuracy detection device for a high-precision airborne laser radar system includes a GPS receiver support frame, a GPS receiver, a detection rod side support frame, a first laser foot point detection rod, a second 2. The laser foot point detection rod and the central support frame of the detection rod. The GPS receiver is fixed on the GPS receiver support frame. The GPS receiver support frame is provided with a GPS receiver level adjustment mechanism. It can be increased or decreased according to the environment. The four detection rod side support frames support the first laser foot detection rod and the second laser foot detection rod on a horizontal plane. One end of the first laser foot detection rod and the second laser foot detection rod One end of the detection rod is intersected on the central support frame of the detection rod. The angle between the first laser foot point detection rod and the second laser foot point detection rod is ≥90°, which is set to 90°.

Wherein, the first laser foot point detection rod and the second laser foot point detection rod are fixed on the central support frame of the detection rod through positioning pins. The GPS receiver support frame and the GPS receiver phase center horizontal alignment point of the detection pole support frame are on the same vertical line.

A detection method for a positioning accuracy detection device of a high-precision airborne laser radar system, comprising the following steps:

a. Set up multiple positioning accuracy detection devices of the above-mentioned high-precision airborne laser radar system in the measurement area. The positioning accuracy detection devices of the high-precision airborne laser radar system are referred to as positioning accuracy detection devices below. The device is a GPS static observation point;

B. Utilize the positioning accuracy detection device erected above to collect the GPS static observation data of the measurement area, and select the GPS static observation point collected by one of the above-mentioned multiple positioning accuracy detection devices as the reference point, and use the GPS static observation data of the above-mentioned collection to GPS static observation points have been set up for adjustment processing, and the coordinates of these GPS static observation points are obtained;

c. Taking the coordinates of the GPS static observation points obtained above as a reference, separate the laser point cloud data detected by the laser foot point detection rod, and store them in groups according to the detection method;

d. Calculate the precise coordinates of each GPS static observation point based on the above-mentioned laser point cloud data.

Wherein, calculating the precise coordinates of the GPS static observation point includes the following steps:

的值最小，公式中di是指激光脚点到直线方程Ax+By+cZ=0的距离； Select a set of laser point cloud data, use the straight line equation Ax+By+Cz=0 to fit the set of laser point cloud data, and find the coefficients A, B, and C in the equation so that the equation

The value of is the smallest, and di in the formula refers to the distance from the laser foot point to the straight line equation Ax+By+cZ=0;

Obtain the projection line equation ax+by=0 of the above linear equation Ax+By+Cz=0 on the XY plane, and then adjust the equation coefficients a and b to a1 and b1, so that the projection point of the above laser point cloud data on the XY plane The numbers distributed on both sides of the straight line a1x+b1y=0 are basically equal;

Obtain the fitting line equation A2x+B2y+C2Z=0 of another set of laser point clouds of the same detection point and its projection equation a2x+b2y=0 on the XY plane;

Solve the intersection point of the equation a1x+b1y=0 and the equation a2x+b2y=0 as the plane coordinate of the checkpoint;

The elevation coordinate of the GPS static observation point is obtained by measuring the height above the ground of the support frame on the side of the detection pole; the height difference obtained by subtracting the height coordinate of the static observation point coordinates of the GPS , which is the height coordinate of the GPS static observation point.

The specific installation and measurement process is as follows:

1. First find a series of relatively flat open ground in the survey area (for the future RTK or GPS base station to observe the data with good quality, it is best to choose the ground with good GPS receiving signal);

2. The detection rod side support frame 4, the detection rod center support frame 6, the detection rod side support frame 7, the detection rod side support frame 11 and the detection rod side support frame 12 are stably erected on the ground according to the length of the detection rod, and the detection rod The rod limit support frame 4, the detection rod center support frame 6, the detection rod limit support frame 7 form a straight line, the detection rod center support frame 6, the detection rod limit support frame 11 and the detection rod limit support frame 12 form another straight line, And ensure that the two straight lines intersect and form a large angle, such as a 90° angle;

3. Place the laser foot point detection rod 5 on the detection rod side support frame 4, the detection rod center support frame 6, and the detection rod side support frame 7;

4. Place the laser foot point detection rod 10 on the detection rod center support frame 6, the detection rod side support frame 11 and the detection rod side support frame 12;

5. Position the laser foot point detection rod 5 and the laser foot point detection rod 10 on the center support frame 6 of the detection rod with the positioning pin 8;

6. The GPS receiver support frame 1 is erected on the top of the detection rod center support frame 6, and its center hole is roughly aligned with the GPS receiver phase center horizontal alignment point 9 on the detection rod center support frame 6;

7. Set up the GPS receiver level adjustment mechanism 2 on the GPS receiver support frame 1, and adjust the length of the three legs on the GPS receiver support frame 1 and the adjustment knob of the GPS receiver level adjustment mechanism 2, so that the GPS receiver is level The adjustment mechanism 2 is basically in a horizontal position (for the specific adjustment method, refer to the relevant erection method of the GPS reference station);

