A dynamic switching system and method for vehicle-mounted satellite communication

Abstract

The application provides a kind of dynamic switching system and method of vehicle-mounted satellite communication, the system includes low-orbit satellite constellation and vehicle-mounted terminal, the vehicle-mounted terminal is arranged on vehicle, vehicle-mounted terminal is accessed network by vehicle-satellite direct link and obtains communication service;The low-orbit satellite constellation includes a plurality of selectable satellite nodes, including current service satellite and candidate satellite;In initial state, vehicle-mounted terminal is provided with communication service by current service satellite, when the link between vehicle and current service satellite passes through weather attenuation influence area, current link quality drops, triggers satellite switching judgment, and according to the result of judgment, vehicle-mounted terminal maintains current service satellite or switches from current service satellite to the determined candidate satellite.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and more specifically, to a dynamic switching system and method for vehicle-mounted satellite communication. Background Technology

[0002] With the large-scale deployment of low-Earth orbit (LEO) broadband constellations and the improvement of onboard processing and beam control capabilities, satellite access networks can provide wide-area connectivity in areas with limited terrestrial network coverage, such as oceans, deserts, plateaus, and remote mountainous regions. Compared with traditional geostationary orbit satellite systems, LEO satellites have advantages such as lower latency and stronger spatial reuse capabilities. However, due to the high-speed orbit of satellites, the coverage area and network topology change rapidly over time, requiring terminals to frequently switch satellites and rebuild links during communication, thus placing higher demands on mobility management.

[0003] In application scenarios not supported by terrestrial networks, vehicle-to-satellite (V2S) communication is a typical high-speed mobile access scenario. Vehicle terminals may face insufficient terrestrial network coverage or service unavailability during cross-regional movement; direct satellite access can achieve wide-area continuous access. However, due to the superposition of high-speed vehicle movement and rapid evolution of low-orbit satellite visibility, the link status and candidate satellite set of V2S systems exhibit significant time-varying characteristics, resulting in higher switching frequency and more sensitive switching timing.

[0004] In low-Earth orbit satellite access networks, ground terminals experience coverage from multiple satellites within a short period due to the continuous high-speed operation of satellites. Therefore, handover algorithms are necessary to maintain link continuity. Existing systems typically employ handover strategies triggered by geometric relationships or instantaneous measurement metrics, such as maximum elevation angle selection, longest remaining service time selection, and shortest distance selection.

[0005] Although the above methods are simple to implement and easy to deploy in engineering, they generally have the following shortcomings:

[0006] (1) Weather factors such as rainfall attenuation are usually not included in the unified evaluation indicators, making it difficult to accurately assess link availability under severe weather conditions;

[0007] (2) It relies heavily on fixed thresholds or instantaneous measurement results, making it difficult to adapt to the rapid time-varying characteristics of millimeter-wave links and prone to switching lag;

[0008] (3) When the link quality of multiple candidate satellites is similar or fluctuates drastically, handover oscillations and unnecessary handovers are likely to occur, increasing signaling overhead and reducing service stability;

[0009] (4) In the presence of measurement noise and processing delay, the switching strategy based on the current measurement is difficult to avoid the risk of impending deep rain attenuation or shading in a timely manner. Summary of the Invention

[0010] To address the shortcomings of existing technologies, the present invention aims to provide a dynamic switching system and method for vehicle-mounted satellite communication. By performing link budget evaluation on the vehicle-satellite link and comprehensively evaluating the communication quality of candidate satellite links in conjunction with environmental attenuation factors, adaptive satellite switching decisions for complex propagation conditions can be achieved, effectively improving the service continuity and link reliability of vehicle-mounted satellite communication.

[0011] To solve the above problems, the technical solution of the present invention is as follows:

[0012] A dynamic switching system for vehicle-mounted satellite communication includes a low-Earth orbit (LEO) satellite constellation and a vehicle-mounted terminal. The vehicle-mounted terminal is installed on a vehicle and accesses the network and obtains communication services through a vehicle-satellite direct link. The LEO satellite constellation includes multiple selectable satellite nodes, including a currently serving satellite and candidate satellites. In the initial state, the vehicle-mounted terminal receives communication services from the currently serving satellite. When the link between the vehicle and the currently serving satellite passes through an area affected by weather attenuation, the quality of the current link degrades, triggering a satellite switching decision. Based on the decision result, the vehicle-mounted terminal either maintains the current serving satellite or switches from the current serving satellite to a determined candidate satellite.

