Integrated inter-satellite laser communication and tracking apparatus and method

Abstract

The present application relates to the technical field of laser communications, and discloses an integrated inter-satellite laser communication and tracking apparatus and method. The apparatus comprises: a master control subsystem, a tracking subsystem, a beam-splitting and isolation subsystem, and a signal processing subsystem. The tracking subsystem is used for performing phase shift processing on a received signal beam and outputting a plurality of first beams having consistent phases. The beam-splitting and isolation subsystem is used for performing filtering processing on the respective first beams and outputting a plurality of second beams. The signal processing subsystem comprises a signal processing module, a communication module, and a tracking module. The signal processing module mixes a local oscillator beam with the second beams and, after multiple conversion operations, generates a plurality of second digital signals. The second digital signals are split into communication signals and tracking signals. The communication module performs communication reception on the basis of the respective communication signals, and the tracking module feeds phase-difference information between two adjacent tracking signals back to the master control subsystem. By adopting the apparatus, stable communication with a corresponding communication device can be achieved.

Description

Inter-satellite laser communication and tracking integrated device and method Technical Field

[0001] This application relates to the field of laser communication technology, and in particular to an integrated device and method for inter-satellite laser communication tracking. Background Technology

[0002] As laser communication technology moves from ground-based verification to spaceborne applications, optical phased array technology, characterized by its flexibility, high speed, high precision, and fast response, is receiving increasing attention.

[0003] Currently, beaconless systems are one of the important directions for the development of laser communication. Their characteristic is that there is no independent beacon light source. Instead, a spatial beam splitter is set up in the communication optical path to split a signal beam as a tracking beam. Then, a near-infrared detector is used in the tracking optical path to detect the signal beam split from the above beam, thereby achieving tracking.

[0004] However, in traditional beaconless systems, the communication axis and tracking axis are difficult to be completely aligned, making it difficult to establish links quickly and maintain stable communication. Summary of the Invention

[0005] The main purpose of this application is to propose an integrated inter-satellite laser communication and tracking device and method, which aims to solve the problem that the communication axis and tracking axis of the traditional beaconless system are difficult to be completely aligned.

[0006] To achieve the above objectives, in a first aspect, this application proposes an integrated inter-satellite laser communication and tracking device, comprising:

[0007] Overall control subsystem;

[0008] The tracking subsystem, electrically connected to the main control subsystem, is used to receive the signal beam, perform phase shifting processing on the signal beam, and output multiple first beams with consistent phase; the tracking subsystem is also used to emit the received carrier laser.

[0009] The beam splitting and isolation subsystem is used to receive each of the first beams, filter each of the first beams, and output multiple second beams; the beam splitting and isolation subsystem is also used to generate carrier laser and split the carrier laser into multiple paths for transmission to the tracking subsystem.

[0010] The signal processing subsystem includes a signal processing module, a communication module, and a tracking module. The signal processing module generates multiple local oscillator beams with the same wavelength and phase as the signal beam, mixes each local oscillator beam with a corresponding second beam, converts the mixed light into electrical signals, generates multiple first digital signals based on the electrical signals, generates multiple second digital signals with consistent frequency and constant phase difference based on the first digital signals, and outputs one communication signal and one tracking signal from each second digital signal. The communication signals are transmitted to the communication module, and the tracking signals are transmitted to the tracking module. The communication module is electrically connected to the master control subsystem and, under the control of the master control subsystem, merges and receives the communication signals. The tracking module is also electrically connected to the master control subsystem and calculates the phase difference information between two adjacent tracking signals, feeding the phase difference information back to the master control subsystem so that the master control subsystem can control the tracking subsystem to adjust the phase shift parameters.

[0011] In one embodiment, the tracking subsystem includes:

[0012] An optical transceiver module is used to receive the signal beam and to transmit the received carrier laser.

[0013] The polarizing module, electrically connected to the main control subsystem, is located in the transmission optical path of the optical transceiver module and is used to receive the signal beam and adjust the transmission direction of the signal beam.

[0014] The phase-shifting module, electrically connected to the main control subsystem, is located in the transmission optical path of the polarizing module. It is used to receive the signal beam output by the polarizing module, perform phase-shifting processing on the signal beam, and output multiple channels of the first beam.

[0015] In one embodiment, the optical transceiver module includes a space optical telescope.

[0016] In one embodiment, the polarizing module includes a galvanometer electrically connected to the main control subsystem. The galvanometer is used to receive the signal beam and adjust the transmission direction of the signal beam under the control of the main control subsystem.

[0017] In one embodiment, the phase-shifting module includes:

[0018] A beam-shrinking antenna, located in the transmission optical path of the polarizing module, is used to receive the signal beam output by the polarizing module and reduce the diameter of the signal beam.

[0019] A microfiber array is used to receive the signal beam output by the beam-shrinking antenna, thereby enabling multi-channel beam transmission.

[0020] Multiple fiber phase shifters, corresponding to the output optical paths of each optical path channel in the microfiber array, are used to perform phase shifting processing on the received beam and output multiple paths of the first beam;

[0021] A phase shifter controller, electrically connected to the main control subsystem, is used to control the phase shifting parameters of each of the fiber optic phase shifters.

[0022] In one embodiment, the optical splitting isolation subsystem includes:

[0023] The guiding module includes multiple guiding units, each of which receives a corresponding first beam. The guiding unit is used to guide the transmission direction of the first beam and includes a first transmission path and a second transmission path.

[0024] The transmission module is used to receive each of the first beams input along the first transmission path of each of the guiding units, and to filter each of the received first beams to output multiple second beams.

[0025] The transmitting module is used to generate the carrier laser and split the carrier laser into multiple paths, which are then transmitted to the tracking subsystem along the second transmission path of each of the guiding units.

[0026] In one embodiment, the guiding unit includes an optical fiber circulator;

[0027] The transmission module includes multiple fiber optic filters, each of which receives the first beam input along the first transmission path of each of the guiding units and performs filtering processing on each of the first beams.

