Free space optical communication link simulation analysis method and interface system

Abstract

The invention discloses a free space optical communication link simulation analysis method and an interface system, relates to the technical field of optical communication, and aims to solve the problems in the prior art. A free space optical communication link simulation analysis method comprises the following steps: determining a link type, determining a receiving and transmitting terminal, configuring parameters of the receiving and transmitting terminal, configuring link parameters, calculating gain of the receiving and transmitting terminal, calculating directional loss, calculating channel transmission loss, calculating link allowance and displaying a calculation result, and covering deep space, near ground and inter-satellite link scenes by a model. And quantitatively evaluating the link performance through a formula. The free space optical communication link simulation interface system comprises the following modules: link type selection, data input, link budgeting, visual analysis and output, support parameter configuration, real-time calculation and chart display, and standardized report generation. According to the scheme, the problems of insufficient parameter coverage and poor interactivity of a traditional method are solved, configuration-calculation-analysis integration is realized, and the link design optimization efficiency and the user experience are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to a free-space optical communication link simulation analysis method and an interface system. Background Art

[0002] Free-space optical communication (FSOC) utilizes lasers to transmit data in free space, offering advantages such as high bandwidth, low latency, and robustness to electromagnetic interference. However, FSCO is susceptible to factors such as atmospheric turbulence, weather conditions, and optical path loss, leading to unstable link performance. Existing simulation and analysis methods typically rely on a single model, making it difficult to comprehensively account for the impact of multiple environmental factors. Furthermore, they lack user-friendly interfaces, limiting analysis efficiency and accuracy.

[0003] In the journal Wireless Communications, Liu Dachang et al. published a paper titled "Performance Budget for Space Optical Communications in Atmospheric Channels." They derived expressions for link margin and link reliability for the entire link, providing a theoretical basis for selecting the optimal beam type, system design parameters, and link budget analysis for space optical communication systems. However, this simulation method still relies on a single environmental parameter input and lacks a simulation framework for multi-physics coupling. Furthermore, the lack of an interface system leads to poor algorithm interactivity and cumbersome parameter adjustments, making it difficult for engineers to efficiently conduct comparative analysis of link performance under different scenarios and limiting the rapid verification of theoretical findings in system design.

[0004] Therefore, there is an urgent need for a technical solution that can integrate multiple environmental factors, provide efficient simulation analysis methods and a user-friendly interactive interface to meet the needs of free-space optical communication system design and optimization. Summary of the Invention

[0005] In order to solve the problems of the prior art, the present invention provides a free-space optical communication link simulation analysis method and interface system, which realizes efficient simulation and analysis of free-space optical communication link performance through comprehensive modeling and a user-friendly interactive interface.

[0006] The technical solution of the present invention to solve the technical problem is:

[0007] A free-space optical communication link simulation analysis method, characterized in that it comprises the following steps:

[0008] Step 1: Identify the link type. According to the actual requirements of the application scenario, determine the link type in deep space, near-Earth and intersatellite links.

[0009] Step 2: Determine the transceiver terminals of the communication system and select the corresponding transceiver devices based on the uplink and downlink technical characteristics;

[0010] Based on the link type identification result in step 1, the system automatically matches the corresponding transceiver terminal type;

[0011] For deep space and near-Earth satellite-to-ground link scenarios, ground stations and satellites are selected as transceiver terminals. For ground stations as Earth-end devices, the simulation parameter system includes geographical location and device characteristics. For satellites as space-end devices, the simulation parameters include orbital parameters and antenna performance.

[0012] The intersatellite link scenario selects dual satellite terminals, and the simulation parameters include orbital relationships, spatial geometric paths, and loss characteristics;

[0013] Step 3: Configure the transceiver terminal parameters, and perform differentiated configurations based on the device type.

[0014] Ground terminal parameter configuration includes altitude, optical antenna efficiency, antenna aperture and pointing error; satellite terminal parameter configuration includes satellite altitude, optical antenna efficiency, antenna aperture and pointing error;

[0015] Step 4: Configure the physical parameters of the link, with differentiated configurations based on the link type.

[0016] For satellite-to-ground link scenarios, the laser operating wavelength, antenna elevation angle, and tropospheric altitude are configured simultaneously. For inter-satellite link scenarios, the parameter configuration includes the laser operating wavelength and the distance between the two satellites.

[0017] Step 5: Calculate the transmit and receive gains. The transmit and receive gains are determined based on antenna design parameters.

[0018] Step 6: Calculate the pointing loss based on the antenna pointing error and wavelength;

[0019] Step 7: Calculate the channel transmission loss. Calculate the free space path loss based on the laser wavelength and transmission distance. For the uplink and downlink of the satellite-to-ground link, superimpose the geometric scattering loss and Mie scattering loss.

[0020] Step 8: Calculate the link margin and display the calculation results. Display key performance indicators in tabular form, including transmit gain, receive gain, pointing loss, path loss, atmospheric attenuation, and link margin. Finally, present the link margin calculation results as quantitative indicators.

[0021] In step 5, the gains of the transmitting end and the receiving end are calculated according to the antenna aperture and wavelength, as follows:

[0022]

[0023] Among them, D t is the aperture of the transmitting antenna, in meters; D r is the aperture of the receiving antenna, in meters; λ is the wavelength, in meters.

