A solution method for airborne multi-beam 3D scanning lidar

Abstract

The present invention provides a solution method for airborne multi-beam three-dimensional scanning laser radar. First, an instantaneous laser beam coordinate system is established, a reference beam is defined, and the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system are calculated. Based on the offset between the remaining beams and the reference beam on the DOE plane, the coordinates of the ground points of each multi-beam laser beam in the instantaneous laser beam coordinate system are calculated. Then, by constructing a coordinate model and performing coordinate transformation, the coordinates of the ground points of each multi-beam laser beam in the geodetic coordinate system are solved, thereby obtaining a point cloud model. The present invention uses the offset between the target beam and the reference beam in the DOE plane in the instantaneous laser beam coordinate system as a reference to obtain the coordinates of the ground foot points of each beam in the instantaneous laser beam coordinate system. Then, based on model construction and coordinate solution, the coordinates of the ground foot points of each beam in the subsequent coordinate system are obtained. This solves the problem of accurately solving the ground foot points of airborne laser radar in a detection mode that combines array detection with scanning, and takes into account both accuracy and operational efficiency.

Description

Technical Field

[0001] The present invention relates to the field of measurement and testing technology, and in particular to a solution method for airborne multi-beam three-dimensional scanning laser radar. Background Art

[0002] As an emerging 3D data acquisition method, 3D scanning LiDAR (LiDAR) is a high-precision, high-density, and high-efficiency active measurement technology that can rapidly capture terrain surface data and features. Traditional airborne LiDAR uses a single-beam laser combined with mechanical scanning to achieve coverage of the target area. Scanning methods include line scanning and conical scanning.

[0003] With the advancement of multi-beam spectrometry and single-photon array detection technologies, 3D scanning LiDAR systems are moving toward a new generation of technologies, characterized by micro-pulse, high-repetition-rate laser emission, optical array reception, and single-photon array detection. Compared to traditional scanning laser 3D imaging methods, these systems can meet the demands of higher imaging resolution, higher positioning accuracy, and more efficient imaging detection applications at longer distances.

[0004] The technical framework of multi-beam array detection combined with a scanning mechanism is the development direction of the next generation of 3D scanning systems. It can quickly and comprehensively obtain high-precision, high-density stereo images, clearly reflecting surface changes in the terrain. Improving the positioning accuracy of LiDAR ground footholds is a key guarantee for improving the accuracy of laser point cloud data, completing multi-source data fusion, and generating effective data products.

[0005] The basic process for solving ground footpoints for airborne lidars is to calculate the three-dimensional coordinates of the laser ground point in the target coordinate system using laser ranging values, platform position information measured by GPS, and platform attitude information measured by the IMU, combined with the system's orientation element parameters. During the solution process, the instantaneous laser beam coordinate system, laser scanning reference coordinate system, inertial platform reference coordinate system, navigation coordinate system, and earth coordinate system are constructed according to the platform's characteristics and actual needs. The final result is obtained through the relative relationships between these coordinate systems. Traditional solution models are only applicable to single-beam, full-waveform scanning lidars and do not match the detection method of array detection combined with scanning. Therefore, it is necessary to propose a coordinate solution method suitable for airborne multi-beam three-dimensional scanning lidar systems. Summary of the Invention

[0006] This invention aims to solve the problem of calculating the ground footpoints of airborne multi-beam 3D scanning LiDAR systems. It provides a calculation method for airborne multi-beam 3D scanning LiDAR systems. Using the offset between the target beam and the reference beam on the DOE plane in the instantaneous laser beam coordinate system as a reference, the coordinates of the ground footpoints of each beam in the instantaneous laser beam coordinate system are obtained. Furthermore, the coordinates of the ground footpoints of each beam in the subsequent coordinate system are obtained based on model construction and coordinate calculation. This invention solves the problem of accurately calculating the ground footpoints of airborne LiDAR systems using an array detection combined with scanning detection mode. It also addresses the overly complex problem of directly constructing a model in this mode, achieving a solution that balances accuracy and operational efficiency.

[0007] The present invention provides a solution method for an airborne multi-beam three-dimensional scanning laser radar, comprising the following steps:

[0008] S1: Define the instantaneous laser beam coordinate system: define the reference beam and calculate the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system; calculate the coordinates of the ground point of each multi-beam laser beam in the instantaneous laser beam coordinate system based on the offset between the remaining beams and the reference beam on the DOE plane;

[0009] S2: Obtaining a point cloud model: By constructing a coordinate model and performing coordinate transformation, the coordinates of each ground point of the multi-beam laser beam in the geodetic coordinate system are calculated to obtain a point cloud model. The solution is completed.