[0028] The transmitting module includes a frequency-stabilized laser, a communication transmitting board, a modulator, an optical amplifier, a beam splitter, and multiple fixed delay units for beam emission. The frequency-stabilized laser is used to emit laser light. The communication transmitting board is used to transmit the emitted signal to the modulator. The modulator is used to modulate the emitted signal onto the laser light emitted by the frequency-stabilized laser and output the carrier laser light to the optical amplifier. The optical amplifier is used to amplify the carrier laser light and output it to the beam splitter. The beam splitter splits the received carrier laser light into multiple paths and transmits them to the corresponding fixed delay units for beam emission. Each fixed delay unit for beam emission ensures that the phase of each carrier laser light path is consistent and transmits each carrier laser light path to the tracking subsystem along the second transmission path of each guiding unit.

[0029] In one embodiment, the signal processing module includes a local oscillator laser, a local oscillator beam splitter, multiple local oscillator fixed delay units, multiple photodetectors, multiple analog-to-digital converters, and multiple digital phase-locked loops;

[0030] The local oscillator laser is used to emit a local oscillator beam with the same wavelength as the signal beam to the local oscillator beam splitter. The local oscillator beam splitter is used to split the received local oscillator beam into multiple paths and transmit them to each of the local oscillator fixed delay units. Each of the local oscillator fixed delay units is used to ensure that the phase of each received local oscillator beam is consistent, and outputs each of the local oscillator beams to be mixed with each of the second beams. The mixed multiple beams are transmitted to each of the photodetectors. Each of the photodetectors is used to convert the received mixed beams into electrical signals and transmit them to each of the analog-to-digital converters. Each of the analog-to-digital converters is used to convert each of the electrical signals into multiple of the first digital signals. Each digital phase-locked loop is used to receive each of the first digital signals and generate multiple of the second digital signals based on each of the first digital signals. Each of the second digital signals is split into one of the communication signals and one of the tracking signals. Each of the communication signals is transmitted to the communication module, and each of the tracking signals is transmitted to the tracking module.

[0031] In one embodiment, the communication module includes a communication receiving board and multiple synchronization units;

[0032] Each of the aforementioned time synchronization units is used to receive the various communication signals and ensure the consistency of the various communication signals through feedback from the communication receiving board. The communication receiving board is used to receive the various communication signals and, under the control of the central control subsystem, merge the various communication signals to achieve communication reception.

[0033] Secondly, this application also provides an integrated method for inter-satellite laser communication and tracking, wherein the integrated method for inter-satellite laser communication and tracking is applied to the integrated inter-satellite laser communication and tracking device as described in the first aspect, and the method includes:

[0034] Obtain the phase difference information between two adjacent tracking signals;

[0035] The phase shift parameters of the tracking subsystem are adjusted based on the phase difference information.

[0036] The aforementioned inter-satellite laser communication and tracking integrated device includes a central control subsystem, a tracking subsystem, a beam splitting and isolation subsystem, and a signal processing subsystem. The signal processing subsystem includes a signal processing module, a communication module, and a tracking module. The tracking subsystem receives a signal beam, performs phase shifting on the signal beam, and outputs multiple first beams with consistent phase. The beam splitting and isolation subsystem filters each of the first beams and outputs multiple second beams. The signal processing module generates multiple local oscillator beams with the same wavelength and phase as the signal beam, mixes each local oscillator beam with its corresponding second beam, and converts the mixed multi-channel light. The signal is converted into an electrical signal. Then, multiple first digital signals are generated based on each electrical signal. Based on each first digital signal, multiple second digital signals with the same frequency and constant phase difference are generated. Finally, each second digital signal can be split into a communication signal and a tracking signal. The communication signals are transmitted to the communication module, thus converting the optical signal into an electrical signal and completing the calculation in the digital domain. Since the same electrical signal can be used for communication and tracking, there is no offset of the physical optical axis. This fundamentally solves the problem of inconsistency between the communication axis and the tracking axis, thus solving the problem of the traditional beaconless system's difficulty in quickly establishing links and stable communication.

[0037] The aforementioned inter-satellite laser communication tracking integrated method acquires the phase difference information between two adjacent tracking signals and adjusts the phase shift parameters of the tracking subsystem according to the phase difference information. This allows for phase compensation of each signal beam, thereby achieving angular displacement tracking through spatial phase compensation and enabling stable communication with the corresponding communication equipment. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0039] Figure 1 is a schematic diagram of the structure of an integrated inter-satellite laser communication and tracking device in one embodiment of this application;

[0040] Figure 2 is a schematic diagram showing the relationship between optical path length and offset angle during laser communication.

[0041] Figure 3 is a schematic diagram showing the relationship between optical path difference and offset angle during laser communication;

[0042] Figure 4 is a schematic diagram of the connection structure between the microfiber array and each fiber phase shifter in Figure 1.

[0043] Figure 5 is a schematic diagram of the connection structure between the optical isolation subsystem and the signal processing subsystem in Figure 1;

[0044] Figure 6 is a schematic diagram of the guiding unit in Figure 1;

[0045] Figure 7 is a schematic diagram of the internal structure of the digital phase-locked loop in Figure 1;

[0046] Figure 8 is a flowchart illustrating an embodiment of the inter-satellite laser communication and tracking integrated method of this application.

[0047] Reference numerals: 1-Master control subsystem, 2-Tracking subsystem, 21-Optical transceiver module, 211-Space optical telescope, 22-Polarizing module, 221-Galvanometer, 23-Phase shifting module, 231-Beam-shrinking antenna, 232-Microfiber array, 233-Fiber phase shifter, 234-Phase shifting controller, 3-Optical splitting and isolation subsystem, 31-Guiding module, 311-Guiding unit, 32-Transmission module, 321-Fiber filter, 33-Transmitting module, 331-Frequency stabilized laser, 332-Communication transmitter board, 333-Modulator, 334-Optical amplifier, 3 35-Beam emitter beam splitter, 336-Beam emitter fixed delay unit, 4-Signal processing subsystem, 41-Signal processing module, 411-Local oscillator laser, 412-Local oscillator beam splitter, 413-Local oscillator fixed delay unit, 414-Photodetector, 415-Analog-to-digital conversion unit, 416-Digital phase-locked loop, 4161-Digital phase detector, 4162-Digital loop filter, 4163-Digital voltage-controlled oscillator, 42-Communication module, 421-Time synchronization unit, 422-Communication receiver board, 43-Tracking module, 431-Phase comparator.

