Microwave Photonics-Assisted Inter-Station Radio Frequency Synchronization Device and Method

Abstract

The application discloses a microwave photon-assisted inter-mobile station radio frequency synchronization device and method, and belongs to the technical field of distributed radar. The device comprises a master station and a slave station, and the master station and the slave station each comprise a coherent light source, a modulator, a phase-locked system, a transceiving antenna and the like. The reference frequency is loaded on a high carrier frequency for directional transmission, the reference frequency is recovered by using a self-mixing receiving mode, the influence of Doppler frequency shift is suppressed by using an uplink-downlink closed-loop phase-locked structure, and high-precision radio frequency synchronization between mobile platforms is realized. The application does not need complex electrical frequency multiplication and phase locking, avoids additional noise, has the advantages of strong anti-multipath interference capability, suitability for high-dynamic environments and the like, and can meet the demand of a double-base synthetic aperture radar system and the like for high-precision frequency synchronization.

Description

Technical Field

[0001] This invention belongs to the field of distributed radar technology, specifically relating to a microwave photonics-assisted inter-station wireless frequency synchronization device and method. Background Technology

[0002] Synthetic Aperture Radar (SAR) boasts advantages such as all-weather, all-time, long-range, high-resolution imaging, making it invaluable in surveying and mapping. However, with the development of electronic countermeasures and stealth technologies, traditional monostatic SAR, due to its co-location of transmit and receive devices, is susceptible to interference and has a limited detection angle, making it difficult to meet the detection requirements in complex electromagnetic environments. Bistatic / multistatic SAR, employing a separate transmit and receive system, can achieve multi-dimensional detection through multi-platform collaboration, enhancing the system's anti-jamming and anti-stealth capabilities, and has become an important direction for radar technology development. However, high-precision wireless frequency synchronization is one of the key technological bottlenecks restricting the development of bistatic SAR, especially under mobile platform conditions, where achieving stable and high-precision frequency synchronization is particularly difficult.

[0003] Existing frequency synchronization technologies mainly include three categories: wireless laser synchronization, fiber optic link synchronization, and wireless microwave synchronization. Wireless laser synchronization offers high accuracy (e.g., picosecond-level time synchronization), but it is sensitive to atmospheric turbulence, requires complex tracking and compensation systems, and involves bulky equipment, making it difficult to apply to mobile platforms. Fiber optic link synchronization can achieve extremely high frequency transmission stability (e.g., 10...). -15 While capable of high-precision frequency synchronization (on a scale of 1000-2000 GHz), it relies on physical connections, resulting in poor mobility and making it unsuitable for airborne, spaceborne, or other mobile platforms or outdoor environments. Wireless microwave synchronization technology offers the advantage of flexible deployment, but in mobile situations, it suffers from difficulties in real-time calculation of synchronization errors and insufficient accuracy, making it difficult to meet the high-precision frequency synchronization requirements of broadband bistatic SAR.

[0004] In recent years, microwave photonics technology has provided a new approach for high-precision wireless frequency synchronization. This technology utilizes optical domain processing of high-frequency signals, avoiding the noise and bandwidth limitations introduced by frequency doubling and other processes in traditional electrical methods. However, existing solutions are mostly geared towards fixed sites, lacking high-precision frequency synchronization solutions for mobile platforms, especially in scenarios with high dynamic relative motion. Therefore, there is an urgent need to develop a wireless synchronization method and device suitable for mobile platforms, capable of suppressing Doppler shift and achieving high-stability frequency distribution, to promote the application of bistatic / multistatic SAR in practical mobile environments. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a microwave photon-assisted inter-station wireless frequency synchronization device and method. The device employs a closed-loop phase-locked loop (PLL) approach for both uplink and downlink. The design fully utilizes the high-frequency characteristics of microwave photons, eliminating the need for high-frequency harmonic generation in conventional electrical signal generation methods. Furthermore, the high carrier wave enables targeted illumination, effectively avoiding multipath interference during propagation. Self-mixing technology effectively recovers the reference signal. The phase-locking system can rationally set the phase-locking frequency based on the motion speed of the platform, thereby maximizing high stability and high precision phase locking.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A microwave photonics-assisted inter-station wireless frequency synchronization device includes a physically separated master station and a slave station in relative motion; the master station and the slave station are respectively equipped with a first phase-locked system and a second phase-locked system; wherein...

