Autonomous learning regulation laser communication device based on channel characteristics

Abstract

The invention relates to the technical field of space laser communication, and discloses a laser communication device based on autonomous learning regulation and control of channel characteristics, which comprises an autonomous regulation and control communication transmitting end, an autonomous regulation and control communication receiving end and an alignment capture tracking module, the device can realize self-adaptive switching between rates V1-V4 and modulation formats M1 / M2 in a complex channel environment, and supports a quick rollback strategy under the conditions of communication out-of-step and link fading; compared with the prior art, miniaturization and full-duplex self-adaptive regulation and control capability of the laser communication device are realized, the link stability and the channel utilization rate are remarkably improved, and the requirements of micro-nano satellites on low-power-consumption and high-reliability laser communication are met.

Description

Technical Field

[0001] This invention relates to the field of space laser communication technology, specifically to a laser communication device based on autonomous learning and control of channel characteristics. Background Technology

[0002] Microsatellites and nanosatellites traditionally use radio frequency (RF) communication. However, the limitations of RF communication are becoming increasingly apparent: limited data transmission rates, susceptibility to interference, poor security, and limited spectrum resources. Space laser communication, which uses light as a carrier to transmit data through the atmosphere, overcomes the shortcomings of traditional RF communication in several ways. First, its narrow beam significantly improves transmission rates and reduces signal loss. Second, electromagnetic effects do not affect the communication performance of laser communication; it possesses strong anti-interference capabilities and is more difficult to intercept and interfere with compared to RF communication, resulting in higher security at the physical layer. Finally, it has richer spectrum resources, and spectrum allocation and constraints are not as limited as those of RF communication.

[0003] Leveraging the advantages of laser communication, it has demonstrated enormous potential in the field of satellite communication. High-speed data transmission between satellites and between satellites and the ground can be achieved through space laser communication, which has become one of the key technologies for low-Earth orbit satellite internet. Micro- and nano-satellite payloads are limited in space and power, with the total satellite mass generally not exceeding 50 kg. The proportion that can be allocated to traditional payloads is no more than 30%. Traditional alignment, acquisition, and tracking systems typically consist of optical telescopes, mechanical turntables, high-power actuators, and high-performance detectors, weighing more than ten kilograms and generating tens of watts of power, which is insufficient to meet the needs of micro- and nano-satellite payloads.

[0004] Remote sensing micro- and nano-satellites require high downlink transmission rates. Traditional radio frequency (RF) technology struggles to quickly and timely transmit high-resolution images to the ground. Laser communication is well-suited for this task. The uplink only needs to transmit commands, so the communication rate requirement is not high, and low-order, stable modulation methods can be used. However, space laser communication is susceptible to turbulence and atmospheric absorption during transmission through the atmosphere, resulting in poor communication efficiency.

[0005] In a space-to-ground communication scenario, the transmitting section of the communication device loads remote sensing image data through a modulation module and converts it into an optical carrier signal for transmission to the ground station. Upon receiving the optical signal, the receiving section of the ground station's communication device performs high-sensitivity demodulation using a coherent receiving module, while simultaneously enhancing the reception effect with a reference optical signal provided by a local oscillator light source. If atmospheric turbulence causes a shift in the optical path, the four-segment detector in the optical path alignment unit quickly detects the change in the light spot position and adjusts the optical path direction using a MEMS miniature galvanometer to ensure the continuity of the communication link.

[0006] When complex channel environments cause fluctuations in the bit error rate (BER), the transmitting section of the communication device dynamically adjusts the transmission rate and modulation mode. For example, in the initial state, the transmitter sends a pseudo-random sequence to the receiver at the lowest rate, and the receiver counts the BER and compares it with a preset threshold. If the BER is low, the transmitter switches to a high-rate mode and uses a more efficient modulation method; if the BER is high, it reverts to the default modulation mode and reduces the transmission rate to cope with adverse channel conditions. This process is implemented by the logic control module communicating with the microprocessor via a digital bus, ensuring the adaptive capability of the communication system.

