Coaxial laser radar with variable scan range

Abstract

A kind of transceiving coaxial laser radar of variable scanning range, comprising: laser, collimator, first fiber coupler, second fiber coupler, third fiber coupler, fourth fiber coupler, Y type optical fiber, optical fiber support, scanning galvanometer, variable periscope, single-photon detector, oscilloscope, the laser is connected with collimator by first fiber coupler after coupling light into optical fiber, the single-photon detector is connected with oscilloscope, the Y type optical fiber is placed horizontally in front of scanning galvanometer using optical fiber support and is connected with collimator by second fiber coupler, is connected with single-photon detector by third fiber coupler, is connected with scanning galvanometer light inlet by fourth fiber coupler, the variable periscope is composed of inner tube, outer tube, pivot, and the outer tube of variable periscope is connected with scanning galvanometer light outlet by pivot, the application increases the scanning field range, improves the ranging accuracy and imaging quality, reduces the subsequent signal processing difficulty.

Description

TECHNICAL FIELD

[0001] The application relates to a transceiving coaxial laser radar with a variable scanning range and belongs to the laser radar field. BACKGROUND

[0002] The laser radar is a radar taking laser as a working beam. The working principle of the laser radar is that a laser pulse is emitted by a laser to the surface of a target object to be reflected, a return signal is collected by a detection device, time information is obtained through comparison of an initial signal and the return signal, and the distance between the laser radar and the target object can be obtained. Due to the advantages of high ranging accuracy, good anti-interference performance and long ranging range of the laser radar, the laser radar is currently widely applied in aerospace, unmanned driving, measurement and control surveying and mapping and the like.

[0003] The traditional laser radar can be divided into a mechanical laser radar and a solid-state laser radar according to types, and can be divided into a coaxial laser radar and a non-coaxial laser radar according to a coaxial mode (Zhu Kunyang, Two-dimensional Galvanometer Laser Radar Data Acquisition and Three-dimensional Reconstruction Research[D], Nanjing University of Technology, 2019.). Although the mechanical laser radar can change a scanning area through a scanning galvanometer, the field of view range is small due to the limited deflection angle of the scanning galvanometer, large-scale scanning imaging cannot be performed, the volume is large, and the scanning speed is slow. Although the solid-state laser radar is smaller in volume and faster in scanning speed than the mechanical laser radar, the production cost is high, and the scanning area is fixed and cannot be changed. The coaxial laser radar can reduce the information processing difficulty, but is interfered by coaxial light, and the imaging quality is affected. The optical axis of the transceiving light path of the non-coaxial laser radar does not coincide, the design cost is low, but the calculation of the light path is complicated, and the information reception and processing are not conducive. SUMMARY

[0004] The technical problem to be solved by the application is to provide a transceiving coaxial laser radar system with a variable scanning range, which increases the range of the scanning field of view, improves the ranging accuracy and imaging quality, and reduces the difficulty of subsequent signal processing, in view of the above defects in the prior art.

[0005] The application solves the technical problem by adopting the following technical scheme:

[0006] A variable scanning range transceiving coaxial laser radar, comprising a laser, a collimator, a first fiber coupler, a second fiber coupler, a third fiber coupler, a fourth fiber coupler, a Y-shaped optical fiber, an optical fiber support, a scanning galvanometer, a variable periscope, a single photon detector and an oscilloscope, the laser is connected with the collimator through the first fiber coupler, the single photon detector is connected with the oscilloscope, the Y-shaped optical fiber is horizontally placed in front of the scanning galvanometer by using the optical fiber support and is connected with the collimator through the second fiber coupler, is connected with the single photon detector through the third fiber coupler and is connected with the light inlet of the scanning galvanometer through the fourth fiber coupler, the variable periscope is composed of an inner cylinder, an outer cylinder and a rotating shaft, and the outer cylinder of the variable periscope is opposite to the light outlet of the scanning galvanometer and is connected through the rotating shaft.

[0007] The laser adopts an ultracolor spectrum laser, the wavelength band of the laser is 470nm-2400nm, the pulse width is about 100ps, and the spectral stability is ≤0.1dB.

[0008] The single photon detector adopts an InGaAs single photon detector, the detectable spectral range is 400nm-1600nm, the dark count rate is ≤10kHz, and the active area diameter is 10μm.

[0009] The scanning galvanometer has two mirror pieces for controlling the vertical and horizontal scanning respectively, the mirror pieces are plated with aluminum, the reflection range is 200-700nm, and the vertical and horizontal scanning angles of the scanning galvanometer are both 11°.

[0010] Beneficial effects

[0011] (1) The transmission direction of the laser can be well controlled through the Y-shaped optical fiber, the light path of the transceiving is coaxial, the ranging precision and the imaging quality are improved, and the difficulty of subsequent signal processing is reduced.

[0012] (2) The variable periscope can change the exit point of the outgoing laser without changing the angle when the laser exits, thereby expanding the scanning range of the laser radar system. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the embodiment of the application.

[0014] Figure 2 It is a structural schematic diagram of the variable periscope in the embodiment of the application.

[0015] Figure 3 It is a working principle diagram of the variable scanning range transceiving coaxial laser radar of the embodiment of the application.

[0016] Figure 4 It is a variable scanning area schematic diagram in the embodiment of the application.

