Deepwater underwater optical communication test system and method with balancing weight

Abstract

The invention relates to the technical field of underwater optical communication, in particular to a deepwater underwater optical communication test system and method with a balancing weight. The optical communication transceiver unit converts an electric signal into an optical signal based on binary phase shift keying and is used for transmitting data; the optical signal amplification unit is used for receiving the optical signal transmitted by the optical communication transceiving unit and carrying out signal amplification, signal suppression and signal regeneration on the optical signal; the optical communication test unit is used for testing the performance of the underwater optical communication machine; and the ROV control unit adjusts the position of the ROV according to the USBL system data. By integrating the static performance test module and the dynamic performance test module, various performance indexes of the underwater optical communication system, including communication distance, communication rate, beam divergence angle, link stability and reliability, can be comprehensively evaluated; compared with a traditional manual test method, the method has the advantages that personal errors are reduced, and reliability and consistency of test results are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater optical communication, and in particular to a deep-water underwater optical communication test system and method with a counterweight. Background Art

[0002] As the development of offshore oil and gas resources moves towards deep water, the demand for deep-sea pipeline laying and offshore construction has increased significantly. As the S-shaped pipe laying technology at a water depth of more than 100 meters matures, mud point monitoring, as a key link in the laying of submarine pipelines, plays an important role in accurately positioning submarine pipelines and detecting submarine pipeline buckling during the laying of submarine pipelines.

[0003] By using autonomous remote-controlled submersibles to replace manually operated remote-controlled unmanned submersibles and unmanned boats to replace multi-functional operation support vessels to carry out mud spot monitoring operations, a set of intelligent monitoring technology solutions for deep-water pipeline laying has been formed. This will lay a good theoretical foundation and technical support for the realization of intelligent and automated monitoring of deep-water pipeline laying, and lay the foundation for the transition from manned monitoring to unmanned monitoring. However, ARVs cannot communicate with the mother ship in real time, and the operator cannot intervene in its behavior in real time during its operation. It can only perform some relatively simple underwater operation tasks and cannot meet the operational needs under some complex operating conditions.

[0004] Therefore, a deep-water underwater optical communication test system and method with a counterweight is provided. Summary of the invention

[0005] The purpose of the present invention is to provide a deep-water underwater optical communication test system and method with a counterweight block, so as to solve the problem mentioned in the above background technology that the ARV cannot communicate with the mother ship in real time, the operator cannot intervene in its behavior in real time during its operation, and can only perform some relatively simple underwater operation tasks, and cannot meet the operation needs under some complex working conditions.

[0006] To achieve the above object, on the one hand, the present invention aims to provide a deep-water underwater optical communication test system with a counterweight, comprising: An optical communication transceiver unit, which converts electrical signals into optical signals based on binary phase shift keying for transmitting data; An optical signal amplifying unit, the optical signal amplifying unit is used to receive the optical signal transmitted by the optical communication transceiver unit, and perform signal amplification, signal suppression and signal regeneration on the optical signal; An optical communication test unit, the optical communication test unit is used to perform performance test on an underwater optical communication machine; the optical communication test unit includes a static performance test module and a dynamic performance test module; An ROV control unit that adjusts the ROV position based on the USBL system data.

[0007] As a further improvement of the present technical solution, the optical communication transceiver unit includes an optical communication receiving module and an optical communication sending module, the optical communication receiving module is used for receiving optical communication data, and the optical communication sending module is used for sending optical communication data.

[0008] As a further improvement of the technical solution, the steps involved in the optical signal processing by the optical signal amplification unit are: The received signal is amplified based on a linear amplification algorithm, specifically: ; In the formula, Represents the output signal voltage after amplification; Represents the original input signal voltage; represents the amplification gain coefficient; The amplified signal is suppressed based on the Butterworth filter algorithm, specifically: ; In the formula, represents the signal response of the filter to the optical signal at frequency f; Indicates the frequency of the optical signal; represents the center frequency of the filter; It represents the quality factor; The suppressed signal is regenerated based on the signal regeneration algorithm, specifically: ; In the formula, Represents the output signal after regeneration; represents the input signal after the suppression signal; represents the angular frequency of the signal; Indicates the phase adjustment parameter.