[0008] The master station is used to modulate the reference signal output by the first phase-locked system onto the optical carrier through the modulator group corresponding to the master station, generate an uplink high carrier frequency wireless signal, and send it to the slave station.

[0009] The slave station is used to receive the uplink high carrier frequency wireless signal. After the photoelectric converter corresponding to the slave station self-mixes and recovers the second harmonic reference electrical signal, the second phase-locked system generates a local reference signal. At the same time, the local reference signal is modulated by the modulator group corresponding to the slave station to generate a downlink high carrier frequency wireless signal and feeds it back to the master station.

[0010] The master station is also used to receive the downlink high carrier frequency wireless signal. After the photoelectric converter corresponding to the master station recovers the feedback second harmonic reference electrical signal through self-mixing, it is input into the first phase-locked system and compared with the internal reference to achieve closed-loop locking, thereby realizing wireless frequency synchronization between the master and slave stations in a dynamic environment.

[0011] On the other hand, the present invention provides a microwave photon-assisted inter-station wireless frequency synchronization method, applied in the aforementioned apparatus comprising a master station and slave stations that are physically separated and in relative motion, comprising:

[0012] At the master station, a reference signal is generated through the first phase-locked loop system, and an optical carrier is provided using the first coherent light source and the first tunable filter. The reference signal is modulated onto the optical carrier by the first modulator, and after being processed by the first beam combiner, the first optical amplifier, the first photoelectric converter and the first power amplifier, an uplink high carrier frequency wireless signal is generated and sent to the slave station.

[0013] At the slave station, a slave station optical carrier is provided through a second coherent light source and a second tunable filter. The received uplink high carrier frequency wireless signal is modulated onto the slave station optical carrier using a third modulator. The signal is then self-mixed by a third photoelectric converter to recover a second harmonic reference electrical signal, which is then input into a second phase-locked system to generate a local reference signal.

[0014] At the slave station, the local reference signal is modulated onto the optical carrier by the fourth modulator, and after being processed by the second beam combiner, the second optical amplifier, the fourth photoelectric converter and the fourth power amplifier, a downlink high carrier frequency wireless signal is generated and fed back to the master station.

[0015] At the master station, the received downlink high carrier frequency wireless signal is modulated onto an optical carrier using a second modulator. The signal is then self-mixed by a second photoelectric converter to recover the feedback second harmonic reference electrical signal. This signal is then input into a first phase-locked system for phase comparison with an internal reference signal from a high-stability frequency source. Based on the comparison result, the phase of the reference signal is adjusted in a closed loop to compensate for the phase change caused by the relative motion between the master and slave stations, thereby achieving frequency synchronization.

[0016] Thirdly, the present invention provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned microwave photon-assisted inter-station wireless frequency synchronization method.

[0017] Fourthly, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enable the processor to implement the aforementioned microwave photonics-assisted inter-station wireless frequency synchronization method.

[0018] The beneficial effects of this invention are as follows:

[0019] High-precision synchronization under mobile conditions is achieved: Through the uplink and downlink closed-loop phase-locked structure, it can effectively track and compensate for the Doppler frequency shift caused by the relative motion of the platform, thereby maintaining high-precision phase locking in dynamic environments and solving the key problem of accuracy degradation of traditional wireless microwave synchronization technology under mobile conditions.

[0020] Simplifying system structure and improving reliability: By utilizing the high-frequency characteristics of microwave photons, high carrier frequency signals are directly generated in the optical domain, eliminating the complex high-frequency harmonic chain in traditional electrical schemes and avoiding the additional phase noise and distortion introduced by it. The system structure is simpler and the reliability is higher.

[0021] Enhanced anti-interference and engineering practicality: Employing high-carrier-frequency directional transmission and self-mixing reception technology not only effectively suppresses multipath interference during propagation but also avoids crosstalk between signals from the same station through uplink and downlink frequency separation design. This solution is insensitive to wireless channel fluctuations, exhibits strong robustness, and is easier to deploy in high-dynamic platforms such as airborne and vehicle-mounted systems.

