Pre-aiming device based on optical wedge lens group and satellite laser communication system

Abstract

The application provides a pre-aiming device based on a light wedge lens group and a satellite laser communication system. The application utilizes two pairs of cemented lens groups respectively formed by two prisms with different refractive indexes, and through relative rotation between the two cemented lens groups, according to the relative position relationship between the satellites, a lead angle is superimposed on the light beam pointing in the process of laser communication light wave transmission, so as to offset the time delay deviation in the process of laser communication light wave transmission between the satellites. The satellite laser communication system of the application realizes the adjustment of the lead angle based on the two cemented lens groups, the transmitting and receiving light paths have high consistency, the wave division multiplexing technology can be used to combine the transmitting and receiving light paths, so that the problem of long-time stable communication caused by slow misadjustment and irregular changes of coaxiality between the transmitting branch and the receiving branch can be effectively avoided.

Description

Technical Field

[0001] This application relates to the field of satellite communication technology, and more specifically to a pre-aiming device based on an optical wedge mirror group and a satellite laser communication system. Background Technology

[0002] In existing satellite communication technologies, even after coarse tracking and fine tracking by fast-reflecting mirrors, laser signals will still experience small angular deviations during transmission due to changes in the relative spatial positions between satellites.

[0003] Existing technologies can use a forward-looking fast-reflecting mirror as the pre-aiming execution unit to overcome this angular deviation. However, such a design requires folding the optical path and separating the receiving and transmitting units of the system, making it impossible to multiplex the optical equipment of the transceiver link. Furthermore, it is necessary to add beam-combining devices to the transmitting and receiving units in the relay optical path, resulting in a complex relay system with a large size and long assembly and adjustment time.

[0004] Furthermore, under current technology, the independence and non-reusability of the transmitting and receiving units place additional demands on the consistency of the system's transmitting and receiving branches during assembly and adjustment. Existing systems must ensure high coaxiality between the transmitting and receiving branches to guarantee communication quality. This introduces additional difficulties for ground assembly and adjustment. After the laser communication terminal is launched into orbit, the space environment will inevitably cause further coaxiality misalignment between the transmitting and receiving branches. Therefore, the existing system requires recalibration after on-orbit operation, necessitating the addition of self-calibration components, further increasing system complexity and the probability of failure. Summary of the Invention

[0005] This application addresses the shortcomings of existing technologies by providing a pre-aiming device and a satellite laser communication system based on an optical wedge mirror assembly. This application utilizes wavelength division multiplexing (WDM) technology to combine the transmitting and receiving optical paths, and employs a special optical wedge mirror assembly to adjust the lead angle. This overcomes the problem in existing technologies where the coaxiality of the transmitting and receiving branches is slowly misaligned and changes irregularly due to the influence of the space environment, resulting in unstable communication over long periods. The specific technical solution adopted in this application is as follows.

[0006] First, to achieve the above objective, a pre-aiming device based on an optical wedge mirror assembly is proposed, comprising: a first cemented mirror assembly, which includes two prisms with different refractive indices, cemented together, wherein laser communication light waves pass through one prism and the cemented surface between the two prisms to reach the other prism; and a second cemented mirror assembly, which includes two additional prisms with different refractive indices, cemented together, wherein laser communication light waves pass through one prism and the cemented surface between the two prisms to reach the other prism; at least two prisms in the first and second cemented mirror assemblies have the same refractive index, and the two prisms with the same refractive index are arranged adjacent to each other, and the relative angle between the cemented surfaces of the two prisms with the same refractive index is adjusted by a rotation drive device.

[0007] Optionally, in any of the above-described pre-aiming devices based on an optical wedge lens assembly, the first cemented lens assembly includes: a first prism having a first refractive index; a second prism having a second refractive index; and a first wedge angle is provided between the cemented surface between the first prism and the second prism and the laser-passing surface of the first prism. A second wedge angle is provided between the adhesive surface between the first prism and the second prism and the laser-passing surface of the second prism. The second cemented lens assembly includes: a third prism having a second refractive index; a fourth prism having a first refractive index; a second wedge angle is provided between the cementing surface between the third and fourth prisms and the laser-passing surface of the third prism; a first wedge angle is provided between the cementing surface between the third and fourth prisms and the laser-passing surface of the fourth prism. .