[0048] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0049] 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 a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0050] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0051] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0052] As described in the background section, with the development of laser communication technology from ground verification to spaceborne applications, optical phased array technology, which has the characteristics of flexibility, high speed, high precision and fast response, is receiving increasing attention.

[0053] Beaconless systems are a key direction in the development of laser communication. They are characterized by the absence of an independent beacon light source. Instead, a spatial beam splitter is used in the communication optical path to separate a signal beam as the tracking beam. A near-infrared detector is then used in the tracking optical path to detect this split signal beam, thus achieving tracking. Beaconless systems eliminate the need for an additional beacon laser, resulting in lower weight and power consumption compared to beacon-based systems. However, in related technologies, the communication and tracking optical paths of beaconless inter-satellite laser communication tracking devices are formed by two separate optical paths through a spatial beam splitter. Factors such as the processing and assembly of optomechanical components, as well as impacts and vibrations on the satellite platform, can cause deviations between the actual and ideal positions of the communication and tracking optical paths. This means the communication axis and tracking axis are not aligned, necessitating pre-calibration of the communication and tracking axes during link establishment. Furthermore, because the communication and tracking axes are not aligned, changes in external temperature and mechanical environment can further shift their original positions. Even when the signal beam spot in the tracking optical path is at the optimal imaging position of the near-infrared detector, the signal beam reception in the communication optical path may not be optimal. The aforementioned shortcomings have become important factors limiting the rapid establishment of laser communication links and stable communication.

[0054] To address the aforementioned issues, this application provides an integrated inter-satellite laser communication and tracking device, as shown in Figure 1. The integrated inter-satellite laser communication and tracking device includes: a central control subsystem 1, a tracking subsystem 2, a beam splitting and isolation subsystem 3, and a signal processing subsystem 4.

[0055] The main control subsystem 1 is a comprehensive control system that may include control equipment and is responsible for coordinating and managing the operation of the tracking subsystem 2, the optical isolation subsystem 3, and the signal processing subsystem 4.

[0056] Tracking subsystem 2 is electrically connected to the main control subsystem 1. It receives the signal beam, performs phase-shifting processing on the signal beam, and outputs a first beam with multiple synchronized phases. The signal beam can be transmitted by equipment communicating with the inter-satellite laser communication tracking integrated device, such as a satellite. If the transmitting equipment for the signal beam is already determined, the wavelength of the signal beam can also be predetermined. Tracking subsystem 2 is also used to transmit the received carrier laser.

[0057] The beam splitting and isolation subsystem 3 is used to receive each first beam and filter each first beam to output multiple second beams. The beam splitting and isolation subsystem 3 is also used to generate carrier laser and split the carrier laser into multiple paths for transmission to the tracking subsystem 2.

[0058] The signal processing subsystem 4 includes a signal processing module 41, a communication module 42, and a tracking module 43. The signal processing module 41 generates multiple local oscillator beams with the same wavelength and phase as the signal beam, mixes each local oscillator beam with corresponding second beams, converts the mixed light into electrical signals, generates multiple first digital signals based on these electrical signals, generates multiple second digital signals with consistent frequency and constant phase difference based on these first digital signals, and outputs one communication signal and one tracking signal from each second digital signal. The communication signals are transmitted to the communication module 42, and the tracking signals are transmitted to the tracking module 43. The communication module 42 is electrically connected to the main control subsystem 1 and is used to merge and receive the communication signals under the control of the main control subsystem 1. The tracking module 43 is electrically connected to the main control subsystem 1 and is used to calculate the phase difference information between two adjacent tracking signals and feed the phase difference information back to the main control subsystem 1 so that the main control subsystem 1 can control the tracking subsystem 2 to adjust the phase shift parameters.

[0059] In the receiving phase of the inter-satellite laser communication tracking integrated device, the tracking subsystem 2 receives the signal beam, then splits the signal beam, performs phase shifting on each beam, and outputs multiple first beams with consistent phase to the beam splitting and isolation subsystem 3. The beam splitting and isolation subsystem 3 filters each first beam and outputs multiple second beams to the signal processing module 41. The signal processing module 41 generates multiple local oscillator beams with the same wavelength and phase as the signal beam, and mixes each local oscillator beam with each corresponding second beam to enhance the detectability of the signal beam. The mixed multiple beams are then... The mixed-frequency optical signal is converted into an electrical signal. Multiple first digital signals are generated based on these electrical signals. Multiple second digital signals with consistent frequency and constant phase difference are then generated based on these first digital signals. Each second digital signal is split into a communication signal and a tracking signal (e.g., through logic gate operations in digital circuits). The communication signals are transmitted to the communication module 42, and the tracking signals are transmitted to the tracking module 43. This allows communication and tracking to be completed using the same electrical signal, eliminating physical optical axis offset and fundamentally solving the problem of inconsistency between the communication and tracking axes. The communication module 42, under the control of the main control subsystem 1, merges and receives the communication signals to achieve communication reception. The tracking module 43 calculates the phase difference between adjacent tracking signals based on the received tracking signals and feeds this phase difference information back to the main control subsystem 1. This allows the main control subsystem 1 to control the tracking subsystem 2 to adjust the phase shift parameters, thereby achieving signal tracking.

