Satellite-borne laser communication ranging integrated system and method with zero value calibration function

Abstract

The invention provides a satellite-borne laser communication ranging integrated system and method with zero value calibration, and is used for solving the technical problems that an inter-satellite communication system and a ranging system in the existing satellite internet are separated, so that the resource utilization rate is low, and an initial system error exists in an inter-satellite laser distance measured by an existing laser ranging system. According to the satellite-borne laser communication and distance measurement integrated system with the zero value calibration function, data transmission is achieved in an inter-satellite laser mode, communication and distance measurement functions are achieved at the same time, and the satellite-borne laser communication and distance measurement integrated system has the advantages of being low in power consumption, high in data rate and the like; besides, the external pyramid is arranged on the outer side of the signal transmitting end of the satellite-borne laser communication load optical head, the zero value calibration function can be achieved through the external pyramid, and compared with an existing laser ranging system, the initial system error is greatly reduced, and the ranging precision is improved.

Description

Technical Field

[0001] The present invention relates to a satellite-borne laser communication ranging method, and in particular to a satellite-borne laser communication ranging integrated system and method with zero-value calibration. Background Art

[0002] Satellite laser communication is like a "highway". It has the advantages of wide bandwidth, small antenna size, small volume, light weight, low power consumption, good confidentiality, strong anti-interference ability, and no frequency regulatory restrictions. It can meet the needs of future space-ground integrated information transmission systems for high-speed, large-capacity, multi-service information transmission and interactive processing, and has become the first choice for the development of satellite communications. It is imperative to establish a two-way laser intersatellite link between satellites in the same orbital plane or adjacent orbital planes of low-orbit constellations, complete high-speed data transmission between satellite Internet nodes, high-precision measurement of intersatellite distances, realize high-speed information interconnection and high-precision ranging of the entire network, and provide high-speed access services for low-orbit application satellites. However, in the existing satellite Internet, the intersatellite laser communication system is separated from the laser ranging system. The intersatellite laser communication system only communicates and cannot realize the ranging function, which makes the system resource utilization rate low. In addition, the existing laser ranging system does not calibrate the system's inherent delay and zero-value distance, resulting in an initial system error in the measured intersatellite laser distance. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problems that the inter-satellite communication system and the ranging system in the existing satellite Internet are separated, resulting in low resource utilization, and the inter-satellite laser distance measured by the existing laser ranging system has an initial system error, and to provide a satellite-borne laser communication and ranging integrated system and method with zero-value calibration.

[0004] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0005] An integrated spaceborne laser communication and ranging system with zero-value calibration is characterized in that it includes two identical ranging units;

[0006] The distance measuring unit comprises a satellite laser communication payload processor, an optical amplifier, a satellite laser communication payload optical head and an external angle cone (10); the satellite laser communication payload processor, the optical amplifier and the satellite laser communication payload optical head in each distance measuring unit communicate with each other bidirectionally;

[0007] The satellite-borne laser communication payload processor is used to receive control instructions from the satellite platform to configure its own working state, and send control signals to the optical amplifier and the satellite-borne laser communication payload optical head according to the control instructions to configure the working states of the optical amplifier and the satellite-borne laser communication payload optical head respectively;

[0008] The satellite-borne laser communication payload processor is used to control its internal laser to emit continuous laser, load and modulate the electrical data information generated by itself and transmit it to the optical amplifier as a transmission optical signal, and receive the optical fiber signal after low-noise optical amplification by the optical amplifier, and process it to achieve the measurement of communication bit error rate in the digital domain, as well as the calculation of the distance between the local satellite and the opposite end;

[0009] The optical amplifier is used to optically amplify the received transmission optical signal to form a high-power transmission optical fiber signal and then output it to the onboard laser communication payload optical head, and receive the optical fiber signal coupled by the onboard laser communication payload optical head, perform low-noise optical amplification on it and then output it to the onboard laser communication payload processor;

[0010] The optical fiber connection between the onboard laser communication payload optical head and the optical amplifier is used to convert the received high-power transmission optical fiber signal into a high-power spatial signal light and then transmit it to the opposite end, and receive the spatial signal light emitted by the distance measurement unit at the opposite end, couple it into an optical fiber signal and then output it to the optical amplifier;

[0011] The external angle cone is used to reflect the spatial signal light emitted by the satellite-borne laser communication payload optical head when the emission optical axis of the satellite-borne laser communication payload optical head points to its reflection surface, so that its back-reflected light is reversely incident into the interior of the satellite-borne laser communication payload optical head for zero value calibration.

