阅读说明：本技术 一种高角分辨率激光雷达及探测方法 (High-angular-resolution laser radar and detection method ) 是由 张祥伟 马群 龚昌妹 韩峰 于洵 于 2020-12-07 设计创作，主要内容包括：本发明为一种高角分辨率激光雷达及探测方法,其克服了现有技术中存在的雷达测量角分辨率受到限制的问题,可大大增加光源的发射频率,在进行探测时点云的分布密度得到显著提高,从而实现高角分辨率。本发明包括主控与数据解算系统,变焦激光发射系统、激光扫描系统和激光接收系统分别与主控与数据解算系统连接；变焦激光发射系统包括依次设置的高重频高功率光纤激光器、光纤分光器、光纤延时器、光纤合束器和光纤准直器；激光接收系统包括激光接收光学系统和光电探测器。激光扫描系统为二维MEMS微扫镜,采用非谐振的扫描方式。(The invention relates to a high angular resolution laser radar and a detection method, which overcome the problem that the angular resolution of radar measurement is limited in the prior art, can greatly increase the emission frequency of a light source, and obviously improve the distribution density of point cloud when detection is carried out, thereby realizing high angular resolution. The system comprises a main control and data calculation system, wherein a zooming laser emission system, a laser scanning system and a laser receiving system are respectively connected with the main control and data calculation system; the zooming laser emission system comprises a high repetition frequency high-power optical fiber laser, an optical fiber beam splitter, an optical fiber time delay device, an optical fiber beam combiner and an optical fiber collimator which are arranged in sequence; the laser receiving system comprises a laser receiving optical system and a photoelectric detector. The laser scanning system is a two-dimensional MEMS micro-scanning mirror and adopts a non-resonant scanning mode.)

1. A high angular resolution lidar characterized by: the system comprises a main control and data calculation system (104), wherein a zooming laser emission system (101), a laser scanning system (102) and a laser receiving system (103) are respectively connected with the main control and data calculation system (104); the zoom laser emission system (101) comprises a high repetition frequency high-power optical fiber laser (201), an optical fiber optical splitter (202), an optical fiber time delayer (203), an optical fiber beam combiner (204) and an optical fiber collimator (205) which are arranged in sequence; the laser light receiving system (103) includes a laser light receiving optical system (209) and a photodetector (208).

2. A high angular resolution lidar according to claim 1, wherein: the laser scanning system (102) is a two-dimensional MEMS micro-scanning mirror (206) and adopts a non-resonant scanning mode.

3. A high angular resolution lidar according to claim 1 or 2, wherein: the high repetition frequency high-power pulse fiber laser (201) is an MOPA mode pulse fiber laser, the seed source is a narrow linewidth VCSEL (301), and the gain medium is a doped gain fiber (302); the high-repetition-frequency high-power pulse optical fiber laser (201) is a variable pulse laser, the output peak power is 1 KW-8 KW, the average power is 1W-20W, the output pulse width is 3 ns-15 ns, the output repetition frequency is 100 KHz-2 MHz, the output pulse energy is 8 muJ-15 muJ, and the divergence angle is 0.5-2 mrad.

4. A high angular resolution lidar according to claim 3, wherein: the optical fiber optical splitter (202) is a 1 × N optical splitter, and the number of paths N of light splitting is related to the accuracy of target detection and the detection distance requirement.

5. A high angular resolution lidar according to claim 4, wherein: the optical fiber delayer (203) is composed of N optical fiber delay structures, the delay time of each optical fiber is limited by N and the pulse period T of the pulse laser, and the delay time interval of each optical fiber is T/N.

6. A high angular resolution lidar according to claim 5, wherein: the size of a light spot collimated by the optical fiber collimator (205) is not more than 2 mm.

7. A high angular resolution lidar according to claim 6, wherein: the focal point of the laser receiving optical system (209) is positioned on the surface of the photoelectric detector (208); the photodetector (208) is a semiconductor device capable of converting light waves into current, and the semiconductor material used by the photodetector (208) is related to laser waves emitted by the radar.