[0013] Preferably, each low-orbit satellite is equipped with an onboard signal processing unit, an electronically controllable beam antenna, and a millimeter-wave communication transceiver module; the electronically controllable beam antenna can dynamically adjust the satellite's service beam direction for the vehicle according to the change in the vehicle's position on the ground, so as to achieve continuous coverage and communication connection for the vehicle.

[0014] Furthermore, the present invention also provides a dynamic switching method for vehicle-mounted satellite communication, comprising the following steps:

[0015] Acquire vehicle-mounted terminal communication status, candidate satellite information, and weather information;

[0016] Construct a candidate satellite set;

[0017] Determine the satellite handover method, which includes one of the weather perception handover process and the prediction enhancement handover process;

[0018] Based on the judgment result, the vehicle-mounted terminal either maintains the current serving satellite or switches from the current serving satellite to the determined target satellite.

[0019] Preferably, the step of constructing the candidate satellite set specifically includes: screening candidate satellites that meet the communication conditions based on satellite coverage, satellite visibility, link budget results and weather attenuation effects, and merging ideal candidate satellites and near-optimal candidate satellites to form a candidate satellite set.

[0020] Preferably, the step of determining the satellite handover method includes a step of either a weather-aware handover process or a prediction-enhanced handover process. Specifically, it includes determining whether the satellite handover method is a weather-aware handover process or a prediction-enhanced handover process based on whether weather forecast data is available, the prediction confidence level, business continuity requirements, and system configuration.

[0021] Preferably, the weather perception switching process specifically includes the following steps:

[0022] Step 1: Calculate the current link quality and the current overall service utility;

[0023] Step 2: Determine if the current service satellite link is invalid, and trigger passive weather sensing switching if it is invalid;

[0024] Step 3: If the current service satellite link is not invalid, determine whether to trigger the weather awareness handover process: If the current service satellite link is not invalid, compare whether the performance improvement margin after the candidate satellite handover is higher than the preset threshold; if it is higher than the preset threshold, trigger the weather awareness handover process and determine the target satellite; if it is not higher than the preset threshold, maintain the current service satellite.

[0025] Preferably, the prediction enhancement switching process specifically includes the following steps:

[0026] Step 1: Predict the quality of each satellite link within the future time window;

[0027] Step 2: Calculate the predicted risks and the utility of the predicted enhancement services;

[0028] Step 3: Determine if the current service satellite link status is invalid, and trigger predictive enhancement passive handover if invalid: When the current service satellite link status is lower than the minimum service quality requirement, determine that the current service satellite link status is invalid, trigger predictive enhancement passive handover, and select the currently available satellite with low predictive risk from the candidate satellite set as the target satellite;

[0029] Step 4: If the current service satellite link is not invalid, determine whether to trigger predictive augmentation active handover: If the current service satellite link is not invalid, compare whether the predictive augmentation performance improvement margin after the candidate satellite handover is higher than a preset threshold; if it is higher than the preset threshold, trigger predictive augmentation active handover and determine the target satellite; if it is not higher than the preset threshold, maintain the current service satellite.

[0030] Compared with existing technologies, this invention addresses the problem of rapidly changing link quality over time when using millimeter-wave communication between high-speed mobile vehicle terminals and satellites in low-Earth orbit satellite access environments. It proposes a dynamic handover method for vehicle-to-satellite communication. This method comprehensively evaluates the communication quality of candidate satellite links by performing link budget assessment on the vehicle-satellite link and incorporating environmental attenuation factors, thereby achieving adaptive satellite handover decisions under complex propagation conditions. This invention can effectively improve the service continuity and link reliability of vehicle-to-satellite communication under complex weather conditions and high-speed mobile scenarios. Attached Figure Description

