阅读说明：本技术 一种跟瞄系统及调整方法 (Tracking and aiming system and adjusting method ) 是由 冯成义 张在琛 陈声健 张可涵 王海卜 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种跟瞄系统及调整方法,属于激光通讯技术领域。所述跟瞄系统包括粗瞄装置、精瞄装置、第三反射镜、四分之一波片、偏振分光棱镜、S线偏振光源、准直器、第一滤光片、聚焦透镜、第二滤光片、第二线偏振器、非偏振分光棱镜、第三线偏振器、第三滤光片和定焦镜头；所述粗瞄装置包括第一反射镜、捕获跟踪探测器,所述捕获跟踪探测器与第一反射镜通信连接,所述精瞄装置包括第二反射镜、四象限探测器,所述四象限探测器与第二反射镜通信连接。与现有技术相比,本发明的跟瞄系统采用粗瞄装置和精瞄装置相结合,能够达到较高的跟瞄精度,能够有效抑制杂散信号对于CCD图像处理及PSD定位精度的影响,减少了位置误判及跟瞄信号丢失的可能。(The invention discloses a tracking and aiming system and an adjusting method, and belongs to the technical field of laser communication. The tracking and aiming system comprises a coarse aiming device, a fine aiming device, a third reflector, a quarter wave plate, a polarization beam splitter prism, an S linearly polarized light source, a collimator, a first optical filter, a focusing lens, a second optical filter, a second linear polarizer, a non-polarization beam splitter prism, a third linear polarizer, a third optical filter and a fixed focus lens; the coarse aiming device comprises a first reflector and a capturing and tracking detector, the capturing and tracking detector is in communication connection with the first reflector, the fine aiming device comprises a second reflector and a four-quadrant detector, and the four-quadrant detector is in communication connection with the second reflector. Compared with the prior art, the tracking and aiming system disclosed by the invention has the advantages that the coarse aiming device and the fine aiming device are combined, higher tracking and aiming precision can be achieved, the influence of stray signals on CCD image processing and PSD positioning precision can be effectively inhibited, and the possibility of position misjudgment and tracking and aiming signal loss is reduced.)

1. a tracking system, comprising: the device comprises a coarse aiming device, a fine aiming device, a third reflector (4), a first quarter wave plate (5), a polarization beam splitter prism (6), an S linearly polarized light source, a collimator (9), a first optical filter (8), a focusing lens (12), a second optical filter (13), a second linear polarizer (14), a non-polarization beam splitter prism (15), a third linear polarizer (16), a third optical filter (17) and a fixed focus lens (18);

the coarse aiming device comprises a first reflecting mirror (1) and a capturing and tracking detector (19), the capturing and tracking detector (19) is in communication connection with the first reflecting mirror (1), the fine aiming device comprises a second reflecting mirror (3) and a four-quadrant detector (11), and the four-quadrant detector (11) is in communication connection with the second reflecting mirror (3);

The S-shaped light emitted by the S-shaped light source passes through the collimator (9) and the first filter (8), is reflected by the polarization beam splitter prism (6), then passes through the first quarter-wave plate (5), is turned by the third reflector (4) and the second reflector (3), and then passes through the first reflector (1) to emit a light beam;

The received circularly polarized light is reflected by the first reflector (1) to enter the second reflector (3), then is deflected by the second reflector (3) and the third reflector (4) to be incident on the first quarter-wave plate (5), then enters the non-polarized beam splitter prism (15) through the polarized beam splitter prism (6), the light beam is split into two paths with mutually vertical propagation directions, wherein one path passes through the second linear polarizer (14) and the second optical filter (13), and then is converged on the four-quadrant detector (11) by the focusing lens (12), and the angle of the second reflector (3) is adjusted according to the position of the light beam converged on the four-quadrant detector (11); the other path of light passes through a third linear polarizer (16) and a third optical filter (17), is converged on a capturing and tracking detector (19) by a fixed-focus lens (18), and the angle of the first reflector (1) is adjusted according to the position of the light beam converged on the capturing and tracking detector (19).