8. Move the GPS receiver level adjustment mechanism 2, make its center be directly above the GPS receiver phase center horizontal alignment point 9 on the detection rod center support frame 6 through its telescope, and lock the GPS receiver level adjustment mechanism 2;

9. Set up the GPS receiver 3 on the GPS receiver level adjustment mechanism 2, and measure the distance from the altimeter of the GPS receiver to the horizontal alignment point 9 of the phase center of the GPS receiver, which is recorded as ΔH;

10. Start the GPS receiver in static observation mode to receive satellite signals;

11. Repeat steps 2 to 10 to complete the erection of detection devices at other detection points;

12. Start the laser radar system, and let the flight platform carry the laser radar system to complete the data collection of the survey area, and also complete the laser point cloud collection of the inspection point by the way;

13. Use the known point or one of the GPS static observation points as the reference point, use the collected GPS static observation data to perform adjustment processing on the established GPS static observation points, and obtain the coordinates of these detection points (or control points);

14. Use the coordinates of the detection point obtained in step 13 as a reference to solve the laser point cloud data, and use laser point cloud processing software (such as TerreaSolid) to separate the laser point cloud detected by the laser foot point detection rod, and store them in groups according to the detection method ;

的值最小，公式中的di是指激光脚点到直线方程Ax+By+cZ=0的距离； 15. Select a set of laser point cloud data, use the straight line equation Ax+By+Cz=0 to fit the set of laser point cloud data, and find the coefficients A, B, and C in the equation so that the equation

The value of is the smallest, di in the formula refers to the distance from the laser foot point to the straight line equation Ax+By+cZ=0;

16. Obtain the projection line equation ax+by=0 of the line equation Ax+By+Cz=0 on the XY plane, and then adjust the equation coefficients a and b to a1 and b1, so that the projection of the laser point cloud data in step 15 on the XY plane The number of points distributed on both sides of the straight line a1x+b1y=0 is basically equal;

17. Repeat steps 15~16 to obtain the fitting line equation A2x+B2y+C2Z=0 and its projection equation on the XY plane a2x+b2y=0 of another set of laser point clouds at the same detection point;

18. Solve the intersection point of equation a1x+b1y=0 and equation a2x+b2y=0 as the plane coordinates of this checkpoint, and the elevation coordinate of this checkpoint is obtained by measuring the height above the ground of the central support frame 6 of the detection rod;

19. Subtract the coordinate obtained by the elevation coordinate in the control point coordinate obtained in step 13 from the height difference measured when erecting the detection device as the true value of the checkpoint;

20. Calculation step 18 and step 19 obtain plane difference value and height difference value, as the laser point cloud precision value of this inspection point;

twenty one. Repeat steps 15 to 20 to obtain the laser point cloud accuracy values of all detection devices erected in the entire survey area, and calculate the root mean square value, maximum value, minimum value, and average value of these inspection points as the survey area. Laser point cloud accuracy evaluation index.

In this embodiment, if there are not enough GPS receivers to be used as base stations, the coordinates of the inspection point can also be replaced by measuring the coordinates of the GPS receiver phase center horizontal alignment point 9 on the central support frame 6 of the detection rod in RTK mode True value, only with slightly reduced precision.

In this embodiment, if the horizontal alignment point 9 of the phase center of the GPS receiver on the central support frame 6 of the detection rod is erected directly above the known point, the coordinates of the known point can be used as the true value, and the processing process is similar.

Finally, it should be noted that: the above is only a preferred embodiment of the utility model, and is not intended to limit the utility model, although the utility model has been described in detail with reference to the foregoing embodiments, for those skilled in the art , it is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (4)

1. the bearing accuracy pick-up unit of a high precision airborne laser radar system, it is characterized in that, comprise GPS receiver bracing frame, the GPS receiver, test rod limit bracing frame, the first laser pin point test rod, the second laser pin point test rod and test rod central supported frame, described GPS receiver is packed on the GPS receiver bracing frame, on the described GPS receiver bracing frame GPS receiver level(l)ing mechanism is set, described test rod limit bracing frame is a plurality of, a plurality of test rods limit bracing frame is supported on the first laser pin point test rod and the second laser pin point test rod on the surface level, one end of one end of the described first laser pin point test rod and the second laser pin point test rod meets on the test rod central supported frame, angle 〉=90 between the described first laser pin point test rod and the second laser pin point test rod °.

2. the bearing accuracy pick-up unit of high precision airborne laser radar according to claim 1 system is characterized in that the described first laser pin point test rod and the second laser pin point test rod are fixed on the test rod central supported frame by tommy.

3. the bearing accuracy pick-up unit of high precision airborne laser radar according to claim 1 and 2 system is characterized in that the angle between the described first laser pin point test rod and the second laser pin point test rod is 90 °.

4. the bearing accuracy pick-up unit of high precision airborne laser radar according to claim 3 system is characterized in that the GPS receiver phase central horizontal alignment point of described GPS receiver bracing frame and test rod limit bracing frame is on the same vertical line.

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