[0031] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0032] Figure 1 This is the overall architecture diagram of the vehicle-mounted satellite communication dynamic switching system of the present invention;

[0033] Figure 2 This is a flowchart of the dynamic switching method for vehicle-mounted satellite communication according to the present invention;

[0034] Figure 3 This is a detailed flowchart of the dynamic switching method for vehicle-mounted satellite communication according to the present invention. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0036] Specifically, the present invention provides a dynamic switching system for vehicle-mounted satellite communication, such as... Figure 1 As shown, the system includes a low-Earth orbit (LEO) satellite constellation and a vehicle-mounted terminal. The vehicle-mounted terminal is installed on vehicle V0 and accesses the network and obtains communication services through a vehicle-satellite direct link. The LEO satellite constellation includes multiple selectable satellite nodes, such as the currently serving satellite S0 and candidate satellites S1, S2, and S3. The weather attenuation impact area is used to characterize the attenuation range and intensity caused by weather factors such as rainfall, clouds, fog, and water vapor on the communication link between the vehicle and the satellite.

[0037] Initially, vehicle V0 receives communication services from satellite S0. When the link between vehicle V0 and satellite S0 crosses a weather-attenuated area, the current link quality deteriorates, potentially triggering a satellite handover decision. At this point, although satellite S1 meets the geometric visibility requirements, its link is also affected by weather attenuation, making it difficult to provide stable service; satellite S2, although located in a low-Earth orbit constellation, does not meet the visibility requirements for the current vehicle location and cannot be considered a valid candidate satellite; satellite S3 meets the geometric visibility requirements and is not significantly affected by weather attenuation, therefore it can be considered a priority candidate target satellite.

[0038] Therefore, when determining the candidate satellite set, this invention not only considers the geometric visibility relationship between the vehicle V0 and each satellite, but also further considers the effect of the weather attenuation area on the quality of the communication link, thus providing a unified system modeling basis for subsequent weather perception handover and prediction enhancement handover.

[0039] Each low-Earth orbit satellite is equipped with an onboard signal processing unit, an electronically controllable beam antenna, and a millimeter-wave communication transceiver module. The electronically controllable beam antenna can dynamically adjust the satellite's service beam direction towards the vehicle based on its location, ensuring continuous coverage and communication connectivity. To describe the relative geometric relationship between the satellite and the vehicle, a local East-North-Sky coordinate system is established with the vehicle as the origin. The relative position at time t is represented as a three-dimensional vector:

[0040]

[0041] The system considers N vehicles equipped with satellite communication terminals, denoted as follows: .vehicle The position vector at time t is represented as:

[0042]

[0043] Its velocity vector is expressed as:

[0044]

[0045] The vehicle-mounted terminal has millimeter-wave transceiver capabilities and a directional antenna, which can measure or estimate candidate satellite links and perform satellite switching operations.

[0046] A millimeter-wave air-to-ground direct communication link is established between the vehicle-mounted terminal and the low-Earth orbit satellite. For vehicles... With satellite The relative position difference vector between the two at time t is expressed as:

[0047]

[0048] The corresponding slope distance is defined as:

[0049]

[0050] Based on the slant range, the elevation angle of the satellite relative to the vehicle can be further defined. With azimuth The elevation angle characterizes the effective cross-path length of the link propagation path in the atmosphere, while the azimuth angle characterizes the pointing direction of the link in the horizontal plane. An elevation angle threshold is introduced to describe satellite visibility. ,when At that time, it was believed that the satellite For vehicles It is evident that this leads to the vehicle's... The set of visible satellites at time t:

[0051]

[0052] In the millimeter-wave band, the propagation loss of the satellite-vehicle link is affected by factors such as free-space diffusion loss, atmospheric absorption, rainfall attenuation, and blockage and beam alignment errors. The total path loss of the link can be expressed as:

[0053]

[0054] in, Where is the carrier frequency, and FSPL is the free space path loss. Atmospheric losses such as gas absorption Rainfall attenuation term Additional losses include occlusion, shadow fading, and beam alignment errors.