[0024] In step 6, the directivity loss of the transmitting end and the receiving end is calculated based on the directivity error of the transmitting and receiving ends and the linear gain of the transmitting and receiving ends. The calculation formulas are as follows:

[0025]

[0026] Among them, Pe t is the transmitter pointing error in radians; Pe r is the receiver pointing error in radians.

[0027] In step 7, the free space path loss is calculated based on the laser wavelength and the transmission distance. The calculation formula is as follows:

[0028]

[0029] Where, for inter-satellite links, d is the distance between two satellites; for satellite-to-ground links, d is the distance from the satellite to the ground station;

[0030] Based on the distance the light beam propagates in the atmospheric troposphere, the attenuation coefficient caused by geometric scattering, and the extinction ratio of Mie scattering, the geometric scattering loss and Mie scattering loss are calculated, from which the total scattering loss can be calculated; specifically, the following:

[0031]

[0032] L sca =L geo +L mie

[0033] Among them, L geo is the attenuation due to geometric scattering in dB; L mie is the attenuation due to Mie scattering in dB; d T is the distance the light beam travels in the atmospheric troposphere; σ mie is the extinction ratio of Mie scattering; A geo is the attenuation coefficient due to geometric scattering;

[0034] Among them, according to the visibility V and the particle size coefficient δ, the attenuation coefficient caused by geometric scattering can be calculated. The calculation formula is as follows:

[0035]

[0036] Where V is visibility in km; δ is the particle size coefficient;

[0037] Calculate the Mie extinction ratio based on the empirical coefficients; specifically:

[0038]

[0039] a=0.000487λ 3 -0.002237λ 2 +0.003864λ-0.004442

[0040] b=-0.00573λ 3 +0.02639λ 2 -0.04552λ+0.05164

[0041] c=0.02565λ 3 -0.1191λ 2 +0.20385λ-0.216

[0042] d=-0.0638λ 3 +0.3034λ 2 -0.5083λ+0.425

[0043] Among them, h GS is the height of the ground station above mean sea level in km; a, b, c, and d are empirical coefficients related to the wavelength λ.

[0044] In step 8, the link margin is calculated by the difference between the received power and the required signal power. The specific formula is as follows:

[0045] L M =P r -P req

[0046] Among them, P r is the received power in dBm, P req is the required signal power in dBm;

[0047] Furthermore, the received power is calculated based on the transmit power, the optical efficiency of the transmitting and receiving end antennas, the transmitting and receiving end antenna gains, the pointing loss, the free space path loss, the atmospheric absorption loss, and the atmospheric scattering loss. The specific formula is as follows:

[0048] P r =P t +μ t +μ r +G t +G r -LP t -LP r -L P -L abs -L sca

[0049] Among them, the transmission power P t is the output power of the transmitter, in dB; the antenna optical efficiency μ tand μ r Respectively represent the antenna optical system efficiency of the transmitting end and the receiving end; the antenna gain G t and G r Respectively represent the gains of the transmitting antenna and the receiving antenna, in dB; the pointing loss LP t and LP r They represent the losses caused by the antenna pointing errors at the transmitting and receiving ends, respectively, in dB; the free space path loss L P is the free space path loss between the ground station and the satellite, in dB; atmospheric absorption loss L abs is the attenuation loss caused by atmospheric absorption, in dB; atmospheric scattering loss L sca It is the attenuation loss caused by atmospheric scattering, measured in dB.

[0050] A free-space optical communication link simulation interface system, characterized in that it comprises:

[0051] The Link Selection module, located in the upper left corner of the operation page, includes three options: "Satellite-Ground", "Satellite-Satellite", and "Deep Space-Ground", representing the three communication link modes of near-Earth laser communication, intersatellite laser communication, and deep space laser communication, respectively. By selecting different laser communication channels, a free-space optical communication simulation channel is constructed. In this module, users can access and modify the attribute parameters of a target entity by selecting the target entity.

[0052] The data input module sets the parameter input function pane, which includes ground station, uplink and downlink, and satellite options. Through these tabs, users can configure the properties of the link, accurately input the satellite's orbital parameters, adjust the antenna size, and realize parameter management of multiple objects. This module provides the system with a precise input parameter system to ensure the accuracy and reliability of subsequent simulation calculations.

[0053] Link Budget module, located in the top area of ​​the center pane of the application, allows you to select uplink, downlink, or intersatellite link calculations; based on the established model, it calculates the link margin performance indicators of the communication link;

[0054] In the Link Budget module, clicking the Calculate button executes the link budget calculation process. After the calculation is complete, the detailed calculation results are displayed in the area below. In the Link Parameter Calculation Display unit, users can view various parameters and calculated values, such as transmitter gain, receiver gain, transmitter linear gain, receiver linear gain, transmitter pointing loss, receiver pointing loss, free space path loss, geometric scattering loss, Mie scattering loss, and link margin. A calculation result output option is provided, allowing users to quickly save the calculated data in a standardized format for subsequent analysis and verification.