[0012] Furthermore, the satellite-borne laser communication payload optical head includes a first lens, an advanced fast-reflection mirror, a polarization beam splitter, a tracking fast-reflection mirror, an energy beam splitter, a tracking detector, a second lens, a reflector, and a collimation and beam expansion system;

[0013] The first lens is used to couple the high-power transmission optical fiber signal transmitted by the optical amplifier into local space signal light;

[0014] The advance fast-reflection mirror, polarization beam splitter, tracking fast-reflection mirror, reflector, and collimation and beam expansion system are sequentially located on the emission optical path of the local space signal light, and are used to form a signal emission branch, and collimate the local space signal light before emitting it; wherein the tracking fast-reflection mirror is located on the optical path of the local space signal light after it is reflected by the polarization beam splitter, and the external angle cone is located outside the collimation and beam expansion system;

[0015] The collimating beam expansion system, the reflector, the tracking fast-reflecting mirror, and the polarization beam splitter are sequentially arranged on the optical path of the spatial signal light emitted by the opposite end, and are used to capture the spatial signal light emitted by the opposite end or the back-reflected light of the external angle cone;

[0016] The energy beam splitter is located on the optical path of the spatial signal light emitted from the opposite end after being transmitted through the polarization beam splitter, and is used to split the spatial signal light from the opposite end or the back-reflected light of the external angle cone to form a beam of transmitted light and a beam of reflected light;

[0017] The second lens is located on the optical path of the transmitted light, and is used to converge the captured opposite-end spatial signal light or the back-reflected light of the external angle cone to the optical fiber, couple it into an optical fiber signal, and then output it to the optical amplifier;

[0018] The tracking detector is located on the optical path of the reflected light, and is used to detect the reflected light from the opposite end or the back-reflected light of the external corner cone, and realizes feedback control of the tracking fast-reflecting mirror by calculating the optical signal energy and position of its target surface.

[0019] Further, it also includes a two-dimensional turntable;

[0020] The satellite-borne laser communication payload optical head is arranged on a two-dimensional turntable, and the pitch angle and azimuth angle of the satellite-borne laser communication payload optical head are adjusted by rotating the two-dimensional turntable;

[0021] The external corner pyramid is arranged on the base of the two-dimensional turntable.

[0022] In addition, the present invention also provides a satellite-borne laser communication ranging method with zero-value calibration, which is special in that it includes the following steps:

[0023] Step 1: construct the above-mentioned satellite-borne laser communication and ranging integrated system with zero-value calibration, and install two ranging units on the ground station or target satellite of the local satellite and the opposite end respectively;

[0024] Step 2, remotely control the two distance measurement units through the satellite platform, perform telemetry and remote control configuration, coaxiality self-calibration, optical axis pointing calibration, and status self-check;

[0025] Step 3, when the satellite-borne laser communication payload processor of this satellite receives the satellite platform control command, the internally generated transmission light signal is emitted outward as the space signal light through the corresponding satellite-borne laser communication payload optical head; the transmission light axis of the satellite-borne laser communication payload optical head is adjusted to point to the reflection surface of the external angle cone, and the back-reflected light reflected by the external angle cone is incident on the inside of the satellite-borne laser communication payload optical head in the opposite direction, and then coupled into an optical fiber signal and output to the satellite-borne laser communication payload processor through the optical amplifier; the satellite-borne laser communication payload processor performs autocorrelation operation based on the data information sent locally and the data information reflected back by the external angle cone at the same sampling time, and obtains the time information corresponding to the local zero-value distance under the triggering of the high-precision second pulse signal and clock signal of this satellite; accordingly, the distance measurement unit of the opposite end has the same working process as the distance measurement unit of this satellite, and obtains the time information corresponding to the zero-value distance of the opposite end;

[0026] Step 4: Capture, track and establish a link of spatial signal light;

[0027] Step 4.1, the optical heads of the satellite-borne laser communication payloads of the two ranging units respectively calculate the tracking pointing guidance data to achieve open-loop pointing tracking of the other end;

[0028] Step 4.2, calibrate the two ranging units. After the calibration is completed, the local satellite and the opposite end begin to scan each other. When the optical head of the onboard laser communication payload of the local satellite detects the space signal light emitted by the opposite end, the scanning is stopped and the visual axis is adjusted to point to the opposite end.

