阅读说明：本技术 一种天文定位的激光雷达的视场匹配装置及方法 (Astronomical positioning field matching device and method for laser radar ) 是由 王积勤 杨勇 林鑫 龚博文 程学武 季凯俊 郑金州 刘林美 陈振威 龚顺生 李发 于 2020-06-11 设计创作，主要内容包括：本发明公开了提供一种天文定位的激光雷达的视场匹配装置,包括计算机,还包括驱动器、角度调节架、激光器、反射镜、接收望远镜、分光镜、CCD相机、接收光纤和信号检测系统,还公开了一种天文定位的激光雷达的视场匹配方法,本发明通过激光光束方位的监测和调整,有利于提高激光雷达的数据反演精度,有效提高激光雷达数据连贯性,可适用于同轴或者离轴激光雷达系统,为激光雷达精准调节提供有效方案。(The invention discloses a field matching device of an astronomical positioning laser radar, which comprises a computer, a driver, an angle adjusting frame, a laser, a reflector, a receiving telescope, a spectroscope, a CCD camera, a receiving optical fiber and a signal detection system.)

1. A field matching device of an astronomical positioning laser radar comprises a computer (1), and is characterized by further comprising a driver (2), an angle adjusting frame (3), a laser (4), a reflector (5), a receiving telescope (6), a spectroscope (7), a CCD camera (8), a receiving optical fiber (9) and a signal detection system (10),

the reflector (5) is arranged on the angle adjusting frame (3), the angle adjusting frame (3) is connected with the driver (2), the driver (2) is connected with the computer (1),

the computer (1) controls the laser (4) to emit laser beams, the laser beams are reflected into the sky by the reflecting surface of the emitting mirror (5),

a spectroscope (7) is arranged in front of a focal plane of a receiving telescope (6), the spectroscope (7) divides received light obtained by the receiving telescope (6) into transmitted light and reflected light, the transmitted light enters a CCD camera (8), the center of a detection plane of the CCD camera (8) is positioned on an optical axis of the transmitted light, and a sky star and a laser beam photo obtained by the CCD camera (8) are transmitted to a computer (1); the reflected light is sent to the receiving end of the receiving optical fiber (9), the center of the end face of the receiving end of the receiving optical fiber (9) is located on the optical axis of the reflected light, the other end of the receiving optical fiber (9) is connected with a signal detection system (10), and the signal detection system (10) detects the laser radar echo signal and outputs the laser radar echo signal to the computer (1).

2. A field-of-view matching method of an astronomical positioning lidar, which uses the field-of-view matching apparatus of the astronomical positioning lidar according to claim 1, comprising the steps of:

step one, a computer (1) controls a laser (4) to generate a laser beam to be emitted, and the laser beam is reflected by a reflector (5) on an angle adjusting frame (3) and then is emitted into the sky;

secondly, the receiving telescope (6) reflects the received light containing sky background light signals and laser radar echo light signals to the spectroscope (7), and the transmitted light and the reflected light are separated by the spectroscope (7);

thirdly, transmitting the transmitted light into a CCD camera (8), obtaining a sky star and a laser beam photo in a field of view of a receiving telescope (6), and storing the sky star and the laser beam photo in a computer (1);

step four, the reflected light is sent into a receiving optical fiber (9), a signal detection system (10) converts laser radar echo optical signals in the reflected light into electric signals, then the electric signals are collected by a computer (1), original laser radar echo signals are obtained, atmosphere related parameters are obtained according to the original laser radar echo signals, and the atmosphere related parameters comprise: atmospheric density, atmospheric temperature, atmospheric wind field;

step five, the computer (1) processes the sky fixed stars and the laser beam photos shot by the CCD camera (8), obtains the coordinates of fixed star pixels in the sky fixed stars and the laser beam photos, performs star map recognition by combining the shooting time, the longitude and latitude, the international universal star catalogue and other information, obtains the star number of the fixed stars in the CCD camera (8) and the coordinates of the star number in the celestial coordinate system, and determines the direction of each pixel in the detection surface of the CCD camera (8) corresponding to the celestial coordinate system through the celestial coordinate system;

step six, carrying out sharpening and denoising treatment on the laser beam from a sky star and a laser beam picture shot by a CCD camera (8), identifying the edge of the laser beam and finding out a pixel at the tail end of the laser beam;

step seven, if the corresponding position of the pixel at the tail end of the laser beam is at the center of the detection surface of the CCD camera (8), the laser beam is positioned at the center of the receiving field of view of the receiving telescope (6); if the corresponding position of the pixel at the tail end of the laser beam is not in the center of the detection surface of the CCD camera (8), the computer (1) is required to control the driver (2) to drive the reflecting mirror (5) on the angle adjusting frame (3) to carry out angle scanning until the corresponding position of the pixel at the tail end of the laser beam is in the center of the detection surface of the CCD camera (8).

