A signal processing method, apparatus, device and readable storage medium

Abstract

The application discloses a signal processing method, device and equipment and a readable storage medium to eliminate Doppler frequency offset and reduce the influence of relative attitude change between satellites on signal transmission. The method comprises the following steps: a first laser is connected with a first polarization controller; the output end of the first polarization controller is connected with a beam splitter; the first output end of the beam splitter is connected with the first input end of a modulator, and the second output end is connected with the first input end of a combiner; the second input end of the modulator receives an electrical signal, and the output end is connected with a second polarization controller; the output end of the second polarization controller is connected with the first input end of a polarization combiner; a second laser is connected with the second input end of the combiner; the output end of the combiner is connected with a third polarization controller; the output end of the third polarization controller is connected with the second input end of the polarization combiner; and the output end of the polarization combiner outputs a transmitting end signal. The embodiment can eliminate Doppler frequency offset and reduce the influence of relative attitude change between satellites on signal transmission.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a signal processing method, apparatus, device and readable storage medium. Background Technology

[0002] Optical communication reception methods mainly include intensity modulation direct detection (IM / DD) and coherent detection. Compared to intensity modulation direct detection, coherent detection has higher performance and sensitivity, and shows advantages in terms of optical payload weight and power consumption, and is considered to be the future direction of application.

[0003] Currently, commercially available coherent optical communication systems on the ground are relatively mature, but space-based coherent optical communication, especially inter-satellite coherent optical communication, still faces many challenges. One of these challenges is the Doppler frequency shift caused by the high-speed relative motion between satellites, which leads to frequency offset between the signal light and the local oscillator light, thereby disrupting coherence and degrading reception performance.

[0004] To address the above issues, there are currently two main solutions: one is to use an optical phase-locked loop to reduce the frequency difference; the other is to perform digital frequency estimation and compensation.

[0005] The above-mentioned solutions effectively address the frequency offset problem caused by Doppler shift for satellites in orbits with relatively small Doppler shifts (e.g., GEO (Geostationary Earth Orbit) and MEO (Medium Earth Orbit)). However, for LEO (Low Earth Orbit) satellites, the solution is less effective; moreover, existing solutions do not consider the impact of relative attitude changes between satellites on signal transmission. Summary of the Invention

[0006] This application provides a signal processing method, apparatus, device, and readable storage medium to eliminate Doppler frequency offset and reduce the impact of relative attitude changes between satellites on signal transmission.

[0007] In a first aspect, embodiments of this application provide a signal processing apparatus, disposed at a transmitting satellite, comprising:

[0008] A first laser; the output of the first laser is connected to a first polarization controller; the output of the first polarization controller is connected to a beam splitter; the first output of the beam splitter is connected to the first input of a modulator, and the second output of the beam splitter is connected to the first input of a beam combiner; the second input of the modulator receives an electrical signal, and the output of the modulator is connected to a second polarization controller; the output of the second polarization controller is connected to the first input of the polarization beam combiner.

[0009] A second laser; the output of the second laser is connected to the second input of the beam combiner, the output of the beam combiner is connected to a third polarization controller, the output of the third polarization controller is connected to the second input of the polarization beam combiner, and the output of the polarization beam combiner outputs a transmitting signal to the receiving end.

[0010] Optionally, the first laser is used to generate an optical carrier and a local oscillator light;

[0011] The first polarization controller is used to adjust the polarization state of the optical carrier and the local oscillator light to obtain a first signal;

[0012] The beam splitter is used to divide the first signal into a second signal and a third signal, wherein the optical power of the second signal and the third signal are equal;

[0013] The modulator is used to modulate the electrical signal onto the second signal to obtain the fourth signal;

[0014] The second laser is used to generate a polarization tracking reference light signal;

[0015] The combiner is used to combine the third signal and the polarization tracking reference optical signal into a fifth signal;

[0016] The third polarization controller is used to adjust the polarization state of the fifth signal to obtain the sixth signal;

[0017] The second polarization controller is used to adjust the polarization state of the fourth signal to obtain the seventh signal, wherein the polarization state of the sixth signal and the polarization state of the seventh signal are orthogonal;

[0018] The polarization combiner is used to combine the sixth signal and the seventh signal into the transmitting signal.

[0019] Optionally, the angle corresponding to the line deflection state of the first signal is: 45° + n × 90°, where n is an integer and n ≥ 0.

[0020] Optionally, the sixth signal is in a Y-polarized state and the seventh signal is in an X-polarized state; or, the sixth signal is in an X-polarized state and the seventh signal is in a Y-polarized state.