[0055] To characterize the directional features of rainfall impacts in spatial distribution, this invention introduces a rain attenuation azimuth window W, used to describe the azimuth range of significant rainfall impacts within a given time t. When the link azimuth... When entering window W, the rainfall attenuation term of this link is considered. The link budget needs to be carefully considered; when If the azimuth window W is not within the range, the impact of rainfall on the link can be considered weak or negligible. The azimuth window W can be determined by meteorological radar data, rainfall distribution estimation, or historical statistical information.

[0056] To uniformly characterize link availability, this invention uses instantaneous carrier-to-noise ratio (CNR) as a link quality indicator, and its expression is:

[0057]

[0058] Where EIRP is the satellite equivalent isotropic radiated power, G / T is the performance index of the vehicle-mounted receiver, k is the Boltzmann constant, and B is the system bandwidth. It can serve as a basic input for candidate satellite selection, link availability assessment, and handover triggering criteria.

[0059] To suppress frequent handovers caused by short-term fast fading or local disturbances, this invention further introduces a short-term stability penalty term, defining the link utility function as follows:

[0060]

[0061] in For stability weighting coefficients, For statistics window The CNR fluctuation within the range is defined as:

[0062]

[0063] in This is the average value within the window. This is the length of the short-term statistical window.

[0064] This utility function can simultaneously reflect the instantaneous quality and short-term stability of the link: when the CNR is similar, the link with smaller fluctuations will achieve higher efficiency, thereby reducing the risk of handover oscillations.

[0065] Furthermore, the present invention also provides a dynamic switching method for vehicle-mounted satellite communication, such as... Figure 2 and Figure 3 As shown, the method includes the following steps:

[0066] S1: Obtain the communication status of the vehicle terminal, candidate satellite information, and weather information;

[0067] Specifically, the system acquires information on currently serving satellites, current link status, vehicle location, candidate satellite information, current weather observation information, and weather forecast information as the basis for subsequent satellite handover decisions.

[0068] S2: Construct a candidate satellite set;

[0069] Specifically, based on satellite coverage, satellite visibility, link budget results, and the impact of weather attenuation, candidate satellites that meet the communication conditions are selected, and ideal candidate satellites and near-suboptimal candidate satellites are merged to form a candidate satellite set.

[0070] S3: Determine the satellite handover method, which includes one of the weather perception handover process and the prediction enhancement handover process;

[0071] Specifically, the satellite handover method is determined based on the availability of weather forecast data, the confidence level of the forecast, business continuity requirements, and system configuration. That is, the satellite handover method adopts either the weather-aware handover process or the forecast-enhanced handover process.

[0072] In one embodiment of the present invention, a weather-aware handover process is employed, incorporating weather-induced link attenuation into the link budget assessment and handover criterion construction process to achieve adaptive handover decisions under adverse weather conditions. In millimeter-wave vehicle-mounted satellite communication scenarios, link quality is not only affected by changes in the satellite-vehicle geometric relationship but also significantly impacted by environmental factors such as rainfall attenuation. Due to the suddenness and directionality of rainfall attenuation, traditional handover mechanisms based solely on instantaneous measurements or fixed thresholds are prone to handover lag, handover oscillations, or unnecessary handovers, leading to increased link interruption probability and signaling overhead.

[0073] The weather perception switching process specifically includes the following steps:

[0074] Step 1: Calculate the current link quality and the current overall service utility;

[0075] Specifically, based on current weather observation information, current service satellite link status, and candidate satellite link conditions, the current link quality of the current service satellite and each candidate satellite is calculated, and the current comprehensive service utility is obtained by combining link quality, switching cost, and connection stability.

[0076] Step 2: Determine if the current service satellite link is invalid, and trigger passive weather sensing switching if it is invalid;

[0077] Specifically, when the current service satellite link status is below the minimum service quality requirement, the current service satellite link status is determined to be invalid, triggering a passive switch for weather perception, and the target satellite is determined from the candidate satellite set.