2. The tracking system of claim 1, wherein: the laser device is characterized by further comprising a first linear polarizer (7), the S-shaped linear light source is replaced by a laser (10), laser emitted by the laser (10) enters the first linear polarizer (7) after passing through a collimator (9) and a first optical filter (8), is modulated into S-shaped linear light by the first linear polarizer (7), and is reflected by the polarization splitting prism (6).

3. The tracking system of claim 2, wherein: the first linear polarizer (7) is replaced by a second quarter wave plate and a half wave plate, and the light beam enters the second quarter wave plate and the half wave plate from the first optical filter (8) and is modulated into S linear polarized light.

4. the tracking system of claim 1, 2 or 3, wherein: also comprises a telescope (2); the light beam reflected by the second reflector (3) reaches the first reflector (1) after passing through the telescope (2); the light beam reflected by the first reflector (1) passes through the telescope (2) and then reaches the second reflector (3).

5. The tracking system of claim 4, wherein: a fourth reflector is arranged between the first reflector (1) and the telescope (2), the emitted light beam is reflected by the second reflector (3) and passes through the telescope (2), and then is reflected back to the telescope (2) by the fourth reflector, the light beam reflected back to the telescope (2) by the fourth reflector is the received circularly polarized light, and the received circularly polarized light directly passes through the telescope (2) and then reaches the second reflector (3).

6. The tracking system of claim 1, 2 or 3, wherein: the first reflector (1) is a two-dimensional rotary table reflector or a six-degree-of-freedom rotary table reflector.

7. The tracking system of claim 1, 2 or 3, wherein: the third reflecting mirror (4) is a dichroic mirror.

8. A method for adjusting a tracking and aiming system is characterized by comprising the following steps:

a. Receiving beacon light which is circularly polarized light;

b. The beacon light is reflected by the first reflector (1), the second reflector (3) and the third reflector (4) and then enters the first quarter-wave plate (5) to be modulated into P polarized light, and the P polarized light is transmitted out through the polarization beam splitter prism (6);

c. The transmitted P polarized light is divided into two paths of light beams with mutually vertical transmission directions by a non-polarized beam splitter prism (15);

d. One path of light beam passes through a third linear polarizer (16) and a third optical filter (17), is condensed by a fixed-focus lens (18) and then irradiates on a capturing and tracking detector (19); adjusting the angle of the first reflector (1) according to the position of the light beam irradiating on the capturing and tracking detector (19) so that the light beam irradiates on the center of the capturing and tracking detector (19);

e. The other path of light beam passes through a second linear polarizer (14) and a second optical filter (13) and is focused by a focusing lens (12), and focused light spots are imaged on a four-quadrant detector (11); the four-quadrant detector (11) adjusts the angle of the second reflector (3) according to the position of the light spot, so that the axial ray angle deviation of the second reflector (3) is reduced.

9. The adjustment method of the tracking system according to claim 8, wherein: the S polarized light is reflected by the polarization beam splitter prism (6), passes through the first quarter wave plate (5), is modulated into circularly polarized light by the first quarter wave plate (5), is reflected by the fourth reflector after being turned by the third reflector (4) and the second reflector (3), and is used as beacon light.

Technical Field

The invention belongs to the technical field of laser communication, and relates to a tracking and aiming system and an adjusting method.

Background

the free space optical communication system is formed by connecting two remote or near communication terminals by using wireless laser to form a communication data transmission link, and has the advantages of large communication capacity, long transmission distance, good confidentiality and the like. Long-range systems employ optical communications between two satellites, e.g., over thousands of kilometers away, and short-range "communication-in-motion" wireless communications systems, e.g., "last mile optical transmission FSO". The signal transmission beam width of the wireless laser communication technology communication is narrow, the transmission distance is long, and the establishment and maintenance of a laser link in a space environment face great difficulty, so a set of high-reliability acquisition, tracking and Aiming (ATP) system must be established to prevent signal loss caused by tracking accuracy or link errors.