[0022] High synchronization accuracy and wide applicability: The frequency synchronization accuracy achieved by this invention is high, which meets the requirements of high-precision systems such as broadband bistatic SAR. Moreover, the solution is not limited by wired links and can be widely used in various distributed radars, cooperative detection systems and other mobile scenarios that require precise frequency distribution, where cables cannot be laid. Attached Figure Description

[0023] Figure 1 This is a structural block diagram of the microwave photonics-assisted inter-station wireless frequency synchronization device of the present invention;

[0024] Figure 2 This is a schematic diagram of the microwave photon-assisted inter-station wireless frequency synchronization device of the present invention.

[0025] Figure 3 This is a flowchart of a method according to an embodiment of the present invention.

[0026] Figure label:

[0027] 1. First coherent light source; 2. First tunable filter; 3. First modulator; 4. First beam combiner; 5. Optical amplifier; 6. First photoelectric converter; 7. First power amplifier; 8. High-stability frequency source; 9. First phase-locked system; 10. Second photoelectric converter; 11. Second modulator; 12. Second power amplifier.

[0028] The third power amplifier 13, the third modulator 14, the third photoelectric converter 15, the second phase-locked system 16, the second coherent light source 17, the second tunable filter 18, the fourth modulator 19, the second beam combiner 20, the second optical amplifier 21, the fourth photoelectric converter 22, and the fourth power amplifier 23. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] First, let's provide a unified introduction to the abbreviations of the terms that may be involved: DWDM: Dense Wavelength Division Multiplexer; MZM: Mach-Zehnder Modulator; EDFA: Fiber Optic Amplifier; PD: Photodetector; PA: Power Amplifier; LNA: Low Noise Amplifier; M: Mixer.

[0031] like Figure 1As shown, this invention provides a microwave photonics-assisted inter-station wireless frequency synchronization device. By loading a reference frequency onto a high carrier frequency, directional transmission of the reference frequency is achieved. The reference frequency is recovered through a self-mixing reception method. The entire process eliminates the need for complex electrical techniques such as frequency multiplication and phase-locking, avoiding additional noise introduced by complex electrical processes. To mitigate Doppler shift caused by relative motion between stations, a closed-loop phase-locked loop (PLL) method is adopted for both uplink and downlink. The PLL frequency can be rationally set according to the motion speed of the moving platform and the performance of the PLL, thereby maximizing high stability and high-precision phase locking. The device includes a physically separated master station and a slave station in relative motion. They interact bidirectionally via a wireless spatial channel, forming a closed-loop phase-locking system to achieve high-precision reference frequency synchronization in dynamic environments.

[0032] The main station includes a first coherent light source 1, a first tunable filter 2, a first modulator 3, a first beam combiner 4, an optical amplifier 5, a first photoelectric converter 6, a first power amplifier 7, a high-stability frequency source 8, a first phase-locked loop system 9, a second photoelectric converter 10, a second modulator 11, a second power amplifier 12, and a first transceiver antenna. The first coherent light source 1 is used to generate broadband coherent light in different frequency bands. The first tunable filter 2 is connected to the output of the first coherent light source 1 and is used to filter and output two channels with a frequency interval of [missing information]. The coherent light is used as the optical carrier of the master station signal branch and the optical carrier of the master station local oscillator, respectively. The optical input terminal of the first modulator 3 receives the optical carrier of the master station signal branch, and its electrical input terminal is connected to the output terminal of the first phase-locked system 9 to receive the reference electrical signal output by the phase-locked system. The first modulator 3 is configured to operate in carrier-suppressed double-sideband modulation mode to modulate the reference electrical signal onto the optical carrier of the master station signal branch. One input terminal of the first combiner 4 is connected to the optical output terminal of the first modulator 3 to receive the modulated optical signal, and the other input terminal is connected to the first tunable filter 2 to receive the optical carrier of the master station local oscillator, for combining the two optical signals. The optical amplifier 5, the first photoelectric converter 6, and the first power amplifier 7 are connected in sequence to amplify, photoelectrically convert, and beat the combined optical signal to generate an uplink signal, which is finally transmitted to the slave station through the first transceiver antenna.