[0010] The solution method for an airborne multi-beam three-dimensional scanning laser radar described in the present invention, as a preferred embodiment, step S1 includes the following steps:

[0011] S101, defining a reference beam, the reference beam is beam 1, the beams of the multi-beam laser other than the reference beam are numbered as beam i, where i is an integer greater than 1, and constructing an instantaneous laser beam coordinate system;

[0012] S102, calculating the coordinates of the ground point of beam 1 in the instantaneous laser beam coordinate system;

[0013] S103, according to the mutual relationship between the beam i and the beam 1, the ground point coordinates of the beam i in the instantaneous laser beam coordinate system are obtained. The mutual relationship is obtained by calculating the X coordinates of the beam i and the beam 1 in the instantaneous laser beam coordinate system. D and Y D The offset of the direction is expressed.

[0014] The present invention provides a solution method for an airborne multi-beam three-dimensional scanning laser radar. As a preferred embodiment, in step S101, beam 1 is the first beam after the instantaneous laser beam coordinate system is split, the intersection of beam 1 and the DOE plane is the origin O, and the DOE plane is X downward. D Axis, DOE plane to the left is Y D Axis, the direction of beam 1 is ZD Axis, right hand is OX D Y D Z D .

[0015] In the solution method for an airborne multi-beam three-dimensional scanning laser radar described in the present invention, as a preferred embodiment, in step S102, the calculation formula for the coordinates of the ground point of beam 1 is:

[0016]

[0017] Where ρ is the laser ranging value.

[0018] In the solution method for an airborne multi-beam three-dimensional scanning laser radar described in the present invention, as a preferred embodiment, in step S103, the ground point coordinates of the light beam i in the instantaneous laser beam coordinate system are calculated as follows:

[0019] In the instantaneous laser beam coordinate system, after passing through the DOE, beam i is divided into an M*N array. The intervals between two adjacent beams i in the X and Y directions are equal, namely x_offset and y_offset. Based on the mutual offset relationship between the ground point coordinates of the reference beam and each laser beam, the ground point coordinates of beam i in the instantaneous laser beam coordinate system are obtained.

[0020] In the solution method for an airborne multi-beam three-dimensional scanning laser radar described in the present invention, as a preferred embodiment, the ground point coordinates of the beam i in the instantaneous laser beam coordinate system are:

[0021]

[0022] Among them, m*η*x_offset and n*η*y_offset are the offsets of beam i and beam 1, m is the number of rows and columns between beam i and beam 1 in the x-direction, n is the number of rows and columns between beam i and beam 1 in the y-direction, and η is the offset coefficient at the current moment.

[0023] The present invention describes a solution method for an airborne multi-beam three-dimensional scanning laser radar, in which, as a preferred embodiment, η is related to the divergence angle and ranging value of the beam splitting design.

[0024] In the solution method for an airborne multi-beam three-dimensional scanning laser radar described in the present invention, as a preferred embodiment, step S2 includes the following steps:

[0025] S201, converting the ground point coordinates in the instantaneous laser beam coordinate system into coordinates in the laser scanning reference coordinate system;

[0026] S202, converting the coordinates of the ground point in the laser scanning reference coordinate system into the coordinates in the inertial platform reference coordinate system;

[0027] S203, converting the ground point coordinates in the inertial platform reference coordinate system into coordinates in the navigation coordinate system;

[0028] S204: Convert the ground point coordinates in the navigation coordinate system into coordinates in the geodetic coordinate system, thereby obtaining a point cloud model, and the solution is completed.

[0029] In the solution method for an airborne multi-beam three-dimensional scanning laser radar described in the present invention, as a preferred embodiment, in step S201, the specific calculation formula for the coordinates in the laser scanning reference coordinate system is:

[0030]

[0031] in, is the offset between the origin of the laser scanning reference coordinate system and the origin of the instantaneous laser beam coordinate system, is the transformation matrix from the instantaneous laser beam coordinate system to the laser scanning reference coordinate system.