[0008] Optionally, a pre-aiming device based on an optical wedge lens group as described in any of the above, wherein the first wedge angle With the second wedge angle The ratio does not exceed 1.2, or the first wedge angle With the second wedge angle The angular difference between them shall not exceed 6°; the ratio of the second refractive index to the first refractive index shall be between 1.02 and 1.1.

[0009] Optionally, in any of the above-described pre-aiming devices based on optical wedge mirror groups, the material Abbe number difference between the first prism and the second prism is not less than 20, and the material Abbe number difference between the third prism and the fourth prism is not less than 20.

[0010] Optionally, in any of the above-described pre-aiming devices based on optical wedge mirror groups, the laser-passing surfaces of the second prism and the third prism are set to be parallel to each other; the third prism and the fourth prism are synchronously driven by a rotation drive device and rotate relative to the second prism with the normal of the laser-passing surface of the third prism as the rotation center.

[0011] To achieve the above objectives, this application also provides a satellite laser communication system, comprising: a beam-expanding antenna for transmitting and receiving laser communication light waves into space; a folding mirror for coarse tracking of the laser communication light wave beam direction; a fine-tracking fast mirror for precise aiming of the laser communication light wave beam direction; a position sensing unit for acquiring the light spot coordinates in the optical path of the fine-tracking fast mirror, so as to adjust the aiming angle of the folding mirror and the fine-tracking fast mirror in real time based on the light spot coordinates; a transceiver lens for receiving the laser communication light waves reflected by the fine-tracking fast mirror and transmitting laser communication light waves to the fine-tracking fast mirror; and a wavelength division multiplexing unit, one end of which is connected to the transceiver lens, and the other end simultaneously... The transmitting and receiving optical fibers within the system are used to provide communication signals from the transmitting fiber to the transceiver lens for transmitting laser communication light waves, and also to feed back the laser communication light waves received by the transceiver lens to the system via the receiving fiber. A pre-aiming device based on an optical wedge mirror assembly, as described above, is installed on the shared optical path between the transceiver lens and the precision tracking mirror. This pre-aiming device refracts the laser communication light waves between the transceiver lens and the precision tracking mirror, and adjusts the relative rotation angle between the two cemented mirror assemblies according to their inter-satellite relative positions. During the transmission of the laser communication light waves, a leading angle is superimposed on the beam direction to compensate for time delay deviations during inter-satellite laser communication light wave transmission.

[0012] Optionally, in any of the satellite laser communication systems described above, the lead angle superimposed on the beam direction during laser communication light wave transmission... The angular range is positively correlated with the first wedge angle between the cemented surface and the laser-passing surface in the cemented lens assembly. Furthermore, it is positively correlated with the difference in refractive index between the two prisms in the cemented lens assembly for the transmit and receive wavelengths of the laser communication light wave. ;in, This indicates the emitted wavelength of the laser communication light wave. Indicates the received wavelength of the laser communication light wave; Indicates the refractive index of the cemented lens assembly. The difference in refractive index of a prism for the received wavelength and the emitted wavelength of laser communication light waves; Indicates the refractive index of the cemented lens assembly. The other prism represents the difference in refractive index between the received wavelength and the emitted wavelength of the laser communication light wave.

[0013] Optionally, in any of the satellite laser communication systems described above, the lead angle superimposed on the beam direction during laser communication light wave transmission... It varies continuously within ±178 urad with the relative rotation between the cemented lens groups.

[0014] Optionally, in any of the above-described satellite laser communication systems, the position sensing unit is disposed between the pre-aiming device and the precision tracking mirror, and includes: a beam splitter for reflecting the light beam between the pre-aiming device and the precision tracking mirror to the camera according to a preset ratio; the camera is used to detect the light spot coordinates in real time, so as to adjust the tracking angle of the folding mirror and the precision tracking mirror in real time based on the light spot coordinates.

[0015] Optionally, in any of the above-described satellite laser communication systems, different wavelengths of laser communication light waves are used between the two satellites in different transmission directions.

[0016] Beneficial effects

[0017] The pre-aiming device and satellite laser communication system based on optical wedge mirror groups provided in this application utilize two pairs of cemented mirror groups, each composed of two prisms with different refractive indices. Through the relative rotation between the two cemented mirror groups, and based on the inter-satellite relative position relationship, a lead angle is superimposed on the beam direction during laser communication light wave transmission to compensate for time delay deviations in inter-satellite laser communication light wave transmission. The satellite laser communication system of this application achieves lead angle adjustment based on two cemented mirror groups, and its receiving and transmitting light paths have high consistency. It can utilize wavelength division multiplexing (WDM) technology to combine the receiving and transmitting light paths, thereby effectively avoiding the problem of unstable long-term communication caused by slow and irregular changes in coaxiality between the transmitting and receiving branches.