Technical Field

The invention relates to the field of automatic control of laser radars, in particular to a field-of-view matching device of an astronomical positioning laser radar and a field-of-view matching method of the astronomical positioning laser radar, which are used for accurately positioning an atmospheric sounding laser radar and a star map.

Background

The laser has the characteristics of good monochromaticity, high brightness, excellent directivity and the like, and the laser radar formed by the interaction of the laser and the atmosphere has the advantages of high space-time resolution capability, high detection sensitivity, capability of distinguishing detected species and the like, and is widely applied to the field of atmosphere detection. The atmospheric detection laser radar system is composed of a laser transmitting system, a telescope receiving system and a signal detection system. The atmospheric laser radar system can be divided into a coaxial type and an off-axis type according to whether the laser axis is coincident with the optical axis of the receiving telescope system (Liuqiaojun and the like, off-axis laser radar overlapping factor calculation and near-field signal correction based on the laser output mode, Physics, 2009,58(10): 7376-7381). When the atmospheric detection laser radar works, because the divergence angle of a laser beam and the receiving field angle of a telescope are very small, usually in the milliradian order (1mrad is 1/17 degrees), in order to realize the transceiving matching of the laser beam at a transmitting end and the receiving field angle of the telescope, the transceiving matching technology is very difficult only when the laser beam completely enters the receiving field angle of the telescope, namely the transceiving matching geometric overlapping factor is 1, otherwise, the laser radar cannot completely receive an atmospheric echo optical signal excited by the transmitting laser beam (Zhangxia and the like, the geometric overlapping factor of the laser radar and the influence thereof on aerosol detection, Quantum electronics, 2005,22(2): 299-304, Wangwei and the like, the calculation of the overlapping factor of the laser radar based on laser intensity distribution and the sensitivity analysis thereof, optics report, 2014,43(2):02280051-7), resulting in deviations in the signal processing and inversion results. On the other hand, when the laser radar works for a long time, due to the influence of factors such as day and night (and winter and summer) environmental temperature change, slight change of laser mode, displacement caused by slight ground vibration and the like, the debugged laser radar receiving and transmitting matching can cause the transmitted laser beam to deviate from the receiving view field of the telescope to generate measurement errors. Therefore, the existing laser radar adopts a series of technical measures to realize the field matching, and three common laser radar field matching methods are explained below, which have the following defects:

the first is a manual adjustment method. In actual observation, a laser radar operator with high proficiency and professional knowledge often adjusts the laser radar according to various indexes of a laser radar echo signal and actual operation experience. In the actual adjusting process, the method is time-consuming and labor-consuming, and the debugging results of different personnel are different under different conditions, so that accidental errors are easy to generate. The laser radar system has low working efficiency under the method, and is not beneficial to conventional observation operation.

The second is echo signal strength method. The direction of the laser beam is adjusted by the intensity of the laser radar echo signal to achieve field matching (Xuan Wang, et al. self-aligning laser system and iterative. SPIE, 1998, 3504: 31-40; Bo Liu, et al. methods for optical adaptation in laser system, Appl. Opt.,44(8): 1480-1484; Shenfara et al, methods and optical devices for fast collimation of laser radar systems, intense lasers and particle beams, 2009,21(3): 335-340). The method utilizes a high-precision angle electric adjusting frame to change the direction of a laser beam, so that the laser beam is subjected to spiral scanning or cross scanning, and the matching of a receiving field and a transmitting field is realized by utilizing the trapezoidal function relation which is obtained by feedback and is satisfied by the intensity of an echo signal at the same height and the pointing angle of the beam. The echo signal intensity method requires multiple scanning of the emitted laser beam and simultaneous acquisition of the laser radar echo signal, and a scanning period usually requires a long time (usually several minutes to half an hour), so the echo signal intensity method needs to assume that the atmospheric state is kept constant during the period of time. In fact, the atmosphere is affected by cloud, aerosol, water vapor and the like, and is difficult to keep stable for a long time, which will seriously affect the reliability of the echo signal intensity method. Secondly, in the process of scanning by the echo signal intensity method, the transmitted laser deviates from the field of view of the receiving telescope due to scanning, so that the laser radar echo data is invalid in the process of transmitting and receiving matching, which can cause short-time interruption of the laser radar data.