[0021] Secondly, embodiments of this application provide a signal processing apparatus, disposed at a receiving satellite, comprising:

[0022] A wavelength division multiplexer, wherein the input terminal of the wavelength division multiplexer receives the signal from the transmitting end;

[0023] The first output terminal of the wave splitter is connected to the polarization analyzer, the second output terminal of the wave splitter is connected to the first input terminal of the polarization beam splitter, the output terminal of the polarization analyzer is connected to the polarization tracking module, and the output terminal of the polarization tracking module is connected to the second input terminal of the polarization beam splitter.

[0024] The first output terminal of the polarization beam splitter is connected to the first input terminal of the coherent receiver, the second output terminal of the polarization beam splitter is connected to the polarization direction adjustment module, and the output terminal of the polarization direction adjustment module is connected to the second input terminal of the coherent receiver; the output terminal of the coherent receiver is connected to the analog-to-digital sampler, and the output terminal of the analog-to-digital sampler is connected to the digital signal processing module.

[0025] Optionally, the polarization direction adjustment module includes a rotator.

[0026] Optionally, the wavelength divider is used to receive the transmitting signal and divide the transmitting signal into an eighth signal and a ninth signal, wherein the eighth signal and the ninth signal have different wavelengths;

[0027] The polarization analyzer is used to detect the polarization state of the eighth signal and obtain the detection result;

[0028] The polarization tracking module is used to calculate the polarization rotation angle of the eighth signal based on the detection result;

[0029] The polarization beam splitter is used to divide the ninth signal into a tenth signal and an eleventh signal according to the polarization rotation angle, wherein the polarization states of the tenth signal and the eleventh signal are orthogonal.

[0030] The polarization direction adjustment module is used to convert the polarization state of the eleventh signal to obtain the twelfth signal, wherein the polarization states of the tenth signal and the twelfth signal are the same;

[0031] The coherent receiver is used to obtain an electrical signal based on the tenth signal and the twelfth signal;

[0032] The analog-to-digital sampler is used to convert the electrical signal into a digital signal;

[0033] The digital signal processing module is used to process the digital signal.

[0034] Optionally, the polarization rotation angle is a rotation angle relative to the Y-polarization state; the tenth signal is in the X-polarization state, the eleventh signal is in the Y-polarization state, and the twelfth signal is in the X-polarization state; or

[0035] The polarization rotation angle is a rotation angle relative to the X-polarization state; the tenth signal is the Y-polarization state, the eleventh signal is the X-polarization state, and the twelfth signal is the Y-polarization state.

[0036] Thirdly, embodiments of this application provide a signal processing method applied at a transmitting end, comprising:

[0037] Generates optical carrier and local oscillator light;

[0038] The polarization states of the optical carrier and the local oscillator light are adjusted to obtain a first signal;

[0039] The first signal is divided into a second signal and a third signal, wherein the optical power of the second signal and the third signal are equal;

[0040] Receive an electrical signal and modulate the electrical signal onto the second signal to obtain a fourth signal;

[0041] Generate a polarization tracking reference optical signal;

[0042] The third signal and the polarization tracking reference optical signal are combined into a fifth signal;

[0043] The polarization state of the fifth signal is adjusted to obtain the sixth signal;

[0044] The polarization state of the fourth signal is adjusted to obtain the seventh signal, wherein the polarization states of the sixth signal and the seventh signal are orthogonal.

[0045] The sixth signal and the seventh signal are combined into a transmitting signal.

[0046] Optionally, the angle corresponding to the line deflection state of the first signal is: 45° + n × 90°, where n is an integer and n ≥ 0.

[0047] Optionally, the sixth signal is in a Y-polarized state and the seventh signal is in an X-polarized state; or, the sixth signal is in an X-polarized state and the seventh signal is in a Y-polarized state.

[0048] Fourthly, embodiments of this application provide a signal processing method applied at a receiving end, including:

[0049] Receive the signal from the transmitting end and divide the signal from the transmitting end into an eighth signal and a ninth signal, wherein the eighth signal and the ninth signal have different wavelengths;

[0050] The polarization state of the eighth signal is detected to obtain the detection result;

[0051] The polarization rotation angle of the eighth signal is calculated based on the detection results;

[0052] Based on the polarization rotation angle, the ninth signal is divided into a tenth signal and an eleventh signal, wherein the polarization states of the tenth signal and the eleventh signal are orthogonal.