[0055] The visualization analysis and output module, located on the right side of the interface, uses visualization technology to intuitively present simulation results. Users can directly perform editing operations, adjust the relevant settings of the X-axis and Y-axis, and customize the value range and step size of the X-axis. Users can select appropriate axis coordinates and their value ranges based on the required data information to accurately display specific parts of the data or chart.

[0056] After selecting the X-axis coordinate, the user can select the isoline information again and draw an isoline image to compare with the X-axis data. At the same time, the simulation results can be generated into a standardized report, integrating data tables, chart analysis, and key parameter descriptions to provide a complete link performance evaluation document.

[0057] The user first inputs parameters in the link selection module and data input module, including altitude, optical antenna efficiency, antenna aperture, pointing error, laser operating wavelength, tropospheric altitude, elevation angle, inter-satellite distance, and transmission power; as well as climate characteristic parameters, including channel attenuation parameters and tropospheric altitude; the system provides five configurable options: near-ground downlink, inter-satellite link, and deep space uplink and downlink; after the user selects the link type, the link attenuation calculation is performed in the link budget module based on the input parameters, specifically analyzing gas absorption attenuation and scattering attenuation; then the transceiver gain, pointing loss, free space path loss, and link margin are calculated; the above calculation results are transmitted to the link The parameter calculation and display unit outputs transmitter gain, receiver gain, transmitter linear gain, receiver linear gain, transmitter pointing loss, receiver pointing loss, free-space path loss, geometric scattering loss, Mie scattering loss, and link margin metrics, enabling full-dimensional budget analysis and reliability assessment of free-space optical communication links. Finally, in the visualization analysis and output module, users can select the horizontal and vertical coordinate parameter type, adjust the parameter value range, and set the contour lines and step size. The system will automatically generate a multi-dimensional graph, presenting the link budget analysis results in real-time graphical form. The drawing results can be stored using the "Save Image" or "Save Image As" buttons.

[0058] Beneficial effects of the present invention:

[0059] 1. The present invention constructs a free-space optical communication link simulation and analysis method, covering the entire process from link scenario modeling, parameter input to link margin calculation. According to the different application scenarios of deep space, near-earth and intersatellite, the corresponding parameter configuration and loss calculation model are matched, and the adaptive transceiver terminal is automatically selected. The multiple influencing factors of antenna design, atmospheric environment, and geographical location are comprehensively considered. By performing refined calculations of transceiver gain, pointing loss, channel transmission loss, and atmospheric loss, an accurate quantitative evaluation of link performance is achieved. Combined with multi-dimensional visual analysis, it supports multi-parameter correlation display. It solves the problem of insufficient parameter coverage of traditional algorithms and improves the adaptability of simulation analysis to diverse scenarios. It intuitively presents key performance indicators and converts complex calculation results into visual decision-making basis. The whole set of methods is highly systematic and logically rigorous, providing an efficient, accurate and comprehensive solution for the simulation and analysis of free-space optical communication links.

[0060] 2. At the interface system level, the present invention integrates parameter input, calculation analysis, visualization and data management functions through structured interface design to build a full-process simulation platform, providing efficient, accurate and intuitive operation solutions for free-space optical communication link budget analysis, significantly improving link design and optimization efficiency. The link canvas supports the dynamic establishment of communication links, and focused operations directly modify entity parameters; the classification tab integrates parameter input and verifies in real time. The calculation results and custom charts are presented on the same screen, supporting independent configuration of multi-dimensional parameters, isoline image drawing and standardized report generation, realizing the integrated operation of "configuration-calculation-analysis", reducing the number of interactive steps compared to traditional interfaces, enhancing the intuitiveness of result interpretation, and significantly improving the simulation efficiency and user experience in engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a flow chart of a free-space optical communication link simulation analysis method according to the present invention;

[0062] Figure 2 This is a schematic diagram of the overall interface of a free-space optical communication link simulation and analysis interface system of the present invention.

[0063] Figure 3 A schematic diagram of a link selection module in a free-space optical communication link simulation and analysis interface system of the present invention;

[0064] Figure 4 This is a schematic diagram of a data input module in a free-space optical communication link simulation analysis interface system of the present invention;

[0065] Figure 5 A schematic diagram of a link budget module in a free-space optical communication link simulation and analysis interface system of the present invention;

[0066] Figure 6A schematic diagram of a drawing display unit in a visualization analysis and output module in a free-space optical communication link simulation analysis interface system of the present invention;

[0067] Figure 7 A schematic diagram of a coordinate axis setting and image export unit in a visualization analysis and output module in a free-space optical communication link simulation analysis interface system of the present invention;

[0068] Figure 8 for Figure 5 A schematic diagram of actual output data results after inputting parameters into a free-space optical communication link simulation analysis interface system is shown;

[0069] Figure 9 for Figure 6 The diagram shows a free-space optical communication link simulation analysis interface system that actually outputs an image after inputting parameters. DETAILED DESCRIPTION

[0070] The present invention will be further described in detail below with reference to the accompanying drawings.