[0018] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the present application and form part of the specification. Together with the embodiments of the present application, they serve to explain the present application but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the pre-aiming device based on the optical wedge mirror group of this application;

[0021] Figure 2 This is a schematic diagram illustrating the working principle of the pre-aiming device based on the optical wedge mirror group in this application;

[0022] Figure 3 This is a schematic diagram of the satellite laser communication system based on the aforementioned pre-aiming device provided in this application; Figure 4 This is a schematic diagram of another satellite laser communication system provided in this application. Detailed Implementation

[0023] To make the objectives and technical solutions of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.

[0024] Those skilled in the art will understand that, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0025] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0026] The terms "receive" and "transmit" as used in this application refer to the direction of receiving laser communication light waves in space as receiving, and the direction of transmitting laser communication light waves from this system into space as transmitting, rather than a specific limitation on the device mechanism of this application.

[0027] According to this application, a satellite laser communication system includes an optical head, an electrical control box, and a single communication unit. The optical head establishes the space optical link and performs beam expansion, transmission, and reception of laser communication light waves. The electrical control box provides power and control to the optical head and the communication unit, and also enables interaction between the laser communication system's status and the satellite platform. The communication unit receives and processes service data from the satellite platform, and simultaneously interacts with the satellite platform based on the satellite's real-time attitude.

[0028] This application addresses the problems of coaxiality deviation between the transceiver paths and the complex optical device architecture in existing optical heads by providing a solution... Figure 3 The optical path system shown can be used for both transmit and receive links, including a shared transmit and receive optical path:

[0029] Beam expander antennas are used to transmit and receive laser communication light waves into space;

[0030] Folding mirrors are used for coarse tracking of the beam direction of laser communication light waves. They are generally used as coarse pointing / tracking units with pitch and azimuth two-axis rotation mechanisms to complete the initial pointing and coarse tracking functions of the laser communication system.

[0031] The precision tracking and fast-reflecting mirror is used to accurately aim the beam of laser communication light waves, enabling precise docking of inter-satellite laser communication systems.

[0032] The position sensing unit is used to acquire the coordinates of the light spot in the optical path of the precision tracking mirror, so as to adjust the aiming angle of the folding mirror and the precision tracking mirror in real time based on the light spot coordinates. It can generally be configured to include a beam splitter arranged between the pre-aiming device and the precision tracking mirror, so as to reflect the light beam between the pre-aiming device and the precision tracking mirror to the camera according to a preset ratio. Then, the camera's imaging is used to determine the coordinate position of the light spot formed by the receiving and receiving optical paths, and then the tracking angle of the folding mirror and the precision tracking mirror is adjusted in real time based on the light spot coordinates obtained by real-time detection.

[0033] The transceiver lens uses the same lens to receive the laser communication light waves reflected by the precision tracking mirror and to transmit the laser communication light waves to the precision tracking mirror.

[0034] A wavelength division multiplexing (WDM) unit connects to both a transceiver lens at one end and to both a transmitting fiber and a receiving fiber within the system at the other. It transmits the communication signal from the transmitting fiber to the transceiver lens to emit laser communication light waves, and also feeds back the laser communication light waves received by the transceiver lens to the system via the receiving fiber. Thus, the transmitting and receiving fibers can be selectively coupled via a wavelength selection device. Figure 3 In WDM (Wavelength Division Multiplexing), after beam combining, the same optical system is used to realize the transmission and reception of communication on the same optical fiber.

[0035] In this application, the shared optical path between the transceiver lens and the high-precision reversing mirror is also provided with, as shown in the example... Figure 1 Figure 2 The pre-aiming device based on the optical wedge mirror assembly shown refracts the laser communication light wave between the transceiver lens and the precision tracking mirror. According to the relative position relationship between the satellites, especially the pre-aiming angle calculated from the satellite position and attitude data, the device adjusts the relative rotation angle between the two cemented mirror assemblies. During the transmission of the laser communication light wave, a leading angle is superimposed on the beam direction to complete the pre-pointing of the transmitted beam, thereby compensating for the time delay deviation during the transmission of the inter-satellite laser communication light wave.