[0032] The solution method for airborne multi-beam three-dimensional scanning laser radar described in the present invention is, as a preferred embodiment, for:

[0033]

[0034] Among them, θ is the scanning angle of the scanning mechanism of the airborne multi-beam three-dimensional scanning laser radar system, δ1 is the angle between the beam 1 and the bottom of the radar when the scanning angle is 0, and the angle is located at Y. L- Z L The angle in the plane, δ2 is the angle between the beam 1 and the bottom of the radar when the scanning angle is 0, which is located at X L- Z L Angle within a plane.

[0035] The present invention constructs a model for an airborne multi-beam three-dimensional scanning laser radar to obtain the coordinates of the laser footprint points in the target area, thereby obtaining a solution method for an accurate three-dimensional point cloud model of the target area.

[0036] The present invention adopts the following technical solutions:

[0037] A solution method for an airborne multi-beam three-dimensional scanning laser radar comprises the following steps:

[0038] 1) Define the reference beam and calculate the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system; calculate the coordinates of the ground point of each multi-beam laser in the instantaneous laser beam coordinate system based on the offset between the remaining beams and the reference beam on the DOE plane.

[0039] 2) By constructing a coordinate model and performing coordinate transformation, the coordinates of each ground point in the multi-beam laser beam are calculated in the geodetic coordinate system to obtain a point cloud model. This includes: converting the coordinates of the ground point in the instantaneous laser beam coordinate system to the coordinates in the laser scanning reference coordinate system; converting the coordinates of the ground point in the laser scanning reference coordinate system to the coordinates in the inertial platform reference coordinate system; converting the coordinates of the ground point in the inertial platform reference coordinate system to the coordinates in the navigation coordinate system; and converting the coordinates of the ground point in the navigation coordinate system to the coordinates in the geodetic coordinate system.

[0040] The instantaneous laser beam coordinate system is defined based on the first beam after beam splitting. The intersection of this beam and the DOE plane is the origin O, as shown in Figure 2 As shown. The plane downward and left are X D Axis and Y D Axis, Z D Axis is the direction of the beam (pointing into the plane), OX D Y D Z D Form the right hand system.

[0041] DOE is a diffraction beam splitter, which is used to split the laser beam. After passing through the DOE, the laser beam is divided into an M*N array, and the intervals between adjacent beams in the X and Y directions are equal, which are x_offset and y_offset respectively.

[0042] The laser scanning reference coordinate system takes the intersection of the first beam and the DOE plane defined above as the origin O, and the flight direction of the aircraft platform is X. L Axis, the zero direction of the scanning system is Z L Axis, OX L Y L Z L Form the right hand system.

[0043] The present invention has the following advantages:

[0044] (1) A coordinate calculation process for airborne multi-beam 3D scanning LiDAR systems is proposed. Compared with the existing technology, it solves the problem of accurate calculation of the ground foot points of airborne LiDAR under the detection mode of array detection combined with scanning.

[0045] (2) Based on the offset between the target beam and the reference beam on the DOE plane in the instantaneous laser beam coordinate system, the ground footpoint coordinates of each beam in the instantaneous laser beam coordinate system are obtained. Then, based on model construction and coordinate solution, the ground footpoint coordinates of each beam in the subsequent coordinate system are obtained. This invention solves the problem of overly complex model construction in the combination of array detection and scanning mode, and the solution model takes into account both accuracy and operational efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart of a solution method for airborne multi-beam 3D scanning lidar;

[0047] Figure 2 Flowchart of step S1 of a solution method for airborne multi-beam three-dimensional scanning laser radar;

[0048] Figure 3 This is a flow chart of step S2 of a solution method for airborne multi-beam three-dimensional scanning laser radar;

[0049] Figure 4 A schematic diagram of the instantaneous laser beam coordinate system for a solution method for airborne multi-beam 3D scanning lidar;

[0050] Figure 5 Schematic diagram of Example 2 of a solution method for airborne multi-beam three-dimensional scanning lidar. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0052] Example 1

[0053] like Figure 1 As shown, a solution method for airborne multi-beam three-dimensional scanning laser radar is characterized by comprising the following steps:

[0054] S1: Define the instantaneous laser beam coordinate system: define the reference beam and calculate the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system; calculate the coordinates of the ground point of each multi-beam laser beam in the instantaneous laser beam coordinate system based on the offset between the remaining beams and the reference beam on the DOE plane;