[0053] The polarization state of the eleventh signal is converted to obtain the twelfth signal, wherein the polarization states of the tenth signal and the twelfth signal are the same;

[0054] An electrical signal is obtained based on the tenth signal and the twelfth signal;

[0055] Convert the electrical signal into a digital signal;

[0056] The digital signal is processed.

[0057] Optionally, the polarization rotation angle is a rotation angle relative to the Y-polarization state; the tenth signal is in the X-polarization state, the eleventh signal is in the Y-polarization state, and the twelfth signal is in the X-polarization state; or

[0058] The polarization rotation angle is a rotation angle relative to the X-polarization state; the tenth signal is the Y-polarization state, the eleventh signal is the X-polarization state, and the twelfth signal is the Y-polarization state.

[0059] Fourthly, embodiments of this application also provide a communication device, including: a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the signal processing method described above.

[0060] Fifthly, embodiments of this application also provide a readable storage medium storing a program that, when executed by a processor, implements the steps in the signal processing method described above.

[0061] In this embodiment, two beams of light from the same source are generated by the first laser at the transmitting end, serving as the optical carrier and the local oscillator, respectively. The orthogonally polarized light is transmitted simultaneously through the first polarization controller, the second polarization controller, and the third polarization controller. Since the two beams experience the same Doppler frequency shift during transmission between satellites, the relative frequency offset between the signal light and the local oscillator light obtained at the receiving end is 0, thereby eliminating the Doppler frequency shift. At the same time, the polarization tracking reference light signal generated by the second laser at the transmitting end can be tracked and adjusted at the receiving end using the polarization tracking module and the polarization direction adjustment module. This avoids the problem that the orthogonally polarized light cannot be segmented due to changes in the relative attitude between satellites, and reduces the impact of the relative motion and rotation of the satellites at the transmitting and receiving ends on signal transmission. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of two-way communication between satellites;

[0063] Figure 2 This is one of the structural schematic diagrams of the signal processing device provided in the embodiments of this application;

[0064] Figure 3 This is a second schematic diagram of the signal processing device provided in the embodiments of this application;

[0065] Figure 4 This is one of the flowcharts of the signal processing method provided in the embodiments of this application;

[0066] Figure 5 This is the second flowchart of the signal processing method provided in the embodiments of this application. Detailed Implementation

[0067] In the embodiments of this application, the term "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0068] In the embodiments of this application, the term "multiple" refers to two or more, and other quantifiers are similar.

[0069] 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.

[0070] See Figure 1 , Figure 1 This is a schematic diagram of two-way communication between satellites. Satellite A and Satellite B communicate bidirectionally, and their optical payloads each include a transmitting unit and a receiving unit. The transmitting unit may include the following: Figure 2 The signal processing apparatus shown may include the following receiving unit: Figure 3 The signal processing device shown.

[0071] See Figure 2 , Figure 2 This is a schematic diagram of the signal processing device provided in an embodiment of this application, which is installed on a transmitting satellite and includes:

[0072] A first laser 21; the output of the first laser 21 is connected to a first polarization controller 22; the output of the first polarization controller 22 is connected to a beam splitter; the first output 231 of the beam splitter 23 is connected to the first input 251 of the modulator 25, and the second output 232 of the beam splitter 23 is connected to the first input 241 of the beam combiner 24; the second input 252 of the modulator 25 receives electrical signals, and the output 253 of the modulator 25 is connected to a second polarization controller 26; the output of the second polarization controller 26 is connected to the first input 271 of the polarization beam combiner 27.

[0073] The second laser 28; the output of the second laser 28 is connected to the second input 242 of the multiplexer 24, the output 243 of the multiplexer 24 is connected to the third polarization controller 29, the output of the third polarization controller 29 is connected to the second input 272 of the polarization beam combiner 27, and the output 273 of the polarization beam combiner 27 outputs the transmitting signal to the receiving end.

[0074] exist Figure 2 The functions implemented by each module are as follows:

[0075] The first laser 21 is used to generate an optical carrier and a local oscillator light;

[0076] The first polarization controller 22 is used to adjust the polarization state of the optical carrier and the local oscillator light to obtain a first signal;

[0077] The beam splitter 23 is used to divide the first signal into a second signal and a third signal, wherein the optical power of the second signal and the third signal are equal;

[0078] The modulator 25 is used to modulate the electrical signal onto the second signal to obtain the fourth signal;

[0079] The second laser 28 is used to generate a polarization tracking reference light signal;

[0080] The combiner 24 is used to combine the third signal and the polarization tracking reference optical signal into a fifth signal;

[0081] The third polarization controller 29 is used to adjust the polarization state of the fifth signal to obtain the sixth signal;

[0082] The second polarization controller 26 is used to adjust the polarization state of the fourth signal to obtain the seventh signal, wherein the polarization state of the sixth signal and the polarization state of the seventh signal are orthogonal;

[0083] The polarization combiner 27 is used to combine the sixth signal and the seventh signal into the transmitting signal.