[0071] like Figure 1 As shown, a free space optical communication link simulation analysis method includes the following steps:

[0072] A free-space optical communication link simulation analysis method comprises the following steps:

[0073] Step 1: Clarify the link type and determine the link type in deep space, near-Earth and intersatellite links based on the actual needs of the application scenario.

[0074] Step 2: Determine the transceiver terminals of the communication system and select the corresponding transceiver devices based on the uplink and downlink technical characteristics.

[0075] Based on the link type identification result in step 1, the system automatically matches the corresponding transceiver terminal type.

[0076] For deep space and near-Earth satellite-to-ground link scenarios, ground stations and satellites are selected as transceiver terminals. For ground stations, which are Earth-side devices, the simulation parameter system includes geographic location and device characteristics; for satellites, which are space-side devices, the simulation parameters include orbital parameters and antenna performance.

[0077] The inter-satellite link scenario selects dual satellite terminals, and the simulation parameters include orbital relationship, spatial geometric path and loss characteristics.

[0078] Step 3: Configure the transceiver terminal parameters, and perform differentiated configuration based on the device type.

[0079] Ground terminal parameter configuration includes altitude, optical antenna efficiency, antenna aperture, and pointing error. Satellite terminal parameter configuration includes satellite altitude, optical antenna efficiency, antenna aperture, and pointing error.

[0080] Step 4: Configure the physical parameters of the link, and perform differentiated configuration based on the link type.

[0081] For satellite-to-ground link scenarios, the laser operating wavelength, antenna elevation angle, and tropospheric altitude are configured synchronously. For inter-satellite link scenarios, the parameter configuration includes the laser operating wavelength and the distance between the two satellites.

[0082] Step 5: Calculate the transmit and receive gains. The transmit and receive gains are determined based on antenna design parameters.

[0083] In step 5, the gains of the transmitter and receiver are calculated based on the antenna aperture and wavelength, as follows:

[0084]

[0085] Among them, D t is the aperture of the transmitting antenna, in meters. r is the aperture of the receiving antenna, in meters. λ is the wavelength, in meters.

[0086] Step 6: Calculate the pointing loss. The pointing loss is calculated based on the antenna pointing error and wavelength.

[0087] In step 6, the pointing loss of the transmitter and receiver is calculated based on the pointing error and linear gain of the transmitter and receiver. The calculation formulas are as follows:

[0088]

[0089] Among them, Pe t Pe is the transmitter pointing error in radians. r is the receiver pointing error in radians.

[0090] Step 7: Calculate channel transmission loss. Calculate free-space path loss based on the laser wavelength and transmission distance. For both the uplink and downlink of the satellite-to-ground link, superimpose the geometric scattering loss and Mie scattering loss.

[0091] The free space path loss is calculated based on the laser wavelength and transmission distance. The calculation formula is as follows:

[0092]

[0093] Where, for inter-satellite links, d is the distance between two satellites. For satellite-to-ground links, d is the distance from the satellite to the ground station.

[0094] According to the distance the light beam propagates in the atmospheric troposphere, the attenuation coefficient caused by geometric scattering and the extinction ratio of Mie scattering, the geometric scattering loss and Mie scattering loss are calculated, and the total scattering loss can be calculated. Specifically, it includes:

[0095]

[0096] L sca =L geo +L mie

[0097] Among them, L geo L is the attenuation due to geometric scattering in dB. mie is the attenuation due to Mie scattering in dB. T is the distance the light beam travels in the troposphere. mie is the extinction ratio of Mie scattering. A geo is the attenuation coefficient due to geometric scattering.

[0098] Among them, according to the visibility V and the particle size coefficient δ, the attenuation coefficient caused by geometric scattering can be calculated. The calculation formula is as follows:

[0099]

[0100] Where V is visibility in km and δ is the particle size coefficient.

[0101] Calculate the Mie extinction ratio based on the empirical coefficient. Specifically include:

[0102]

[0103] a=0.000487λ 3 -0.002237λ 2 +0.003864λ-0.004442

[0104] b=-0.00573λ 3 +0.02639λ 2 -0.04552λ+0.05164

[0105] c=0.02565λ 3 -0.1191λ 2 +0.20385λ-0.216

[0106] d=-0.0638λ 3 +0.3034λ 2 -0.5083λ+0.425

[0107] Among them, h GSrepresents the height of the ground station above mean sea level in km. a, b, c, and d are empirical coefficients related to the wavelength λ.

[0108] Step 8: Calculate the link margin and present the results. Display key performance indicators (KPIs) in a table, including transmit gain, receive gain, pointing loss, path loss, atmospheric attenuation, and link margin. Finally, present the link margin calculation results as quantitative indicators.

[0109] The link margin in step 8 is calculated by the difference between the received power and the required signal power. The specific formula is as follows:

[0110] L M =P r -P req

[0111] Among them, P r is the received power in dBm, P req is the desired signal power in dBm.