8. A detection method of a high angular resolution laser radar is characterized in that: the method comprises the following steps:

the method comprises the steps that a main control and data calculation system (104) is adopted, pulse light emitted by a high-repetition-frequency high-power pulse light fiber laser (201) is averagely divided into N paths of pulse light through a 1 x N optical fiber light splitter (202), each path of pulse light is connected with an optical fiber delayer (203) in an optical connection mode for delaying, the delayed light beams enter an N x 1 optical fiber beam combiner (204) along the optical fibers for combining, the combined pulse light is collimated through an optical fiber collimator (204) and then enters a two-dimensional scanning device for scanning, when the light beams are scanned in space, reflected echoes are received through a detector, the reflected echoes are compared with initial signals to obtain the flight time of each pulse light, and therefore the distance of a target is determined, the orientation of the pulse light is determined by a two-dimensional scanning mirror, and the position coordinates of any point cloud can be determined according to the scanning.

9. The method of claim 8, wherein the method comprises: the main control and data calculation system (104) controls the scanning speed and the scanning angle of the MEMS micro-scanning mirror (206);

the program flow is as follows: the main control and data calculation system (104) stores emission sequence waveforms and scanning waveforms of the two-dimensional MEMS micro-mirror (206); during scanning, the main control and data calculation system (104) enables a laser emitting end to send a pulse sequence according to a fixed frequency, and the other side sends a deflection data instruction to an MEMS driving board through communication to control the two-dimensional MEMS micro-mirror (206) to perform quasi-static scanning.

10. The method of claim 9, wherein the method comprises: the main control and data resolving system (104) processes the point cloud data to obtain a spatial three-dimensional distribution profile of the target;

the program flow is as follows: firstly, the main control and data resolving system (104) carries out point cloud filtering and point cloud registration processing on the obtained original target point cloud data, and then carries out mesh subdivision and mesh splicing on the target point cloud data to obtain a three-dimensional reconstruction map of the point cloud data.

The technical field is as follows:

the invention belongs to the technical field of laser detection, and relates to a high-angular-resolution laser radar and a detection method.

Background art:

the laser radar is a radar system for detecting the position, speed and other characteristic quantities of a target by emitting laser beams, and consists of a laser transmitter, an optical receiver, an information processing system and the like. The working principle is to emit laser beam to the target, then compare the received signal reflected from the target with the emitted signal, and after proper processing, the relevant information of the target, such as target distance, direction, height, speed, posture and shape, etc. parameters can be obtained.

When the laser radar carries out long-distance detection, the light spot of laser becomes larger along with the distance, when the detected object is smaller than the size of the light spot, the position of the object is deviated, because the radar marks the position of the detected target, the position is determined by the laser emission direction and the echo time, therefore, the small target appears at any position in the light spot, the obtained directions are the same, the measurement error is brought, and the error is increased along with the increase of the distance.

The invention content is as follows:

the invention aims to provide a high-angular-resolution laser radar and a detection method, which overcome the problem that the radar measuring angular resolution is limited in the prior art, can greatly increase the emission frequency of a light source, and remarkably improve the distribution density of point cloud during detection, thereby realizing high angular resolution.

In order to achieve the purpose, the invention adopts the technical scheme that:

a high angular resolution lidar characterized by: the system comprises a main control and data calculation system, wherein a zooming laser emission system, a laser scanning system and a laser receiving system are respectively connected with the main control and data calculation system; the zooming laser emission system comprises a high repetition frequency high-power optical fiber laser, an optical fiber beam splitter, an optical fiber time delay device, an optical fiber beam combiner and an optical fiber collimator which are arranged in sequence; the laser receiving system comprises a laser receiving optical system and a photoelectric detector.

The laser scanning system is a two-dimensional MEMS micro-scanning mirror and adopts a non-resonant scanning mode.

The high repetition frequency high-power pulse fiber laser is an MOPA mode pulse fiber laser, the seed source is a VCSEL with narrow line width, and the gain medium is a doped gain fiber; the high repetition frequency high power pulse optical fiber laser is a variable pulse laser, the output peak power is 1 KW-8 KW, the average power is 1W-20W, the output pulse width is 3 ns-15 ns, the output repetition frequency is 100 KHz-2 MHz, the output pulse energy is 8 muJ-15 muJ, and the divergence angle is 0.5-2 mrad.

The optical fiber optical splitter is a 1 × N optical splitter, and the number of paths N of optical splitting is related to the accuracy of target detection and the detection distance requirement.

The optical fiber delayer is composed of N paths of optical fiber delay structures, the delay time of each path of optical fiber is limited by N and the pulse period T of the pulse laser, and the delay time interval of each path of optical fiber is T/N.