[0007] Therefore, this invention proposes a laser communication device based on autonomous learning and control of channel characteristics to solve the above problems. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a laser communication device based on autonomous learning and control of channel characteristics. By autonomously controlling the communication transmitter, the communication receiver, and the alignment, acquisition, and tracking module, the communication rate and modulation format are switched according to the channel state, ensuring the effectiveness of communication, miniaturizing the communication device, and solving the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention specifically adopts the following technical solution: A laser communication device based on channel characteristics autonomous learning and control includes an autonomous control communication transmitter, an autonomous control communication receiver, and an alignment, acquisition, and tracking module. It achieves the goal of autonomously controlling the communication rate and modulation format adaptively according to channel characteristics, meeting the miniaturization requirements of micro / nano communication devices.

[0010] This invention provides a miniaturized, full-duplex laser communication device that can autonomously adapt and switch modulation formats and communication rates according to channel conditions. It includes: an autonomously adjustable communication transmitter, an autonomously adjustable communication receiver, and an alignment, acquisition, and tracking module. The autonomous control communication transmitter includes a laser, an electro-optic modulator, an RF input module, an FPGA, an MCU, and an SFP+, which loads signals onto light waves to transmit information; The autonomous control receiver includes a coherent receiver, an FPGA, and an ADC; the coherent receiver section includes a 90° optical bridge, a balanced detector, and a local oscillator light source. The alignment, capture, and tracking module includes a photoelectric detection section, an integrated control section, and a tracking control section; The transmitting end of communication device A sends serial data to the receiving end of communication device B. The data includes a frame header designed by end A, the expected transmission rate of end A, and the pseudo-random sequence K1 to the receiving end of communication device B. The frame header is used to determine the position of user data, and the pseudo-random sequence K1 is a sequence preset by communication device A; after receiving the serial data, communication device B generates a pseudo-random sequence K2 according to a preset rule, calculates the number of bits of the error code with different codes of pseudo-random sequences K1 and K2, and selects the transmission rate for the next cycle; The pseudo-random sequence K1 transmits F frames of control data as a statistical cycle. The length of the pseudo-random sequence of each frame is l, and the length of the pseudo-random sequence within each cycle is F l (both F and l are integers). After each statistical cycle, the number of error codes of pseudo-random sequences K1 and K2 is counted; When the transmission rate of communication device A after statistical calculation is V1, if the bit error rate is less than threshold one, in the next statistical cycle, the bias voltage of the MZM is adjusted through the FPGA and DAC, the modulation format is regulated, and it is switched to modulation format M2 and the transmission rate V4 is switched. Otherwise, if the bit error rate is greater than threshold two, the communication rate of communication device A in the next cycle remains V1, and the modulation format remains M1. The V1 < V4; When the communication rate transmitted in the previous cycle is V1, if the bit error rate is less than threshold three, communication device A selects communication rate V2 in the next cycle. If the bit error rate is greater than threshold four, the communication rate remains unchanged in the next cycle and is still V1. The communication rate V1 < V2; the threshold three is less than threshold four, and both threshold one and threshold two are less than F l; When the communication rate of communication device A in the previous cycle is V2, if the bit error rate is less than threshold three, the transmission rate of communication device A in the next cycle is V3. If the bit error rate is less than threshold four, communication device A still maintains the communication rate V2 in the next cycle. The communication rate V2 < V3; When the transmission rate of communication device A in the previous cycle is V3, if the bit error rate is less than threshold three, the transmitting end selects transmission rate V4 in the next cycle. If the bit error rate is greater than threshold four, the transmission rate remains V3 in the next cycle. The transmission rate V3 < V4; Optionally, communication device A and communication device B can achieve the switching of communication rates among V1, V2, V3, V4 and the switching between modulation formats M1 and M2 through the following method; Clock one and clock two are provided by a crystal oscillator. The clock frequencies of clock three and clock four are generated by a frequency multiplier as multiples of the clock frequencies of clock one and clock two; clock one corresponds to communication rate V1, clock two corresponds to communication rate V2, clock three corresponds to communication rate V3, and clock four corresponds to communication rate V4; The pseudo-random sequence generator is used to generate a pseudo-random sequence K2 based on the serial data received by the communication device B; the control data is used to select the expected value of the communication rate of the communication device in the next cycle based on the bit error rate between the pseudo-random sequences K1 and K2 as a criterion. Optionally, when the transmitted synchronization code data and valid signal fail to achieve synchronized transmission, i.e., when frame synchronization is lost, if the modulation format is M1 and the selected communication rate of the previous cycle is communication rate V1, the communication rate of the next module remains at communication rate V1; if the modulation format is M2 and the communication rate is V4, the communication rate of the communication device in the next cycle is selected as V1, and the modulation format is switched to M1; if the modulation format of the previous cycle is M1 and the communication rate is communication rate V2, communication rate V3, or communication rate V4, the communication rate of the communication device in the next cycle is selected as the transmission rate V1; if severe frame loss or severe signal attenuation occurs during communication, the control alignment, acquisition, and tracking module realigns, maintaining the lowest speed state V1 and modulation format M1 until frame synchronization is achieved again. Furthermore, the laser communication terminal based on channel autonomous learning and control includes an autonomous control communication transmitter, an autonomous control communication receiver, and an alignment, acquisition, and tracking module. The laser is emitted as a carrier at the transmitter. First, data is modulated onto the light source by an optical modulator and then transmitted to the atmospheric channel. The receiver receives the information-carrying optical carrier, and a photodetector converts the optical signal into an electrical signal. Signal processing and demodulation are then performed. Specifically, pseudo-random coding is modulated and then transmitted to the atmospheric channel using a 1550nm laser as the carrier in an MZM modulator. After receiving the laser signal transmitted from the atmospheric channel, the receiver receives the signal through a four-quadrant detector, completing the photoelectric conversion. The signal is then demodulated by a coherent receiving section to achieve electrical signal reception. Furthermore, the laser is transmitted to the receiving end in the atmospheric channel. After being reflected by the MEMS galvanometer and the beam splitter, the laser is focused on the target surface of the four-quadrant detector through the optical path to form a light spot of a suitable size. The radius of the light spot is less than one-quarter of the target surface of the four-quadrant detector. The photocurrent generated in the four quadrants is determined according to the energy distribution of the light spot in the four quadrants. Each path is amplified by transimpedance and converted into an amplified voltage signal. Furthermore, after the analog signal output from the photoelectric amplifier is converted into a digital signal through digital-to-analog conversion, the offset of the light spot position and the tracking execution quantity are converted into pitch angle and azimuth angle by the MCU as the execution unit. After the digital quantity is converted into an analog quantity through analog-to-digital conversion, the MEMS galvanometer is controlled to complete the angle deflection. The FPGA chip implements the modulation and demodulation function. It sums the four voltage signals by addition, recovers the demodulation clock information by clocking, and transmits the recovered clock and data to the FPGA to complete the data demodulation. Compared with the prior art, the present invention provides a laser communication device based on autonomous learning and control of channel characteristics, which has the following beneficial effects: This invention designs a miniaturized laser communication device that integrates the alignment, acquisition, and tracking module, significantly reducing the size, weight, and cost of the laser communication device. It enables full-duplex communication by assessing channel conditions based on the receiver's reception, solving the problems of unstable communication links and low channel utilization caused by fixed communication rates and single modulation formats in traditional laser communication. Attached Figure Description