[0009] As a further improvement of the technical solution, the static performance test module is used to evaluate the performance of optical communication under static conditions; The static performance test module includes a communication distance test module, a communication rate test module, a beam divergence angle test module and a link stability and reliability test module.

[0010] As a further improvement of the technical solution, the communication distance test module is based on a time-of-flight algorithm for calculating the communication distance. The time-of-flight algorithm is specifically: ; In the formula, Indicates the distance between the transmitter and the receiver; Indicates the speed at which a signal propagates in a medium; Indicates the signal round trip time; Considering the influence of signal loss, a free space path loss model is established based on the time-of-flight algorithm. The free space path loss model is specifically: ; In the formula, represents the free space path loss; Indicates the distance between the transmitter and the receiver; Indicates the signal frequency; In underwater optical communication, in addition to considering the impact of signal loss, the impact of water absorption coefficient and scattering coefficient on optical signals also needs to be considered based on the balance between signal loss and communication distance. The specific functional relationship involved in the impact of the absorption coefficient and scattering coefficient on optical signals is: ; In the formula, represents the total path loss; represents the absorption coefficient; represents the scattering coefficient; Indicates the transmission distance; Introducing the absorption coefficient and scattering coefficient of water into the free space path loss model, the optimized free space path loss model is: ; In the formula, represents the absorption coefficient; represents the scattering coefficient.

[0011] As a further improvement of the technical solution, the communication rate test module is used to evaluate the performance of the communication link under different data transmission rates based on the Shannon capacity algorithm.

[0012] As a further improvement of the present technical solution, the light beam divergence angle test module is based on the light beam divergence angle formula, and its main goal is to determine the communication performance of the optical communication link at different angles.

[0013] As a further improvement of the technical solution, the link stability and reliability test module is used to analyze the performance of the system in multiple dimensions based on a comprehensive scoring algorithm, and the steps of the comprehensive scoring algorithm are: The bit error rate is used to calculate the ratio of the number of bits received in error to the total number of bits transmitted, specifically: BER= ; In the formula, Indicates the number of error bits; Indicates the total number of bits; BER indicates the bit error rate; The packet loss rate is used to calculate the ratio of the number of lost data packets to the total number of sent data packets, specifically: PLR= ; In the formula, Indicates the number of packets lost; Indicates the total number of packets sent; PLR indicates the packet loss rate; The average delay is used to calculate the average transmission time of data from the sending end to the receiving end, specifically: Latency= ; In the formula, Indicates the transmission time of each data packet; Indicates the total number of packets sent; Latency indicates the average delay; As mentioned above, the standard deviation is used to calculate the change in delay, specifically: ; In the formula, Indicates the transmission time of each data packet; Indicates the total number of packets sent; represents standard deviation; The bit error rate, packet loss rate, average delay and standard deviation are combined to form a comprehensive scoring algorithm, which is as follows: ; In the formula, represents the comprehensive score; Indicates the weight of the packet loss rate; Indicates the weight of the packet loss rate; Indicates the weight of the normal delay; Indicates the weight of the standard deviation; BER indicates the bit error rate; PLR indicates the packet loss rate; Latency indicates the average delay; Represents standard deviation.

[0014] As a further improvement of the technical solution, the dynamic performance test module is based on the sliding window maximum and minimum algorithm to evaluate the fluctuation range of the data and help identify extreme values ​​and abnormal situations. The sliding window maximum and minimum algorithm is specifically: ; ; In the formula, Represents the maximum value of the sliding window at time t; Represents the minimum value of the sliding window at time t; Indicates the window size; represents the maximum value function, represents the minimum function; Substitute the comprehensive scoring algorithm into the sliding window maximum and minimum algorithms to dynamically evaluate the bit error rate, packet loss rate, average delay, and standard deviation fluctuation range, specifically: ; In the formula, represents the comprehensive performance evaluation value at time t; Indicates the weight of the packet loss rate; Indicates the weight of the packet loss rate; Indicates the weight of the normal delay; represents the weight of the standard deviation; represents the maximum value of the bit error rate sliding window at time t; represents the minimum value of the bit error rate sliding window at time t; Represents the maximum value of the packet loss rate sliding window at time t; Represents the minimum value of the packet loss rate sliding window at time t; represents the maximum value of the average delay sliding window at time t; Represents the minimum value of the average delay sliding window at time t; represents the maximum value of the delay standard deviation sliding window at time t; Represents the minimum value of the sliding window of the delay standard deviation at time t.