[0078] Step 3: If the current service satellite link status is not invalid, determine whether to trigger the weather awareness handover process;

[0079] Specifically, when the current serving satellite link is not invalid, the performance improvement margin after switching candidate satellites is compared to see if it exceeds a preset threshold. If it exceeds the preset threshold, the weather awareness switching process is triggered and the target satellite is determined; if it does not exceed the preset threshold, the current serving satellite is maintained.

[0080] Furthermore, to enable the subsequent prediction-enhanced handover process to output quantifiable handover decision criteria, in this invention, the short-term prediction model can determine the weather attenuation prediction value and link quality prediction value within a future time window as follows. The future time window is denoted as... Any prediction time within the window is denoted as t+τ, where τ=1,2,... .

[0081] Specifically, the inputs to the predictive enhancement handover process include weather forecast information, historical weather attenuation information, vehicle motion status, satellite ephemeris information, and link budget parameters. Weather forecast information includes at least one of the following: rainfall intensity, rainfall area, rainfall movement direction, cloud cover, or humidity information within the future time window; historical weather attenuation information includes historical rainfall attenuation or weather attenuation sequences in the area where the vehicle terminal is located or along the candidate link direction; vehicle motion status includes the vehicle's current position, speed, and direction of travel; satellite ephemeris information is used to determine the positions of candidate satellites within the future time window; and link budget parameters include at least one of the following: transmitted equivalent isotropic radiated power, received antenna gain, carrier frequency, bandwidth, noise power, free-space path loss parameters, and atmospheric loss parameters.

[0082] In the future link geometry prediction step, the position of vehicle terminal i at the future time t+τ is predicted based on the vehicle's motion state, and the position of candidate satellite j at the future time t+τ is determined based on satellite ephemeris information. The future position of vehicle terminal i can be determined according to the following formula:

[0083]

[0084] in, This indicates the position of vehicle terminal i at the current time t. Let represent the velocity vector of vehicle terminal i. Calculate the satellite-to-ground distance between vehicle terminal i and candidate satellite j based on their future positions. Angle of elevation and azimuth The distance between the satellite and the Earth can be determined using the following formula:

[0085]

[0086] The satellite-to-ground distance, elevation angle, azimuth angle, vehicle speed, vehicle direction, weather forecast information, and historical weather attenuation information are time-aligned and normalized to construct a spatiotemporal feature sequence corresponding to vehicle terminal i and candidate satellite j. The spatiotemporal feature sequence can be represented as:

[0087]

[0088] in, Let W(t+1:t+) represent a historical weather decay sequence of length K. This represents a weather forecast sequence within a future time window. Indicates vehicle speed. Indicates the direction of vehicle travel.

[0089] In one implementation, the spatiotemporal feature sequence is input into a spatiotemporal prediction model, which outputs the predicted weather attenuation value between vehicle terminal i and candidate satellite j within a future time window. The spatiotemporal prediction model can employ a Convolutional Long Short-Term Memory (Conv-LSTM) network to extract spatial features related to weather attenuation regions, link azimuth angles, and elevation angles through the convolutional structure, and to extract dynamic features of weather attenuation evolution over time through the long short-term memory structure.

[0090]

[0091]

[0092]

[0093] in, This represents the spatial features obtained from the convolutional structure. Indicates the timing hidden state. This represents the prediction output layer, and Θ represents the model parameters. This represents the predicted weather decay value at a future time t+τ. In other implementations, the spatiotemporal prediction model can also employ recurrent neural networks, gated recurrent unit networks, spatiotemporal graph neural networks, or Transformer time series prediction models that can characterize temporal and spatial correlations.

[0094] After obtaining the predicted weather attenuation value, the predicted weather attenuation value is used as an additional loss item in the future link budget to calculate the total path loss at the future time t+τ. The total path loss includes at least one of free-space path loss, atmospheric absorption loss, predicted weather attenuation loss, and other additional link losses, and can be expressed as:

[0095]

[0096] Where FSPL represents free space path loss, Indicates the carrier frequency. This indicates atmospheric absorption loss. It represents at least one of shadow fading, polarization loss, or other additional losses.