[0011] Figure 1 A flowchart of the laser communication device based on channel characteristic autonomous learning and control provided by the present invention; Figure 2 This is a schematic diagram of the laser communication device system model of the present invention; Figure 3 This is a schematic diagram of the laser communication device based on channel characteristic autonomous learning and control according to the present invention; Figure 4 This is a schematic diagram of the alignment, capture, and tracking module structure of the present invention; Figure 5 This is a schematic diagram of the rate and modulation switching structure of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] This invention provides a laser communication device based on autonomous learning and control of channel characteristics. The design flowchart of the laser communication device is as follows: Figure 1 As shown, it includes the following steps: Step 1: Construct a model of a laser communication device based on autonomous learning and control of channel characteristics; Step 2: Construct the transmitter of the self-learning and controllable laser communication device, and construct the signal processing module, including an FPGA chip as the main control chip, pseudo-random encoding of the transmitter, control of bias voltage; analog-to-digital converter, STM32, digital-to-analog converter, MEMS driver; Step 3: Construct the receiver of the self-learning and controllable laser communication device, including a coherent receiving module, a logic control module, and a digital-to-analog conversion module; Step 4: Construct the alignment, acquisition, and tracking module, including the photoelectric detection section, the integrated control section, and the tracking control section; Specifically, communication device models such as Figure 2 The diagram shows the transmitting part of the communication device, the receiving part of the communication device, and the alignment, acquisition, and tracking module. The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0014] The internal structure of the transmitting section of the communication device is as follows: Figure 3 As shown, the laser source generates continuous-wave laser light, which, after being loaded with information by the electro-optic modulator in the modulation module, forms a carrier signal. The modulation module adjusts the operating state of the electro-optic modulator through the bias voltage signal output by the logic control module to switch the modulation mode of signal transmission. The RF input module loads the information to be transmitted onto the modulated optical carrier, and the interface module serves as a port for signal debugging and loopback testing to achieve signal self-testing. The laser source and modulation module are connected via optical fiber, and the modulation module and RF input module are connected via RF cable. The logic control module communicates with the modulation module via a digital bus, and also connects to the interface module via a dedicated interface for signal debugging and loopback testing.