[0015] On the other hand, the present invention provides a deep-water underwater optical communication test method with a counterweight, which is used in any one of the deep-water underwater optical communication test systems with a counterweight as described above, comprising the following steps: S10.1. The ROV and repeater end are deployed by means of the cooperation of the crane, winch, guide pulley and fixing; S10.2, control the ROV to a certain depth, and turn on the optical communication transceiver units (1) at both ends to prepare for the underwater optical communication device performance test; S10.3. Perform communication distance test, communication rate test, beam divergence angle test, and link stability and reliability test through the static performance test module; S10.4, control the ROV to move at a low speed, and the dynamic performance test module observes the communication link status in the moving state; S10.5. After completing the test of the optical communication test unit (3), turn off the optical communication transceiver unit (1) and control the ROV to surface; S10.6. Recover the ROV and repeater to the tugboat deck; S10.7. Rinse the ROV, repeater and other equipment with fresh water and inspect the equipment. If no problems are found, power off the ROV and the dive test is completed.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. A deep-water underwater optical communication test system and method with a counterweight block can comprehensively evaluate various performance indicators of the underwater optical communication system, including communication distance, communication rate, beam divergence angle, link stability and reliability, by integrating static performance test modules and dynamic performance test modules; through the coordinated work of ROV and repeater, the whole process from deployment to recovery is automated, greatly improving the test efficiency and accuracy; compared with the traditional manual test method, the present invention reduces human errors and ensures the reliability and consistency of the test results.

[0017] 2. In a deep-water underwater optical communication test system and method with a counterweight, the precise deployment and recovery of the ROV and repeater are achieved through the cooperation of the crane, winch and guide pulley, ensuring the stable operation of the test equipment at different depths and environments; the dynamic performance test module can observe the state of the communication link when the ROV moves at a low speed, and evaluate the performance of the system under actual working conditions; in addition, through fresh water flushing and equipment inspection, the long-term reliability and maintainability of the equipment are guaranteed. Compared with the prior art, the present invention not only improves the adaptability and flexibility of the test, but also extends the service life of the equipment and reduces maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the overall flow chart of the present invention; The meaning of each number in the figure is: 1. Optical communication transceiver unit; 2. Optical signal amplification unit; 3. Optical communication test unit; 4. ROV control unit. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1: Please refer to Figure 1 As shown, a deep-water underwater optical communication test system with a counterweight is provided, comprising: An optical communication transceiver unit 1, which converts an electrical signal into an optical signal based on binary phase shift keying for transmitting data; An optical signal amplifying unit 2, the optical signal amplifying unit 2 is used to receive the optical signal transmitted by the optical communication transceiver unit, and perform signal amplification, signal suppression and signal regeneration on the optical signal; An optical communication test unit 3, the optical communication test unit 3 is used to perform a performance test on an underwater optical communication machine; the optical communication test unit 3 includes a static performance test module and a dynamic performance test module; The ROV control unit 4 adjusts the ROV position according to the USBL system data.

[0021] The optical communication transceiver unit 1 comprises an optical communication receiving module and an optical communication sending module. The optical communication receiving module is used for receiving optical communication data, and the optical communication sending module is used for sending optical communication data.

[0022] The optical communication transceiver unit 1 adopts binary phase shift keying to change the phase of the carrier signal to transmit information; the carrier signal of the binary phase shift keying can be expressed as: ; In the formula, Indicates the signal amplitude; Indicates the carrier frequency; Indicates phase; represents pi; represents the instantaneous value of the optical signal at time t.

[0023] The optical communication transceiver unit 1 comprises an optical communication receiving module and an optical communication sending module. The optical communication receiving module is used for receiving optical communication data, and the optical communication sending module is used for sending optical communication data.