[0036] The system combines the receiving and transmitting lenses into a single lens; it merges the receiving and transmitting optical fibers into a single fiber after passing through a wavelength management device; and it sets the pre-aiming unit to consist of two relatively rotatable cemented lens groups connected by an optical wedge structure, which greatly simplifies the optical head. By sharing a single lens and eliminating the need for a calibration prism, it simplifies the assembly process and reduces equipment and assembly labor costs.

[0037] The optical head of this application consists of a coarse pointing unit, a fine tracking unit, a beam splitter, a position sensor, and a transceiver unit. It does not require on-orbit calibration of the transceiver coaxiality, thus enabling rapid link establishment.

[0038] Specific reference Figure 1 , Figure 2 As shown, the pre-aiming device based on an optical wedge mirror assembly used in this application specifically includes:

[0039] The first cemented mirror assembly shown on the left includes two prisms with different refractive indices, which are cemented together. The laser communication light wave passes through one of the prisms, through the cemented surface between the two prisms, and reaches the other prism.

[0040] And the second cemented mirror assembly shown on the right, which includes two other prisms with different refractive indices, which are cemented together, and the laser communication light wave passes through one of the prisms through the cemented surface between the two prisms to reach the other prism.

[0041] Since at least two prisms in these two cemented mirror groups have the same refractive index, and these prisms with the same refractive index are arranged adjacent to each other, light rays incident on the left side of the first cemented mirror group will be deflected for the first time at the inclined cemented surface between the two prisms in the first cemented mirror group before entering the second cemented mirror group. Because the adjacent prisms in the two cemented mirror groups have the same refractive index, the direction of the laser light incident on the second cemented mirror group will not change. However, when the light reaches the inclined cemented surface between the two prisms in the second cemented mirror group, it will be deflected a second time at that inclined plane, thus changing its emission direction. Since the rotation between the two cemented mirror groups changes the spatial angle between the two inclined cemented surfaces, it can effectively change the deflection angle of the light rays emitted from the right side. In other words, the pre-aiming device can adjust the relative angle between the cemented surfaces of two prisms with the same refractive index by a rotary drive device. Based on the inter-satellite relative position relationship, especially the pre-aiming angle calculated from the satellite position and attitude data, the device can superimpose a leading angle on the beam direction during the transmission of laser communication light waves to complete the pre-pointing of the emitted beam, thereby compensating for the time delay deviation during the transmission of inter-satellite laser communication light waves.

[0042] To elaborate on the optical characteristics of this pre-aiming device, this application defines its first cemented lens assembly as including:

[0043] The first prism has a first refractive index. ;

[0044] The second prism has a second refractive index. ;

[0045] A first wedge angle is provided between the adhesive surface between the first prism and the second prism and the laser-passing surface of the first prism. ;

[0046] A second wedge angle is provided between the adhesive surface between the first prism and the second prism and the laser-passing surface of the second prism. ;

[0047] In contrast, this application defines its second cemented lens assembly as including:

[0048] The third prism has a second refractive index. ;

[0049] The fourth prism has the first refractive index. ;

[0050] Among them, the laser passing surfaces of the second prism and the third prism are set to be parallel to each other to avoid uncontrollable deflection of the beam direction;

[0051] A second wedge angle is provided between the adhesive surface between the third and fourth prisms and the laser-passing surface of the third prism. ;

[0052] A first wedge angle is provided between the adhesive surface between the third and fourth prisms and the laser-passing surface of the fourth prism. .

[0053] For each prism, when the beam is incident at a small angle, the angle of deflection of the outgoing light is... It can be approximated as:

[0054]

[0055] in, The wedge angle corresponding to the incident surface of the prism. Let be the refractive index of the prism.

[0056] Therefore, in a pair of parallel double prisms, when the second cemented lens group rotates relative to the first cemented lens group, the total exit angle between the two prism groups is... for:

[0057]

[0058] in , Different prism pairs with wavelengths of The refractive index of light, This refers to the wedge angle of the wedge prism.