[0112] Furthermore, the received power is calculated based on the transmit power, the optical efficiency of the transmitting and receiving end antennas, the transmitting and receiving end antenna gains, the pointing loss, the free space path loss, the atmospheric absorption loss, and the atmospheric scattering loss. The specific formula is as follows:

[0113] P r =P t +μ t +μ r +G t +G r -LP t -LP r -L P -L abs -L sca

[0114] Among them, the transmission power P t is the output power of the transmitter, in dB; the antenna optical efficiency μ t and μ r Respectively represent the antenna optical system efficiency of the transmitting end and the receiving end; the antenna gain G t and G r Respectively represent the gains of the transmitting antenna and the receiving antenna, in dB; the pointing loss LP t and LP r They represent the losses caused by the antenna pointing errors at the transmitting and receiving ends, respectively, in dB; the free space path loss L P is the free space path loss between the ground station and the satellite, in dB; atmospheric absorption loss L abs is the attenuation loss caused by atmospheric absorption, in dB; atmospheric scattering loss Lsca It is the attenuation loss caused by atmospheric scattering, measured in dB.

[0115] like Figure 2 As shown, a free space optical communication link simulation analysis interface system includes: a link selection module, a data input module, a link budget calculation module and a visual analysis and output module.

[0116] The Link Selection module, located in the upper left corner of the operation page, includes three options: "Satellite-Ground," "Satellite-Satellite," and "Deep Space-Ground," representing three communication link modes: near-Earth laser communication, intersatellite laser communication, and deep space laser communication. By selecting different laser communication channels, a free-space optical communication simulation channel is constructed. Within this module, users access and modify the properties of a target entity by selecting it.

[0117] The Data Input module provides a pane for parameter input, including options for ground stations, uplinks, downlinks, and satellites. These tabs allow users to configure link properties, precisely input satellite orbital parameters, adjust antenna dimensions, and manage parameters for multiple objects. This module provides the system with a precise input parameter system, ensuring the accuracy and reliability of subsequent simulation calculations.

[0118] Link Budget Module. In the top area of ​​the center pane of the application, select to perform calculations for uplinks, downlinks, or intersatellite links. Based on the established model, the link margin performance indicator of the communication link is calculated.

[0119] In the Link Budget module, clicking the Calculate button executes the link budget calculation. Once the calculation is complete, the detailed results are displayed in the area below. In the Link Parameter Calculation Display section, users can view various parameters and calculated values, such as transmitter gain, receiver gain, transmitter linear gain, receiver linear gain, transmitter pointing loss, receiver pointing loss, free space path loss, geometric scattering loss, Mie scattering loss, and link margin. A calculation result output option allows users to quickly save the calculated data in a standardized format for subsequent analysis and verification.

[0120] The Visualization Analysis and Output module, located on the right side of the interface, uses visualization technology to provide an intuitive presentation of simulation results. Users can directly edit and adjust the X- and Y-axis settings, customizing the X-axis range and step size. Based on the required data, users can select appropriate axis coordinates and ranges to accurately display specific parts of the data or chart.

[0121] After selecting the X-axis coordinate, users can select the contour information again and draw contour images to compare with the X-axis data. Simulation results can also be generated into standardized reports, integrating data tables, chart analysis, and key parameter descriptions to provide complete link performance evaluation documentation.

[0122] like Figure 3 As shown in the figure, the link selection module includes three link types: satellite-to-ground, satellite-to-satellite, and deep space-to-ground. Users can select the corresponding link for simulation analysis based on the space communication scenario requirements. Each type has preset typical parameters.

[0123] The Link Selection module provides a synchronous link diagram. Using a "satellite-to-ground" link architecture as an example, the system displays the link relationship between the ground station and Satellite A and supports parameter configuration. Users select a target entity in this module to navigate between the visualization scene and the parameter configuration area, allowing real-time input of key parameters such as satellite altitude, optical antenna efficiency, antenna aperture, and pointing error.

[0124] like Figure 4 The data entry module, shown below, allows users to customize input parameters. In the lower left corner, a columnar parameter input area is located. This pane displays three switchable options: ground station, link, and satellite. Users configure parameters within each option, customizing them within the numeric input box according to their needs.

[0125] Under the Satellite option, user-configurable parameters include satellite altitude, optical antenna efficiency, antenna aperture, and pointing error. Under the Link option settings, for satellite-to-ground links, configurable parameters include laser operating wavelength, antenna elevation angle, and tropospheric altitude; for intersatellite links, parameter configuration includes laser operating wavelength and the orbital spacing between the two satellites. Under the Ground Station option, user-configurable parameters include altitude, optical antenna efficiency, antenna aperture, and pointing error.

[0126] In the data input module, all parameter input boxes are equipped with data validation mechanisms. When the input value exceeds the preset range, a red border warning and prompts are triggered. These operations are directly synchronized with the system's calculation model, and the link budget module performs relevant link budget analysis.

[0127] like Figure 5 As shown, the Link Budget module is located in the center of the application's main interface. This module adopts a layered layout design, with an operation toolbar at the top and a link parameter calculation display unit below.

[0128] The core components of the operation toolbar are the "Link Type" drop-down menu, the power input area, the dual operation button group, and the operation control area.

[0129] Click the "Link Type" drop-down menu to expand the list of options, which includes five standard link types, categorized by scenario: "Satellite-Ground Uplink," "Satellite-Ground Downlink," "Intersatellite Link," "Deep Space Uplink," and "Deep Space Downlink." Select the appropriate link type based on your actual computing needs.