[0084] The angle corresponding to the linear deflection state of the first signal is 45° + n × 90°, where n is an integer and n ≥ 0. For example, it can be 45°, 135°, 225°, 315°, etc. Adjusting the linear deflection state of the first signal is beneficial to the power balance between the X-polarization state and the Y-polarization state.

[0085] Wherein, the sixth signal is in the Y-polarization state and the seventh signal is in the X-polarization state; or, the sixth signal is in the X-polarization state and the seventh signal is in the Y-polarization state.

[0086] For example, the second polarization controller adjusts the fourth signal to an X-polarization state to obtain the seventh signal; the third polarization controller adjusts the fifth signal to a Y-polarization state to obtain the sixth signal.

[0087] In this embodiment, the signals generated by the first laser and the second laser have different wavelengths. Therefore, the multiplexer combines signals of different wavelengths into a fifth signal.

[0088] In this embodiment, two beams of light from the same source are generated by the first laser at the transmitting end, which serve as the optical carrier and the local oscillator, respectively. The light with orthogonal polarization is transmitted simultaneously through the first polarization controller, the second polarization controller, and the third polarization controller. Since the two beams experience the same Doppler frequency shift when they are transmitted between satellites, the relative frequency offset between the signal light and the local oscillator obtained at the receiving end is 0, thereby eliminating the Doppler frequency shift.

[0089] See Figure 3 , Figure 3 This is a schematic diagram of the signal processing device provided in the embodiments of this application, which is disposed at the receiving satellite and includes:

[0090] Wavelength divider 31, the input terminal of which receives the signal from the transmitting end;

[0091] The first output terminal 311 of the polarizer 31 is connected to the polarizer 32, the second output terminal 312 of the polarizer 31 is connected to the first input terminal 331 of the polarization beam splitter 33, the output terminal of the polarizer 32 is connected to the polarization tracking module 34, and the output terminal of the polarization tracking module 34 is connected to the second input terminal 332 of the polarization beam splitter 33.

[0092] The first output terminal 333 of the polarization beam splitter 33 is connected to the first input terminal 351 of the coherent receiver 35, the second output terminal 334 of the polarization beam splitter 33 is connected to the polarization direction adjustment module 36, and the output terminal of the polarization direction adjustment module 36 is connected to the second input terminal 352 of the coherent receiver 35; the output terminal of the coherent receiver 35 is connected to the analog-to-digital sampler 37, and the output terminal of the analog-to-digital sampler 37 is connected to the digital signal processing module 38.

[0093] exist Figure 3 The functions implemented by each module are as follows:

[0094] The wavelength divider 31 is used to receive the transmitting signal and divide the transmitting signal into an eighth signal and a ninth signal, wherein the eighth signal and the ninth signal have different wavelengths.

[0095] The polarization analyzer 32 is used to detect the polarization state of the eighth signal and obtain the detection result;

[0096] The polarization tracking module 34 is used to calculate the polarization rotation angle of the eighth signal based on the detection result;

[0097] The polarization beam splitter 33 is used to divide the ninth signal into a tenth signal and an eleventh signal according to the polarization rotation angle, wherein the polarization states of the tenth signal and the eleventh signal are orthogonal.

[0098] The polarization direction adjustment module 36 is used to convert the polarization state of the eleventh signal to obtain the twelfth signal, wherein the polarization states of the tenth signal and the twelfth signal are the same;

[0099] The coherent receiver 35 is used to obtain an electrical signal based on the tenth signal and the twelfth signal;

[0100] The analog-to-digital sampler 37 is used to convert the electrical signal into a digital signal;

[0101] The digital signal processing module 38 is used to process the digital signal.

[0102] In this embodiment, the polarization direction adjustment module includes a rotator. Of course, other modules capable of achieving the same function can also be used.