[0060] In the laser communication workflow, as shown in Figure 2, after the master optical transceiver 5 and slave optical transceiver 6 complete acquisition, a bidirectional communication link (including two wavelengths of light beams) is established between them. Taking a unidirectional link with one wavelength as an example, the slave optical transceiver 6 emits a beam of light, which is received by the master optical transceiver 5. When the angle of the slave optical transceiver 6 changes (θ), the optical path from the slave optical transceiver 6 to the master optical transceiver 5 also changes accordingly (ΔL). By detecting the phase change of the light beam, the angle change can be calculated with high precision.

[0061] As shown in Figure 3, when the optical transceiver 6 is offset by an angle θ, the angle between the optical axis of the master optical transceiver 5 and the optical axis of the optical transceiver 6 is θ. The optical path length of the beam emitted by the optical transceiver 6 along path C to the master optical transceiver 5 is inconsistent with the optical path length of the beam emitted by the optical transceiver 6 along path D to the master optical transceiver 5, and the optical path difference is ΔR. As can be seen from Figure 3, the offset angle is related to the phase difference (optical path difference = phase difference Δφ × beam wavelength λ), specifically θ = arcsin(Δφ*λ / d), where θ is the offset angle and d is the distance between the two detector target surfaces in the master optical transceiver 5. After the phase difference is compensated, the angle difference is also compensated, thereby realizing the re-alignment and tracking of the master optical transceiver 5 by the optical transceiver 6. Corresponding to this application, the phase difference can be compensated by dynamically adjusting the phase shift parameters in real time, thereby performing angular displacement tracking in real time and realizing stable communication with the corresponding communication equipment.

[0062] In applications, the signal with the best signal-to-noise ratio among the various tracking signals can be determined as the reference signal. The phase difference between the reference signal and the adjacent tracking signal can be determined as the reference phase difference. After determining the phase difference information between two adjacent tracking signals, the tracking subsystem 2 is controlled by the main control subsystem 1 to adjust the phase shift parameters so that the phase difference between the two adjacent tracking signals is the reference phase difference, thus achieving angular displacement tracking. By repeating this process, the phase shift parameters can be dynamically adjusted in real time, thereby performing angular displacement tracking in real time and achieving stable communication with the corresponding communication equipment (such as satellite).

[0063] During the transmission phase of the inter-satellite laser communication tracking integrated device, the beam splitting and isolation subsystem 3 generates a carrier laser and splits the carrier laser into multiple paths for transmission to the tracking subsystem 2. The tracking subsystem 2 performs phase shifting processing on the carrier laser and then transmits the phase-shifted carrier laser.

[0064] The aforementioned inter-satellite laser communication and tracking integrated device includes a central control subsystem 1, a tracking subsystem 2, a beam splitting and isolation subsystem 3, and a signal processing subsystem 4. The signal processing subsystem 4 includes a signal processing module 41, a communication module 42, and a tracking module 43. The tracking subsystem 2 receives the signal beam, performs phase shifting on the signal beam, and outputs multiple first beams with consistent phase. The beam splitting and isolation subsystem 3 filters each of the first beams and outputs multiple second beams. The signal processing module 41 generates multiple local oscillator beams with the same wavelength and phase as the signal beam, mixes each local oscillator beam with each of the second beams, and then processes the mixed beams... The optical signal is converted into an electrical signal, and then multiple first digital signals are generated based on each electrical signal. Multiple second digital signals with consistent frequency and constant phase difference are generated based on each first digital signal. Finally, each second digital signal can be split into a communication signal and a tracking signal, and the communication signals are transmitted to the communication module 42. Thus, the optical signal can be converted into an electrical signal and the calculation is completed in the digital domain. Since the same electrical signal can be used to complete communication and tracking, there is no offset of the physical optical axis, which fundamentally solves the problem of inconsistency between the communication axis and the tracking axis. This solves the problem of the traditional beaconless system being unable to quickly establish a link and achieve stable communication.

[0065] In one embodiment, as shown in FIG1, the tracking subsystem 2 includes an optical transceiver module 21, a polarizing module 22, and a phase shifting module 23.

[0066] The optical transceiver module 21 is used to receive signal beams and transmit received carrier lasers. As an optical antenna, the optical transceiver module 21 can support the reception of signal beams and the transmission of carrier lasers.

[0067] The polarizing module 22 is electrically connected to the main control subsystem 1 and is located in the transmission optical path of the optical transceiver module 21. It is used to receive the signal beam and adjust the transmission direction of the signal beam. By adjusting the transmission direction of the signal beam through the polarizing module 22, the signal beam can be transmitted to the phase shifting module 23.

[0068] The phase-shifting module 23 is electrically connected to the main control subsystem 1 and is located in the transmission optical path of the polarizing module 22. It receives the signal beam output by the polarizing module 22, performs phase-shifting processing on the signal beam, and outputs multiple first beams. By splitting the signal beam through the phase-shifting module 23 and performing phase-shifting processing on each signal beam, multiple first beams with consistent phase can be output. Each first beam corresponds to multiple channels, so the optimal quality channel can be determined based on each first beam. Adjustments can then be made based on the optimal quality channel to achieve alignment and tracking of the communication equipment.

[0069] In one embodiment, as shown in FIG1, the optical transceiver module 21 includes a space optical telescope 211.

[0070] In related technologies, when a phased array is used directly as a transceiver antenna, the spacing between array elements needs to be less than half the wavelength of the laser beam (usually several hundred nanometers). However, due to limitations in phased array materials, manufacturing, and packaging processes, the array element size cannot be increased, which in turn limits the size of the phased array (phased array size = array element size × phased array size). Therefore, phased array transceiver antennas cannot achieve greater gain, making it difficult for optical phased array technology to adapt to inter-satellite laser communication scenarios with distances of hundreds or thousands of kilometers or even further.

[0071] Using the space optical telescope 211 as the optical transceiver module, that is, using the space optical telescope 211 as the optical transceiver antenna, can take advantage of the aperture of the space optical telescope 211 and realize high-gain beam transmission and reception, which is conducive to adapting to inter-satellite laser communication scenarios with distances of hundreds or thousands of kilometers or even longer.