[0130] Below the "Link Type" drop-down menu, the power input area contains two parameter input boxes: "Transmit Power (dB)" and "Required Signal Power (dB)." In the default system configuration, the "Transmit Power (dB)" input box is preset to 17.5dB, corresponding to typical satellite communication scenarios; the "Required Signal Power (dB)" input box is set to -35.5dB by default. Users can adjust the "Transmit Power" value by entering a value.

[0131] The dual action button group, located on the right side of the action toolbar, includes a "Save Output Data" button and a "Save Output Data As" button. When the user clicks "Save Output Data," the system automatically generates a timestamp-protected CSV file in the installation directory folder, and the status bar displays a message stating "Data has been saved to the default path." Selecting "Save Output Data As" triggers a system file dialog box, which supports customizing the storage path and file name and is compatible with export formats such as .xlsx, .txt, and .dat. After saving, a successful operation notification window pops up containing the file path details, ensuring that the user is aware of the data storage location.

[0132] The Run control area features a "Run" button. Clicking this button initiates calculations based on the user-defined data parameters: first, the input parameters are parsed, the calculations are performed, and finally, the data is displayed. The calculations generate a real-time link budget analysis report containing core metrics such as transceiver gain, transceiver pointing loss, free space path loss, geometric scattering loss, Mie scattering loss, and link margin.

[0133] In the link parameter calculation display, all parameter values ​​are displayed as "0" before clicking "Run." After clicking "Run," the calculation results are recorded in the information panel at the bottom of the interface, including transmitter gain, receiver gain, transmitter linear gain, receiver linear gain, transmitter pointing loss, receiver pointing loss, free space path loss, geometric scattering loss, Mie scattering loss, and link margin. The calculation results can be exported in table format.

[0134] like Figure 6 The figure shows the drawing display unit in the visual analysis and output module, which is located in the right area of ​​the interface and adopts interactive visual design.

[0135] The chart display area features an intelligent legend layout mechanism, with a floating legend box permanently displayed in the upper right corner of the chart. A dual-color coding and line type annotation system clearly identifies the specific parameters corresponding to different line styles. Multi-touch zooming and drag-and-pan functionality are supported, allowing users to adjust the viewing angle.

[0136] like Figure 7 As shown, this is the coordinate axis setting and image export unit in the visual analysis and output module, which is below the above-mentioned drawing display area.

[0137] In the coordinate axis setting area, users can use the drop-down menu to select parameter variables in the three dimensions of X-axis, Y-axis and isoline. After selecting the parameter, the information bar on the right will synchronously display the dimension unit, typical value range and calculation step of the parameter. Taking the X-axis as the ground station altitude as an example, the default value range is 1.0-3.0km, with a step size of 0.1. Users can adjust the range and step size by directly entering the numerical value. The system has a built-in range validity check function, and a border warning will be triggered when the input value exceeds the reasonable range. Typical application scenarios, such as analyzing the sudden change characteristics of link performance in the 2-5km altitude range, can achieve data focusing by accurately limiting the X-axis range.

[0138] In the image export unit, below the coordinate axis setting area mentioned above, three control buttons are set: the "Draw" button realizes the one-click drawing function; the "Save Image" button stores the image as a 600dpi vector image to the preset project directory by default; the "Save Image As" button provides three format options: PNG, SVG, and PDF.

[0139] Example:

[0140] Figure 8 for Figure 5 The figure shows a schematic diagram of the actual output data results after the system inputs parameters into a free space optical communication link simulation analysis interface.

[0141] like Figure 8 As shown, combined Figure 5 Interactive configuration interface of the data input module, Figure 8 The calculation results are shown in Table 1.

[0142] Table 1

[0143]

[0144] The calculation results are displayed in a visual form as follows Figure 8 The panel area in the center of the overall interface is shown. Users can adjust the display scale using the zoom control. The system also provides a multi-format export function, supporting saving the current data as an SVG file. The storage path defaults to the project workspace, but users can also customize the local directory.

[0145] Figure 9 Shown Figure 6 The diagram shows a free-space optical communication link simulation analysis interface system that actually outputs an image after inputting parameters.

[0146] like Figure 9 As shown, combined with the parameters entered in Table 1 above, Figure 9 This is the drawing result when the parameters shown in Table 2 are entered in the coordinate axis setting unit.

[0147] Table 2

[0148] Parameter Category Specific parameters Value range step length unit Independent variable (horizontal axis) Ground station - altitude 0-5 0.1 km Grouping variable (equal lines) elevation 50-80 5 degrees Dependent variable (vertical axis) Link Margin - - dB

[0149] The drawing results are displayed in a visual form as follows Figure 9 In the panel area on the right side of the interface shown, users can adjust the display ratio in real time using the zoom controls. If the displayed content exceeds the visible range, users can also scroll horizontally using the pan slider on the right or click the reset button to restore the default display state.