[0024] The steps involved in the optical signal processing by the optical signal amplifying unit 2 are: The received signal is amplified based on a linear amplification algorithm, specifically: ; In the formula, Represents the output signal voltage after amplification; Represents the original input signal voltage; represents the amplification gain coefficient; The amplified signal is suppressed based on the Butterworth filter algorithm, specifically: ; In the formula, represents the signal response of the filter to the optical signal at frequency f; Indicates the frequency of the optical signal; represents the center frequency of the filter; It represents the quality factor; The suppressed signal is regenerated based on the signal regeneration algorithm, specifically: ; In the formula, Represents the output signal after regeneration; represents the input signal after the suppression signal; represents the angular frequency of the signal; Indicates the phase adjustment parameter.

[0025] The static performance test module is used to evaluate the performance of optical communications under static conditions; The static performance test module includes a communication distance test module, a communication rate test module, a beam divergence angle test module and a link stability and reliability test module.

[0026] The communication distance test module is based on the time flight algorithm and is used to calculate the communication distance. The time flight algorithm is specifically: ; In the formula, Indicates the distance between the transmitter and the receiver; Indicates the speed at which a signal propagates in a medium; Indicates the signal round trip time; The specific steps involved in modeling the free space path loss model are: According to the characteristics of spherical wave propagation, the signal strength at the receiving point is: ; In the formula, Indicates the received power; Indicates the transmit power; represents the transmit antenna gain; represents the receiving antenna gain; Indicates the signal wavelength; Indicates the distance between the transmitter and the receiver; represents pi; The path loss is defined as the logarithmic value of the ratio of the transmit power Pt to the receive power Pr, which can be simplified as follows: ; Where, L represents the path loss definition; represents the transmit antenna gain; represents the receiving antenna gain; Indicates the signal wavelength; Using the properties of logarithms, we can further split the data into: ; Further simplification yields: ; By calculating the constant term and the variable term and combining the formula, it is specifically: ; ; Substitute c as the speed of light: ; After normalizing the constant term, the final free space path loss formula is: ; Considering the influence of signal loss, a free space path loss model is established based on the time-of-flight algorithm. The free space path loss model is specifically: ; In the formula, represents the free space path loss; Indicates the distance between the transmitter and the receiver; Indicates the signal frequency; In underwater optical communication, in addition to considering the impact of signal loss, the impact of water absorption coefficient and scattering coefficient on optical signals also needs to be considered based on the balance between signal loss and communication distance. The specific functional relationship involved in the impact of the absorption coefficient and scattering coefficient on optical signals is: ; In the formula, represents the total path loss; represents the absorption coefficient; represents the scattering coefficient; Indicates the transmission distance; Introducing the absorption coefficient and scattering coefficient of water into the free space path loss model, the optimized free space path loss model is: ; In the formula, represents the absorption coefficient; represents the scattering coefficient.

[0027] The communication rate test module is used to evaluate the performance of the communication link at different data transmission rates based on the Shannon capacity algorithm. The Shannon capacity formula is specifically: ; In the formula, represents the channel capacity; represents the channel bandwidth; represents the average signal power; represents the average noise power; Represents the signal-to-noise ratio.

[0028] The actual data transmission rate is compared with the calculated channel capacity; if the actual rate is close to or equal to the channel capacity, the channel utilization is very high and the performance is close to optimal; if the actual rate is much lower than the channel capacity, it may mean that there is room for improvement.

[0029] The beam divergence angle test module is based on the beam divergence angle formula. The main goal is to determine the communication performance of the optical communication link at different angles. The beam divergence angle formula is specifically: ; In the formula, represents the beam divergence angle; Indicates the wavelength of the signal; represents the initial diameter of the beam; represents pi; The smaller the beam divergence angle, the slower the beam spreads during propagation, and the more concentrated the energy is, which is conducive to long-distance transmission. On the contrary, the larger the divergence angle, the faster the beam spreads, and the energy is dispersed, which may cause the light intensity received by the receiving end to weaken, affecting the communication quality.

[0030] The receiver field of view angle refers to the maximum angle at which the receiver can effectively receive signals. The receiver field of view angle is specifically: ; In the formula, represents the receiver field of view angle; represents the effective diameter of the receiver; Indicates the distance between the receiver and the light source.