[0103] In this embodiment, the polarization rotation angle is a rotation angle relative to the Y-polarization state; the tenth signal is the X-polarization state, the eleventh signal is the Y-polarization state, and the twelfth signal is the X-polarization state; or, the polarization rotation angle is a rotation angle relative to the X-polarization state; the tenth signal is the Y-polarization state, the eleventh signal is the X-polarization state, and the twelfth signal is the Y-polarization state.

[0104] For example, the polarization tracking module calculates the polarization rotation angle of the eighth signal relative to the Y-polarization state based on the detection result; the polarization beam splitter divides the ninth signal into a tenth signal in the X-polarization state and an eleventh signal in the Y-polarization state. The polarization direction adjustment module adjusts the eleventh signal to become a twelfth signal in the X-polarization state. The coherent receiver mixes the tenth and twelfth signals and outputs the corresponding electrical signals. The digital signal processing may include clock recovery, phase compensation, etc.

[0105] In this embodiment, two beams of light from the same source are generated by the first laser at the transmitting end, serving as the optical carrier and the local oscillator, respectively. The orthogonally polarized light is transmitted simultaneously through the first polarization controller, the second polarization controller, and the third polarization controller. Since the two beams experience the same Doppler frequency shift during transmission between satellites, the relative frequency offset between the signal light and the local oscillator light obtained at the receiving end is 0, thereby eliminating the Doppler frequency shift. At the same time, the polarization tracking reference light signal generated by the second laser at the transmitting end can be tracked and adjusted at the receiving end using the polarization tracking module and the polarization direction adjustment module. This avoids the problem that the orthogonally polarized light cannot be segmented due to changes in the relative attitude between satellites, and reduces the impact of the relative motion and rotation of the satellites at the transmitting and receiving ends on signal transmission.

[0106] Combination Figure 1 , Figure 2 and Figure 3 Because it has polarization tracking and adjustment capabilities, the application scenarios of this application are very wide, and it can be used for communication between satellite A and satellite B in any orbit (such as LEO, MEO, GEO).

[0107] exist Figure 1 In this scenario, assuming satellite A is the transmitter and satellite B is the receiver, the specific signal processing procedure is as follows:

[0108] At the transmitting end, the first laser outputs an optical carrier and a local oscillator beam with wavelength λ1. A first polarization controller adjusts the polarization of the carrier and oscillator beam to 45° linear polarization, thus facilitating power balance between the X and Y polarization states. A beam splitter splits the signal from the first polarization controller into two signals of equal power (wavelength λ1). One of these, wavelength λ1, is used as the optical carrier and input to a modulator, which modulates an electrical signal onto this carrier to obtain the adjusted optical signal. A second polarization controller adjusts the modulated optical signal to X-polarization (wavelength λ1) and inputs it to a polarization combiner. The other optical signal with wavelength λ1 output from the beam splitter, along with the optical signal with wavelength λ2 output from the second laser, is input to a combiner. The combiner combines the two signals into a single signal. A third polarization controller adjusts the output light from the combiner to Y-polarization (including wavelengths λ1 and λ2) and inputs it to the polarization combiner. The polarization combiner combines the orthogonal X-polarized and Y-polarized light into a single beam for transmission.

[0109] For the receiving segment, after receiving the optical signal from the transmitting end, the optical signal is first split into two optical waves with wavelengths λ1' and λ2' by a beam splitter (due to the Doppler frequency shift, the wavelength of the optical signal has a certain frequency shift relative to the wavelength of the transmitting end). Among them, optical wave λ1' serves as the signal light and local oscillator light, and optical wave λ2' serves as the polarization reference light. The polarization state of optical wave λ2' is detected by an analyzer, and the polarization tracking module calculates and outputs the polarization rotation angle θ of the polarization state of optical wave λ2' relative to the Y polarization state (the original polarization state of optical wave λ2'). Since optical waves λ1' and λ2' travel through the same path, the polarization rotation angle of optical wave λ1' (containing both X and Y polarization states) can be considered to be θ as well. Based on θ, the reference axis of the polarization beam splitter can be adjusted to accurately separate the X and Y polarization states in optical wave λ1'. The update speed of this feedforward loop depends on the speed of polarization detection and polarization update. The polarization beam splitter outputs signal light (wavelength λ1') in the X-polarized state and local oscillator light (wavelength λ1') in the Y-polarized state. The polarization direction adjustment module converts the Y-polarized light into the X-polarized state and uses it as the local oscillator light. The signal light and the local oscillator light are mixed by a coherent receiver to complete coherent detection.