[0150] Figure 9 The plot in the figure below analyzes the effect of ground station altitude on link margin. The horizontal axis represents the ground station altitude, with a range of 0-5 km and a step size of 0.1, reflecting continuous changes in altitude. The vertical axis corresponds to the link margin indicator, expressed in dB, which quantifies link performance. The contour lines in the figure represent the link margin variation curves for different elevation angles (ranging from 50-80°, with a step size of 5). The curve clusters use a color gradient to distinguish elevation parameters, with different colored curves representing different link elevation angles. From the blue curve (elevation angle = 50°) to the red curve (elevation angle = 80°), curves are plotted every 5°. The analysis of the effect of ground station altitude on link margin also considers the range of link elevation angles from 50° to 80°. For example, when analyzing the link margin at an altitude of 2 km, the specific values ​​of the link margin under seven conditions are examined: link elevation angles of 50°, 55°, 60°, 65°, 70°, 75°, and 80°.

[0151] like Figure 9 As shown in the analysis of the impact of ground station altitude on link margin, the dynamic changes in altitude (the horizontal axis) allow for intuitive analysis of the link margin's trend as altitude increases. Combined with the clusters of curves corresponding to different elevation angles, this allows for exploring the impact of ground station altitude on link margin under different elevation conditions. This provides visual data reference for link design optimization and performance evaluation, facilitating the rapid identification of link margin characteristics under the synergistic effects of altitude and elevation angle.

Claims

1. A free-space optical communication link simulation analysis method, characterized in that: It includes the following steps: Step 1: Identify the link type. According to the actual requirements of the application scenario, determine the link type in deep space, near-Earth and intersatellite links. Step 2: Determine the transceiver terminals of the communication system and select the corresponding transceiver devices based on the uplink and downlink technical characteristics; Based on the link type identification result in step 1, the system automatically matches the corresponding transceiver terminal type; For deep space and near-Earth satellite-to-ground link scenarios, ground stations and satellites are selected as transceiver terminals; The ground station is an earth-end device, and the simulation parameter system includes geographical location and device characteristics; Satellites are space-side devices, and simulation parameters include orbital parameters and antenna performance; The intersatellite link scenario selects dual satellite terminals, and the simulation parameters include orbital relationships, spatial geometric paths, and loss characteristics; Step 3: Configure the transceiver terminal parameters, and perform differentiated configurations based on the device type. Ground terminal parameter configuration includes altitude, optical antenna efficiency, antenna aperture and pointing error; satellite terminal parameter configuration includes satellite altitude, optical antenna efficiency, antenna aperture and pointing error; Step 4: Configure the physical parameters of the link, with differentiated configurations based on the link type. For satellite-to-ground link scenarios, the laser operating wavelength, antenna elevation angle, and tropospheric altitude are configured simultaneously. For inter-satellite link scenarios, the parameter configuration includes the laser operating wavelength and the distance between the two satellites. Step 5: Calculate the transmit and receive gains. The transmit and receive gains are determined based on antenna design parameters. Step 6: Calculate the pointing loss based on the antenna pointing error and wavelength; Step 7: Calculate the channel transmission loss. Calculate free-space path loss based on laser wavelength and transmission distance; superimpose geometric scattering loss and Mie scattering loss for uplink and downlink of satellite-to-ground links; Step 8: Calculate the link margin and display the calculation results; Key performance indicators are displayed in tabular form, including transmit gain, receive gain, pointing loss, path loss, atmospheric attenuation, and link margin, and the link margin calculation results are finally presented as quantitative indicators.

2. A free-space optical communication link simulation analysis method according to claim 1, characterized in that: In step 5, the gains of the transmitting end and the receiving end are calculated according to the antenna aperture and wavelength, as follows: Among them, D t is the aperture of the transmitting antenna, in meters; D r is the aperture of the receiving antenna, in meters; λ is the wavelength, in meters.

3. The free-space optical communication link simulation analysis method according to claim 1, characterized in that: In step 6, the directivity loss of the transmitting end and the receiving end is calculated based on the directivity error of the transmitting and receiving ends and the linear gain of the transmitting and receiving ends. The calculation formulas are as follows: Among them, Pe t is the transmitter pointing error in radians; Pe r is the receiver pointing error in radians.

4. The free-space optical communication link simulation analysis method according to claim 1, characterized in that: In step 7, the free space path loss is calculated based on the laser wavelength and the transmission distance. The calculation formula is as follows: Where, for inter-satellite links, d is the distance between two satellites; for satellite-to-ground links, d is the distance from the satellite to the ground station; Based on the distance the light beam propagates in the atmospheric troposphere, the attenuation coefficient caused by geometric scattering, and the extinction ratio of Mie scattering, the geometric scattering loss and Mie scattering loss are calculated, from which the total scattering loss can be calculated; specifically, the following: L sca =L geo +L mie Among them, L geo is the attenuation due to geometric scattering in dB; L mie is the attenuation due to Mie scattering in dB; d T is the distance the light beam travels in the atmospheric troposphere; σ mie is the extinction ratio of Mie scattering; A geo is the attenuation coefficient due to geometric scattering; Among them, according to the visibility V and the particle size coefficient δ, the attenuation coefficient caused by geometric scattering can be calculated. The calculation formula is as follows: Where V is visibility in km; δ is the particle size coefficient; Calculate the Mie extinction ratio based on the empirical coefficients; specifically: a=0.000487λ 3 -0.002237l 2 +0.003864λ-0.004442 b=-0.00573λ 3 +0.02639s 2 -0.04552λ+0.05164 c=0.02565λ 3 -0.1191l 2 +0.20385λ-0.216 d=-0.0638λ 3 +0.3034min 2 -0.5083λ+0.425 Among them, h GS represents the height of the ground station above mean sea level in km; a, b, c and d are empirical coefficients related to the wavelength λ.