[0033] Simultaneously, the first transceiver antenna is also used to receive downlink feedback signals from the slave station. The second power amplifier 12 is connected to the first transceiver antenna and is used to amplify the downlink feedback signal with low noise. The electrical input terminal of the second modulator 11 is connected to the output terminal of the second power amplifier 12, and its optical input terminal receives the master station local oscillator optical carrier provided by the first tunable filter 2, and is used to modulate the downlink radio frequency signal onto the optical carrier. The second photoelectric converter 10 is connected to the optical output terminal of the second modulator 11 and is used to demodulate the modulated optical signal through self-mixing to recover the second harmonic reference electrical signal carrying phase information. One input terminal of the first phase-locked system 9 is connected to the output terminal of the second photoelectric converter 10 to receive the second harmonic reference electrical signal, and the other input terminal is connected to the high-stability frequency source 8; by comparing the phases of the two input signals, the first phase-locked system 9 generates an error control signal to adjust the frequency and phase of its output reference electrical signal in real time, thereby forming a closed-loop lock.

[0034] The slave station includes a second transceiver antenna, a third power amplifier 13, a third modulator 14, a third photoelectric converter 15, a second phase-locked loop system 16, a second coherent light source 17, a second tunable filter 18, a fourth modulator 19, a second beam combiner 20, a second optical amplifier 21, a fourth photoelectric converter 22, and a fourth power amplifier 23. The second transceiver antenna receives uplink signals from the master station. The third power amplifier 13 is connected to the second transceiver antenna and amplifies the uplink signal with low noise. The electrical input of the third modulator 14 is connected to the output of the third power amplifier 13, and its optical input is connected to the second coherent light source 17 via the second tunable filter 18; the third modulator 14 modulates the amplified uplink RF signal onto the slave station's optical carrier. The third photoelectric converter 15 is connected to the optical output of the third modulator 14 and demodulates a second-harmonic reference electrical signal using self-mixing technology. The input terminal of the second phase-locked system 16 is connected to the output terminal of the third photoelectric converter 15, and is used to lock the internal oscillator according to the signal and output a stable local reference signal of frequency multiplication.

[0035] The electrical input terminal of the fourth modulator 19 is connected to the output terminal of the second phase-locked system 16 to receive the local reference signal, and its optical input terminal is connected to the second tunable filter 18 to receive another coherent light as the slave station's local oscillator light. The fourth modulator 19 is used to modulate the local reference signal onto the optical carrier. The second beam combiner 20, the second optical amplifier 21, the fourth photoelectric converter 22, and the fourth power amplifier 23 are connected in sequence to combine the modulated optical signal output by the fourth modulator 19 with the slave station's local oscillator light, amplify it, and perform photoelectric conversion to beat the signal, generating a downlink feedback signal, which is finally transmitted back to the master station through the second transceiver antenna.

[0036] Through the connection and cooperation of the various components of the master station and slave station, a complete wireless frequency synchronization closed-loop system is formed, which can adapt to the relative motion of the platform and achieve high-precision phase locking.

[0037] like Figure 2 As shown, a schematic diagram of the device is presented. First, the master station selects two coherent optical carriers that meet the requirements by adjusting the comb spacing of the first coherent light source 1 or a tunable optical filter. One carrier is used as the signal loading branch light, and the other is used as the local oscillator (LO). The reference source signal is loaded onto the Mach-Zehnder first modulator 3 and made to operate in carrier-suppressed double-sideband mode to achieve conjugate modulation of the reference phase. Finally, the carrier is flexibly controlled by the beat frequency, overcoming the technical bottleneck of generating complex high-frequency electrical signals. The reference source signal can be a docile rubidium clock, cesium clock, or other high-stability frequency source, represented as:

[0038] (1)

[0039] in, Indicates the reference source signal. Represented as the reference frequency, The reference source phase is represented by t, and time is represented by t. The reference signal output from the voltage-controlled oscillator of the first phase-locked system (PLS) 9. Represented as: , This is represented as the oscillator phase.