Such systems are generally classified into a tracking subsystem and a communication subsystem, and a transmission/reception integrated optical system is generally used to integrate, reduce the size, and reduce the weight of the system. In the prior art, due to the film coating reason and the influence of stray light, a non-polarization beam splitter prism of a tracking subsystem often causes a bright spot with energy of nearly 5% left on a CCD (charge coupled device) and a PSD (phase-sensitive detector) to cause the possibility of misjudgment, the tracking precision reduction or the signal loss of the tracking system.

Disclosure of Invention

The invention aims to establish a visible light tracking system and an adjusting method for a free space optical communication system, and solves the problems that a non-polarizing beam splitter prism leaves bright spots with energy of nearly 5% on a CCD (charge coupled device) and a PSD (position sensitive detector) due to film coating reasons and the influence of stray light, so that the tracking system is misjudged, the tracking precision is reduced or signals are lost.

the invention provides a tracking and aiming system which comprises a coarse aiming device, a fine aiming device, a third reflector, a first quarter wave plate, a polarization splitting prism, an S linearly polarized light source, a collimator, a first filter, a focusing lens, a second filter, a second linear polarizer, a non-polarization splitting prism, a third linear polarizer, a third filter and a fixed focus lens, wherein the first quarter wave plate is arranged on the front end of the coarse aiming device;

The coarse aiming device comprises a first reflector and a capture tracking detector, the capture tracking detector is in communication connection with the first reflector, the fine aiming device comprises a second reflector and a four-quadrant detector, and the four-quadrant detector is in communication connection with the second reflector;

After the S-shaped polarized light emitted by the S-shaped polarized light source passes through the collimator and the first filter, the S-shaped polarized light is reflected by the polarization beam splitter prism, then passes through the first quarter-wave plate, is turned by the third reflector and the second reflector, and then passes through the first reflector to emit a light beam;

The received circularly polarized light enters a second reflecting mirror after being reflected by a first reflecting mirror, then is incident on a first quarter wave plate after being turned by the second reflecting mirror and a third reflecting mirror, and then enters a non-polarizing beam splitter prism through the polarizing beam splitter prism, the light beam is divided into two paths with mutually vertical transmission directions, wherein one path passes through a second linear polarizer and a second optical filter, and then is converged on a four-quadrant detector by a focusing lens, and the angle of the second reflecting mirror is adjusted according to the position of the light beam converged on the four-quadrant detector; the other path of light passes through a third linear polarizer and a third optical filter, is converged on the capturing and tracking detector by the fixed-focus lens, and the angle of the first reflector is adjusted according to the position of the light beam converged on the capturing and tracking detector.

the laser emitted by the laser passes through the collimator and the first optical filter, enters the first linear polarizer, is modulated into S-shaped linear polarized light by the first linear polarizer, and is reflected by the polarization splitting prism.

Further, the first linear polarizer is replaced by a second quarter wave plate and a half wave plate, and the light beam enters the second quarter wave plate and the half wave plate from the first optical filter and is modulated into S linear polarized light.

Further, the device also comprises a telescope; the light beam reflected by the second reflector reaches the first reflector after passing through the telescope; the light beam reflected by the first mirror passes through the telescope and reaches the second mirror.

Furthermore, a fourth reflector is arranged between the first reflector and the telescope, the emitted light beam is reflected by the second reflector and passes through the telescope, and then is reflected back to the telescope by the fourth reflector, the light beam reflected back to the telescope by the fourth reflector is the received circularly polarized light, and the received circularly polarized light directly reaches the second reflector after passing through the telescope.