[0072] In one embodiment, as shown in FIG1, the polarizing module 22 includes a galvanometer 221, which is electrically connected to the main control subsystem 1. The galvanometer 221 is used to receive the signal beam and adjust the transmission direction of the signal beam under the control of the main control subsystem 1.

[0073] The galvanometer 221 is a high-precision optical scanning device, mainly consisting of a motor, a reflector, an angle sensor, and a control circuit. Its basic principle is to drive the reflector to swing rapidly and precisely via a motor, thereby changing the direction of the light beam transmission. By electrically connecting the galvanometer 221 to the main control subsystem 1, the operating parameters of the galvanometer 221 can be controlled through the main control subsystem 1, enabling the galvanometer 221 to transmit the signal beam in the appropriate direction.

[0074] In one embodiment, as shown in Figures 1 and 4, the phase shifting module 23 includes: a beam-shrinking antenna 231, a microfiber array 232, a phase shifting controller 234, and a plurality of fiber optic phase shifters 233.

[0075] The beam-shrinking antenna 231 is located in the transmission optical path of the polarizing module 22. It is used to receive the signal beam output by the polarizing module 22 and reduce the diameter of the signal beam. The beam-shrinking antenna 231 can be a beam shrinker, which can be composed of two or more lenses. When the signal beam passes through these lenses, the refraction of the lenses will change the propagation path of the beam, causing the divergence angle or convergence angle of the beam to change, thereby achieving the purpose of reducing the diameter of the beam and transmitting the signal beam to the microfiber array 232.

[0076] The microfiber array 232 is used to receive the signal beam output from the beam-shrinking antenna 231, enabling multi-channel beam transmission. The microfiber array 232 typically refers to an ordered arrangement of fibers with diameters at the micrometer level or even smaller. These fibers can be glass fibers, polymer fibers, or fibers of other materials. They can be arranged in one-dimensional (e.g., linear arrangement), two-dimensional (e.g., planar grid or hexagonal arrangement), or even three-dimensional (e.g., three-dimensional stacking) arrays. For example, the microfiber array 232 can be an optical fiber array; multiple optical fibers arranged together can create the microfiber array 232. The microfiber array 232 is a highly efficient optical transmission medium. Due to the small size of the microfibers, the signal beam can achieve low-loss, high-integration transmission when propagating within the microfiber array 232. The microfiber array 232 can split the signal beam into multiple paths for transmission. By using the beam-shrinking antenna 231 to cover the surface of the microfiber array 232, the advantages of high agility and flexibility of phased arrays are combined, thereby achieving long-distance inter-satellite communication with a small-sized optical phased array. In addition, the microfiber array 232 has the function of arbitrary channel combination and allocation, and supports simultaneous transmission and reception of single beam and multiple beams, thereby enabling the inter-satellite laser communication and tracking integrated device to achieve point-to-point communication and point-to-multipoint communication.

[0077] Each fiber phase shifter 233 corresponds to the output optical path of each optical path channel in the microfiber array 232. Each fiber phase shifter 233 is used to perform phase shifting processing on the received beam, outputting multiple first beams. The fiber phase shifter 233 mainly achieves phase change based on various physical properties of optical fibers. Its core principle is to adjust the optical phase by changing the optical path length or refractive index in the fiber. By utilizing the synchronous control of the array of fiber phase shifters 233, higher precision beam deflection and more dimensional optical field manipulation can be achieved.

[0078] The phase shift controller 234 is electrically connected to the main control subsystem 1 and is used to control the phase shift parameters of each fiber phase shifter 233.

[0079] It is understandable that the main control subsystem 1 can determine the phase compensation parameters based on the phase difference information between two adjacent tracking signals. On this basis, the main control subsystem 1 can adjust the phase shift parameters of each fiber phase shifter 233 through the phase shift controller 234, so that each fiber phase shifter 233 performs phase shift processing on each signal beam, thereby performing phase compensation on each signal beam, performing angular displacement tracking in real time, and realizing alignment tracking of the communication equipment.

[0080] It should be noted that in this embodiment, corresponding to the scheme of this application, in the formula θ=arcsin(Δφ*λ / d), θ is the offset angle, Δφ is the phase difference between two adjacent tracking signals, λ is the wavelength of the signal beam, and d corresponds to the distance between adjacent microfibers in the microfiber array 232.

[0081] In one embodiment, as shown in FIG1, the optical splitting isolation subsystem 3 includes: a guiding module 31, a transmission module 32, and a transmitting module 33.

[0082] The guiding module 31 includes multiple guiding units 311, each guiding unit 311 receiving a first beam. The guiding unit 311 is used to guide the transmission direction of the first beam and includes a first transmission path and a second transmission path.

[0083] The transmission module 32 is used to receive each first beam input along the first transmission path of each guide unit 311, and to filter each received first beam to output multiple second beams.

[0084] The transmitting module 33 is used to generate carrier laser and divide the carrier laser into multiple paths, which are then transmitted to the tracking subsystem 2 along the second transmission path of each guiding unit 311.

[0085] It can be understood that by using the first transmission path as the transmission path of the signal beam and the second transmission path as the transmission path of the carrier laser, the guiding unit 311 can separate the beam receiving path and the beam transmitting path, avoiding conflicts between them. This allows the inter-satellite laser communication and tracking integrated device to achieve both beam reception and transmission. Furthermore, by filtering the received first beams through the transmission module 32, the isolation between the tracking subsystem 2 and the signal processing subsystem 4 can be improved.

[0086] In one embodiment, as shown in Figures 1, 5, and 6, the guiding unit 311 includes an optical fiber circulator. An optical fiber circulator is a multi-port non-reciprocal optical device, typically with three or more ports. An optical fiber circulator allows optical signals to be transmitted unidirectionally between the ports in a specific order; therefore, a first transmission path and a second transmission path can be formed through the optical fiber circulator, separating the transmission paths of the signal beam and the carrier laser. Exemplarily, as shown, the path between port 1 and port 2 is the first transmission path, and the path between port 3 and port 1 is the second transmission path.

