Airborne laser radar three-dimensional measurement equipment

Abstract

The utility model provides airborne laser radar three-dimensional measuring equipment, which belongs to the technical field of laser radar measurement and comprises an unmanned aerial vehicle, a laser radar is mounted at the lower end of a vehicle body of the unmanned aerial vehicle, an annular array substrate is mounted in the laser radar, and a plurality of groups of transmitting modules and receiving modules are arranged in the laser radar. An optical lens mechanism is further arranged in the laser radar, an optical window is arranged in the center of the bottom of the laser radar, and the multiple transmitting modules are controlled through the control module. The utility model solves the problems that the existing traditional airborne laser radar mostly realizes scanning coverage through mechanical rotation (such as rotating mirror or motor driving), the overall mechanical structure is complex, rotating parts are easily influenced by vibration and abrasion, the failure rate is high, the stability is poor, the rotating mechanism occupies space, the equipment weight is increased, and the endurance of an unmanned aerial vehicle is influenced; the overall scanning efficiency is low, a single light beam needs to be scanned line by line, and the data acquisition rate is limited.

Description

Technical Field

[0001] This utility model belongs to the field of lidar measurement technology, specifically relating to an airborne lidar three-dimensional measurement device. Background Technology

[0002] As is well known, 3D lidar is a process testing instrument used in mechanical engineering and transportation engineering. When measuring large areas such as terrain, an airborne lidar 3D measurement device is generally used.

[0003] Existing traditional airborne lidar systems mostly employ a single-beam transmitter-receiver module, achieving scanning coverage through mechanical rotation (such as a rotating mirror or motor drive). This approach has the following drawbacks: the overall mechanical structure is complex, rotating components are susceptible to vibration and wear, resulting in a high failure rate, especially with poor stability during high-speed drone flight. Furthermore, the mechanical rotation mechanism occupies space, increases equipment weight, and affects drone endurance; the overall scanning efficiency is low, requiring line-by-line scanning with a single beam, limiting data acquisition rates and making it difficult to meet high-resolution or large-area mapping requirements. Summary of the Invention

[0004] This invention provides an airborne LiDAR 3D measurement device, aiming to solve the problem that existing traditional airborne LiDARs mostly use a single-beam transmitter-receiver module, achieving scanning coverage through mechanical rotation (such as a rotating mirror or motor drive). This approach has the following drawbacks: the overall mechanical structure is complex, rotating parts are susceptible to vibration and wear, resulting in a high failure rate, especially with poor stability during high-speed UAV flight; the mechanical rotation mechanism also occupies space, increases equipment weight, and affects UAV endurance; the overall scanning efficiency is low, as a single beam needs to scan line by line, limiting the data acquisition rate and making it difficult to meet the needs of high-resolution or large-area mapping.

[0005] This utility model provides an airborne lidar three-dimensional measurement device, including a drone. A lidar is installed on the lower part of the drone's fuselage. A ring array substrate is installed inside the lidar. The lidar has multiple sets of transmitting and receiving modules inside, as well as an optical lens mechanism inside. An optical window is located at the center of the bottom of the lidar. The multiple sets of transmitting modules are controlled by a control module.

[0006] Furthermore, the transmitting module includes multiple laser emitters, and the receiving module includes multiple laser receivers. The laser emitters and the laser receivers are both mounted on a ring array substrate and are spaced apart from each other by -mm. A partition is provided between the laser emitters and the laser receivers.

[0007] By adopting the above technical solution, the laser emitted by the laser emitter can be received by the laser receiver, thereby realizing multi-beam solid-state scanning without the need for a rotating mechanism.

[0008] Furthermore, the optical lens mechanism includes lenses fixed to the upper surfaces of the laser emitter and the laser receiver.

[0009] By adopting the above technical solutions, the lens can correct problems such as beam divergence and aberrations, and achieve more precise optical path control.

[0010] Furthermore, the optical lens mechanism also includes a first prism and a second prism fixed inside the lidar, both of which are located on the upper side of the lens.

[0011] By adopting the above technical solution, the first prism and the second prism can adjust the direction of the beam and finally converge it into the optical window, avoiding the need to open a separate window for each beam.

[0012] Furthermore, the annular array substrate has a transmission port in the middle, which corresponds to the optical window.

[0013] By adopting the above technical solution, the light beam adjusted by the first prism and the second prism can be emitted from the transmission port and the optical window without being obstructed.