[0015] The structure of the receiving part of the communication device is as follows: Figure 3 As shown, the coherent receiving module includes a beam splitter, a balanced detector, and a local oscillator light source. The beam splitter splits the incident light into two orthogonal optical signals, the balanced detector performs differential detection on the two optical signals to generate an electrical signal, and the local oscillator light source provides a stable reference optical signal for the coherent receiving module. The analog-to-digital converter (ADC) module converts the analog signal output from the balanced detector into a digital signal for demodulation and processing by the logic control module. The beam splitter is connected to an external optical path via optical fiber, the balanced detector is connected to the ADC module via a coaxial cable, the local oscillator light source is connected to the beam splitter via optical fiber to provide a stable reference optical signal, and the logic control module communicates with the ADC module via a digital bus to complete signal demodulation and processing.

[0016] The working principle of the optical path alignment unit is as follows: Figure 4As shown, the optical signal detection module includes a four-quadrant detector for receiving optical signals and generating corresponding photocurrent signals. The photocurrent signals are amplified by a transimpedance amplifier and then sent to an analog-to-digital converter (ADC) for digital processing. The integrated control module calculates the positional offset of the light spot on the detector based on the digitized signal and outputs a control signal to the optical path tracking module via the ADC. The optical path tracking module includes a miniature mirror and its driving circuit. The MEMS miniature mirror adjusts the optical path direction through dual-axis rotation, and the driving circuit drives the miniature mirror to complete the deflection action according to the control signal output by the integrated control module. The four-quadrant detector is connected to the external optical path via optical fiber. The transimpedance amplifier is connected to the ADC via a coaxial cable. The integrated control module communicates with the ADC via a digital bus and also connects to the ADC via a dedicated interface to output control signals. The ADC connects to the MEMS miniature mirror via the driving circuit to complete the adjustment of the optical path direction.

[0017] The bias voltage control in the modulation module employs a pilot signal calibration method, which involves introducing a low-frequency pilot signal into the modulation signal to monitor the operating point drift of the electro-optic modulator in real time. The logic control module adjusts the bias voltage based on the feedback information from the pilot signal to maintain the stable operation of the electro-optic modulator. The pilot signal calibration module is connected to the modulation module via an RF cable to introduce a low-frequency pilot signal. The logic control module communicates with the pilot signal calibration module via a digital bus to obtain feedback information from the pilot signal and adjusts the bias voltage accordingly.

[0018] The transmitting section of the communication device dynamically adjusts the signal transmission rate and modulation mode based on the channel bit error rate (BER). The transmitter sends a pseudo-random sequence to the receiver, which counts the number of bit errors between the received pseudo-random sequence and the transmitted sequence. When the BER is below a first threshold, the transmitter switches to a high-rate mode and adjusts the modulation mode; when the BER is above a second threshold, the transmitter maintains the current transmission rate and modulation mode. If frame synchronization is not achieved, the transmitting section dynamically adjusts the transmission parameters for the next cycle based on the current transmission rate. If the current rate is the minimum rate, it remains unchanged; if the current rate is higher, it switches to the minimum rate mode and restores the default modulation mode. The logic control module communicates with the microprocessor via a digital bus to obtain BER information and adjusts the signal transmission rate and modulation mode accordingly.