[0110] In the above embodiments, a polarization reference light is introduced into the satellite coherent communication based on polarization multiplexing. Its wavelength differs from that of the signal light, thus it can be used for polarization monitoring and polarization tracking. Simultaneously, the polarization beam splitter can be adjusted based on the polarization state change of the polarization reference light to accurately separate the orthogonal signal light and local oscillator light. Therefore, compared to traditional frequency offset compensation schemes, the scheme of this application, using two beams of the same origin as the signal light and local oscillator light respectively, and introducing a polarization reference light for polarization tracking, can theoretically completely eliminate Doppler frequency offset, eliminating the need for frequency offset compensation and solving the problem of degraded coherent reception performance. It has advantages such as a large coverage frequency shift range, fast response speed, high performance, power saving, and performance unaffected by the relative motion and rotation of the transmitting and receiving satellites.

[0111] See Figure 4 , Figure 4 This is a flowchart of the signal processing method provided in the embodiments of this application, such as... Figure 4 As shown, it includes the following steps:

[0112] Step 401: Generate optical carrier and local oscillator light;

[0113] Step 402: Adjust the polarization state of the optical carrier and the local oscillator light to obtain the first signal;

[0114] Step 403: Divide the first signal into a second signal and a third signal, wherein the optical power of the second signal and the third signal are equal;

[0115] Step 404: Receive an electrical signal and modulate the electrical signal onto the second signal to obtain a fourth signal;

[0116] Step 405: Generate a polarization tracking reference light signal;

[0117] Step 406: Combine the third signal and the polarization tracking reference light signal into a fifth signal;

[0118] Step 407: Adjust the polarization state of the fifth signal to obtain the sixth signal;

[0119] Step 408: Adjust the polarization state of the fourth signal to obtain the seventh signal, wherein the polarization state of the sixth signal and the polarization state of the seventh signal are orthogonal;

[0120] Step 409: Combine the sixth signal and the seventh signal into a transmitting signal.

[0121] The method described in this application embodiment can be applied to... Figure 2 The apparatus shown.

[0122] The angle corresponding to the linear deflection state of the first signal is 45° + n × 90°, where n is an integer and n ≥ 0. For example, it can be 45°, 135°, 225°, 315°, etc. Adjusting the linear deflection state of the first signal is beneficial to the power balance between the X-polarization state and the Y-polarization state.

[0123] Wherein, the sixth signal is in the Y-polarization state and the seventh signal is in the X-polarization state; or, the sixth signal is in the X-polarization state and the seventh signal is in the Y-polarization state.

[0124] In this embodiment, two beams of light from the same source are generated at the transmitting end and used as optical carrier and local oscillator light respectively, so that the light with orthogonal polarization is transmitted simultaneously. Since the two beams experience the same Doppler frequency shift when they are transmitted between satellites, the relative frequency offset between the signal light and the local oscillator light obtained at the receiving end is 0, thereby eliminating the Doppler frequency shift.

[0125] See Figure 5 , Figure 5 This is a flowchart of the signal processing method provided in the embodiments of this application, such as... Figure 5 As shown, it includes the following steps:

[0126] Step 501: Receive the signal from the transmitting end and divide the signal from the transmitting end into an eighth signal and a ninth signal, wherein the eighth signal and the ninth signal have different wavelengths;

[0127] Step 502: Detect the polarization state of the eighth signal to obtain the detection result;

[0128] Step 503: Calculate the polarization rotation angle of the eighth signal based on the detection results;

[0129] Step 504: According to the polarization rotation angle, divide the ninth signal into a tenth signal and an eleventh signal, wherein the polarization states of the tenth signal and the eleventh signal are orthogonal.

[0130] Step 505: Convert the polarization state of the eleventh signal to obtain the twelfth signal, wherein the polarization states of the tenth signal and the twelfth signal are the same;

[0131] Step 506: Obtain an electrical signal based on the tenth signal and the twelfth signal;

[0132] Step 507: Convert the electrical signal into a digital signal;

[0133] Step 508: Process the digital signal.

[0134] Here, the processing may include clock recovery, phase compensation, etc.

[0135] Wherein, the polarization rotation angle is a rotation angle relative to the Y-polarization state; the tenth signal is the X-polarization state, the eleventh signal is the Y-polarization state, and the twelfth signal is the X-polarization state; or, the polarization rotation angle is a rotation angle relative to the X-polarization state; the tenth signal is the Y-polarization state, the eleventh signal is the X-polarization state, and the twelfth signal is the Y-polarization state.