[0055] like Figure 2 As shown, S101, define the reference beam, the reference beam is beam 1, the beams of the multi-beam laser other than the reference beam are numbered as beam i, i is an integer greater than 1, and construct an instantaneous laser beam coordinate system; beam 1 is the first beam after the instantaneous laser beam coordinate system is split, the intersection of beam 1 and the DOE plane is the origin O, and the DOE plane is downward as X D Axis, DOE plane to the left is Y D Axis, the direction of beam 1 is Z D Axis, right hand is OX D Y D Z D ;

[0056] S102, calculating the coordinates of the ground point of beam 1 in the instantaneous laser beam coordinate system;

[0057] The calculation formula for the ground point coordinates of beam 1 is:

[0058]

[0059] Where, ρ is the laser ranging value;

[0060] S103, according to the mutual relationship between the beam i and the beam 1, the ground point coordinates of the beam i in the instantaneous laser beam coordinate system are obtained. The mutual relationship is obtained by calculating the X coordinates of the beam i and the beam 1 in the instantaneous laser beam coordinate system. D and Y D The offset of the direction is expressed;

[0061] The calculation method of the ground point coordinates of beam i in the instantaneous laser beam coordinate system is:

[0062] In the instantaneous laser beam coordinate system, after passing through the DOE, beam i is divided into an M*N array. The intervals between two adjacent beams i in the X and Y directions are equal, namely x_offset and y_offset respectively. Based on the mutual offset relationship between the ground point coordinates of the reference beam and each laser beam, the ground point coordinates of beam i in the instantaneous laser beam coordinate system are obtained;

[0063] The ground point coordinates of beam i in the instantaneous laser beam coordinate system are:

[0064]

[0065] Where m*η*x_offset and n*η*y_offset are the offsets between beam i and beam 1, m is the number of rows and columns between beam i and beam 1 in the x-direction, n is the number of rows and columns between beam i and beam 1 in the y-direction, and η is the offset coefficient at the current moment; η is related to the divergence angle and ranging value of the beam splitting design;

[0066] S2: Obtaining the point cloud model: By constructing a coordinate model and performing coordinate transformation, the coordinates of each ground point of the multi-beam laser beam in the geodetic coordinate system are calculated to obtain the point cloud model. The solution is completed.

[0067] like Figure 3 As shown, S201, converting the ground point coordinates in the instantaneous laser beam coordinate system into coordinates in the laser scanning reference coordinate system;

[0068] The specific calculation formula of the coordinates in the laser scanning reference coordinate system is:

[0069]

[0070] in, is the offset between the origin of the laser scanning reference coordinate system and the origin of the instantaneous laser beam coordinate system, is the transformation matrix from the instantaneous laser beam coordinate system to the laser scanning reference coordinate system;

[0071] for:

[0072]

[0073] Among them, θ is the scanning angle of the scanning mechanism of the airborne multi-beam three-dimensional scanning laser radar system, δ1 is the angle between the beam 1 and the bottom of the radar when the scanning angle is 0, and the angle is located at Y. L- Z L The angle in the plane, δ2 is the angle between the beam 1 and the bottom of the radar when the scanning angle is 0, which is located at X L- Z L Angle within a plane;

[0074] S202, converting the coordinates of the ground point in the laser scanning reference coordinate system into the coordinates in the inertial platform reference coordinate system;

[0075] S203, converting the ground point coordinates in the inertial platform reference coordinate system into coordinates in the navigation coordinate system;

[0076] S204: Convert the ground point coordinates in the navigation coordinate system into coordinates in the geodetic coordinate system, thereby obtaining a point cloud model, and the solution is completed.

[0077] Example 2

[0078] The present invention provides a solution model for an airborne multi-beam three-dimensional scanning laser radar system. By defining a reference beam, the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system are calculated; based on the offset between the remaining beams and the reference beam on the DOE plane, the coordinates of the ground point of each multi-beam laser beam in the instantaneous laser beam coordinate system are calculated; by constructing a coordinate model and coordinate transformation, the coordinates of the ground point of each multi-beam laser beam in the geodetic coordinate system are solved, thereby obtaining an accurate three-dimensional point cloud model of the target area.