[0019] In practical applications, the transmitting section of the communication device first generates a continuous-wave laser using a laser source. This laser, after being modulated by a modulation module, forms a carrier signal and is transmitted to the external optical path via optical fiber. The modulation module adjusts the operating state of the electro-optic modulator using a bias voltage signal output from the logic control module to switch the modulation mode of the signal transmission. The RF input module loads the information to be transmitted onto the modulated optical carrier. The interface module serves as a port for signal debugging and loopback testing, enabling signal self-testing. The signal receiving unit receives the optical signal transmitted from the external optical path through a coherent receiving module. A beam splitter splits the incident light to generate two orthogonal optical signals. A balanced detector performs differential detection on the two optical signals to generate an electrical signal. A local oscillator provides a stable reference optical signal for the coherent receiving module. The analog-to-digital converter (ADC) converts the analog signal output from the balanced detector into a digital signal for demodulation and processing by the logic control module. The optical path alignment unit receives the optical signal through a four-quadrant detector and generates a corresponding photocurrent signal. This photocurrent signal is amplified by a transimpedance amplifier and then sent to the ADC for digital processing. The integrated control module calculates the position offset of the light spot on the detector based on the digitized signal and outputs a control signal to the optical path tracking module via the digital-to-analog converter. The optical path tracking module adjusts the optical path direction using a MEMS micro-mirror and its driving circuit to ensure accurate transmission of the optical signal. The bias voltage control in the modulation module employs a pilot signal calibration method. By introducing a low-frequency pilot signal into the modulation signal, the operating point drift of the electro-optic modulator is monitored in real time. The logic control module adjusts the bias voltage based on the feedback information from the pilot signal to maintain the stable operation of the electro-optic modulator. The transmitting section of the communication device dynamically adjusts the signal transmission rate and modulation mode based on the channel bit error rate. The transmitter sends a pseudo-random sequence to the receiver. The receiver counts the bit error rate between the received pseudo-random sequence and the transmitted sequence. When the bit error rate is below a first threshold, the transmitter switches to a high-rate mode and adjusts the modulation mode. When the bit error rate is above a second threshold, the transmitter maintains the current transmission rate and modulation mode. When the transmission part of the communication device has not reached the frame synchronization state, it dynamically adjusts the transmission parameters of the next cycle according to the current transmission rate. If the current rate is the lowest rate, it keeps the current rate unchanged. If the current rate is a higher rate, it switches to the lowest rate mode and restores the default modulation mode.

[0020] To enable those skilled in the art to fully understand and implement this invention, the specific implementation principle of this invention will be further explained below in conjunction with a specific application scenario.

[0021] In the laser communication system of micro-nano satellites, the transmitting part of the communication device first generates a continuous-wave laser through a laser source, which is transmitted to the modulation module via optical fiber. The electro-optic modulator in the modulation module loads information based on the bias voltage signal output by the logic control module, forming a carrier signal carrying data. The RF input module loads the information to be transmitted onto the modulated optical carrier and completes signal debugging and loopback testing through the interface module to ensure signal quality. If the channel environment changes, the logic control module adjusts the bias voltage based on the low-frequency pilot signal fed back by the pilot signal calibration module, thereby maintaining the stable operation of the electro-optic modulator.

[0022] The receiving section of the communication device receives optical signals transmitted from the external optical path via a coherent receiving module. A beam splitter divides the incident light into two orthogonal optical signals, and a balanced detector performs differential detection on these two signals to generate an electrical signal. A local oscillator provides a stable reference optical signal to the coherent receiving module, improving receiving sensitivity. An analog-to-digital converter digitizes the analog signal output from the balanced detector and transmits it to the logic control module for demodulation and processing. During this process, the logic control module dynamically adjusts the signal transmission rate and modulation mode based on the bit error rate (BER). For example, when the BER is below a first threshold, the transmitter switches to a high-rate mode and optimizes the modulation scheme; when the BER is above a second threshold, the current transmission parameters remain unchanged to ensure the stability of the communication link.

[0023] The optical alignment unit receives optical signals and generates corresponding photocurrent signals through a four-segment detector. These photocurrent signals are amplified by a transimpedance amplifier and then sent to an analog-to-digital converter for digital processing. The integrated control module calculates the positional offset of the light spot on the detector and outputs control signals to the MEMS micromirror and its driving circuit via the digital-to-analog converter. The MEMS micromirror adjusts the optical path direction through dual-axis rotation, ensuring that the optical signal is accurately focused on the receiver. Furthermore, the integrated control module incorporates an embedded processor that calculates the light spot offset in real time and generates angle adjustment commands, further improving the optical alignment accuracy.