[0029] Step 4.3, using a tracking strategy to track the space signal light emitted by the other end to the center of the field of view until the optical heads of the satellite-borne laser communication payloads of both parties continuously detect the space signal light emitted by the other party;

[0030] Step 4.4, according to the light signal intensity and position information output by the tracking detector in the optical head of the satellite laser communication payload of the other end, and the light signal intensity received by the corresponding optical amplifier, adjust the tracking point until the light spot detected by the tracking detectors of both parties is located at the center of its target surface, and the satellite laser communication payload processors of both parties continue to detect the space light signal;

[0031] Step 4.5: After receiving the optical fiber signal after low-noise optical amplification by the corresponding optical amplifier, the onboard laser communication payload processors of both parties compensate for the optical carrier Doppler and code Doppler, complete frame synchronization and bit synchronization, realize correct demodulation, and complete the link establishment;

[0032] Step 5: The satellite-borne laser communication payload processors of both parties perform autocorrelation operations based on the data information sent locally and the data information sent by the other party at the same sampling time, and obtain the time information corresponding to the local pseudorange and the time information corresponding to the other party's pseudorange respectively under the triggering of the high-precision second pulse signal and the clock signal;

[0033] Step 6, calculate the distance between the local satellite and the other end according to the time information corresponding to the zero-value distance of the other end, the time information corresponding to the pseudo-range, and the time information corresponding to the local zero-value distance and the pseudo-range, and the ranging is completed.

[0034] Furthermore, in step 3, the pointing accuracy of the emission optical axis of the satellite-borne laser communication payload optical head is ≤5 μrad.

[0035] Further, in step 3, adjusting the emission optical axis of the optical head of the satellite-borne laser communication payload to point to the reflection surface of the external angle cone is specifically as follows:

[0036] The pitch angle and azimuth angle of the optical head of the satellite-borne laser communication payload are adjusted through a two-dimensional turntable, and the reflection angle of the advanced fast reflection mirror in the optical head of the satellite-borne laser communication payload is adjusted to achieve the direction adjustment of the emission optical axis of the optical head of the satellite-borne laser communication payload.

[0037] Furthermore, in step 4.4, the tracking point is adjusted as follows:

[0038] The tracking point is adjusted by adjusting the reflection angle of the tracking fast-reflection mirror.

[0039] Furthermore, in step 6, the distance L between the local satellite and the ground station or the target satellite is calculated by the following formula:

[0040] L=(T1+T3-T0-T2) / 2*c

[0041] Among them, T0 is the time information corresponding to the local zero-value distance, T1 is the time information corresponding to the pseudo-range sent by the other end, T2 is the time information corresponding to the zero-value distance sent by the other end, T3 is the time information corresponding to the local pseudo-range, and c is the speed of light.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The present invention provides a satellite-borne laser communication and ranging integrated system with zero-value calibration, which realizes data transmission by means of inter-satellite lasers, and realizes communication and ranging functions at the same time, and has the advantages of low power consumption and high data rate. In addition, the present invention is provided with an external angle cone on the outside of the signal transmitting end of the optical head of the satellite-borne laser communication payload, and the zero-value calibration function can be realized through the external angle cone. Compared with the existing laser ranging system, the present invention greatly reduces the initial system error and improves the ranging accuracy.

[0044] 2. The present invention integrates digital signal processing and control into the satellite-borne laser communication payload processor, so that the control box of the traditional communication and ranging system can be omitted. The communication and ranging integration can be realized by only three single machines: the satellite-borne laser communication payload optical head, the optical amplifier, and the satellite-borne laser communication payload processor. The entire system is lighter in weight and smaller in size, which greatly saves on-board resources.

[0045] 3. The present invention has a satellite-borne laser communication and ranging integrated system with zero-value calibration, high integration, strong compatibility, and high utilization rate, and has great research significance and practical value for the new generation of satellite Internet transmission networking system.

[0046] 4. The present invention provides a satellite-borne laser communication ranging method with zero-value calibration, which adopts an integrated laser communication ranging method in a single inter-satellite laser link environment, combines communication with ranging, and realizes communication modulation and demodulation and distance calculation in the digital domain through high-speed digital sampling. The sensitivity and distance calculation accuracy are higher than those of analog demodulation solutions.

[0047] 5. The present invention realizes the measurement of the inherent time delay of the system based on the high-precision second pulse signal, performs zero-value calibration to solve the absolute distance, and greatly reduces the initial system error in the measurement value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a communication principle block diagram of a single ranging unit in an embodiment of a satellite-borne laser communication and ranging integrated system with zero-value calibration of the present invention;

[0049] Figure 2 It is a schematic diagram of the core components of the satellite-borne laser communication payload optical head in an embodiment of a satellite-borne laser communication and ranging integrated system with zero-value calibration of the present invention.