[0087] The transmission module 32 includes multiple fiber optic filters 321. Each fiber optic filter 321 receives a first beam input along the first transmission path of each guiding unit 311 and performs filtering processing on each first beam. The fiber optic filter 321 is an optical device used for frequency selection of optical signals. It can selectively allow or block light of a specific frequency (wavelength), thereby achieving filtering of the optical signal spectrum. Filtering the first beam with the fiber optic filter 321 and outputting a second beam can improve the quality of the second beam, which is beneficial to improving the reliability of the inter-satellite laser communication tracking integrated device.

[0088] The transmitting module 33 includes a frequency-stabilized laser 331, a communication transmitting board 332, a modulator 333, an optical amplifier 334, a beam transmitting beam splitter 335, and multiple beam transmitting fixed delay units 336.

[0089] A frequency-stabilized laser 331 emits laser light. A communication transmitter 332 transmits the emitted signal to a modulator 333. The modulator 333 modulates the emitted signal onto the laser emitted by the frequency-stabilized laser 331, outputting a carrier laser to an optical amplifier 334. The optical amplifier 334 amplifies the carrier laser and outputs it to a beam splitter 335. The beam splitter 335 splits the received carrier laser into multiple paths, which are then transmitted to corresponding fixed delay units 336. Each fixed delay unit 336 ensures the phase consistency of each carrier laser path and transmits each carrier laser path along the second transmission path of each guiding unit 311 to the tracking subsystem 2. The tracking subsystem 2 can perform phase-shifting processing on the received multiple carrier laser paths and reflect them. The tracking subsystem 2 may include a space optical telescope, a galvanometer 221, a beam-shrinking antenna 231, a microfiber array 232, a phase-shifting controller 234, and multiple fiber optic phase shifters 233. Each carrier laser output through the second transmission path of each guiding unit 311 will be transmitted to each fiber optic phase shifter 233. Each carrier laser is phase-shifted by each fiber optic phase shifter 233, and then transmitted to the space optical telescope through the microfiber array 232, the beam-shrinking antenna 231, and the galvanometer 221. The space optical telescope realizes the transmission of the carrier laser.

[0090] In one embodiment, as shown in Figures 1 and 7, the signal processing module 41 includes a local oscillator laser 411, a local oscillator beam splitter 412, multiple local oscillator fixed delay units 413, multiple photodetectors 414, multiple analog-to-digital converters 415, and multiple digital phase-locked loops 416.

[0091] The local oscillator laser 411 emits a local oscillator beam with the same wavelength as the signal beam to the local oscillator beam splitter 412. The local oscillator beam splitter 412 splits the received local oscillator beam into multiple paths, which are then transmitted to each local oscillator fixed delay unit 413. Each local oscillator fixed delay unit 413 ensures that the phases of the received local oscillator beams are consistent and outputs each local oscillator beam to be mixed with each second beam. The mixed multi-path light is then transmitted to each photodetector 414. Each photodetector 414 converts the received multi-path mixed light into electrical signals. The signal should be transmitted to each analog-to-digital converter 415. Each analog-to-digital converter 415 is used to convert each electrical signal into multiple first digital signals. Each digital phase-locked loop 416 is used to receive each first digital signal and generate multiple second digital signals based on each first digital signal. Each second digital signal is split (the circuit splitting can be achieved by using logic gate operations of digital circuits) to output one communication signal and one tracking signal. Each communication signal is transmitted to the communication module 42, and each tracking signal is transmitted to the tracking module 43.

[0092] The digital phase-locked loop 416 includes a digital phase detector 4161, a digital loop filter 4162, and a digital voltage-controlled oscillator 4163. The digital phase detector 4161 compares the phase difference between the input signal and the local signal (generated by the digitally controlled oscillator) and outputs a digital signal proportional to the phase difference. The digital loop filter 4162 filters the signal output by the phase detector to remove high-frequency noise and unwanted signal components, while adjusting the dynamic response characteristics of the loop. The digitally controlled oscillator changes the frequency and phase of its output signal according to the output signal of the loop filter, gradually aligning the phase of the local signal with the phase of the input signal.

[0093] It is understandable that multiple local oscillator beams with consistent phase can be output through the local oscillator laser 411, the local oscillator beam splitter 412, and multiple local oscillator fixed delay units 413. Mixing each phase local oscillator beam with each second beam in the transmission path (e.g., optical fiber) can enhance the detectability of the signal beam and improve communication quality. The analog-to-digital converter unit 415 can convert the mixed light into an electrical signal, and each analog-to-digital converter unit 415 can convert each electrical signal into multiple first digital signals. Each digital phase-locked loop 416 generates multiple second digital signals based on each first digital signal. Each second digital signal is split into one communication signal and one tracking signal. The communication signals are transmitted to the communication module 42, and the tracking signals are transmitted to the tracking module 43. Thus, communication and tracking can be completed using the same electrical signal, achieving integrated communication and tracking. There is no offset of the physical optical axis, fundamentally solving the problem of inconsistency between the communication axis and the tracking axis.

[0094] In this embodiment, the arrayed photodetector 414 can realize high-frequency response for communication detection and large field-of-view detection for tracking detection. The logic gate operation of digital circuits is used to perform de-circuiting instead of the spatial light mirror used in related technologies, which can realize integrated communication and tracking. Then, the timing unit 421 is used to ensure circuit consistency, thereby realizing single-link multi-channel synchronization and multi-link multi-channel synchronization of communication.

[0095] In one embodiment, as shown in FIG1, the communication module 42 includes a communication receiving board 422 and a plurality of synchronization units 421.

[0096] The synchronous unit 421 is used to receive various communication signals and ensure the consistency of various communication signals through feedback from the communication receiving board 422. The communication receiving board 422 is used to receive various communication signals and merge the various communication signals under the control of the main control subsystem 1 to realize communication reception.