[0017] 1-laser; 2-collimator; 3-Y-type optical fiber; 4-scanning galvanometer; 5-variable periscope; 51-friction layer; 52-rotating shaft; 53-inner cylinder; 54-outer cylinder; 6-single photon detector; 7-oscilloscope; 8-optical fiber support; 9-first optical fiber coupler; 10-second optical fiber coupler; 11-third optical fiber coupler; 12-fourth optical fiber coupler. DETAILED DESCRIPTION

[0018] As Figure 1 , a transceiver coaxial laser radar with variable scanning range, comprising: laser 1, collimator 2, first optical fiber coupler 9, second optical fiber coupler 10, third optical fiber coupler 11, fourth optical fiber coupler 12, Y-type optical fiber 3, optical fiber support 8, scanning galvanometer 4, variable periscope 5, single photon detector 6, oscilloscope 7, supercontinuum laser 1 is connected with collimator 2 after coupling light into optical fiber through first optical fiber coupler 9, laser 1 adopts supercontinuum laser, its wave band is 470nm-2400nm, pulse width is about 100ps, spectral stability is ≤0.1dB. Single photon detector 6 is connected with oscilloscope 7, single photon detector 6 adopts InGaAs single photon detector, the detectable spectral range is 400nm-1600nm, dark count rate is ≤10kHz, active area diameter is 10μm. Y-type optical fiber 3 is placed horizontally in front of scanning galvanometer 4 by using optical fiber support 8 and is connected with collimator 2 through second optical fiber coupler 10, connected with single photon detector 6 through third optical fiber coupler 11, and connected with scanning galvanometer 4 light inlet through fourth optical fiber coupler 12, scanning galvanometer 4 has two pieces of mirror pieces respectively controlling vertical direction and horizontal direction scanning, mirror piece surface is plated with aluminum, reflection range is 200-700nm, and the vertical scanning angle and horizontal scanning angle of scanning galvanometer 4 are both 11°, variable periscope 5 is composed of inner cylinder 53, outer cylinder 54 and rotating shaft 52, outer cylinder 54 of variable periscope 5 is opposite to light outlet of scanning galvanometer 4 and is connected through rotating shaft 52.

[0019] As Figure 2 , there is friction layer 51 between inner cylinder 53 and outer cylinder 54, which prevents inner cylinder 53 from falling off, and there is a mirror piece in each of inner cylinder 53 and outer cylinder 54, and the two mirror pieces are parallel to each other, rotating shaft 52 can drive the rotation of the whole variable periscope 5 by being controlled by a motor.

[0020] As Figure 3, laser 1 exit laser after collimating mirror 2 to produce collimated laser, after the exit laser into the Y-shaped optical fiber 3, through the Y-shaped optical fiber 3 selection transmission path to scanning galvanometer 4, scanning galvanometer 4 by adjusting the lens deflection angle to adjust the laser exit angle, scanning galvanometer 4 in the laser into the variable periscope 5, can along with variable periscope 5 in the vertical direction of telescopic and rotation of the shaft so as to change the scanning range, and after the scanning galvanometer 4 lens angle change also will not affect its emission direction, the exit laser to the target, by the target object reflected back echo signal through the Y-shaped optical fiber 3 selection transmission path into by single photon detector 6 detection, oscilloscope 7 received single photon detector 6 signal, with the initial signal together analysis and calculation, can get the time of flight, that is, depth information. Through scanning galvanometer 4 ceaseless two-dimensional scanning to obtain two-dimensional coordinates, combined with time of flight, through computer signal processing and analysis can be three-dimensional imaging.

[0021] As Figure 4 , the initial scanning range of scanning galvanometer 4 is Figure 4 The range shown in region one, and through the telescopic of variable periscope 5 inner tube 53 can obtain the range shown in region two, region three, through the rotation of the shaft 52 can obtain the range shown in region four. In this way, the scanning range of the laser radar can be significantly improved without changing the scanning angle of the laser radar.

Claims

1. A variable scan range transceiver on-axis lidar, comprising: The laser, the collimator, the first fiber coupler, the second fiber coupler, the third fiber coupler, the fourth fiber coupler, the Y-shaped fiber, the fiber support, the scanning galvanometer, the variable periscope, the single photon detector, the oscilloscope, the laser is connected with the collimator through the first fiber coupler to couple light into the optical fiber, the single photon detector is connected with the oscilloscope, characterized in that the Y-shaped fiber is horizontally placed in front of the scanning galvanometer by the fiber support and is connected with the collimator through the second fiber coupler, the single photon detector through the third fiber coupler, and the scanning galvanometer through the fourth fiber coupler, the variable periscope is composed of an inner cylinder, an outer cylinder and a rotating shaft, the outer cylinder of the variable periscope is connected with the scanning galvanometer through the rotating shaft, the single photon detector adopts an InGaAs single photon detector, the detectable photon range is 400-1600 nm, the dark count rate is less than or equal to 10 kHz, the active area diameter is 10 microns, the scanning galvanometer has two mirror pieces for controlling the vertical and horizontal scanning directions, the mirror pieces are plated with aluminum on the surface, the reflection range is 200-700 nm, and the vertical and horizontal scanning angles of the scanning galvanometer are both 11 degrees.

2. The variable scan range transceiver coaxial lidar according to claim 1, wherein, The laser adopts an ultracontinuous spectrum laser, the wavelength band of the laser is 470-2400 nm, the pulse width is 100 ps, and the spectral stability is less than or equal to 0.1 dB.

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