[0050] The specific reference numerals are as follows:

[0051] 1-first lens; 2-advanced fast-reflection mirror; 3-polarization beam splitter; 4-tracking fast-reflection mirror; 5-energy beam splitter; 6-tracking detector; 7-second lens; 8-reflector; 9-collimation and beam expansion system; 10-external angle cone. DETAILED DESCRIPTION

[0052] In order to make the advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] like Figure 1 As shown, a satellite-borne laser communication ranging system with zero-value calibration includes two identical ranging units, one for the local satellite (local satellite) and one for the opposite end (ground station or target satellite). Each ranging unit includes a satellite-borne laser communication payload processor, an optical amplifier, a satellite-borne laser communication payload optical head, an external angle cone 10, and a two-dimensional turntable. In this embodiment, the opposite end of the local satellite is the target satellite, and the satellite-borne laser communication payload processor, optical amplifier, and satellite-borne laser communication payload optical head in each ranging unit communicate bidirectionally with each other.

[0054] The satellite-borne laser communication payload processor is used to receive and respond to control commands from the satellite platform. It configures its own working status by parsing the control commands from the satellite platform. At the same time, it sends control signals to the optical amplifier and the satellite-borne laser communication payload optical head to configure the working status of the optical amplifier and the satellite-borne laser communication payload optical head respectively.

[0055] The satellite-borne laser communication payload processor is used to control its internal laser to emit continuous laser at the transmitting end, load and modulate the electrical data information generated by itself and transmit it to the local optical amplifier as a transmitted light signal. At the receiving end, it receives the optical fiber signal after low-noise optical amplification by the local optical amplifier, processes it, and realizes the measurement of communication bit error rate in the digital domain, as well as the calculation of the distance between the satellite and the opposite end.

[0056] The optical amplifier is used to amplify the received transmitted optical signal to form a high-power transmitted optical fiber signal and then output it to the satellite-borne laser communication payload optical head, and receive the optical fiber signal coupled by the satellite-borne laser communication payload optical head, perform low-noise optical amplification on it and then output it to the satellite-borne laser communication payload processor.

[0057] The optical fiber connection between the optical head of the satellite-borne laser communication payload and the optical amplifier is used to convert the received high-power transmission fiber signal into high-power space signal light and transmit it to the other end, and receive the space signal light transmitted after stable tracking by the other end, couple it into a fiber optic signal and output it to the optical amplifier.

[0058] like Figure 2 As shown, the core components of the optical head for satellite laser communication payload include a first lens 1, an advance fast reflection mirror 2 (PAA), a polarization beam splitter 3, a tracking fast reflection mirror 4 (FSM), an energy beam splitter 5, a tracking detector 6, a second lens 7, a reflector 8, and a collimation and expansion system 9. The first lens 1 is used to couple the high-power transmission optical fiber signal transmitted by the optical amplifier into a spatial signal light; the advance fast reflection mirror 2, the polarization beam splitter 3, the tracking fast reflection mirror 4, the reflector 8, and the collimation and expansion system 9 are sequentially located on the optical path of the local spatial signal light, and are used to form a signal transmission branch, collimate the spatial signal light, and then transmit it to the opposite end or to the reflection surface of the external angle cone 10. The collimation and expansion system 9, the reflector 8, the tracking fast reflection mirror 4, and the polarization beam splitter 3 are sequentially located on the optical path of the spatial signal light emitted from the opposite end, and are used to capture the spatial signal light emitted from the opposite end or the back-reflected light of the external angle cone 10.

[0059] The collimation and expansion system 9, as the signal transmitting end of the optical head of the satellite-borne laser communication payload, transmits the spatial signal light to the opposite end and receives the spatial signal light emitted by the opposite end at the same time; the advanced fast reflection mirror 2 is used to adjust the pointing angle of the spatial signal light emitted by the optical head of the satellite-borne laser communication payload; the tracking fast reflection mirror 4 is located on the optical path of the spatial signal light after the spatial signal light is reflected by the polarization beam splitter, and is used to adjust the transmission angle of the spatial signal light emitted by the other party received by the optical head of the satellite-borne laser communication payload, so that its light spot accurately enters the target field of view of the tracking detector 6; the energy beam splitter 5 is located on the optical path of the spatial signal light of the opposite end after the polarization beam splitter 3 is transmitted, and is used to split the spatial signal light emitted by the other party or the back-reflected light of the external angle cone 10 to form a beam of transmitted light and a beam of reflected light. In this embodiment, the splitting ratio of the energy beam splitter 5 is 9:1, wherein 90% of the transmitted light is used as the communication receiving signal, and 10% of the reflected light is used as the precise tracking receiving signal. The polarization beam splitter 3 is used to separate the transmitted light and the received light through different polarization states.