The third method is the spot auto-collimation method. The method comprises the steps of parallelly deflecting a transmitted laser beam by using a pyramid prism and returning the reflected laser beam to a focal plane of a receiving telescope, placing a light barrier at the focal plane, monitoring the position of a light focus at the plane by using a CCD camera, and enabling the focus of the laser beam reflected to the telescope to be located at the axis position of the telescope by adjusting the direction of the transmitted laser beam so as to realize the matching of a transmitting and receiving view field (Tan roller and the like, a vehicle-mounted laser radar automatic collimation system, atmosphere and environment optics journal 2008, 3 (5): 344-348). The method skillfully utilizes the characteristic that the pyramid prism returns to the original path of the incident light path, so that the method does not depend on the echo signal of the laser radar, and the matching result is not influenced by atmospheric fluctuation. Of course, during the automatic collimation of the light spot, the light blocking sheet needs to be inserted into the focus of the telescope, and therefore, the data of the laser radar is also interrupted. In addition, this method requires a cube-corner prism to reflect a portion of the light back to the receiving telescope in parallel, and is not suitable for off-axis lidar systems.

The star map is an atlas drawn by projecting persistent stars, galaxy, clouds and the like in the night sky onto a plane, the star map identification is used for comparing and analyzing a constantogram shot by a camera in the sky with the star map so as to determine the position of the camera (Trachua and the like, an autonomous star map identification algorithm based on pattern matching, university of Beijing technology, 2015,35(10): 1032-1037; high-level of dawn and the like, a new multi-triangle star map identification algorithm, photonics, 2009,38(7): 1867-1; European birch, research on a method of star map simulation and navigation star extraction based on a CCD star sensor [ D ] science and technology university of Huazhong, 2005 ]), and the method is widely applied to positioning and navigation of space vehicles. The method has not been applied to laser radars.

Disclosure of Invention

The invention aims to provide a field of view matching device of an astronomical positioning laser radar and a field of view matching method of the astronomical positioning laser radar aiming at the problems in the prior art.

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

a field-of-view matching device for astronomical positioning laser radar comprises a computer, a driver, an angle adjusting frame, a laser, a reflector, a receiving telescope, a spectroscope, a CCD camera, a receiving optical fiber and a signal detection system,

the reflector is arranged on the angle adjusting frame, the angle adjusting frame is connected with the driver, the driver is connected with the computer, the computer controls the laser to emit laser beams, the laser beams are reflected into the sky through the reflecting surface of the reflector,

a spectroscope is arranged in front of a focal plane of the receiving telescope, the spectroscope divides received light obtained by the receiving telescope into transmitted light and reflected light, the transmitted light enters a CCD camera, the center of a detection plane of the CCD camera is positioned on an optical axis of the transmitted light, and a sky fixed star and a laser beam photo obtained by the CCD camera are transmitted to a computer; the reflected light is sent to the receiving end of the receiving optical fiber, the center of the end face of the receiving end of the receiving optical fiber is located on the optical axis of the reflected light, the other end of the receiving optical fiber is connected with a signal detection system, and the signal detection system detects the laser radar echo signal and outputs the laser radar echo signal to a computer.