[0136] In this embodiment, two beams of light from the same source generated at the transmitting end are used as the optical carrier and the local oscillator, respectively, and the orthogonally polarized light is transmitted simultaneously. Since the two beams experience the same Doppler frequency shift when they are transmitted between satellites, the relative frequency offset between the signal light and the local oscillator light obtained at the receiving end is 0, thereby eliminating the Doppler frequency shift. At the same time, the polarization tracking reference light signal generated at the transmitting end can be tracked and adjusted at the receiving end, thereby avoiding the problem that the orthogonally polarized light cannot be segmented due to the relative attitude change between satellites, and reducing the impact of the relative motion and rotation of the satellites at the transmitting and receiving ends on signal transmission.

[0137] This application provides a communication device, including: a memory, a processor, and a program stored in the memory and executable on the processor; the processor is configured to read the program in the memory to implement the steps in the signal processing method described above.

[0138] This application also provides a readable storage medium storing a program. When executed by a processor, this program implements the various processes of the above-described signal processing method embodiments and achieves the same technical effects. To avoid repetition, it will not be described again here. The readable storage medium can be any available medium or data storage device that the processor can access, including but not limited to magnetic storage (e.g., floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (e.g., CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (e.g., ROMs, EPROMs, EEPROMs, non-volatile memory (NAND flash), solid-state drives (SSDs)).

[0139] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0140] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0141] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A signal processing device, disposed at a transmitting satellite, characterized in that, include: First laser; The output of the first laser is connected to the first polarization controller; The output of the first polarization controller is connected to the beam splitter; The first output terminal of the beam splitter is connected to the first input terminal of the modulator, and the second output terminal of the beam splitter is connected to the first input terminal of the beam combiner; the second input terminal of the modulator receives an electrical signal, and the output terminal of the modulator is connected to the second polarization controller; the output terminal of the second polarization controller is connected to the first input terminal of the polarization beam combiner. Second laser; The output of the second laser is connected to the second input of the beam combiner, the output of the beam combiner is connected to the third polarization controller, the output of the third polarization controller is connected to the second input of the polarization beam combiner, and the output of the polarization beam combiner outputs the transmitting signal to the receiving end. The first laser is used to generate two beams of light from the same source, which serve as the optical carrier and the local oscillator, respectively. The first polarization controller is used to adjust the polarization state of the optical carrier and the local oscillator light to obtain a first signal; The beam splitter is used to divide the first signal into a second signal and a third signal, wherein the optical power of the second signal and the third signal are equal; The modulator is used to modulate the electrical signal onto the second signal to obtain the fourth signal; The second laser is used to generate a polarization tracking reference light signal, the polarization tracking reference light signal having a wavelength different from that of the optical carrier and the local oscillator light; The combiner is used to combine the third signal and the polarization tracking reference optical signal into a fifth signal; The third polarization controller is used to adjust the polarization state of the fifth signal to obtain the sixth signal; The second polarization controller is used to adjust the polarization state of the fourth signal to obtain the seventh signal, wherein the polarization state of the sixth signal and the polarization state of the seventh signal are orthogonal; The polarization combiner is used to combine the sixth signal and the seventh signal into the transmitting signal.

2. The apparatus according to claim 1, characterized in that, The angle corresponding to the line deflection state of the first signal is: 45° + n × 90°, where n is an integer and n ≥ 0.

3. The apparatus according to claim 1, characterized in that, The sixth signal is in a Y-polarized state and the seventh signal is in an X-polarized state; or, the sixth signal is in an X-polarized state and the seventh signal is in a Y-polarized state.

4. A signal processing device, disposed at a receiving satellite, characterized in that, include: A wavelength division multiplexer, wherein the input terminal of the wavelength division multiplexer receives the signal from the transmitting end; The first output terminal of the wave splitter is connected to the polarization analyzer, the second output terminal of the wave splitter is connected to the first input terminal of the polarization beam splitter, the output terminal of the polarization analyzer is connected to the polarization tracking module, and the output terminal of the polarization tracking module is connected to the second input terminal of the polarization beam splitter. The first output terminal of the polarization beam splitter is connected to the first input terminal of the coherent receiver; the second output terminal of the polarization beam splitter is connected to the polarization direction adjustment module; the output terminal of the polarization direction adjustment module is connected to the second input terminal of the coherent receiver; the output terminal of the coherent receiver is connected to the analog-to-digital sampler; and the output terminal of the analog-to-digital sampler is connected to the digital signal processing module. The wavelength divider is used to receive the transmitting signal and divide the transmitting signal into an eighth signal and a ninth signal. The eighth signal is used for polarization detection, and the ninth signal is used for coherent reception. The eighth signal and the ninth signal have different wavelengths. The polarization analyzer is used to detect the polarization state of the eighth signal and obtain the detection result; The polarization tracking module is used to calculate the polarization rotation angle of the eighth signal based on the detection result; The polarization beam splitter is used to divide the ninth signal into a tenth signal and an eleventh signal according to the polarization rotation angle, wherein the polarization states of the tenth signal and the eleventh signal are orthogonal. The polarization direction adjustment module is used to convert the polarization state of the eleventh signal to obtain the twelfth signal, wherein the polarization states of the tenth signal and the twelfth signal are the same; The coherent receiver is used to obtain an electrical signal based on the tenth signal and the twelfth signal; The analog-to-digital sampler is used to convert the electrical signal into a digital signal; The digital signal processing module is used to process the digital signal.