[0040] By loading the voltage-controlled oscillator (VCO) signal onto the Mach-Zehnder first modulator 3 and operating it in carrier-suppressed double-sideband mode, conjugate modulation of the VCO phase is achieved. After beating with the LO, a pair of frequency differences is obtained. High-carrier frequency dual-tone signal , :

[0041] (2)

[0042] in, The frequency interval between the two coherent beams, This represents the beat frequency phase difference between the two coherent beams.

[0043] After signal transmission, the receiving end signal , for , After a delay, the result can be represented as:

[0044] (3)

[0045] The transmission delay is related to the platform's real-time position. The received signal is received after optical domain modulation and filtering, and the output signal after the third photoelectric converter 15 can be expressed as:

[0046] (4)

[0047] At this point, we can see that the propagation delay is due to platform movement. The introduction of Doppler frequency shift during transmission affects frequency stability. The output signal from the third photoelectric converter 15, after passing through the second phase-locked loop system 16, is divided by two and used as a modulation signal, which is then applied to the downlink carrier frequency to obtain the signal. , :

[0048] (5)

[0049] in, As the center carrier frequency for the downlink, This is the downlink carrier frequency phase. Through formulas (3) and (5), it can be seen that the phase conjugation technique will... The complete phase is preserved in the uplink and downlink dual-tone carrier pairs, and can be recovered using beat frequency modulation. At this point, the downlink modulated carrier pair propagates to the master station, and after passing through the second photoelectric converter 10, the downlink reference signal can be obtained. :

[0050] (6)

[0051] After comparing with the main station reference signal After mixing and phase-locked control, the error signal in the first phase-locked system 9 can be expressed as:

[0052] (7)

[0053] Where N represents the frequency multiple, which can be determined based on the optimal performance parameters of the phase-locked loop and the platform motion parameters.

[0054] After phase locking by the system, the above error is 0 or a certain value, that is, the phase is fixed. Therefore, the phase error between the master and slave stations is a fixed value: It can be seen that the reference signal received from the slave station It can be represented as :

[0055] (8)

[0056] Phase locking is achieved, and compared with the master station reference signal in formula (1), the slave reference signal differs from the master station reference signal by only one fixed phase difference while doubling the frequency. The master station reference signal can be recovered by frequency division by two. This system is less affected by the wireless channel, has strong anti-interference ability, is easy to extend to complex environments such as high dynamics, and is more suitable for frequency synchronization under mobile platforms.

[0057] On the other hand, the present invention provides a synchronization method applied to the aforementioned apparatus, comprising:

[0058] At the master station, a reference signal is generated by the first phase-locked loop system 9, and an optical carrier is provided by the first coherent light source 1 and the first tunable filter 2. The reference signal is modulated onto the optical carrier by the first modulator 3, and after being processed by the first beam combiner 4, the optical amplifier 5, the first photoelectric converter 6 and the first power amplifier 7, an uplink high carrier frequency wireless signal is generated and sent to the slave station.

[0059] At the slave station, a slave station optical carrier is provided through a second coherent light source 17 and a second tunable filter 18. The received uplink high carrier frequency wireless signal is modulated onto the slave station optical carrier by a third modulator 14. The signal is then self-mixed by a third photoelectric converter 15 to recover a second harmonic reference electrical signal, which is then input into a second phase-locked system 16 to generate a local reference signal.

[0060] At the slave station, the local reference signal is modulated onto the optical carrier by the fourth modulator 19, and after being processed by the second beam combiner 20, the second optical amplifier 21, the fourth photoelectric converter 22 and the fourth power amplifier 23, a downlink high carrier frequency wireless signal is generated and fed back to the master station.

[0061] At the master station, the received downlink high carrier frequency wireless signal is modulated onto an optical carrier by the second modulator 11, and self-mixed by the second photoelectric converter 10 to recover the feedback second harmonic reference electrical signal. This signal is then input into the first phase-locked system 9 and compared with the internal reference signal from the high-stability frequency source 8. Based on the comparison result, the phase of the reference signal is adjusted in a closed loop to compensate for the phase change caused by the relative motion between the master and slave stations, thereby achieving frequency synchronization.