[0097] The communication receiver board 422 is responsible for receiving, processing and converting external communication signals into a signal form that can be recognized and processed by the electronic device.

[0098] In the application, each timing unit 421 transmits communication signals to the communication receiving board 422. The communication receiving board 422 controls each timing unit 421 to perform clock calibration on each communication signal based on the received communication signals, so as to ensure the consistency of each communication signal. This allows the communication signals to be merged, so that the communication receiving board 422 can receive the merged communication signal and realize communication reception.

[0099] In one embodiment, as shown in FIG1, the tracking module 43 includes a phase comparator 431, which is used to receive each tracking signal, calculate the phase difference information between two adjacent tracking signals, and feed back the phase difference information to the main control subsystem 1.

[0100] Among them, the phase comparator 431 is an electronic device used to compare the phase difference between two signals. The phase comparator 431 can output a signal related to the phase difference between the two tracking signals, thereby outputting the phase difference information between two adjacent tracking signals to the main control subsystem 1, so that the main control subsystem 1 controls the phase shift controller 234 to adjust the phase shift parameters of each fiber phase shifter 233, and performs phase compensation on each first beam, thereby achieving angular displacement tracking through spatial phase compensation, and realizing stable communication with the corresponding communication equipment (e.g., satellite).

[0101] Based on the foregoing embodiments, the tracking subsystem 2 may include a space optical telescope, a galvanometer 221, a beam-shrinking antenna 231, a microfiber array 232, a phase-shifting controller 234, and multiple fiber optic phase shifters 233. The beam splitting and isolation subsystem 3 may include a frequency-stabilized laser 331, a communication transmitter board 332, a modulator 333, an optical amplifier 334, a beam splitter 335, multiple beam delay units 336, multiple fiber optic circulators, and multiple fiber optic filters 321. The signal processing subsystem 4 may include a local oscillator laser 411, a local oscillator beam splitter 412, multiple local oscillator delay units 413, multiple photodetectors 414, multiple analog-to-digital converters 415, multiple digital phase-locked loops 416, multiple timing units 421, a communication receiver board 422, and a phase comparator 431.

[0102] During the receiving phase of the inter-satellite laser communication tracking integrated device, the space optical telescope receives the signal beam and transmits it to the galvanometer 221. The galvanometer 221 changes the transmission direction of the signal beam, so that the signal beam is transmitted to the microfiber array 232. The microfiber array 232, together with multiple fiber phase shifters 233, generates multiple first beams.

[0103] Each first beam is transmitted to each fiber filter 321 via the first transmission path of the fiber optic circulator. Each fiber filter 321 filters each first beam and outputs multiple second beams.

[0104] Local oscillator laser 411 emits a local oscillator beam with the same wavelength as the signal beam to local oscillator beam splitter 412. Local oscillator beam splitter 412 splits the received local oscillator beam into multiple paths, which are then transmitted to each local oscillator fixed delay unit 413. Each local oscillator fixed delay unit 413 outputs local oscillator beams with consistent phase and mixes them with each second beam. The mixed beams are then transmitted to each photodetector 414. Each photodetector 414 converts the received mixed beams into electrical signals, which are then transmitted to each analog-to-digital converter unit 415. Each analog-to-digital converter unit 415 converts each electrical signal into multiple first digital signals. Each digital phase-locked loop 416 receives each first digital signal and generates multiple second digital signals based on each first digital signal. Each second digital signal is then split into one communication signal and one tracking signal for output.

[0105] Each communication signal is transmitted to a corresponding timing unit 421. The timing unit 421 performs clock calibration on each communication signal under the feedback of the communication receiving board 422 to ensure the consistency of each communication signal, so that the communication receiving board 422 can merge the communication signals to achieve communication reception.

[0106] Each tracking signal is transmitted to the phase comparator 431. The phase comparator 431 outputs the phase difference information between two adjacent tracking signals to the main control subsystem 1, so that the main control subsystem 1 controls the phase shift controller 234 to adjust the phase shift parameters of each fiber phase shifter 233 and perform phase compensation on each first beam. Thus, angular displacement tracking is achieved through spatial phase compensation, and stable communication with the corresponding communication equipment (e.g., satellite) is realized.

[0107] This application also provides an integrated method for inter-satellite laser communication tracking, which is applied to an integrated inter-satellite laser communication tracking device as described above, as shown in Figure 8. The integrated method for inter-satellite laser communication tracking includes the following steps S801 and S802.

[0108] S801: Obtain the phase difference information between two adjacent tracking signals.

[0109] S802: Adjust the phase shift parameters of the tracking subsystem based on the phase difference information.

[0110] The aforementioned inter-satellite laser communication tracking integrated method acquires the phase difference information between two adjacent tracking signals and adjusts the phase shift parameters of the tracking subsystem according to the phase difference information. This allows for phase compensation of each signal beam, thereby achieving angular displacement tracking through spatial phase compensation and enabling stable communication with the corresponding communication equipment.

[0111] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. An integrated inter-satellite laser communication and tracking device, characterized in that, include: Overall control subsystem; The tracking subsystem, electrically connected to the main control subsystem, is used to receive the signal beam, perform phase shifting processing on the signal beam, and output multiple first beams with consistent phase. The tracking subsystem is also used to transmit the received carrier laser. The beam splitting and isolation subsystem is used to receive each of the first beams, filter each of the first beams, and output multiple second beams; the beam splitting and isolation subsystem is also used to generate carrier laser and split the carrier laser into multiple paths for transmission to the tracking subsystem. The signal processing subsystem includes a signal processing module, a communication module, and a tracking module. The signal processing module generates multiple local oscillator beams with the same wavelength and phase as the signal beam, mixes each local oscillator beam with a corresponding second beam, converts the mixed light into electrical signals, generates multiple first digital signals based on the electrical signals, generates multiple second digital signals with consistent frequency and constant phase difference based on the first digital signals, and outputs one communication signal and one tracking signal from each second digital signal. The communication signals are transmitted to the communication module, and the tracking signals are transmitted to the tracking module. The communication module is electrically connected to the main control subsystem and is used to merge and receive the communication signals under the control of the main control subsystem. The tracking module is electrically connected to the master control subsystem and is used to calculate the phase difference information between two adjacent tracking signals and feed the phase difference information back to the master control subsystem so that the master control subsystem can control the tracking subsystem to adjust the phase shift parameters.