[0079] Specifically, such as Figure 1 As shown, the solution method for airborne multi-beam three-dimensional scanning laser radar provided by the present invention includes the following steps:

[0080] S1. Define the instantaneous laser beam coordinate system. Define the reference beam and calculate the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system. Based on the offset between the remaining beams and the reference beam on the DOE plane, calculate the coordinates of the ground points of each multi-beam laser in the instantaneous laser beam coordinate system.

[0081] like Figure 2 As shown, S101: number each beam and define the reference beam, that is, beam 1. The definition of beam 1 is detailed in Figure 4As shown in Figure 2, the instantaneous laser beam coordinate system is constructed through the reference beam.

[0082] S102: The coordinates of the ground point of beam 1 are:

[0083]

[0084] Where ρ is the laser ranging value.

[0085] S103: According to the mutual relationship of each laser beam, the ground point coordinates of the remaining beams in the instantaneous laser beam coordinate system are obtained. The mutual relationship is obtained by comparing the remaining beams under the instantaneous laser beam with the beam 1 in X D and Y D The offset of the direction is expressed.

[0086] Taking beam i as an example, its offset from beam 1 is m*η*x_offset and n*η*y_offset, respectively. Here, m and n are the number of rows and columns between beam i and beam 1 in the x and y directions, respectively, and η is the offset coefficient at the current moment, which is related to the divergence angle and ranging value of the beam splitting design.

[0087] The ground point coordinates of beam i under the instantaneous laser beam can be expressed as:

[0088]

[0089] S2. By constructing a coordinate model and coordinate transformation, the coordinates of each ground point of the multi-beam laser beam in the geodetic coordinate system are solved to obtain a point cloud model.

[0090] like Figure 3 As shown, S201: converting the ground point coordinates in the instantaneous laser beam coordinate system into coordinates in the laser scanning reference coordinate system.

[0091] The coordinates of the ground point in the laser scanning reference coordinate system are:

[0092]

[0093] In formula 3 is the transformation matrix from the instantaneous laser beam coordinate system to the laser scanning reference coordinate system:

[0094]

[0095] In formula 4, θ is the scanning angle of the scanning mechanism of the airborne multi-beam 3D scanning laser radar system, and δ1 and δ2 are the two plane angles of the three-dimensional angle between the beam 1 and the bottom of the radar when the scanning angle is 0. δ1 is the angle at Y L- Z L The angle in the plane, δ2 is the angle between L- Z L Angle within a plane.

[0096] In formula 3 is the offset between the origin of the laser scanning reference coordinate system and the origin of the instantaneous laser beam coordinate system.

[0097] S202: Convert the ground point coordinates in the laser scanning reference coordinate system into coordinates in the inertial platform reference coordinate system.

[0098] The coordinates of the ground point in the inertial platform reference coordinate system are:

[0099]

[0100] In formula 5 is the transformation matrix from the laser scanning reference coordinate system to the inertial platform reference coordinate system:

[0101]

[0102] S203: Convert the ground point coordinates in the inertial platform reference coordinate system into coordinates in the navigation coordinate system.

[0103] The coordinates of the ground point in the navigation coordinate system are:

[0104]

[0105] In formula 7 is the transformation matrix from the laser scanning reference coordinate system to the inertial platform reference coordinate system:

[0106]

[0107] S204: Convert the ground point coordinates in the navigation coordinate system into coordinates in the geodetic coordinate system.

[0108] The coordinates of the ground point in the geodetic coordinate system are:

[0109]

[0110] In formula 9 is the transformation matrix from the laser scanning reference coordinate system to the inertial platform reference coordinate system:

[0111]

[0112] The present invention calculates the foot point arrangement of the airborne multi-beam three-dimensional scanning laser radar when the aircraft is flying. Figure 5 shown.

[0113] In summary, the present invention provides a solution method for airborne multi-beam three-dimensional scanning laser radar. The method comprises: taking beam 1 as the reference beam, calculating the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system; calculating the coordinates of the ground point of each multi-beam laser beam in the instantaneous laser beam coordinate system according to the offset between the remaining beams and the reference beam on the DOE plane. Convert the coordinates of the ground point in the instantaneous laser beam coordinate system to the coordinates in the laser scanning reference coordinate system. Convert the coordinates of the ground point in the laser scanning reference coordinate system to the coordinates in the inertial platform reference coordinate system. Convert the coordinates of the ground point in the inertial platform reference coordinate system to the coordinates in the navigation coordinate system. Convert the coordinates of the ground point in the navigation coordinate system to the coordinates in the geodetic coordinate system. The present invention solves the problem of accurate solution of ground points of airborne platform laser radar under multi-beam array scanning.