Further, the first reflector is a two-dimensional rotary table reflector or a six-degree-of-freedom rotary table reflector. The third reflecting mirror is a dichroic mirror or a plane reflecting mirror. The third reflecting mirror can adopt a dichroic mirror, and the function of the third reflecting mirror is realized by enabling all light for communication to penetrate through and all light for tracking to reflect, so that light beams of the tracking system can be reflected onto the second reflecting mirror through the dichroic mirror, laser for communication reaches the second reflecting mirror after penetrating through the dichroic mirror, and two light beams are coaxially and parallelly output and received on the surface of the second reflecting mirror.

the invention provides an adjusting method of a tracking and aiming system, which comprises the following steps:

a. Receiving beacon light which is circularly polarized light;

b. the beacon light is reflected by the first reflector, the second reflector and the third reflector and then enters the first quarter-wave plate to be modulated into P polarized light, and the P polarized light is transmitted out through the polarization beam splitter prism;

c. The transmitted P polarized light is divided into two paths of light beams with mutually vertical transmission directions by a non-polarized beam splitter prism;

d. One path of light beam passes through a third linear polarizer and a third optical filter, is condensed by a fixed-focus lens and then irradiates on a capture tracking detector; adjusting the angle of the first reflector according to the position of the light beam irradiated on the capturing and tracking detector, so that the light beam is irradiated on the center of the capturing and tracking detector;

e. The other path of light beam passes through a second linear polarizer and a second optical filter and is focused by a focusing lens, and focused light spots are imaged on a four-quadrant detector; the four-quadrant detector adjusts the angle of the second reflector according to the position of the light spot, so that the axial ray angle deviation of the second reflector is gradually reduced.

further, after being reflected by the polarization beam splitter prism, the S polarized light passes through the first quarter wave plate and is modulated into circularly polarized light by the first quarter wave plate, the circularly polarized light is reflected by the fourth reflector after being turned by the third reflector and the second reflector, and the reflected light beam serves as beacon light.

compared with the prior art, the tracking and aiming system disclosed by the invention has the advantages that the coarse aiming device and the fine aiming device are combined, so that higher tracking and aiming precision can be achieved. The invention successfully and effectively eliminates the invalid bright spots on the CCD and the PSD, effectively inhibits the influence of stray signals on CCD image processing and PSD positioning accuracy, and reduces the possibility of position misjudgment and tracking signal loss.

Drawings

FIG. 1 is a schematic view of the tracking system of the present invention.

Reference numerals: 1. a first reflector; 2. a telescope; 3. a second reflector; 4. a third reflector; 5. a first quarter wave plate; 6. a polarization splitting prism; 7. a first linear polarizer; 8. a first optical filter; 9. a collimator; 10. a laser; 11. a four-quadrant detector; 12. a focusing lens; 13. a second optical filter; 14. a second linear polarizer; 15. a non-polarizing beam splitter prism; 16. a third linear polarizer; 17. a third optical filter; 18. a fixed focus lens; 19. a tracking detector is captured.

Detailed Description

as shown in fig. 1, the tracking and aiming system of the present invention includes a first reflecting mirror 1, a telescope 2, a second reflecting mirror 3, a third reflecting mirror 4, a first quarter-wave plate 5, a polarization beam splitter prism 6, a first linear polarizer 7, a first optical filter 8, a collimator 9, a laser 10, a four-quadrant detector 11, a focusing lens 12, a second optical filter 13, a second linear polarizer 14, a non-polarization beam splitter prism 15, a third linear polarizer 16, a third optical filter 17, a fixed focus lens 18, and a capture tracking detector 19.