[0059] Because the rotating double-prism array scheme is for both transmission and reception, and the two satellites conducting laser communication will use different wavelengths of laser communication light waves in different transmission directions, for example, the laser communication transmitted from satellite A to satellite B will remain in the same direction. The wavelength, the laser communication received by satellite A from satellite B, is maintained at... Wavelength; simultaneously, when satellite B communicates with satellite C, it can use the wavelength. The wavelength of the laser communication light wave emitted by Star B to Star C will be used as the wavelength. As the wavelength of the laser communication received by Star B from Star C, it enables the differentiation of different communication parties and communication directions.

[0060] Therefore, due to the difference between the emission and reception wavelengths, the laser beams in the above-mentioned laser receiving and receiving path will bend at different angles after passing through the prism group due to the dispersion characteristics of the material.

[0061] For commonly used laser communication terminals, the transmit and receive wavelengths are around 1550nm, with a wavelength interval of 20nm-30nm. Considering transmit and receive wavelengths of 1535nm and 1565nm respectively, in the aforementioned optical system:

[0062] Two wavelength beams, one for transmitting and one for receiving, pass through a prism assembly. The outgoing beam is refracted, and due to dispersion, the refraction angles differ. The greater the difference in refraction angles between the two wavelengths, the larger the achievable lead angle. Furthermore, by setting the two wedge angles of the cemented wedge mirror within the prism assembly, the 1550nm communication wavelength beam can be prevented from refracting when passing through the prism assembly. Using this communication wavelength, the system's transmission and reception are configured to acquire and exchange signals at center wavelengths of 1535nm and 1565nm, respectively. Figure 1 , Figure 2 In this state, the angles of the transmitted and received signals are both near 0 degrees, thus ensuring both signal optical axis stability and enabling lead angle modulation. At this time, the wedge angles of the two wedge mirrors... , Must meet:

[0063]

[0064] From the above formula, we can obtain the wedge mirror. , The following relationship exists:

[0065]

[0066] Therefore, the prism assembly described above in this application can reduce the first wedge angle With the second wedge angle ratio Set it to be close to 1, for example, no more than 1.2, or directly set the first wedge angle. With the second wedge angle The angle difference between them is set to not exceed 6°; therefore, it is necessary to calculate accordingly. Approximately 0 means that the refractive indices of the two materials in a cemented prism must be close to each other. Specifically, the second refractive index can be... With the first refractive index The ratio is set between 1.02 and 1.1 to achieve deflection angle modulation at the urad level.

[0067] To achieve a larger difference in refraction angle between the transmission and reception, the Abbe number difference between the materials of the two wedge mirrors should be relatively large. Generally, the Abbe number difference between the materials of the first and second prisms, and between the materials of the third and fourth prisms, is set to be no less than 20.

[0068] At this time, the wavelength is The emitted light and wavelength are The angle difference of the received light after passing through the double prism group can be expressed as:

[0069]

[0070] make ,and Therefore, we have:

[0071] This can be achieved through the biprism assembly rotation device. Lead angle control.

[0072] Specifically, in this application, when the first wedge angle is... Set to 49.4°, second wedge angle When the angle is set to 44.1°, and the materials of the first and fourth prisms are selected as H-QF1, while the materials of the second and third prisms are selected as H-ZPK5, the third and fourth prisms are synchronously driven by a rotation drive device. Rotating relative to the second prism with the normal to the laser-passing surface of the third prism as the rotation center, a continuous change in the lead angle between ±178 urads can be achieved. That is, from... Figure 1 Between the two cemented lens groups, with the two cemented surfaces parallel to each other, rotate to... Figure 2 When the two cemented surfaces are rotated 180° relative to each other, the lead angle can continuously change from 0 urad to 178 urad as the relative rotation between the cemented lens groups increases.

[0073] Considering the pre-aiming device of this application, the lead angle superimposed on the beam direction during laser communication optical wave transmission. The angular range is positively correlated with the wedge angle between the cemented surface and the laser-passing surface in the cemented lens assembly. Furthermore, it is positively correlated with the difference in refractive index between the two prisms in the cemented lens assembly for the transmit and receive wavelengths of the laser communication light wave. Therefore, this application can select the appropriate prism material according to the modulation range requirements of the leading angle, and accordingly calculate and process the wedge angle of the prism. In the above formula, This indicates the emitted wavelength of the laser communication light wave. Indicates the received wavelength of the laser communication light wave; Indicates the refractive index of the cemented lens assembly. The difference in refractive index of a prism for the received wavelength and the emitted wavelength of laser communication light waves; Indicates the refractive index of the cemented lens assembly. The other prism represents the difference in refractive index between the received wavelength and the emitted wavelength of the laser communication light wave.