[0062] Figure 3 This is a flowchart illustrating an embodiment of this application. The solution utilizes the above principles and mainly includes the following steps:

[0063] In step S1, the reference frequency signal output by the first phase-locked system 9 is loaded onto the first modulator 3 of the signal branch. By adjusting its bias point, it is made to work at the minimum bias point, thereby generating a high carrier frequency signal with a conjugate reference phase.

[0064] In step S2, the bias point of the third modulator 14 at the slave station receiver is adjusted so that it operates at the minimum bias point. After self-mixing reception, the reference frequency of the second harmonic can be obtained.

[0065] In step S3, the reference frequency of the second harmonic of the slave station receiving end is input into the second phase-locked system 16 of the receiving end, and an appropriate harmonic frequency N is selected based on the performance and motion parameters of the second phase-locked system 16 of the slave station.

[0066] In step S4, the reference frequency output by the second phase-locked system 16 at the receiving end is loaded onto the fourth modulator 19. By adjusting its bias point, it is made to work at the minimum bias point, thereby generating a high carrier frequency signal with a conjugate reference phase.

[0067] In step S5, the modulator bias point of the master station receiver is adjusted so that it operates at the minimum bias point. After self-mixing reception, the reference frequency of the second harmonic can be obtained.

[0068] In step S6, the reference frequency of the second harmonic of the master station receiver is input into the first phase-locked system 9. Based on the performance and motion parameters of the master station's first phase-locked system 9, a suitable harmonic frequency N is selected to form a feedback loop and achieve highly stable fast phase locking.

[0069] Thirdly, the present invention provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned microwave photon-assisted inter-station wireless frequency synchronization method.

[0070] Fourthly, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enable the processor to implement the aforementioned microwave photonics-assisted inter-station wireless frequency synchronization method.

[0071] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A microwave photonics-assisted inter-station wireless frequency synchronization device, characterized in that, It includes a master station and a slave station that are physically separated and in relative motion; the master station and the slave station are respectively equipped with a first phase-locked system and a second phase-locked system; wherein... The master station is used to modulate the reference signal output by the first phase-locked system onto the optical carrier through the modulator group corresponding to the master station, generate an uplink high carrier frequency wireless signal, and send it to the slave station. The slave station is used to receive the uplink high carrier frequency wireless signal. After the photoelectric converter corresponding to the slave station self-mixes and recovers the second harmonic reference electrical signal, the second phase-locked system generates a local reference signal. At the same time, the local reference signal is modulated by the modulator group corresponding to the slave station to generate a downlink high carrier frequency wireless signal and feeds it back to the master station. The master station is also used to receive the downlink high carrier frequency wireless signal. After the photoelectric converter corresponding to the master station recovers the feedback second harmonic reference electrical signal through self-mixing, it is input into the first phase-locked system and compared with the internal reference to achieve closed-loop locking, thereby realizing wireless frequency synchronization between the master and slave stations in a dynamic environment.

2. The microwave photonics-assisted inter-station wireless frequency synchronization device according to claim 1, characterized in that, The main station includes a first coherent light source, a first tunable filter, a first modulator, a first beam combiner, a first optical amplifier, a first photoelectric converter, a first power amplifier, a second modulator, and a second photoelectric converter; the first tunable filter is connected to the first coherent light source and is used to provide the signal loading branch optical carrier and the local oscillator branch optical carrier; The first modulator is used to modulate the reference signal output by the first phase-locked system onto the optical carrier of the signal loading branch; The first beam combiner is used to combine the output light of the first modulator with the local oscillator branch optical carrier; The first optical amplifier, the first photoelectric converter, and the first power amplifier are connected in sequence to generate and amplify the uplink high carrier frequency wireless signal. The second modulator is used to modulate the received downlink high-carrier frequency radio signal onto an optical carrier; The second photoelectric converter is used to self-mix the output light of the second modulator to recover the feedback second harmonic reference electrical signal.