The laser 10 serving as a laser light source is a HeNe laser of a model HNL5632.8-10, the laser 10 emits laser of 633nm, the laser is collimated by a collimator 9 and emits monochromatic light through a first optical filter 8, the laser beam is modulated by a first linear polarizer 7 and then is changed into S-polarized linear polarized light, the S-polarized light is reflected to a first quarter-wave plate 5 through a polarization beam splitter prism 6 without loss, an included angle between the optical axis direction of the first quarter-wave plate 5 and the polarization direction of the S-polarized light is 45 degrees, the emergent light beam passing through the first quarter-wave plate 5 is modulated into circular polarized light, the circular polarized light beam is turned through a third reflector 4 and a second reflector 3, the divergence angle of the light beam is further compressed through a telescope 2, and the light beam is emitted at a certain alignment angle through the first reflector 1. The first linear polarizer 7 of this embodiment may be replaced by a quarter-wave plate and a half-wave plate, and the light beam passing through the first filter 8 is modulated into S-polarized linearly polarized light by the quarter-wave plate and the half-wave plate. The laser emitter 10 may adopt a light source directly emitting S-linearly polarized light, so that the first linear polarizer 7 may be omitted, and the S-linearly polarized light emitted by the polarized light source is reflected by the polarization splitting prism 6 after passing through the collimator 9 and the first filter 8.

The telescope 2 is a Galileo telescope with the model number GBE10-A, and the first reflector 1 consists of a universal rotary table and a reflector on the universal rotary table. The universal rotary table is formed by combining large constant photoelectric GCD series rotary tables, the resolution ratio is about 0.1-0.2 mrad, the universal rotary table rotates 360 degrees in the horizontal direction, and the pitching direction is +/-15 degrees. The second reflector 3 is a piezoceramic reflector with the model number POLARIS-K1S3P, and the third reflector 4 is a plane reflector or a dichroic mirror. The first linear polarizer 7, the second linear polarizer 14 and the third linear polarizer 16 are all nanoparticle linear polarizers of model LPVISC100-MP 2. The first optical filter 8, the second optical filter 13 and the third optical filter 17 are all filters with model FL 05632.8-10. The polarizing beam splitter prism 6 is of the type PBS201, and the non-polarizing beam splitter prism 15 is of the type BS 016. When the third reflecting mirror adopts the dichroic mirror, the realized function is that the light for communication is totally transmitted, the light for tracking is totally reflected, the light beam of the tracking system can be reflected to the second reflecting mirror through the dichroic mirror, the laser for communication reaches the second reflecting mirror after penetrating through the dichroic mirror, and the two beams of light are coaxially and parallelly output and received on the surface of the second reflecting mirror; as shown in fig. 1, a laser for emitting a light beam for communication may be disposed below the dichroic mirror, and the communication light beam may be transmitted through the dichroic mirror to reach the second reflecting mirror.

the laser beam emitted far away is circularly polarized light, is reflected by a first reflector 1 and enters a telescope 2, the beam width of the beam is compressed and is changed into a thinner polarized beam, the polarized beam is deflected by a second reflector 3 and a third reflector 4 and then enters a first quarter wave plate 5, the emergent beam penetrating through the first quarter wave plate 5 is modulated into P polarized light, the P polarized light is totally transmitted out through a polarized beam splitter prism 6, the light intensity is divided into two beams with mutually vertical transmission directions of 50:50 through a non-polarized beam splitter prism 15, one beam passes through a second linear polarizer 14 (namely an analyzer) and a second optical filter 13, and the beam is converged on a four-quadrant detector 11 through a focusing lens 12 for fine positioning; the other path is directly transmitted into a third linear polarizer 16 and a third optical filter 17, and then is converged on a capture tracking detector 19 by a fixed-focus lens 18 for coarse positioning.

the fixed focus lens 18 is a 75mm fixed focus lens (Thorlabs MVL75M23), has a focal length of 75mm, a field angle of 8.3 °, and F/# ═ 2.5. The capture tracking detector 19 is a Barsel CMOS industrial camera, namely a CCD camera, the size of a photosensitive chip is 4.2mmx2.4mm, the array is 1920x1080, the pixel is 2.2um, the frame rate is 26fps, and the capture tracking detector is matched with a 75mm focus lens (MVL75M23) to realize large-field-of-view target capture.