[0074] refer to Figure 4 Another embodiment is shown. Considering that vibrations during satellite launch may cause the center of the optical wedge mirror assembly to deviate from the optical path center of the equipment, thus introducing a certain error when adjusting the lead angle of the optical wedge mirror assembly's rotation system, this application can further set a corner cone on the other side of the beam splitter, and correspondingly set a calibration fiber at the fiber end to achieve quantitative calibration and adjustment correction of the optical wedge mirror assembly.

[0075] Specifically, this embodiment, based on the previous scheme, adds a corner pyramid on the side of the beam splitter facing away from the camera. A fiber optic circulator is added at the receiving fiber, and through the circulator's unidirectional transmission of light, the calibration fiber is connected to the optical path system of the device via the circulator during system calibration. During stable communication, only the optical signal received by the system is transmitted to the receiving fiber for processing and decoding. Thus, the calibration light provided by the calibration fiber can be reflected by the transceiver lens, optical wedge, and beam splitter into the corner pyramid, and after being reflected 180 degrees by the corner pyramid, it enters the camera, forming a calibration spot. Since the wavelength of the calibration light is similar to the transmit and receive wavelengths, the coordinates of the calibration spot on the camera can largely represent the transmit and receive optical axes. In this way, the system can effectively monitor deviations in the optical axis caused by factors such as vibration and stress release during satellite launch and on-orbit operation by monitoring changes in the position of the calibration spot. Therefore, this system can use the coordinates of the calibration spot as a tracking point during the laser communication terminal acquisition and link establishment process, based on the offset of the calibration spot, to achieve tracking and link establishment between communication terminals, thereby overcoming the coaxiality problem caused by displacement or angular deviation between optical devices.

[0076] For this system, common calibration schemes include:

[0077] The transmission wavelength of the entire system under normal operating and interactive conditions is set to 1540nm;

[0078] Set the system's receiving wavelength to 1563nm;

[0079] The wavelength of the calibration light provided by the calibration fiber is set to 1567nm.

[0080] Simply set the beam backscattering accuracy of the cone to less than 3".

[0081] In summary, this application achieves the deflection of transmitted and received laser signals by using two identical prism sets, each consisting of two wedge prisms made of different materials bonded together. The deflection is achieved by utilizing the corresponding wedge angles of the two wedge prisms. , and the refractive index of the prism material , By combining motor control with prism rotation, high-precision advanced pointing function can be achieved.

[0082] This application can achieve different lead angles by separately controlling the rotation angles of the front and rear prism groups, utilizing the different relative rotational relationships of the front and rear prism groups when the beam is incident at a small angle. Figure 1 As shown, due to the complementarity of the front and rear prism groups, the beam deflects at a zero angle after passing through the prism group, corresponding to a zero lead angle. The relative rotation relationship between the front and rear prism groups is as follows: Figure 2 As shown, the maximum refraction angle δ of the light beam can be achieved. Furthermore, because the emission wavelength and the reception wavelength are different, the refraction angles of the emitted light and the received light are also different, thus achieving… The angle difference. That is, this application relies on the rotation drive of the front and rear motors to control the rotation of the front and rear prism groups respectively, which can control the lead angle within (- ). , Within the angular range. The above are merely embodiments of this application, and their descriptions are quite specific and detailed, but they should not be construed as limiting the scope of this application's patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A satellite laser communication system, characterized in that, Including those sharing a common optical path for transmission and reception: Beam expander antennas are used to transmit and receive laser communication light waves into space; A folding mirror is used for coarse tracking of the beam direction of laser communication light waves; A precision-tracking, fast-reflecting mirror is used for precise aiming of the laser beam in laser communication. The position sensing unit is used to acquire the coordinates of the light spot in the optical path of the precision tracking mirror, so as to adjust the aiming angle of the folding mirror and the precision tracking mirror in real time based on the light spot coordinates; The transceiver lens is used to receive laser communication light waves reflected by the precision tracking mirror and to transmit laser communication light waves to the precision tracking mirror. The wavelength division multiplexing unit has one end connected to the transceiver lens and the other end connected to both the transmitting fiber and the receiving fiber in the system. It is used to provide the communication signal in the transmitting fiber to the transceiver lens to transmit laser communication light waves, and also to feed back the laser communication light waves received by the transceiver lens to the system through the receiving fiber. Among them, a pre-aiming device based on an optical wedge mirror group is set on the shared optical path between the transceiver lens and the precision tracking mirror. The pre-aiming device refracts the laser communication light wave between the transceiver lens and the precision tracking mirror, and adjusts the relative rotation angle between the two cemented mirror groups according to the relative position relationship between the satellites. During the transmission of the laser communication light wave, a leading angle is superimposed on the beam direction to compensate for the time delay deviation during the transmission of the inter-satellite laser communication light wave. The pre-aiming device based on the optical wedge lens group includes: The first cemented mirror assembly includes two prisms with different refractive indices, which are cemented together. The laser communication light wave passes through one of the prisms, through the cemented surface between the two prisms, and reaches the other prism. The second cemented mirror assembly includes two additional prisms with different refractive indices, which are cemented together. The laser communication light wave passes through one of the prisms, through the cemented surface between the two prisms, and reaches the other prism. In the first and second cemented mirror groups, at least two prisms have the same refractive index, and the two prisms with the same refractive index are arranged adjacent to each other, and the relative angle between the cemented surfaces of the two prisms with the same refractive index is adjusted by a rotation drive device. Furthermore, the laser-passing surfaces between the first and second cemented mirror groups are set to be parallel to each other; the second cemented mirror group is synchronously driven by a rotation drive device and rotates relative to the first cemented mirror group with the normal of the laser-passing surface in the second cemented mirror group as the rotation center.