[0060] The second lens 7 is located on the optical path of the transmitted light, and it forms a communication receiving branch with the collimating beam expansion system 9, the reflector 8, the tracking fast mirror 4, and the polarization beam splitter 3, which is used to converge the captured opposite-end spatial signal light or the back-reflected light of the external angle cone 10 to the optical fiber and then output. The tracking detector 6 is located on the optical path of the reflected light, and it forms a precise tracking receiving branch with the collimating beam expansion system 9, the reflector 8, the tracking fast mirror 4, and the polarization beam splitter 3, which is used to detect the opposite-end reflected light or the back-reflected light of the external angle cone 10, and realize feedback control of the tracking fast mirror 4 by calculating the optical signal energy and position (tracking the miss amount) of its target surface.

[0061] The satellite-borne laser communication payload optical head is arranged on a two-dimensional turntable, and the pitch angle and azimuth angle of the satellite-borne laser communication payload optical head are adjusted by rotating the two-dimensional turntable. The external angle cone 10, as the core component of the present invention, is used to perform self-transmission and self-reception of light to realize the function of zero-value calibration. It is arranged on the outside of the collimation and beam expansion system 9, and is also arranged on the fixed plane of the two-dimensional turntable. When the emission optical axis of the satellite-borne laser communication payload optical head points to the reflection surface of the external angle cone 10, the emitted spatial signal light forms a retroreflected light on the reflection surface of the external angle cone 10, so that the retroreflected light is incident in reverse to the inside of the satellite-borne laser communication payload optical head. Specifically, the pointing angle of the emission optical axis of the satellite-borne laser communication payload optical head is coarsely adjusted by the two-dimensional turntable, and fine adjustment is achieved by adjusting the reflection angle of the advance fast reflection mirror 2.

[0062] Based on the above-mentioned satellite-borne laser communication ranging system with zero-value calibration, the present invention also provides a satellite-borne laser communication ranging method with zero-value calibration, which specifically includes the following steps:

[0063] Step 1: install one ranging unit of the above-mentioned satellite-borne laser communication ranging system with zero-value calibration on the local satellite, and install the other ranging unit on the target satellite at the opposite end.

[0064] Step 2: Use the satellite platform to perform telemetry and remote control configuration, coaxiality self-calibration, optical axis pointing calibration, and status self-check on the two ranging units.

[0065] Step 3: Zero value calibration.

[0066] Zero value calibration of the ranging unit on this satellite: adjust the pitch angle and azimuth angle of the satellite-borne laser communication payload optical head through the two-dimensional turntable, and adjust the reflection angle of the advance fast reflection mirror 2 in the satellite-borne laser communication payload optical head, so that the emission optical axis of the satellite-borne laser communication payload optical head points to the reflection surface of the external angle cone 10; when the satellite-borne laser communication payload processor of this satellite receives the control command of the satellite platform, it generates continuous laser, which loads and modulates the electrical data generated by itself, and then transmits it to the optical amplifier of this satellite. After the optical amplification, it is converted into high-power space signal light through the satellite-borne laser communication payload optical head of this satellite and then emitted. The emitted space signal light is reflected by the external angle cone 10 of this satellite to generate retroreflected light, and its retroreflected light is incident on this satellite in the opposite direction. The satellite-borne laser communication payload optical head of the satellite is coupled into a fiber optic signal and then output to the optical amplifier of the satellite, and then output to the satellite-borne laser communication payload processor of the satellite after low-noise optical amplification by the optical amplifier; the satellite-borne laser communication payload processor of the satellite converts the fiber optic signal after low-noise optical amplification into an electrical signal and performs digital signal processing, so that it can complete frame synchronization and bit synchronization in the digital domain and realize correct demodulation; the satellite-borne laser communication payload processor of the satellite obtains the number of integer code elements of the frame phase sent at the receiving frame sampling moment of the satellite and the subdivided phase within a single code element of the frame phase sent at the receiving frame sampling moment of the satellite through autocorrelation operation, under the triggering of the high-precision second pulse signal and clock signal of the satellite, and then calculates and obtains the time information T0 corresponding to the local zero-value distance.

[0067] Zero value calibration of the ranging unit on the opposite target satellite: The zero value calibration of the ranging unit on the opposite end is the same as that of the ranging unit on this satellite, and finally the time information T2 corresponding to the zero value distance of the opposite end is calculated.