5. The free-space optical communication link simulation analysis method according to claim 1, characterized in that: In step 8, the link margin is calculated by the difference between the received power and the required signal power. The specific formula is as follows: L M =P r -P req Among them, P r is the received power in dBm, P req is the required signal power in dBm; Furthermore, the received power is calculated based on the transmit power, the optical efficiency of the transmitting and receiving end antennas, the transmitting and receiving end antenna gains, the pointing loss, the free space path loss, the atmospheric absorption loss, and the atmospheric scattering loss. The specific formula is as follows: P r =P t +μ t +μ r +G t +G r -LP t -LP r -L P -L abs -L sca Among them, the transmission power P t is the output power of the transmitter, in dB; the antenna optical efficiency μ t and μ r Respectively represent the antenna optical system efficiency of the transmitting end and the receiving end; the antenna gain G t and G r Respectively represent the gains of the transmitting antenna and the receiving antenna, in dB; the pointing loss LP t and LP r They represent the losses caused by the antenna pointing errors at the transmitting and receiving ends, respectively, in dB; the free space path loss L P is the free space path loss between the ground station and the satellite, in dB; atmospheric absorption loss L abs is the attenuation loss caused by atmospheric absorption, in dB; atmospheric scattering loss L sca It is the attenuation loss caused by atmospheric scattering, measured in dB.

6. A free space optical communication link simulation interface system, characterized in that include: The Link Selection module, located in the upper left corner of the operation page, includes three options: "Satellite-Ground," "Satellite-Satellite," and "Deep Space-Ground," representing three communication link modes: near-Earth laser communication, intersatellite laser communication, and deep space laser communication. Free-space optical communication simulation channels are constructed by selecting different laser communication channels. Within this module, users access and modify the attribute parameters of a target entity by selecting it. Data input module, setting parameter input function pane, which includes ground station, uplink and downlink and satellite options; Through these tabs, users can configure the properties of the link, accurately input satellite orbital parameters, adjust antenna size, and manage parameters for multiple objects. This module provides the system with a precise input parameter system to ensure the accuracy and reliability of subsequent simulation calculations. Link Budget module, located in the top area of ​​the center pane of the application, allows you to select uplink, downlink, or intersatellite link calculations; based on the established model, it calculates the link margin performance indicators of the communication link; In the link budget module, after clicking the calculate button, the link budget calculation process will be executed; After the calculation is completed, the area below will display detailed calculation results; In the link parameter calculation display unit, users can view various parameters and calculated values, such as transmitter gain, receiver gain, transmitter linear gain, receiver linear gain, transmitter pointing loss, receiver pointing loss, free space path loss, geometric scattering loss, Mie scattering loss, and link margin. A calculation result output option allows users to quickly save the calculated data in a standardized format for subsequent analysis and verification. The visualization analysis and output module, located on the right side of the interface, uses visualization technology to intuitively present simulation results. Users can directly perform editing operations, adjust the relevant settings of the X-axis and Y-axis, and customize the value range and step size of the X-axis. Users can select appropriate axis coordinates and their value ranges based on the required data information to accurately display specific parts of the data or chart. After selecting the X-axis coordinate, the user can select the isoline information again and draw an isoline image to compare with the X-axis data. At the same time, the simulation results can be generated into a standardized report, integrating data tables, chart analysis, and key parameter descriptions to provide a complete link performance evaluation document.

7. A free-space optical communication link simulation interface system according to claim 6, characterized in that: The user first enters parameters in the link selection module and data input module, including altitude, optical antenna efficiency, antenna aperture, pointing error, laser operating wavelength, tropospheric altitude, elevation angle, inter-satellite distance, and transmit power; as well as climate characteristic parameters, including channel attenuation parameters and tropospheric altitude. The system provides five configurable options: near-ground downlink, inter-satellite link, and deep-space uplink and downlink. After the user selects the link type, the link budget module performs link attenuation calculations based on the input parameters, specifically analyzing gas absorption attenuation and scattering attenuation. The transmitter-receiver gain, pointing loss, free-space path loss, and link margin are then calculated. The results are transmitted to the link parameter calculation and display unit, where the output includes transmitter gain, receiver gain, transmitter linear gain, receiver linear gain, transmitter pointing loss, receiver pointing loss, free-space path loss, geometric scattering loss, Mie scattering loss, and link margin metrics, enabling full-dimensional budget analysis and reliability assessment of free-space optical communication links. Finally, in the visualization analysis and output module, the user selects the horizontal and vertical coordinate parameter type, adjusts the parameter value range, and sets the contour lines and step size. The system automatically generates a multi-dimensional plot, presenting the link budget analysis results in real-time graphical form. The plot results can be stored using the "Save Image" or "Save Image As" buttons.

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