[0031] The larger the field of view of the receiver, the wider the range of optical signals that the receiver can capture, which is conducive to receiving optical signals from different directions. However, if the field of view is too large, more background noise may be received, affecting the quality of the signal.

[0032] The link stability and reliability test module is based on a comprehensive scoring algorithm to analyze the performance of the system in multiple dimensions. It evaluates the overall performance of the link by calculating the performance indicators of bit error rate, packet loss rate, average delay and standard deviation. The steps of the comprehensive scoring algorithm are as follows: The bit error rate is used to calculate the ratio of the number of bits received in error to the total number of bits transmitted, specifically: BER= ; In the formula, Indicates the number of error bits; Indicates the total number of bits; BER indicates the bit error rate; The packet loss rate is used to calculate the ratio of the number of lost data packets to the total number of sent data packets, specifically: PLR= ; In the formula, Indicates the number of packets lost; Indicates the total number of packets sent; PLR indicates the packet loss rate; The average delay is used to calculate the average transmission time of data from the sending end to the receiving end, specifically: Latency= ; In the formula, Indicates the transmission time of each data packet; Indicates the total number of packets sent; Latency indicates the average delay; As mentioned above, the standard deviation is used to calculate the change in delay, specifically: ; In the formula, Indicates the transmission time of each data packet; Indicates the total number of packets sent; represents standard deviation; The bit error rate, packet loss rate, average delay and standard deviation are combined to form a comprehensive scoring algorithm, which is as follows: ; In the formula, represents the comprehensive score; Indicates the weight of the packet loss rate; Indicates the weight of the packet loss rate; Indicates the weight of the normal delay; Indicates the weight of the standard deviation; BER indicates the bit error rate; PLR indicates the packet loss rate; Latency indicates the average delay; Represents standard deviation.

[0033] The lower the comprehensive score S is, the better the stability and reliability of the link is. By adjusting the weights w1, w2, w3, and w4, the analysis results can be optimized according to actual needs and application scenarios. Through this comprehensive scoring algorithm, the stability and reliability of the communication link at the maximum communication distance can be more comprehensively analyzed.

[0034] The dynamic performance test module is based on the sliding window maximum and minimum algorithm to evaluate the fluctuation range of data and help identify extreme values ​​and abnormal situations. The sliding window maximum and minimum algorithm is specifically: ; ; In the formula, Represents the maximum value of the sliding window at time t; Represents the minimum value of the sliding window at time t; Indicates the window size; represents the maximum value function, represents the minimum function; The maximum value of the sliding window indicates the highest value in a specific time period, which is used to detect abnormal peaks or extreme situations. If the maximum value is significantly higher than the normal range, it means that the system has experienced a sharp increase in bit error rate or an increase in packet loss rate in the time period. The minimum value of the sliding window indicates the lowest value in a specific time period, which is used to detect abnormal valleys or extreme situations. If the minimum value is significantly lower than the normal range, it means that the system has experienced a failure or performance degradation in the time period. Substitute the comprehensive scoring algorithm into the sliding window maximum and minimum algorithms to dynamically evaluate the bit error rate, packet loss rate, average delay, and standard deviation fluctuation range, specifically: ; In the formula, represents the comprehensive performance evaluation value at time t; Indicates the weight of the packet loss rate; Indicates the weight of the packet loss rate; Indicates the weight of the normal delay; represents the weight of the standard deviation; represents the maximum value of the bit error rate sliding window at time t; Represents the minimum value of the bit error rate sliding window at time t; Represents the maximum value of the packet loss rate sliding window at time t; Represents the minimum value of the packet loss rate sliding window at time t; represents the maximum value of the average delay sliding window at time t; Represents the minimum value of the average delay sliding window at time t; represents the maximum value of the delay standard deviation sliding window at time t; Represents the minimum value of the sliding window of the delay standard deviation at time t.