[0014] Furthermore, the control module includes a time-division multiplexing controller that is connected to both the UAV and the laser emitter.

[0015] By adopting the above technical solution, the time-division multiplexing controller sequentially activates each group of laser emitters, each group covers a limited horizontal area, and several groups are superimposed to achieve 360° omnidirectional scanning.

[0016] The beneficial effects of this utility model are as follows:

[0017] 1. This utility model, through the setting of a laser emitter and a laser receiver, enables the laser emitted by the laser emitter to be received by the laser receiver, thereby realizing multi-beam solid-state scanning, eliminating the need for a rotating mechanism, reducing overall wear, lowering the failure rate, and improving stability.

[0018] 2. By setting up a lens, the laser emitted by the laser emitter and the reflected light received by the laser receiver must pass through the lens. The lens can correct problems such as beam divergence and aberrations, and achieve more precise optical path control.

[0019] 3. By setting up the first prism and the second prism, the direction of the light beam can be adjusted and finally converged into the optical window, thus avoiding the need to open a separate window for each group of light beams.

[0020] 4. This utility model uses a time-division multiplexing controller to activate each group of laser emitters in sequence. Each group covers a limited horizontal area, and several groups are superimposed to achieve 360° omnidirectional scanning.

[0021] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the description and the drawings. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a side-view top view of the UAV structure according to an embodiment of the present utility model;

[0024] Figure 2 This is a front view structural diagram of the UAV according to an embodiment of the present utility model;

[0025] Figure 3 This is a schematic diagram of the internal structure of the lidar according to an embodiment of the present invention;

[0026] Figure 4 This is a top view of the ring array substrate structure according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the workflow structure of an embodiment of the present utility model;

[0028] Reference numerals: 1. Unmanned Aerial Vehicle (UAV); 2. LiDAR; 3. Circular Array Substrate; 31. Transmission Port; 4. Transmitting Module; 41. Laser Emitter; 5. Receiving Module; 51. Laser Receiver; 6. Optical Lens Mechanism; 61. Lens; 62. First Prism; 63. Second Prism; 7. Optical Window; 8. Control Module; 81. Time Division Multiplexing Controller. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0030] Reference Figure 1-5 This utility model embodiment proposes an airborne lidar three-dimensional measurement device, including a drone 1. A lidar 2 is installed on the lower part of the drone 1. A ring array substrate 3 is installed inside the lidar 2. The lidar 2 has multiple sets of transmitting modules 4 and receiving modules 5. The transmitting modules 4 include multiple laser emitters 41, which are Osram SPL PL90_3. The receiving modules 5 include multiple laser receivers 51, which are Hamamatsu S12572-010P. The laser emitters 41 and laser receivers 51 are both mounted on the ring array substrate 3 and are spaced 5-10 mm apart. A partition is provided between the laser emitters 41 and laser receivers 51. The laser emitted by the laser emitters 41 can be received by the laser receivers 51, thereby realizing multi-beam solid-state scanning without the need for a rotation mechanism. The initial tilt angle of the laser emitters 41 and laser receivers 51 is α (hereinafter, 30° is used as an example), which is determined by the coverage area.

[0031] Reference Figure 1-5 The lidar 2 also includes an optical lens mechanism 6. An optical window 7 is located at the center of the bottom of the lidar 2. The optical lens mechanism 6 includes a lens 61 fixed to the upper surfaces of the laser emitter 41 and the laser receiver 51. The lens 61 covers the surfaces of the laser emitter 41 and the laser receiver 51, with an tilt angle consistent with α. The lens 61 can correct beam divergence, aberrations, and other problems, achieving more precise optical path control. The optical lens mechanism 6 also includes a first prism 62 and a second prism 63 fixed inside the lidar 2. Both the first prism 62 and the second prism 63 are located above the lens 61 and connected to the inner wall of the lidar 2. The tilt angle of the first prism 62 is β1 = (90° - α) / 2. The beam can be deflected to a horizontal direction. The tilt angle of the second prism 63 is β2 = 45°, which deflects the horizontal beam to vertical downward. The first prism 62 and the second prism 63 can adjust the beam direction and finally converge to the optical window 7, avoiding the need to open a separate window for each beam. The center of the annular array substrate 3 is provided with a transmission port 31, which corresponds to the optical window 7, so that the beam adjusted by the first prism 62 and the second prism 63 can be emitted from the transmission port 31 and the optical window 7 without being obstructed. The overall optical path deflection is: initial tilt angle α of laser emitter 41 → deflection of the first prism 62 by (90°-α) → deflection of the second prism 63 by 90° → vertical downward.