A field matching method for astronomical positioning lidar comprises the following steps:

step one, a computer controls a laser to generate a laser beam, and the laser beam is reflected by a reflector on an angle adjusting frame and then is emitted into the sky;

step two, the receiving telescope reflects the received light containing the sky background light signal and the laser radar echo light signal to the spectroscope, and the transmitted light and the reflected light are separated by the spectroscope;

thirdly, transmitting the transmitted light into a CCD camera to obtain a sky fixed star and a laser beam photo in a field of view of the receiving telescope, and storing the sky fixed star and the laser beam photo in a computer;

step four, the reflected light is sent into a receiving optical fiber, a laser radar echo optical signal in the reflected light is converted into an electric signal by a signal detection system, then the electric signal is collected by a computer, an original echo signal of the laser radar is obtained, and atmosphere related parameters are obtained according to the original echo signal of the laser radar, wherein the atmosphere related parameters comprise: atmospheric density, atmospheric temperature, atmospheric wind field;

processing the sky fixed star and the laser beam photo shot by the CCD camera by the computer to obtain coordinates of star pixels in the sky fixed star and the laser beam photo, carrying out star map recognition by combining information such as shooting time, longitude and latitude, an international universal star table and the like to obtain the star number of the fixed star in the CCD camera and the coordinates of the fixed star in a celestial coordinate system, and determining the direction of each pixel in the detection surface of the CCD camera corresponding to the celestial coordinate system by the celestial coordinate system;

step six, carrying out sharpening and denoising treatment on the laser beam from a sky star and a laser beam picture shot by a CCD camera, identifying the edge of the laser beam, and finding out a pixel at the tail end of the laser beam;

step seven, if the corresponding position of the pixel at the tail end of the laser beam is at the center of the detection surface of the CCD camera, the laser beam is positioned at the center of the receiving field of view of the receiving telescope; if the corresponding position of the pixel at the tail end of the laser beam is not in the center of the detection surface of the CCD camera, the computer is required to control the driver to drive the reflecting mirror on the angle adjusting frame to carry out angle scanning until the corresponding position of the pixel at the tail end of the laser beam is in the center of the detection surface of the CCD camera.

Compared with the prior art, the invention has the following beneficial effects:

the invention can monitor the laser beam and the absolute direction of the receiving telescope at the same time, which is beneficial to improving the data inversion precision of the laser radar; the direction of the transmitted laser beam is monitored and adjusted in real time to match with the receiving telescope, so that the normal receiving of the laser radar echo signal is not influenced, and the time continuity of the laser radar echo signal data acquisition is improved; the receiving optical fiber, the CCD camera and the receiving telescope are matched with each other in view field, so that the adjustment of the receiving and transmitting matching of the laser radar is facilitated.

The method can accurately know the absolute directions of the receiving telescope and the emitted laser beam, and provides accurate azimuth data for the data inversion of the laser radar; the CCD camera monitors the direction of the reflected light in real time, and can directly control the driver to realize the accurate adjustment of the direction of the emitted laser beam if the direction of the reflected light needs to be adjusted, so that the real-time performance is good, the adjusting and judging speed is high, the rapid and accurate adjustment of the second order can be realized, and the normal receiving of the echo signal of the laser radar is not influenced; the axes corresponding to the field of view of the receiving optical fiber, the CCD camera and the receiving telescope are consistent, so that the receiving optical fiber, the CCD camera and the receiving telescope can be suitable for both coaxial receiving and transmitting and off-axis receiving and transmitting; the detection surface of the CCD camera is much larger than the receiving end surface of the receiving optical fiber, and the laser divergence angle of the emitted laser beam is smaller than the receiving visual field of the optical fiber, so that the visual field of the CCD camera is much larger than the receiving visual field angle of the receiving optical fiber, and the receiving and sending matching adjustment of the receiving telescope is facilitated.

Drawings

Fig. 1 is a schematic structural diagram of the inventive device.

Wherein, 1-computer; 2-a driver; 3-an angle adjusting frame; 4-a laser; 5-a reflector; 6-a receiving telescope; a 7-spectroscope; 8-CCD camera; 9-a receiving fiber; 10-signal detection system.

Detailed Description

The present invention will be described in further detail with reference to examples for the purpose of facilitating understanding and practice of the invention by those of ordinary skill in the art, and it is to be understood that the present invention has been described in the illustrative embodiments and is not to be construed as limited thereto.

As shown in fig. 1, the field matching device for the astronomical positioning lidar comprises a computer 1, a driver 2, an angle adjusting frame 3, a laser 4, a reflecting mirror 5, a receiving telescope 6, a spectroscope 7, a CCD8 and a receiving optical fiber 9.