2. The inter-satellite laser communication and tracking integrated device as described in claim 1, characterized in that, The tracking subsystem includes: An optical transceiver module is used to receive the signal beam and to transmit the received carrier laser. The polarizing module, electrically connected to the main control subsystem, is located in the transmission optical path of the optical transceiver module and is used to receive the signal beam and adjust the transmission direction of the signal beam. The phase-shifting module, electrically connected to the main control subsystem, is located in the transmission optical path of the polarizing module. It is used to receive the signal beam output by the polarizing module, perform phase-shifting processing on the signal beam, and output multiple channels of the first beam.

3. The inter-satellite laser communication and tracking integrated device as described in claim 2, characterized in that, The optical transceiver module includes a space optical telescope.

4. The inter-satellite laser communication and tracking integrated device as described in claim 2, characterized in that, The polarizing module includes a galvanometer, which is electrically connected to the main control subsystem. The galvanometer is used to receive the signal beam and adjust the transmission direction of the signal beam under the control of the main control subsystem.

5. The inter-satellite laser communication and tracking integrated device as described in claim 2, characterized in that, The phase shifting module includes: A beam-shrinking antenna, located in the transmission optical path of the polarizing module, is used to receive the signal beam output by the polarizing module and reduce the diameter of the signal beam. A microfiber array is used to receive the signal beam output by the beam-shrinking antenna, thereby enabling multi-channel beam transmission. Multiple fiber phase shifters, corresponding to the output optical paths of each optical path channel in the microfiber array, are used to perform phase shifting processing on the received beam and output multiple paths of the first beam; A phase shifter controller, electrically connected to the main control subsystem, is used to control the phase shifting parameters of each of the fiber optic phase shifters.

6. The inter-satellite laser communication and tracking integrated device as described in claim 1, characterized in that, The optical splitting and isolation subsystem includes: The guiding module includes multiple guiding units, each of which receives a corresponding first beam. The guiding unit is used to guide the transmission direction of the first beam and includes a first transmission path and a second transmission path. The transmission module is used to receive each of the first beams input along the first transmission path of each of the guiding units, and to filter each of the received first beams to output multiple second beams. The transmitting module is used to generate the carrier laser and split the carrier laser into multiple paths, which are then transmitted to the tracking subsystem along the second transmission path of each of the guiding units.

7. The inter-satellite laser communication and tracking integrated device as described in claim 6, characterized in that, The guiding unit includes an optical fiber circulator; The transmission module includes multiple fiber optic filters, each of which receives the first beam input along the first transmission path of each of the guiding units and performs filtering processing on each of the first beams. The transmitting module includes a frequency-stabilized laser, a communication transmitting board, a modulator, an optical amplifier, a beam splitter, and multiple fixed delay units for beam emission. The frequency-stabilized laser is used to emit laser light. The communication transmitting board is used to transmit the emitted signal to the modulator. The modulator is used to modulate the emitted signal onto the laser light emitted by the frequency-stabilized laser and output the carrier laser light to the optical amplifier. The optical amplifier is used to amplify the carrier laser light and output it to the beam splitter. The beam splitter splits the received carrier laser light into multiple paths and transmits them to the corresponding fixed delay units for beam emission. Each fixed delay unit for beam emission ensures that the phase of each carrier laser light path is consistent and transmits each carrier laser light path to the tracking subsystem along the second transmission path of each guiding unit.

8. The inter-satellite laser communication and tracking integrated device as described in claim 1, characterized in that, The signal processing module includes a local oscillator laser, a local oscillator beam splitter, multiple local oscillator fixed delay units, multiple photodetectors, multiple analog-to-digital converters, and multiple digital phase-locked loops; The local oscillator laser is used to emit a local oscillator beam with the same wavelength as the signal beam to the local oscillator beam splitter. The local oscillator beam splitter is used to split the received local oscillator beam into multiple paths and transmit them to each of the local oscillator fixed delay units. Each of the local oscillator fixed delay units is used to ensure that the phase of each received local oscillator beam is consistent, and outputs each of the local oscillator beams to be mixed with each of the second beams. The mixed multiple beams are transmitted to each of the photodetectors. Each of the photodetectors is used to convert the received mixed beams into electrical signals and transmit them to each of the analog-to-digital converters. Each of the analog-to-digital converters is used to convert each of the electrical signals into multiple of the first digital signals. Each digital phase-locked loop is used to receive each of the first digital signals and generate multiple of the second digital signals based on each of the first digital signals. Each of the second digital signals is split into one of the communication signals and one of the tracking signals. Each of the communication signals is transmitted to the communication module, and each of the tracking signals is transmitted to the tracking module.

9. The inter-satellite laser communication and tracking integrated device as described in claim 1, characterized in that, The communication module includes a communication receiving board and multiple synchronization units; Each of the aforementioned time synchronization units is used to receive the various communication signals and ensure the consistency of the various communication signals through feedback from the communication receiving board. The communication receiving board is used to receive the various communication signals and, under the control of the central control subsystem, merge the various communication signals to achieve communication reception.

10. An integrated method for inter-satellite laser communication and tracking, characterized in that, The inter-satellite laser communication tracking integrated method is applied to the inter-satellite laser communication tracking integrated device as described in any one of claims 1 to 9, the method comprising: Obtain the phase difference information between two adjacent tracking signals; The phase shift parameters of the tracking subsystem are adjusted based on the phase difference information.

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