the four-quadrant detector 11 is a Thorlabs four-quadrant detector PDQ80A, namely PSD, with a wavelength range of 400-1500nm, a light-sensitive surface of Φ 7.8mm, which is divided into four separate detectors, which can be represented as Q1, Q2, Q3, and Q4, when an optical signal falls on the quadrant surface, the optical signal is converted into an electrical signal, and the value is output as X-AXIS (Q2+ Q3) - (Q1+ Q4), Y-AXIS (Q1+ Q2) - (Q3+ Q4), SUM (Q1+ Q2+ Q3+ Q4), so that the difference of positions can be obtained by calculating the difference of electrical signals on the four quadrants, thereby driving the piezoceramic reflector 3 to gradually reduce the angular deviation of axial light, and thus realizing precise aiming.

The adjustment process of the light beam transmitting, receiving and tracking system of the invention is as follows:

A. The light emitted by the laser 10 is collimated by the collimating mirror 9, then passes through the first optical filter 8, and then passes through the polarizer, namely the first linear polarizer 7, the power meter is arranged behind the first linear polarizer, and the collimating mirror 9 and the polarizer are adjusted in a matching manner to enable the reading of the power meter to be maximum, so that the emergent light is S-shaped linearly polarized light.

B. The S linearly polarized light passes through the polarization beam splitter prism 6, the polarization beam splitter prism 6 can ensure that the light realizes the total reflection of the S linearly polarized light on the surface of the light splitting film layer and the total transmission of the light in the P direction, and the extinction ratio is 10000 at a 632nm wave band: 1, so that the S linearly polarized light is totally reflected to the first quarter wave plate 5.

C. The reflected S-linearly polarized light passes through the first quarter-wave plate 5 and is changed into circularly polarized light, and at this time, the fast axis direction of the first quarter-wave plate 5 forms an included angle of 45 degrees with the vibration direction of the S-linearly polarized light.

D. The circularly polarized light is emitted through the optical antennas such as the third reflector 4, the second reflector 3, the first reflector 1, etc.

E. The beacon light at the receiving end enters a receiving light path through the antenna in a circularly polarized light mode, passes through the first reflector 1, the second reflector 3 and the third reflector 4, is unchanged in polarization state, and is changed into P polarized light through the first quarter wave plate 5, and the P polarized light is completely transmitted out through the polarization beam splitter prism 6.

F. the P light transmitted by the polarization beam splitter prism 6 needs to be split, one path is to the four-quadrant detector, and the other path is to the capture tracking detector, so that the non-polarization beam splitter prism 15 needs to be used, and the function of the non-polarization beam splitter prism 15 is to make the incident light reflect and transmit light according to the proportion of 50/50.

G. The transmitted light passes through an analyzer, namely a third line polarizer 16 to eliminate stray light, further filters the stray light through a third optical filter 17, and is condensed by a 75mm fixed-focus lens 18 to irradiate an imaging surface of a capture tracking detector 19. The image of the beacon light is obtained by the capture tracking detector, the position of the focusing light is calculated by an image processing mode, and the rotation of the first reflecting mirror 1 (specifically, the rotation of a two-dimensional turntable for installing the first reflecting mirror 1 is adjusted, and the two-dimensional turntable can be replaced by a six-degree-of-freedom turntable) is adjusted through a control circuit and a program, so that the light energy is gradually adjusted to the center of the capture tracking detector.

the coarse aiming process is completed by the rotation of a universal joint with two rotating shafts on a two-dimensional turntable, and the rotation of the universal joint causes the direction of the first reflecting mirror 1 to be changed, thereby achieving the purpose of coarse aiming. The method comprises the steps that firstly, a first reflector 1 points to a detection target according to the preset direction, paraxial laser received by the first reflector is imaged on a CMOS of a capture tracking detector, a light spot of the paraxial laser inevitably deviates from the center of the CMOS, the capture tracking detector converts an optical signal and outputs an image data digital signal to an electronic part of the capture tracking sensor, a control system calculates the distance of the light spot deviating from the center according to an image processing technology and converts the distance of the light spot deviating from the center into a control signal of a universal joint, the angle of the first reflector is adjusted by rotating the universal joint, and the light spot falling point is gradually imaged on the center of the CMOS in a step-by-step iteration mode.