2. The satellite laser communication system as described in claim 1, characterized in that, The first set of cemented lenses includes: The first prism has a first refractive index; The second prism has a second refractive index; A first wedge angle is provided between the adhesive surface between the first prism and the second prism and the laser-passing surface of the first prism. ; A second wedge angle is provided between the adhesive surface between the first prism and the second prism and the laser-passing surface of the second prism. ; The second set of cemented lenses includes: The third prism has a second refractive index; The fourth prism has the first refractive index; A second wedge angle is provided between the adhesive surface between the third and fourth prisms and the laser-passing surface of the third prism. ; A first wedge angle is provided between the adhesive surface between the third and fourth prisms and the laser-passing surface of the fourth prism. .

3. The satellite laser communication system as described in claim 1, characterized in that, First wedge angle With the second wedge angle The ratio does not exceed 1.2, or the first wedge angle With the second wedge angle The angular difference between them shall not exceed 6°; the ratio of the second refractive index to the first refractive index shall be between 1.02 and 1.

1.

4. The satellite laser communication system as described in claim 1, characterized in that, The difference in Abbe number between the materials of the first prism and the second prism shall not be less than 20, and the difference in Abbe number between the materials of the third prism and the fourth prism shall not be less than 20.

5. The satellite laser communication system as described in claim 1, characterized in that, The lead angle superimposed on the beam direction during laser communication optical wave transmission. The angular range is positively correlated with the first wedge angle between the cemented surface and the laser-passing surface in the cemented lens assembly. Furthermore, it is positively correlated with the difference in refractive index between the two prisms in the cemented lens assembly for the transmit and receive wavelengths of the laser communication light wave. ; in, This indicates the emitted wavelength of the laser communication light wave. Indicates the received wavelength of the laser communication light wave; Indicates the refractive index of the cemented lens assembly. The difference in refractive index of a prism for the received wavelength and the emitted wavelength of laser communication light waves; Indicates the refractive index of the cemented lens assembly. The other prism represents the difference in refractive index between the received wavelength and the emitted wavelength of the laser communication light wave.

6. The satellite laser communication system as described in claim 5, characterized in that, The lead angle superimposed on the beam direction during laser communication optical wave transmission. It varies continuously within ±178 urad with the relative rotation between the cemented lens groups.

7. The satellite laser communication system as described in claim 6, characterized in that, The position sensing unit is disposed between the pre-aiming device and the precision tracking quick-reflection mirror, and includes: A beam splitter is used to reflect the light beam between the pre-aiming device and the precision tracking mirror to the camera according to a preset ratio. The camera is used to detect the light spot coordinates in real time, so as to adjust the tracking angle of the folding mirror and the high-speed tracking mirror in real time based on the light spot coordinates.

8. The satellite laser communication system as described in claim 6, characterized in that, In laser communication, two satellites use different wavelengths of laser communication light waves in different transmission directions.

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