[0114] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A solution method for airborne multi-beam three-dimensional scanning laser radar, characterized in that: The following steps are involved: S1: Define the instantaneous laser beam coordinate system: define the reference beam and calculate the coordinates of the ground point of the reference beam in the instantaneous laser beam coordinate system; calculate the coordinates of the ground point of each multi-beam laser beam in the instantaneous laser beam coordinate system based on the offset between the remaining beams and the reference beam on the DOE plane; Step S1 includes the following steps: S101, defining a reference beam, wherein the reference beam is beam 1, and the beams of the multi-beam laser other than the reference beam are numbered as beam i, where i is an integer greater than 1, and constructing an instantaneous laser beam coordinate system; S102, calculating the coordinates of the ground point of beam 1 in the instantaneous laser beam coordinate system; S103, according to the mutual relationship between the beam i and the beam 1, the ground point coordinates of the beam i in the instantaneous laser beam coordinate system are obtained, wherein the mutual relationship is obtained by calculating the X coordinates of the beam i and the beam 1 in the instantaneous laser beam coordinate system. D and Y D The offset of the direction is expressed; S2: Obtaining a point cloud model: By constructing a coordinate model and performing coordinate transformation, the coordinates of each ground point of the multi-beam laser beam in the geodetic coordinate system are calculated to obtain a point cloud model. The solution is completed.

2. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 1, characterized in that: In step S101, beam 1 is the first beam after the instantaneous laser beam coordinate system is split, the intersection of beam 1 and the DOE plane is the origin O, and the DOE plane is X D Axis, DOE plane to the left is Y D Axis, the direction of beam 1 is Z D Axis, right hand is OX D Y D Z D .

3. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 2, characterized in that: In step S102, the calculation formula of the ground point coordinates of beam 1 is: Where ρ is the laser ranging value.

4. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 3, characterized in that: In step S103, the ground point coordinates of the light beam i in the instantaneous laser beam coordinate system are calculated as follows: In the instantaneous laser beam coordinate system, after passing through the DOE, beam i is divided into an M*N array. The intervals between two adjacent beams i in the X and Y directions are equal, namely x_offset and y_offset. Based on the mutual offset relationship between the ground point coordinates of the reference beam and each laser beam, the ground point coordinates of beam i in the instantaneous laser beam coordinate system are obtained.

5. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 4, characterized in that: The ground point coordinates of beam i in the instantaneous laser beam coordinate system are: Among them, m*η*x_offset and n*η*y_offset are the offsets of beam i and beam 1, m is the number of rows and columns between beam i and beam 1 in the x-direction, n is the number of rows and columns between beam i and beam 1 in the y-direction, and η is the offset coefficient at the current moment.

6. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 5, characterized in that: η is related to the divergence angle and ranging value of the beam splitting design.

7. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 1, characterized in that: Step S2 includes the following steps: S201, converting the ground point coordinates in the instantaneous laser beam coordinate system into coordinates in the laser scanning reference coordinate system; S202, converting the coordinates of the ground point in the laser scanning reference coordinate system into the coordinates in the inertial platform reference coordinate system; S203, converting the ground point coordinates in the inertial platform reference coordinate system into coordinates in the navigation coordinate system; S204: Convert the ground point coordinates in the navigation coordinate system into coordinates in the geodetic coordinate system, thereby obtaining a point cloud model, and the solution is completed.

8. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 7, characterized in that: In step S201, the specific calculation formula of the coordinates in the laser scanning reference coordinate system is: in, is the offset between the origin of the laser scanning reference coordinate system and the origin of the instantaneous laser beam coordinate system, is the transformation matrix from the instantaneous laser beam coordinate system to the laser scanning reference coordinate system.

9. The method for solving airborne multi-beam three-dimensional scanning laser radar according to claim 8, characterized in that: for: Among them, θ is the scanning angle of the scanning mechanism of the airborne multi-beam three-dimensional scanning laser radar system, δ1 is the angle between the beam 1 and the bottom of the radar when the scanning angle is 0, and the angle is located at Y. L- Z L The angle in the plane, δ2 is the angle between the beam 1 and the bottom of the radar when the scanning angle is 0, which is located at X L- Z L Angle within a plane.

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