[0097] Based on the total path loss, the predicted link quality at the future time t+τ is calculated. In one implementation, the predicted carrier-to-noise ratio (CNR) is used as the link quality metric, and the predicted CNR_ij(t+τ) can be expressed as:

[0098]

[0099] in, This represents the equivalent isotropic radiated power of candidate satellite j. Let N represent the receiving antenna gain of vehicle terminal i, and let N represent the noise power or equivalent noise term. This yields the predicted link quality sequence for each candidate satellite link within the future time window.

[0100] To facilitate handover decisions, the predicted performance margin is calculated based on the predicted carrier-to-noise ratio and the service quality threshold Γ_th. :

[0101]

[0102] When the predicted performance margin is positive, it means that the corresponding candidate satellite link will meet the service quality requirements at a future time; when the predicted performance margin is negative, it means that the corresponding candidate satellite link is at risk of insufficient link quality at a future time.

[0103] In one implementation, a link risk loss can also be constructed based on the predicted carrier-to-noise ratio to describe the extent to which the link quality falls below the service quality threshold within a future time window:

[0104]

[0105] When using the predictive confidence level α for risk assessment, risk metrics can be calculated based on link risk losses within a future time window. In one implementation, the risk metric is represented by Conditional Value at Risk (CVaR):

[0106]

[0107] Where L represents the link risk loss variable within the future time window, α represents the prediction confidence level, η represents the auxiliary variable, and (·)^+ represents taking the positive part. The prediction confidence level α is used to control the conservatism of the handover decision regarding the risk of future short-term deep fading.

[0108] Furthermore, a prediction utility function for candidate satellite j can be constructed based on the predicted carrier-to-noise ratio, risk metrics, and switching overhead. :

[0109]

[0110] Where ω_τ represents the weights at different prediction times, λ represents the risk penalty weight, ζ represents the switching overhead weight, I(·) represents the indicator function, and j_0 represents the currently serving satellite. The target satellite j* is selected based on the prediction utility function:

[0111] A handover is triggered when the predicted utility of target satellite j* improves by more than a preset threshold Δ relative to the predicted utility of the current serving satellite j_0; otherwise, the current connection is maintained. The handover trigger condition can be expressed as:

[0112]

[0113] Through the above processing, the present invention can transform weather forecast information, vehicle motion status and satellite link budget results into quantitative predicted link quality of each candidate satellite link within a future time window, and further make a handover decision based on the predicted link quality, risk measurement and handover margin, thereby performing a forward-looking handover before the millimeter-wave link deteriorates rapidly due to weather attenuation.

[0114] In another embodiment, the present invention also provides a predictive enhanced handover process, which uses a short-term prediction model to predict weather attenuation or link quality change trends, so as to trigger handover in advance and reduce the risk of link interruption.

[0115] The predictive enhancement handover process specifically includes the following steps:

[0116] Step 1: Predict the quality of each satellite link within the future time window;

[0117] Specifically, by combining weather forecast information, vehicle motion status, and satellite link budget results, the link quality changes of currently serving satellites and candidate satellites within future time windows are predicted.

[0118] Step 2: Calculate the predicted risks and the utility of the predicted enhancement services;

[0119] Specifically, based on the predicted link quality of each satellite within the future window, the link degradation risk of the current service satellites and candidate satellites is assessed, and the predicted enhanced service utility is calculated by combining the predicted link quality, weather risk, handover cost and connection stability.

[0120] Step 3: Determine if the current service satellite link is in failure, and trigger predictive augmentation passive handover if it is in failure;

[0121] Specifically, when the current service satellite link status is below the minimum service quality requirement, the current service satellite link status is determined to be invalid, triggering a predictive enhancement passive handover, and selecting a currently available satellite with a low predictive risk from the candidate satellite set as the target satellite.

[0122] Step 4: If the current service satellite link status is not invalid, determine whether to trigger predictive augmentation active handover;

[0123] Specifically, when the current serving satellite link is not invalid, the margin for performance improvement in prediction enhancement after switching candidate satellites is compared to whether it exceeds a preset threshold. If it exceeds the preset threshold, an active prediction enhancement switch is triggered and the target satellite is determined; if it does not exceed the preset threshold, the current serving satellite is maintained.