The computer 1 is a core control component of the invention and is responsible for controlling the driver 2 to drive the angle adjusting frame 3 and controlling the laser 4 to generate laser; the reflector 5 is arranged on the angle adjusting frame 3, and the angle adjusting frame 3 drives the reflector 5 to deflect the angle, so that the reflected laser beam has the angle pointing adjusting capability; a spectroscope 7 is arranged in front of a focal plane of a receiving telescope 6, the received light reflected by the telescope 6 is divided into two paths, one path of transmitted light is directly sent to a CCD camera 8, the center of a detection plane of the CCD camera 8 is positioned on an optical axis of a transmission light path of the receiving telescope 6, the CCD camera 8 is controlled by a computer, and the obtained sky star and laser beam photos are also transmitted to the computer 1 for analysis and processing; the other path of reflected light is sent to a receiving end of a receiving optical fiber 9, the center of the end face of the receiving end of the receiving optical fiber 9 is also positioned on the optical axis of the reflected light path of the telescope 6, and the center of the end face of the receiving end of the receiving optical fiber 9 and the center of the detection face of the CCD camera 8 are ensured to correspond to the center of the receiving view field of the laser radar telescope. The receiving optical fiber 9 is connected with the signal detection system 10, and the computer 1 is responsible for controlling and reading the laser radar echo signal in the signal detection system 10 and storing the laser radar echo signal in the computer 1.

A field matching method for astronomical positioning lidar comprises the following steps:

firstly, a computer 1 controls a laser 4 to generate a laser beam to be emitted, and the laser beam is reflected by a reflector 5 on an angle adjusting frame 3 and then is emitted into the sky to excite an atmospheric atomic molecular spectrum;

step two, the receiving telescope 6 collects and reflects the received light containing the sky background light signal and the laser radar echo light signal to the spectroscope 7, and the received light is divided into two paths by the spectroscope 7, wherein one path is transmitted light, and the other path reflects light, and the reflected light and the transmitted light both contain the sky background light signal and the laser radar echo signal;

transmitting the transmitted light passing through the reflector 5 into a CCD camera 8, and taking a picture in real time under the control of the computer 1 to obtain a picture of a sky star and a laser beam in a field of view of the telescope 6, and storing the picture in the computer 1 for processing and analysis;

step four, the reflected light after passing through the reflector 5 is sent into a receiving optical fiber 9, a laser radar echo optical signal in the reflected light is converted into an electric signal by a signal detection system 10, and then the electric signal is acquired and stored at a high speed by a computer 1 to obtain an original echo signal of the laser radar, and atmosphere related parameters can be obtained after processing, wherein the atmosphere related parameters comprise: information such as atmospheric density, atmospheric temperature, atmospheric wind field and the like;

step five, the computer 1 processes the sky fixed stars and the laser beam photos shot by the CCD camera 8 to obtain the coordinates of fixed star pixels in the sky fixed stars and the laser beam photos, performs star map recognition by combining the shooting time, longitude and latitude, international universal star tables and other information to obtain the star numbers of the fixed stars in the CCD camera 8 and the coordinates of the fixed stars in the celestial coordinate system, and then determines the direction of each pixel in the detection surface of the CCD camera 8 corresponding to the celestial coordinate system through the celestial coordinate system;

and step six, carrying out sharpening and denoising treatment on the laser beam from the sky star and the laser beam picture shot by the CCD camera 8, and calculating the edge of the laser beam by combining an edge recognition algorithm. The pixel position of the tail end of the laser beam (the emergent end of the reflector 5 is the head end) is found out through curve fitting, and the current direction of the emitted laser beam can be found out;

step seven, if the corresponding position of the pixel at the tail end of the laser beam is at the center of the detection surface of the CCD camera 8, the laser beam is positioned at the center of the receiving field of view of the receiving telescope 6; if the corresponding position of the pixel at the tail end of the laser beam is not in the center of the detection surface of the CCD camera 8, the computer 1 is required to control the driver 2 to drive the reflector 5 on the angle adjusting frame 3 to carry out angle scanning until the corresponding position of the pixel at the tail end of the laser beam is in the center of the detection surface of the CCD camera 8.

By the method, the laser beam can successfully fall into the target field of view.

The specific embodiments described herein are merely illustrative of the invention. Various modifications, additions and substitutions may be made by those skilled in the art to which the invention pertains without departing from the spirit of the invention or exceeding the scope of the claims defined thereby.