5. The apparatus according to claim 4, characterized in that, The polarization direction adjustment module includes a polarizer.

6. The apparatus according to claim 4, characterized in that, The polarization rotation angle is a rotation angle relative to the Y-polarization state; the tenth signal is in the X-polarization state, the eleventh signal is in the Y-polarization state, and the twelfth signal is in the X-polarization state; or The polarization rotation angle is a rotation angle relative to the X-polarization state; the tenth signal is the Y-polarization state, the eleventh signal is the X-polarization state, and the twelfth signal is the Y-polarization state.

7. A signal processing method, characterized in that, Applied to the signal processing apparatus of claim 1, the method includes: Two beams of light from the same source are generated and used as the optical carrier and the local oscillator, respectively. The polarization states of the optical carrier and the local oscillator light are adjusted to obtain a first signal; The first signal is divided into a second signal and a third signal, wherein the optical power of the second signal and the third signal are equal; Receive an electrical signal and modulate the electrical signal onto the second signal to obtain a fourth signal; A polarization tracking reference optical signal is generated, the wavelength of which is different from that of the optical carrier and the local oscillator light; The third signal and the polarization tracking reference optical signal are combined into a fifth signal; The polarization state of the fifth signal is adjusted to obtain the sixth signal; The polarization state of the fourth signal is adjusted to obtain the seventh signal, wherein the polarization states of the sixth signal and the seventh signal are orthogonal. The sixth signal and the seventh signal are combined into a transmitting signal.

8. The method according to claim 7, characterized in that, The angle corresponding to the line deflection state of the first signal is: 45° + n × 90°, where n is an integer and n ≥ 0.

9. The method according to claim 7, characterized in that, The sixth signal is in a Y-polarized state and the seventh signal is in an X-polarized state; or, the sixth signal is in an X-polarized state and the seventh signal is in a Y-polarized state.

10. A signal processing method, characterized in that, Applied to the signal processing apparatus of claim 4, the method comprises: The system receives a signal from the transmitting end and divides the signal into an eighth signal and a ninth signal. The eighth signal is used for polarization detection, and the ninth signal is used for coherent reception. The eighth signal and the ninth signal have different wavelengths. The polarization state of the eighth signal is detected to obtain the detection result; The polarization rotation angle of the eighth signal is calculated based on the detection results; Based on the polarization rotation angle, the ninth signal is divided into a tenth signal and an eleventh signal, wherein the polarization states of the tenth signal and the eleventh signal are orthogonal. The polarization state of the eleventh signal is converted to obtain the twelfth signal, wherein the polarization states of the tenth signal and the twelfth signal are the same; An electrical signal is obtained based on the tenth signal and the twelfth signal; Convert the electrical signal into a digital signal; The digital signal is processed.

11. The method according to claim 10, characterized in that, The polarization rotation angle is a rotation angle relative to the Y-polarization state; the tenth signal is in the X-polarization state, the eleventh signal is in the Y-polarization state, and the twelfth signal is in the X-polarization state; or The polarization rotation angle is a rotation angle relative to the X-polarization state; the tenth signal is the Y-polarization state, the eleventh signal is the X-polarization state, and the twelfth signal is the Y-polarization state.

12. A communication device, comprising: A memory, a processor, and a program stored in the memory and executable on the processor; characterized in that the processor is configured to read the program from the memory to implement the steps of the signal processing method as described in any one of claims 7 to 11.

13. A readable storage medium for storing a program, characterized in that, When the program is executed by the processor, it implements the steps of the signal processing method as described in any one of claims 7 to 11.

Images