The size of the light spot after the collimation of the optical fiber collimator is not more than 2 mm.

The focal point of the laser receiving optical system is positioned on the surface of the photoelectric detector; the photoelectric detector is a semiconductor device capable of converting light waves into current, and the semiconductor material used by the photoelectric detector is related to laser waves emitted by the radar.

A detection method of a high angular resolution laser radar is characterized in that: the method comprises the following steps:

the method comprises the steps that a master control and data calculation system is adopted, pulse light emitted by a high-repetition-frequency high-power pulse light laser is averagely divided into N paths of pulse light through a 1 x N optical fiber beam splitter, each path of pulse light is connected with an optical fiber time delay unit in a connected mode for time delay, the delayed light beams enter an N x 1 optical fiber beam combiner along the optical fibers for beam combination, the combined pulse light is collimated through an optical fiber collimator and then enters a two-dimensional scanning device for scanning, when the light beams are scanned in space, reflected echoes are received through a detector and are compared with initial signals to obtain the flight time of each pulse light, and therefore the distance of a target is determined.

The main control and data resolving system controls the scanning speed and the scanning angle of the MEMS micro-scanning mirror;

the program flow is as follows: the main control and data resolving system stores emission sequence waveforms and scanning waveforms of the two-dimensional MEMS micro-mirror; when scanning is carried out, the main control and data calculation system enables the laser transmitting end to transmit a pulse sequence according to a fixed frequency on one side, and transmits a deflection data instruction to the MEMS driving board through communication on the other side to control the two-dimensional MEMS micro-mirror to carry out quasi-static scanning.

The master control and data resolving system processes the point cloud data to obtain a spatial three-dimensional distribution profile of the target;

the program flow is as follows: firstly, the main control and data resolving system carries out point cloud filtering and point cloud registration processing on the obtained original target point cloud data, and then carries out mesh subdivision and mesh splicing on the target point cloud data to obtain a three-dimensional reconstruction map of the point cloud data.

Compared with the prior art, the invention has the advantages and effects that:

1. according to the invention, each pulse light emitted by the laser source of the laser radar is averagely divided into multiple paths of pulse lasers through the optical fiber beam splitter, the multiple paths of pulse lasers respectively enter the multiple paths of optical fiber delay devices for delay, the delayed multiple paths of laser beams are combined into one path through sequencing, at the moment, the combined laser beam comprises multiple pulses, the emission frequency of the laser is greatly improved, the detected point cloud density can be obviously improved during scanning, and thus the detection angle resolution of the radar is improved.

2. The invention has no mechanical parts and high reliability.

Description of the drawings:

FIG. 1 is a schematic diagram of a radar system of the present invention;

fig. 2 is a schematic diagram of the structure and the optical path of the radar of the present invention.

In the figure, 101-zoom laser emission system, 102-laser scanning system, 103-laser receiving system, 104-main control and data resolving system, 201-high repetition frequency high power optical fiber laser, 202-optical fiber beam splitter, 203-optical fiber delay device, 204-optical fiber beam combiner, 205-optical fiber collimator, 206-two-dimensional MEMS micro-scanning mirror, 207-computer, 208-photoelectric detector, 209-laser receiving optical system, 301-narrow linewidth VCSEL, 302-gain optical fiber.

The specific implementation mode is as follows:

in order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention relates to a long-distance high-resolution laser radar and a detection method, wherein a radar light source is subjected to light splitting, each path of light splitting is subjected to beam combination after time delay, and the emission frequency of the radar light source can be increased in multiples, so that the point cloud density of radar scanning is increased, and the radar angular resolution is improved. Referring to fig. 1, a main control and data calculation system 104 is included, and a zoom laser emitting system 101, a laser scanning system 102 and a laser receiving system 103 are respectively connected with the main control and data calculation system 104. Referring to fig. 2, the zoom laser emission system 101 includes a high repetition frequency high power fiber laser 201, a fiber splitter 202, a fiber delay 203, a fiber combiner 204, and a fiber collimator 205, which are sequentially arranged. The laser light receiving system 103 includes a laser light receiving optical system 209 and a photodetector 208. The laser scanning system 102 employs a two-dimensional MEMS micro-scan mirror 206.