[0035] The maximum value of the sliding window can be used to detect whether there is an abnormally high bit error rate peak, packet loss rate evaluation, average delay evaluation, and an indicator to measure data volatility; if Significantly higher than the normal range; this indicates that the system experienced a sharp increase in bit error rate during this period and the network encountered severe congestion or failure during this period; if Significantly lower than the normal range, indicating that the system performance has degraded during this period; if and An increase in the gap between indicates that it is caused by system instability or external interference; Embodiment 2: Embodiment 2 of the present invention differs from Embodiment 1 in that the present embodiment introduces a method for collecting and analyzing static mechanical properties used in a deep-water underwater optical communication test system with a counterweight. A deep-water underwater optical communication test method with a counterweight is used in any of the above-mentioned deep-water underwater optical communication test systems with a counterweight, and comprises the following steps: S10.1. The ROV and repeater end are deployed by means of the cooperation of the crane, winch, guide pulley and fixing; S10.2, control the ROV to a certain depth, and turn on the optical communication transceiver units (1) at both ends to prepare for the underwater optical communication device performance test; S10.3. Perform communication distance test, communication rate test, beam divergence angle test, and link stability and reliability test through the static performance test module; S10.4, control the ROV to move at a low speed, and the dynamic performance test module observes the communication link status in the moving state; S10.5. After completing the test of the optical communication test unit (3), turn off the optical communication transceiver unit (1) and control the ROV to surface; S10.6. Recover the ROV and repeater to the tugboat deck; S10.7. Rinse the ROV, repeater and other equipment with fresh water and inspect the equipment. If no problems are found, power off the ROV and the dive test is completed.

[0036] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only preferred examples of the present invention, and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A deep-water underwater optical communication test system with a counterweight, characterized in that: include: An optical communication transceiver unit (1), wherein the optical communication transceiver unit (1) converts an electrical signal into an optical signal based on binary phase shift keying for transmitting data; An optical signal amplifying unit (2), the optical signal amplifying unit (2) being used to receive the optical signal transmitted by the optical communication transceiver unit (1), and to amplify, suppress and regenerate the optical signal; An optical communication test unit (3), the optical communication test unit (3) being used to perform a performance test on an underwater optical communication device; the optical communication test unit (3) comprising a static performance test module and a dynamic performance test module; An ROV control unit (4), wherein the ROV control unit (4) adjusts the ROV position according to USBL system data.

2. The deep-water underwater optical communication test system with a counterweight according to claim 1, characterized in that: The optical communication transceiver unit (1) comprises an optical communication receiving module and an optical communication sending module, wherein the optical communication receiving module is used for receiving optical communication data, and the optical communication sending module is used for sending optical communication data.

3. The deep-water underwater optical communication test system with a counterweight according to claim 1, characterized in that: The steps involved in the optical signal processing by the optical signal amplification unit (2) are: The received signal is amplified based on a linear amplification algorithm, specifically: Represents the output signal voltage after amplification; Represents the original input signal voltage; represents the amplification gain coefficient; The amplified signal is suppressed based on the Butterworth filter algorithm, specifically: represents the signal response of the filter to the optical signal at frequency f; Indicates the frequency of the optical signal; represents the center frequency of the filter; It represents the quality factor; The suppressed signal is regenerated based on the signal regeneration algorithm, specifically: Represents the output signal after regeneration; represents the input signal after the suppression signal; represents the angular frequency of the signal; Indicates the phase adjustment parameter.

4. The deep-water underwater optical communication test system with a counterweight according to claim 1, characterized in that: The static performance test module is used to evaluate the performance of optical communication under static conditions; The static performance test module includes a communication distance test module, a communication rate test module, a beam divergence angle test module and a link stability and reliability test module.

5. The deep-water underwater optical communication test system with a counterweight according to claim 4, characterized in that: The communication distance test module is used to calculate the communication distance based on the time-of-flight algorithm, and the time-of-flight algorithm is specifically: Indicates the distance between the transmitter and the receiver; Indicates the speed at which a signal propagates in a medium; Indicates the signal round trip time; A free space path loss model is established based on the time-of-flight algorithm. The free space path loss model is specifically: represents the free space path loss; Indicates the distance between the transmitter and the receiver; Indicates the signal frequency; Introducing the absorption coefficient and scattering coefficient of water into the free space path loss model, the optimized free space path loss model is: represents the absorption coefficient; represents the scattering coefficient.