H. The reflected light passes through an analyzer, namely a second linear polarizer 14 to eliminate stray light, and then passes through a second optical filter 13 and a focusing lens 12, a focusing light spot is imaged on a four-quadrant detector 11, and the four-quadrant detector can output position information according to the conversion voltage difference obtained by the light spot in four quadrants. This position information is transmitted to the second mirror 3 by the control program. The second reflector 3 adopts a piezoelectric ceramic reflector, the adjusting range of the piezoelectric ceramic reflector is 500urad, and the precision reaches 1urad, so that the precise adjustment of the beam direction can be realized, and the beam alignment is more precise. The piezoceramic reflectors may be replaced with MEMS deflection mirrors or liquid crystal free space light modulators.

After coarse aiming, the emitted light beam and the received light beam are basically aligned, and the axial deviation is in mrad level, but in order to realize higher-speed and higher-bandwidth laser data transmission, the communication photosensitive area requirement is smaller, for example, the used communication detector is Si APD (Thorlabs APD210), the photosensitive area is 500um, and therefore the aiming precision needs to be further improved to urad level.

The fine aiming device drives the optical reflector to rotate around the X axis and the Y axis through piezoelectric ceramics to realize the two-dimensional small-angle deflection control of the light beam. The piezo ceramic mirror (second mirror 3) has three piezo regulators on its adjusting frame, which provide a step of 0.5urad per 0.1v by a measuring range of 500 urad. The four-quadrant detector PDQ80A has the wavelength range of 400-1500nm, the light-sensitive surface is phi 7.8mm, the light-sensitive surface is divided into four independent detectors which can be represented as Q1, Q2, Q3 and Q4, when an optical signal falls on the surface of a quadrant, the optical signal is converted into an electric signal, the numerical output of the electric signal is X-AXIS (Q2+ Q3) - (Q1+ Q4), Y-AXIS (Q1+ Q2) - (Q3+ Q4) and SUM (Q1+ Q2+ Q3+ Q4), therefore, the position difference can be obtained by calculating the electric signal difference on the four quadrants, the piezoelectric ceramic reflector is driven to gradually reduce the angle deviation of axial light rays, and accurate aiming is achieved.

In order to better reduce the influence inside the system and the system itself, an adjustable fourth mirror is placed between the telescope 2 and the first mirror 1 during actual operation. After the transmitting light is transmitted out through the telescope 2 and the first reflector 1, the fourth reflector is adjusted, the transmitting light can return to the beacon light received in a simulation mode according to the original path, and the angles of the polarization beam splitter prism 6 and the first quarter-wave plate 5 are precisely adjusted, so that the light power in front of the non-polarization beam splitter prism 15 is the maximum, and the receiving power of the system at the moment can be considered to be the maximum.

The invention uses a transmitting-receiving integrated optical system, so that the whole optical system is relatively miniaturized. Compared with a transceiving separation system, the system has the advantages of fewer elements and more compact structure. Meanwhile, the receiving and transmitting integrated system can better adjust the coaxial degree of the signal light and the beacon light, and the difficulty of light path adjustment is reduced. The invention can realize the light beam transmission with high extinction ratio by a polarization isolation scheme, and further eliminates stray light. In the non-polarization optical system used before the invention, because the non-polarization prism BS016 is used, the light transmittance is 47% and the emissivity is 47%, so that the stray light approaching 5% enters the surface of the detector, and the light beam does not change along with the rotation angle of the optical antenna, thereby influencing the positioning of the capturing tracking detector and the four-quadrant detector, easily causing misreading and low signal-to-noise ratio, and further influencing the rotation angle control and tracking precision of the optical antenna system.