3. The microwave photonics-assisted inter-station wireless frequency synchronization device according to claim 2, characterized in that, The slave station includes a second coherent light source, a second tunable filter, a third modulator, a third photoelectric converter, a fourth modulator, a second beam combiner, a second optical amplifier, a fourth photoelectric converter, and a fourth power amplifier; the second tunable filter is connected to the second coherent light source and is used to provide the slave station optical carrier. The third modulator is used to modulate the received uplink high carrier frequency wireless signal onto the slave station optical carrier; The third photoelectric converter is used to self-mix the output light of the third modulator to recover the second harmonic reference electrical signal; The fourth modulator is used to modulate the local reference signal generated by the second phase-locked system onto the optical carrier; the second beam combiner is used to combine the output light of the fourth modulator with the local oscillator light of the slave station; the second optical amplifier, the fourth photoelectric converter and the fourth power amplifier are connected in sequence to generate and amplify the downlink high carrier frequency wireless signal.

4. The microwave photonics-assisted inter-station wireless frequency synchronization device according to claim 3, characterized in that, The first and second modulators of the master station, as well as the third and fourth modulators of the slave station, are all configured to operate in carrier-suppressed double-sideband modulation mode.

5. A microwave photonics-assisted inter-station wireless frequency synchronization device according to claim 3, characterized in that, The center carrier frequency of the uplink high carrier frequency radio signal is different from the center carrier frequency of the downlink high carrier frequency radio signal; The first tunable filter and the second tunable filter are respectively configured to filter coherent light with different frequency intervals to generate high carrier frequency wireless signals with different center carrier frequencies by beat frequency method.

6. The microwave photonics-assisted inter-station wireless frequency synchronization device according to claim 1, characterized in that, The first phase-locked system and the second phase-locked system are configured to: select a frequency point close to the Doppler frequency shift corresponding to the relative motion speed between the master station and the slave station for phase locking by multiplying the reference frequency to a frequency point close to the Doppler frequency shift.

7. The microwave photonics-assisted inter-station wireless frequency synchronization device according to claim 1, characterized in that, The master station also includes a high-stability frequency source for providing an internal reference signal to the first phase-locked system; the local reference signal generated by the slave station through the second phase-locked system has the same frequency as the reference signal output by the first phase-locked system, and the phase difference between the two is a fixed constant.

8. A microwave photonics-assisted inter-station wireless frequency synchronization method, applied to the apparatus according to any one of claims 1-7, comprising a physically separated master station and a slave station in relative motion, characterized in that... include: At the master station, a reference signal is generated through the first phase-locked loop system, and an optical carrier is provided using the first coherent light source and the first tunable filter. The reference signal is modulated onto the optical carrier by the first modulator, and after being processed by the first beam combiner, the first optical amplifier, the first photoelectric converter and the first power amplifier, an uplink high carrier frequency wireless signal is generated and sent to the slave station. At the slave station, a slave station optical carrier is provided through a second coherent light source and a second tunable filter. The received uplink high carrier frequency wireless signal is modulated onto the slave station optical carrier using a third modulator. The signal is then self-mixed by a third photoelectric converter to recover a second harmonic reference electrical signal, which is then input into a second phase-locked system to generate a local reference signal. At the slave station, the local reference signal is modulated onto the optical carrier by the fourth modulator, and after being processed by the second beam combiner, the second optical amplifier, the fourth photoelectric converter and the fourth power amplifier, a downlink high carrier frequency wireless signal is generated and fed back to the master station. At the master station, the received downlink high carrier frequency wireless signal is modulated onto an optical carrier using a second modulator. The signal is then self-mixed by a second photoelectric converter to recover the feedback second harmonic reference electrical signal. This signal is then input into a first phase-locked system for phase comparison with an internal reference signal from a high-stability frequency source. Based on the comparison result, the phase of the reference signal is adjusted in a closed loop to compensate for the phase change caused by the relative motion between the master and slave stations, thereby achieving frequency synchronization.

9. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When one or more programs are executed by the one or more processors, the one or more processors implement the microwave photonics-assisted inter-station wireless frequency synchronization method of claim 8.

10. A computer-readable storage medium, characterized in that, It stores executable instructions that, when executed by a processor, enable the processor to implement the microwave photonics-assisted inter-station wireless frequency synchronization method as described in claim 8.

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