6. The deep-water underwater optical communication test system with a counterweight according to claim 4, characterized in that: The communication rate test module is used to evaluate the performance of the communication link under different data transmission rates based on the Shannon capacity algorithm.

7. The deep-water underwater optical communication test system with a counterweight according to claim 4, characterized in that: The light beam divergence angle test module is used to test the communication performance of the optical communication link at different angles based on the light beam divergence angle formula.

8. The deep-water underwater optical communication test system with a counterweight according to claim 5, characterized in that: The link stability and reliability test module is used to analyze the performance of the system in multiple dimensions based on a comprehensive scoring algorithm, and the steps of the comprehensive scoring algorithm are as follows: The bit error rate is used to calculate the ratio of the number of bits received in error to the total number of bits transmitted, specifically: BER= ; In the formula, Indicates the number of error bits; Indicates the total number of bits; BER indicates the bit error rate; The packet loss rate is used to calculate the ratio of the number of lost data packets to the total number of sent data packets, specifically: PLR= ; In the formula, Indicates the number of packets lost; Indicates the total number of sent data packets; PLR indicates the packet loss rate; The average delay is used to calculate the average transmission time of data from the sending end to the receiving end, specifically: Latency= ; In the formula, Indicates the transmission time of each data packet; Indicates the total number of packets sent; Latency indicates the average delay; As mentioned above, the standard deviation is used to calculate the change in delay, specifically: Indicates the transmission time of each data packet; Indicates the total number of packets sent; represents standard deviation; The bit error rate, packet loss rate, average delay and standard deviation are combined to form a comprehensive scoring algorithm, which is as follows: represents the comprehensive score; Indicates the weight of the packet loss rate; Indicates the weight of the packet loss rate; Indicates the weight of the normal delay; represents the weight of the standard deviation; BER represents the bit error rate; PLR means packet loss rate; Latency means average delay; Represents standard deviation.

9. The deep-water underwater optical communication test system with a counterweight according to claim 4, characterized in that: The dynamic performance test module is based on the sliding window maximum and minimum algorithm, which is used to evaluate the fluctuation range of data and help identify extreme values ​​and abnormal situations. The sliding window maximum and minimum algorithm is specifically: Represents the maximum value of the sliding window at time t; Represents the minimum value of the sliding window at time t; Indicates the window size; represents the maximum value function, represents the minimum function; Substitute the comprehensive scoring algorithm into the sliding window maximum and minimum algorithms to dynamically evaluate the bit error rate, packet loss rate, average delay, and standard deviation fluctuation range, specifically: represents the comprehensive performance evaluation value at time t; Indicates the weight of the packet loss rate; Indicates the weight of the packet loss rate; Indicates the weight of the normal delay; represents the weight of the standard deviation; represents the maximum value of the bit error rate sliding window at time t; Represents the minimum value of the bit error rate sliding window at time t; Represents the maximum value of the packet loss rate sliding window at time t; Represents the minimum value of the packet loss rate sliding window at time t; represents the maximum value of the average delay sliding window at time t; Represents the minimum value of the average delay sliding window at time t; represents the maximum value of the delay standard deviation sliding window at time t; Represents the minimum value of the sliding window of the delay standard deviation at time t.

10. A deep-water underwater optical communication test method with a counterweight, used in a deep-water underwater optical communication test system with a counterweight as claimed in any one of claims 1 to 9, characterized in that: The steps include: S10.

1. The ROV and repeater end are deployed by means of the cooperation of the crane, winch, guide pulley and fixing; S10.2, control the ROV to a certain depth, and turn on the optical communication transceiver units (1) at both ends to prepare for the underwater optical communication device performance test; S10.

3. Perform communication distance test, communication rate test, beam divergence angle test, and link stability and reliability test through the static performance test module; S10.4, control the ROV to move at a low speed, and the dynamic performance test module observes the communication link status in the moving state; S10.

5. After completing the test of the optical communication test unit (3), turn off the optical communication transceiver unit (1) and control the ROV to surface; S10.

6. Recover the ROV and repeater to the tugboat deck; S10.

7. Rinse the ROV, repeater and other equipment with fresh water and inspect the equipment. If no problems are found, power off the ROV and the dive test is completed.

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