Example (b):

fig. 1 shows a schematic diagram of the structure of the present invention, and the specific structure includes a zoom laser emitting system 101, a laser scanning system 102, a laser receiving system 103, and a master control and data resolving system 104. The zooming laser emitting system 101, the laser scanning system 102 and the laser receiving system 103 are respectively connected with a main control and data resolving system 104,

as shown in fig. 2, the zoom laser emitting system 101 includes a high repetition frequency high power fiber laser 201, a fiber splitter 202, a fiber delay 203, a fiber combiner 204, and a fiber collimator 205, which are sequentially arranged. The laser scanning system 102 is a two-dimensional MEMS micro-scanning mirror 206, which employs a non-resonant scanning mode. The laser light receiving system 103 includes a laser light receiving optical system 209 and a photodetector 208. The high repetition frequency high power pulse fiber laser 201 is a MOPA mode pulse fiber laser, the seed source is a narrow linewidth VCSEL301, and the gain medium is a doped gain fiber 302. The high repetition frequency high power pulse optical fiber laser 201 is a variable pulse laser, the output peak power is 1 KW-8 KW, the average power is 1W-20W, the output pulse width is 3 ns-15 ns, the output repetition frequency is 100 KHz-2 MHz, the output pulse energy is 8 muJ-15 muJ, and the divergence angle is 0.5-2 mrad. The optical fiber splitter 202 is a 1 × N splitter, the number of paths N of splitting is related to the accuracy of target detection and the detection distance requirement, and theoretically, the larger N is, the higher the detection accuracy is, and the closer the detection distance is. The optical fiber delay 203 is composed of N optical fiber delay structures, each delay time of the N optical fiber delay structures is not arbitrary, the delay time of each optical fiber is limited by N and the pulse period T of the pulse laser, and the delay time interval of each optical fiber is required to be T/N. The optical fiber combiner 204 can combine the N laser beams into one beam, and the optical fiber combiner 204 is coupled to the optical fiber collimator 205. The optical fiber collimator 205 can perform beam expanding and collimating on the laser beam of the optical fiber beam combiner 204, and the size of a light spot collimated by the optical fiber collimator 205 is not larger than 2 mm. The light beam emitted from the fiber collimator 205 is incident on the two-dimensional scanning mirror 206. The two-dimensional scanning mirror 206 is a MEMS micro-scanning mirror, and the two-dimensional scanning mirror 206 adopts a non-resonant scanning mode. The laser light receiving system 103 includes a laser light receiving optical system 209 and a photodetector 208, and the focal point of the laser light receiving optical system 209 is located on the surface of the photodetector 208. The photodetector 208 is a semiconductor device that converts light waves into electrical current, and the semiconductor material used for the photodetector 208 is related to the radar-emitting laser wave designed.

The detection method of the high angular resolution laser radar comprises the following steps:

by adopting the main control and data calculation system 104, the pulse light emitted by the high-repetition-frequency high-power pulse light fiber laser 201 is averagely divided into N paths of pulse light through the 1 × N optical fiber beam splitter 202, each path of pulse light is connected with an optical fiber time delay unit 203 for time delay, the delayed light beams enter the N × 1 optical fiber beam combiner 204 along the optical fibers for beam combination, the combined pulse light is collimated through the optical fiber collimator 204 and then enters the two-dimensional scanning device for scanning, when the light beams are scanned in space, the light beams are reflected by a target, reflected echoes are received through a detector, and the reflected echoes are compared with initial signals to obtain the flight time of each pulse light, so that the distance of the target is determined.

The master control and data calculation system 104 controls the scanning speed and scanning angle of the MEMS micro-scanning mirror 206. The program flow comprises the following steps: the master control and data calculation system 104 stores the emission sequence waveform and the scanning waveform of the two-dimensional MEMS micro-mirror 206. During scanning, the main control and data calculation system 104 allows the laser emitting end to transmit a pulse sequence at a fixed frequency, and transmits a deflection data command to the MEMS driving board through communication to control the two-dimensional MEMS micro-mirror 206 to perform quasi-static scanning.

The main control and data calculation system 104 processes the point cloud data to obtain a spatial three-dimensional distribution profile of the target. The program flow comprises the following steps: firstly, the main control and data calculation system 104 performs point cloud filtering and point cloud registration processing on the obtained original target point cloud data, and then performs mesh generation and mesh splicing on the target point cloud data to obtain a three-dimensional reconstruction map of the point cloud data.

The above embodiments are merely illustrative of the principles and effects of the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept of the present invention, and the scope of the present invention is defined by the appended claims.