[0124] S4: Based on the judgment result, the vehicle terminal maintains the current serving satellite or switches from the current serving satellite to the determined target satellite.

[0125] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A dynamic switching system for vehicle-mounted satellite communication, characterized in that, The system includes a low-Earth orbit (LEO) satellite constellation and a vehicle-mounted terminal. The vehicle-mounted terminal is installed on a vehicle and accesses the network and obtains communication services through a vehicle-satellite direct link. The LEO satellite constellation includes multiple selectable satellite nodes, including currently serving satellites and candidate satellites. In the initial state, the vehicle terminal is provided with communication services by the current serving satellite. When the link between the vehicle and the current serving satellite passes through the area affected by weather attenuation, the quality of the current link degrades, triggering a satellite switching judgment. Based on the judgment result, the vehicle terminal either maintains the current serving satellite or switches from the current serving satellite to the determined candidate satellite.

2. The dynamic switching system for vehicle-mounted satellite communication according to claim 1, characterized in that, Each low-Earth orbit satellite is equipped with an onboard signal processing unit, an electronically controllable beam antenna, and a millimeter-wave communication transceiver module. The electronically controllable beam antenna can dynamically adjust the satellite's service beam direction for the vehicle according to the vehicle's location, so as to achieve continuous coverage and communication connection for the vehicle.

3. A dynamic switching method for vehicle-mounted satellite communication, characterized in that, The method includes the following steps: Acquire vehicle-mounted terminal communication status, candidate satellite information, and weather information; Construct a candidate satellite set; Determine the satellite handover method, which includes one of the weather perception handover process and the prediction enhancement handover process; Based on the judgment result, the vehicle-mounted terminal either maintains the current serving satellite or switches from the current serving satellite to the determined target satellite.

4. The dynamic switching method for vehicle-mounted satellite communication according to claim 3, characterized in that, The steps for constructing the candidate satellite set specifically include: screening candidate satellites that meet communication conditions based on satellite coverage, satellite visibility, link budget results, and weather attenuation effects, and merging ideal candidate satellites and near-optimal candidate satellites to form a candidate satellite set.

5. The dynamic switching method for vehicle-mounted satellite communication according to claim 3, characterized in that, The steps for determining the satellite handover method include either a weather-aware handover process or a prediction-enhanced handover process. Specifically, it includes determining whether the satellite handover method is a weather-aware handover process or a prediction-enhanced handover process based on whether weather forecast data is available, the prediction confidence level, business continuity requirements, and system configuration.

6. The dynamic switching method for vehicle-mounted satellite communication according to claim 5, characterized in that, The weather perception switching process specifically includes the following steps: Step 1: Calculate the current link quality and the current overall service utility; Step 2: Determine if the current service satellite link is invalid, and trigger passive weather sensing switching if it is invalid; Step 3: If the current service satellite link is not invalid, determine whether to trigger the weather awareness handover process: If the current service satellite link is not invalid, compare whether the performance improvement margin after the candidate satellite handover is higher than the preset threshold; if it is higher than the preset threshold, trigger the weather awareness handover process and determine the target satellite; if it is not higher than the preset threshold, maintain the current service satellite.

7. The dynamic switching method for vehicle-mounted satellite communication according to claim 5, characterized in that, The predictive enhancement handover process specifically includes the following steps: Step 1: Predict the quality of each satellite link within the future time window; Step 2: Calculate the predicted risks and the utility of the predicted enhancement services; Step 3: Determine if the current service satellite link status is invalid, and trigger predictive enhancement passive handover if invalid: When the current service satellite link status is lower than the minimum service quality requirement, determine that the current service satellite link status is invalid, trigger predictive enhancement passive handover, and select the currently available satellite with low predictive risk from the candidate satellite set as the target satellite; Step 4: If the current service satellite link is not invalid, determine whether to trigger predictive augmentation active handover: If the current service satellite link is not invalid, compare whether the predictive augmentation performance improvement margin after the candidate satellite handover is higher than a preset threshold; if it is higher than the preset threshold, trigger predictive augmentation active handover and determine the target satellite; if it is not higher than the preset threshold, maintain the current service satellite.

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