[0068] The standard for correct demodulation in this embodiment is that the bit error is less than 10 -7 The pointing accuracy of the transmitting optical axis of the optical head of the satellite-borne laser communication payload is ≤5μrad.

[0069] Step 4: Capture, track and establish a link of spatial signal light.

[0070] Step 4.1, open-loop pointing: The onboard laser communication payload optical head of the satellite calculates the tracking and pointing guidance data according to the target satellite ephemeris, the local satellite ephemeris and the platform attitude information of the satellite, so as to control the optical antenna boresight to realize the open-loop pointing tracking of the other end in a digital guidance and tracking manner. Specifically, according to the reading of the photoelectric encoder in the onboard laser communication payload optical head of the satellite (the angle information of the pitch axis and azimuth axis of the onboard laser communication payload optical head), it is judged that the ranging units of both parties have completed the open-loop pointing to the predetermined position, and then the next process can be started.

[0071] Step 4.2, capture starts: the two ranging units are corrected through open-loop pointing and advanced fast-reflection mirrors. After the correction is completed, the local satellite and the target satellite on the other end begin to scan each other. When the tracking detector 6 in the optical head of the onboard laser communication payload of the local satellite detects the space signal light emitted by the other end, the scanning is stopped and the line of sight is adjusted to point to the target satellite.

[0072] Step 4.3, when the tracking detector 6 detects the other party's space signal light, a tracking strategy is used to track the space signal light emitted by the other end to the center of the field of view of the tracking detector 6 until the optical heads of the satellite-borne laser communication payloads of both parties continuously detect the other party's space signal light;

[0073] Step 4.4, according to the optical signal intensity and position information output by the tracking detectors 6 of both parties, and the optical signal intensity received by the corresponding optical amplifier, adjust the reflection angle of the tracking fast mirror 4 to adjust the tracking point, until the light spot detected by the tracking detectors 6 of both parties is located at the center of its target surface, and the communication detectors in the satellite-borne laser communication payload processors of both parties continue to detect the spatial optical signal emitted by the other party.

[0074] Step 4.5: The satellite-borne laser communication payload processors of both parties respectively receive the optical fiber signal (modulated signal light) after low-noise light amplification by the corresponding optical amplifier, compensate for the optical carrier Doppler and code Doppler, complete frame synchronization and bit synchronization, achieve correct demodulation, and complete the link establishment.

[0075] Step 5: The satellite-borne laser communication payload processor of the local satellite performs autocorrelation operation based on the data information sent locally and the data information sent by the other party at the same sampling time. Under the triggering of the high-precision second pulse signal and clock signal of the local satellite, the integer code element number of the frame phase sent at the local satellite receiving frame sampling time and the subdivided phase within a single code element of the frame phase sent at the local satellite receiving frame sampling time are obtained, and then the time information T3 corresponding to the local pseudorange is calculated. Correspondingly, the satellite-borne laser communication payload processor of the opposite target satellite calculates the time information T1 corresponding to the opposite pseudorange.

[0076] Step 6, after the link between the local satellite and the opposite end is established, the time information corresponding to the zero-value distance and the time information corresponding to the pseudo-range of the opposite end can be transmitted to the satellite-borne laser communication payload processor of the local satellite through the spatial optical signal, and at the same time, the time information corresponding to the local zero-value distance and the time information corresponding to the pseudo-range can also be transmitted to the satellite-borne laser communication payload processor of the opposite end through the spatial optical signal, and the distance between the local satellite and the opposite end is calculated by the time information corresponding to the zero-value distance and the time information corresponding to the pseudo-range of the opposite end in any of the two satellite-borne laser communication payload processors and the time information corresponding to the local zero-value distance and the time information corresponding to the pseudo-range. Preferably, the relevant calculation is usually performed through the data in the satellite-borne laser communication payload processor of the local satellite, and the specific calculation formula is as follows:

[0077] L=(T1+T3-T0-T2) / 2*c

[0078] Among them, L is the distance between the star and the other end, and c is the speed of light.

[0079] The above description is only used to illustrate the technical solution of the present invention rather than to limit it. For ordinary professional and technical personnel in the field, the specific technical solution recorded in the above embodiment can be modified, or some of the technical features therein can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution protected by the present invention.