[0032] Reference Figure 1-5Multiple sets of transmitting modules 4 are controlled by a control module 8. The control module 8 includes a time-division multiplexing controller 81 connected to the UAV 1 and the laser transmitters 41 respectively. The time-division multiplexing controller 81 uses a Xilinx Spartan-7XC7S50. The time-division multiplexing controller 81 sequentially activates each set of laser transmitters 41. Each set covers a limited horizontal area, and several sets are superimposed to achieve 360° omnidirectional scanning. The scanning period T is divided into N sub-windows (T1, T2, ..., T_N). Each set of laser transmitters 41 operates within its corresponding window. For example, if N = 8 sets and T = 1ms, then each window T1 = T2 = ... = T8 = 125μs. This allows multiple sets of laser transmitters 41 to be activated sequentially in time, avoiding crosstalk between multiple channels. At the same time, the laser receiver 51 is only turned on within its corresponding window to suppress background noise. Parallel acquisition significantly improves acquisition efficiency. The time-division multiplexing controller 81 (FPGA) outputs a drive signal, which is amplified by a MOSFET drive circuit (such as Infineon IPB180N10S4) to drive the VCSEL to emit laser pulses. When the reflected light from the ground enters the lidar 2 through the optical window 7, it is deflected in opposite directions by the first prism 62 and the second prism 63 and focused by the lens 61, and then captured by the laser receiver 51. The laser receiver 51 converts the optical signal into an electrical signal and outputs a pulsed current. The reflected light signal is converted into a current pulse by the APD and amplified into a voltage signal by the transimpedance amplifier (such as Texas Instruments OPA657), which is then input into the FPGA for time difference calculation. At the same time, the signal is further processed to generate point cloud data. The processing and generation of point cloud data are existing technologies and will not be elaborated on here.

[0033] The specific implementation method is as follows: In use, the lidar 2 is carried to a high altitude by the drone 1, and the laser emitter 41 is controlled by the time-division multiplexing controller 81 to emit lasers intermittently. The laser beam is corrected by the lens 61 and the directions of the first prism 62 and the second prism 63 are adjusted so that the laser beam is perpendicular to the ground and then emitted from the optical window 7. After touching the object being measured, the reflected light is reflected back from the optical window 7 into the lidar 2. After the directions of the first prism 62 and the second prism 63 are adjusted, it passes through the lens 61 and is captured by the laser receiver 51, thereby forming corresponding point cloud data. Based on the time-of-flight ranging method, combined with the correction algorithm, a high-precision three-dimensional point cloud is generated, thereby realizing three-dimensional measurement.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An airborne lidar three-dimensional measurement device, comprising a UAV (1), characterized in that, The UAV (1) is equipped with a lidar (2) at the lower end of its body. The lidar (2) has a ring array substrate (3) installed inside. The lidar (2) has multiple sets of transmitting modules (4) and receiving modules (5) inside. The lidar (2) also has an optical lens mechanism (6) inside. The lidar (2) has an optical window (7) at the center of its bottom. The multiple sets of transmitting modules (4) are controlled by a control module (8).

2. The airborne lidar three-dimensional measurement device according to claim 1, characterized in that: The transmitting module (4) includes multiple laser emitters (41), and the receiving module (5) includes multiple laser receivers (51). The laser emitters (41) and the laser receivers (51) are both mounted on the annular array substrate (3) and are spaced 5-10 mm apart. A partition is provided between the laser emitters (41) and the laser receivers (51).

3. The airborne lidar three-dimensional measurement device according to claim 2, characterized in that: The optical lens mechanism (6) includes a lens (61) fixed to the upper surface of the laser emitter (41) and the laser receiver (51).

4. The airborne lidar three-dimensional measurement device according to claim 3, characterized in that: The optical lens mechanism (6) further includes a first prism (62) and a second prism (63) fixed inside the lidar (2), both the first prism (62) and the second prism (63) being located on the upper side of the lens (61).

5. The airborne lidar three-dimensional measurement device according to claim 4, characterized in that: The annular array substrate (3) has a transmission port (31) in the middle, and the transmission port (31) corresponds to the optical window (7).

6. The airborne lidar three-dimensional measurement device according to claim 1, characterized in that: The control module (8) includes a time-division multiplexing controller (81) that is connected to the UAV (1) and the laser transmitter (41) respectively.

Images