[0024] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 laser communication device based on channel characteristics with autonomous learning and control, comprising an autonomous control communication transmitter, an autonomous control communication receiver, and an alignment, acquisition, and tracking module; the autonomous control transmitter includes a laser, an electro-optic modulator, an RF input module, an FPGA, an MCU, and an SFP+; the autonomous control receiver includes a coherent receiver, an FPGA, and an ADC; the coherent receiver includes a 90° optical bridge, a balanced detector, and a local oscillator; the alignment, acquisition, and tracking module includes a photoelectric detection section, a comprehensive control section, and a tracking control section.

2. The laser communication device based on channel characteristics and autonomous learning control according to claim 1, characterized in that, It emits laser through a laser, and after passing through an MZM modulator and a radio frequency transmission module, the loaded information is transmitted with light as the carrier. The transmitted pseudo-random sequence K1 at the transmitting end is sent to the receiving end. The number of error codes between the received pseudo-random sequence K2 at the receiving end and the transmitted pseudo-random sequence K1 at the transmitting end. The transmitted pseudo-random sequence K1 takes the transmitted F-frame control data as a statistical period. The length of the transmitted pseudo-random sequence K1 for each frame is l, and the length of the pseudo-random sequence within each period is F l; both F and l are integers. The receiving end calculates the number of error codes of the two groups of pseudo-random sequences. When the transmission rate of the transmitting end calculated in the previous period is the transmission rate V1, if the bit error rate is less than threshold one, then the modulation format M2 is switched in the next statistical period, and the transmission rate V4 is switched. Otherwise, when the bit error rate is greater than threshold two, the transmitting end still maintains the transmission rate V1 in the next period, and the modulation format is M1, and the transmission rate V1 < V4; when the expected transmission rate in the previous period is the transmission rate V1, the bit error rate is less than threshold three, and the transmitting end selects the transmission rate V2 in the next period. If the bit error rate is greater than threshold four, then the transmission rate V1 is still maintained in the next period, and the transmission rate V1 < V2; when the transmission rate of the transmitting end in the previous period is V2, the bit error rate is less than threshold three, then the transmitting end selects the transmission rate V3 in the next period. If the bit error rate is greater than threshold four, then the transmission rate V2 is maintained in the next period, and the transmission rate V2 < V3; when the transmission rate of the transmitting end in the previous period is V3, the bit error rate is less than threshold three, then the transmitting end selects the transmission rate V4 in the next period. If the bit error rate is greater than threshold four, then the transmission rate V3 is maintained in the next period, and the transmission rate V3 < V4; the threshold one is less than the threshold three is less than the threshold four is less than the threshold two.

3. The laser communication device based on channel characteristics and autonomous learning control according to claim 1, characterized in that, It enables MZM modulators to reduce DC operating point drift and achieve accurate modulation format; SFP+ serves as the interface for Ethernet services and debugging.

4. The laser communication device based on channel characteristics and autonomous learning control according to claim 1, characterized in that... The photoelectric detection section includes a four-quadrant detector, the tracking control section includes a MEMS galvanometer and galvanometer driver, and the integrated control section includes an ADC, a DAC, an MCU, and an FPGA.

5. The laser communication device based on channel characteristics and autonomous learning control according to claim 2, characterized in that: When the transmitted synchronization code data and valid signal fail to achieve synchronized transmission, i.e., when the frame synchronization is lost, if the transmission rate of the transmitting end is transmission rate V1, the transmission rate of the next cycle will remain at transmission rate V1; if the expected transmission rate is V2, V3, or V4, the transmission rate will switch to transmission rate V1 in the next cycle; if the transmission rate is V4 and the modulation format is M2, the transmitting end will switch to transmission rate V1 and modulation format M1 in the next cycle.

6. The laser communication device based on channel characteristics and autonomous learning control according to claim 5, characterized in that: When the photoelectric detection part transmits the light to the target surface of the four-quadrant detector, the photocurrent is generated accordingly based on the energy distribution of the light spot in the four quadrants. The photocurrent is then amplified by transimpedance and converted into a digital signal by analog-to-digital conversion.

7. The laser communication device based on channel characteristics and autonomous learning control according to claim 5, characterized in that: The STM32 sub-part of the integrated control section obtains the spot offset from the digital signal transmitted by the four-quadrant detector, calculates the change in the dual axes of the MEMS galvanometer, and transmits the position signal to be deflected to the galvanometer driver through the digital-to-analog module, thereby controlling the galvanometer deflection; the FPGA part completes the communication transmission through modulation and demodulation.

Images