Claims

1. A satellite-borne laser communication and ranging integrated system with zero-value calibration, characterized in that: Includes two identical range-finding units; The distance measuring unit comprises a satellite laser communication payload processor, an optical amplifier, a satellite laser communication payload optical head and an external angle cone (10); the satellite laser communication payload processor, the optical amplifier and the satellite laser communication payload optical head in each distance measuring unit communicate with each other bidirectionally; The satellite-borne laser communication payload processor is used to receive control instructions from the satellite platform to configure its own working state, and send control signals to the optical amplifier and the satellite-borne laser communication payload optical head according to the control instructions to configure the working states of the optical amplifier and the satellite-borne laser communication payload optical head respectively; The satellite-borne laser communication payload processor is used to control its internal laser to emit continuous laser, load and modulate the electrical data information generated by itself and transmit it to the optical amplifier as a transmission optical signal, and receive the optical fiber signal after low-noise optical amplification by the optical amplifier, and process it to achieve the measurement of communication bit error rate in the digital domain, as well as the calculation of the distance between the local satellite and the opposite end; The optical amplifier is used to optically amplify the received transmission optical signal to form a high-power transmission optical fiber signal and then output it to the onboard laser communication payload optical head, and receive the optical fiber signal coupled by the onboard laser communication payload optical head, perform low-noise optical amplification on it and then output it to the onboard laser communication payload processor; The optical fiber connection between the onboard laser communication payload optical head and the optical amplifier is used to convert the received high-power transmission optical fiber signal into a high-power spatial signal light and then transmit it to the opposite end, and receive the spatial signal light emitted by the distance measurement unit at the opposite end, couple it into an optical fiber signal and then output it to the optical amplifier; The external angle cone (10) is used to reflect the spatial signal light emitted by the satellite-borne laser communication payload optical head when the emission optical axis of the satellite-borne laser communication payload optical head points to its reflection surface, so that the back-reflected light is incident in the opposite direction into the interior of the satellite-borne laser communication payload optical head for zero value calibration.

2. The integrated satellite-borne laser communication and ranging system with zero-value calibration according to claim 1, characterized in that: The satellite-borne laser communication payload optical head comprises a first lens (1), an advanced fast-reflection mirror (2), a polarization beam splitter (3), a tracking fast-reflection mirror (4), an energy beam splitter (5), a tracking detector (6), a second lens (7), a reflector (8) and a collimation and beam expansion system (9); The first lens (1) is used to couple the high-power transmission optical fiber signal transmitted by the optical amplifier into local space signal light; The advance fast-reflection mirror (2), the polarization beam splitter (3), the tracking fast-reflection mirror (4), the reflector (8), and the collimation and beam expansion system (9) are sequentially located on the emission optical path of the local space signal light, and are used to form a signal emission branch path, and collimate the local space signal light before emitting it; wherein the tracking fast-reflection mirror (4) is located on the optical path of the local space signal light after it is reflected by the polarization beam splitter (3), and the external angle cone (10) is located outside the collimation and beam expansion system (9); The collimating beam expansion system (9), the reflector (8), the tracking fast reflector (4), and the polarization beam splitter (3) are sequentially located on the optical path of the spatial signal light emitted by the opposite end, and are used to capture the spatial signal light emitted by the opposite end or the back-reflected light of the external angle cone (10); The energy beam splitter (5) is located on the optical path of the spatial signal light emitted from the opposite end after being transmitted through the polarization beam splitter (3), and is used to split the spatial signal light from the opposite end or the back-reflected light of the external angle cone (10) to form a beam of transmitted light and a beam of reflected light; The second lens (7) is located on the optical path of the transmitted light and is used to converge the captured opposite-end spatial signal light or the back-reflected light of the external angle cone (10) onto the optical fiber and then couple it into an optical fiber signal and then output it to the optical amplifier; The tracking detector (6) is located on the optical path of the reflected light and is used to detect the reflected light from the opposite end or the back-reflected light from the external angle cone (10), and realizes feedback control of the tracking fast reflection mirror (4) by calculating the optical signal energy and position of its target surface.

3. The satellite-borne laser communication and ranging integrated system with zero-value calibration according to claim 1 or 2, characterized in that: Also included is a two-dimensional turntable; The satellite-borne laser communication payload optical head is arranged on a two-dimensional turntable, and the pitch angle and azimuth angle of the satellite-borne laser communication payload optical head are adjusted by rotating the two-dimensional turntable; The external corner pyramid (10) is arranged on a base of a two-dimensional turntable.

4. A method for measuring distance in satellite-borne laser communication with zero-value calibration, characterized in that: The following steps are involved: Step 1, constructing a satellite-borne laser communication and ranging integrated system with zero-value calibration as described in any one of claims 1-3, and installing two ranging units therein on the ground station or target satellite of the local satellite and the opposite end respectively; Step 2, remotely control the two distance measurement units through the satellite platform, perform telemetry and remote control configuration, coaxiality self-calibration, optical axis pointing calibration, and status self-check; Step 3, when the satellite-borne laser communication payload processor of this satellite receives the satellite platform control command, the internally generated transmission light signal is emitted outward as the space signal light through the corresponding satellite-borne laser communication payload optical head; the transmission light axis of the satellite-borne laser communication payload optical head is adjusted to point to the reflection surface of the external angle cone, and the back-reflected light reflected by the external angle cone is incident on the inside of the satellite-borne laser communication payload optical head in the opposite direction, and then coupled into an optical fiber signal and output to the satellite-borne laser communication payload processor through the optical amplifier; the satellite-borne laser communication payload processor performs autocorrelation operation based on the data information sent locally and the data information reflected back by the external angle cone at the same sampling time, and obtains the time information corresponding to the local zero-value distance under the triggering of the high-precision second pulse signal and clock signal of this satellite; accordingly, the distance measurement unit of the opposite end has the same working process as the distance measurement unit of this satellite, and obtains the time information corresponding to the zero-value distance of the opposite end; Step 4: Capture, track and establish a link of spatial signal light; Step 4.1, the optical heads of the satellite-borne laser communication payloads of the two ranging units respectively calculate the tracking pointing guidance data to achieve open-loop pointing tracking of the other end; Step 4.2, calibrate the two ranging units. After the calibration is completed, the local satellite and the opposite end begin to scan each other. When the optical head of the onboard laser communication payload of the local satellite detects the space signal light emitted by the opposite end, the scanning is stopped and the visual axis is adjusted to point to the opposite end. Step 4.3, using a tracking strategy to track the space signal light emitted by the other end to the center of the field of view until the optical heads of the satellite-borne laser communication payloads of both parties continuously detect the space signal light emitted by the other party; Step 4.4, according to the light signal intensity and position information output by the tracking detector in the optical head of the satellite laser communication payload of the other end, and the light signal intensity received by the corresponding optical amplifier, adjust the tracking point until the light spot detected by the tracking detectors of both parties is located at the center of its target surface, and the satellite laser communication payload processors of both parties continue to detect the space light signal; Step 4.5: After receiving the optical fiber signal after low-noise optical amplification by the corresponding optical amplifier, the onboard laser communication payload processors of both parties compensate for the optical carrier Doppler and code Doppler, complete frame synchronization and bit synchronization, realize correct demodulation, and complete the link establishment; Step 5: The satellite-borne laser communication payload processors of both parties perform autocorrelation operations based on the data information sent locally and the data information sent by the other party at the same sampling time, and obtain the time information corresponding to the local pseudorange and the time information corresponding to the other party's pseudorange respectively under the triggering of the high-precision second pulse signal and the clock signal; Step 6, calculate the distance between the local satellite and the other end according to the time information corresponding to the zero-value distance of the other end, the time information corresponding to the pseudo-range, and the time information corresponding to the local zero-value distance and the pseudo-range, and the ranging is completed.

5. A method for measuring distance in satellite-borne laser communication with zero-value calibration according to claim 4, characterized in that: In step 3, the pointing accuracy of the transmitting optical axis of the optical head of the satellite-borne laser communication payload is ≤5μrad.

6. A method for measuring distance in satellite-borne laser communication with zero-value calibration according to claim 5, characterized in that: In step 3, the emission optical axis of the optical head of the satellite-borne laser communication payload is adjusted to point to the reflection surface of the external angle cone as follows: The pitch angle and azimuth angle of the optical head of the satellite-borne laser communication payload are adjusted through a two-dimensional turntable, and the reflection angle of the advanced fast reflection mirror in the optical head of the satellite-borne laser communication payload is adjusted to achieve the direction adjustment of the emission optical axis of the optical head of the satellite-borne laser communication payload.

7. A method for measuring distance in satellite-borne laser communication with zero-value calibration according to claim 5, characterized in that: In step 4.4, adjust the tracking point as follows: The tracking point is adjusted by adjusting the reflection angle of the tracking fast-reflection mirror.

8. A method for measuring distance in satellite-borne laser communication with zero-value calibration according to claim 4, characterized in that: In step 6, the distance L between the local satellite and the ground station or target satellite is calculated by the following formula: L=(T1+T3-T0-T2) / 2*c Among them, T0 is the time information corresponding to the local zero-value distance, T1 is the time information corresponding to the pseudo-range sent by the other end, T2 is the time information corresponding to the zero-value distance sent by the other end, T3 is the time information corresponding to the local pseudo-range, and c is the speed of light.

Images