Communication method, system, device, medium, program product and chip of very small aperture terminal

Abstract

This disclosure provides a communication method, system, device, medium, and program product for a Very Small Aperture (VSA) terminal. The communication method includes: acquiring first ephemeris information; receiving a first synchronization signal from a first satellite corresponding to the first ephemeris information using a first beam; determining initial positioning information of the VSA terminal based on the first synchronization signal and the first ephemeris information; determining a first beam pointing based on the initial positioning information and the first ephemeris information; receiving a second synchronization signal and second ephemeris information from a second satellite using a second beam according to the first beam pointing; wherein the beamwidth of the second beam is smaller than the beamwidth of the first beam; and determining target positioning information of the VSA terminal based on the second synchronization signal and the second ephemeris information. This improves positioning speed and accuracy, providing a reliable beam pointing and uplink synchronization reference for subsequent narrow-beam communication. It also provides an effective alternative communication scheme when GNSS functionality degrades, further enhancing the terminal's environmental adaptability and robustness.

Description

Technical Field

[0001] This disclosure relates to the field of terminal communication methods, and in particular to a communication method, system, device, medium, program product and chip for a very small aperture terminal. Background Technology

[0002] Cellular communication systems have evolved to the fifth generation (5G). In the 5G New Radio (NR) system, its second release (R16) standardized several location methods based on radio access technology dependent, such as Downlink Time Difference of Arrival (DL-TDOA), Uplink Time Difference of Arrival (UL-TDOA), and Multi-Round Trip Time (Multi-RTT). These methods typically rely on the coordination of the Location Management Function (LMF) in the core network and terrestrial base stations.

[0003] In non-terrestrial networks (NTNs) (such as those supported by 5G NR), user equipment (UE) typically relies on its built-in Global Navigation Satellite System (GNSS) receiver to obtain its precise position and combines the received satellite ephemeris information to calculate uplink timing advance (TA) and frequency offset pre-compensation value, thereby achieving uplink synchronization and network access.

[0004] However, in satellite communication terminal applications such as Very Small Aperture Terminals (VSATs), high-gain directional antennas are typically used to ensure high throughput. When the terminal lacks GNSS functionality, the GNSS signal is lost, or the functionality degrades, the terminal cannot determine its own precise location. In this case, even if the terminal can estimate the approximate location of the satellite based on stored coarse ephemeris information, it cannot accurately determine the beam pointing angle, making narrow beam alignment with the satellite extremely difficult. Traditional beam scanning alignment methods consume a significant amount of time, resulting in low access efficiency or even access failure.

[0005] Several alternative positioning schemes have been proposed in the existing technology. For example, the Time Difference of Arrival (TDOA) positioning method based on multiple satellite synchronization signal blocks (SSBs) requires multiple satellites to simultaneously cover the area where the terminal is located, and the inter-satellite synchronization accuracy is extremely high. In addition, the TDOA positioning method based on signals from a single satellite at different times can simulate multi-satellite positioning, but it is difficult to continuously receive signals for measurement when the terminal position is unknown and the beam cannot be accurately pointed to and track the satellite.

[0006] Another approach is to use a wide beam to receive broadcast signals from multiple satellites for positioning. However, this requires multiple satellites to participate simultaneously, and the accuracy of the stored ephemeris information is insufficient. The accuracy will gradually decrease over time, resulting in insufficient positioning accuracy. Consequently, the subsequent narrow beam pointing error will still be large, and it may be unable to stably receive or parse system information blocks (SIBs) containing accurate ephemeris, such as SIB19, leading to access failure. Summary of the Invention

[0007] The technical problem to be solved by this disclosure is to overcome the shortcomings of existing very small aperture terminals in that the beam cannot accurately track the satellite and it is difficult to continuously receive signals when the precise location of the terminal is unknown. The disclosure provides a communication method, system, device, medium, program product and chip for very small aperture terminals.

[0008] This disclosure solves the above-mentioned technical problems through the following technical solution:

[0009] Firstly, a communication method for a very small aperture terminal is provided, the communication method comprising:

[0010] Obtain first ephemeris information;

[0011] The first synchronization signal of the first satellite corresponding to the first ephemeris information is received with the first beam, and the initial positioning information of the very small aperture terminal is determined based on the first synchronization signal and the first ephemeris information.

[0012] Based on the initial positioning information and the first ephemeris information, the first beam direction is determined, and the second synchronization signal and second ephemeris information of the second satellite are received with the second beam according to the first beam direction;

[0013] Wherein, the beamwidth of the second beam is smaller than the beamwidth of the first beam;

[0014] The target positioning information of the very small aperture terminal is determined based on the second synchronization signal and the second ephemeris information.

[0015] Optionally, the very small aperture terminal includes a phased array antenna, and the phased array antenna includes S antenna elements;

[0016] The very small aperture terminal generates the first beam by activating M of the S antenna elements, and the very small aperture terminal generates the second beam by activating N of the S antenna elements.

[0017] Where S, M, and N are all positive integers, M is greater than or equal to the first antenna element number threshold P, N is greater than or equal to the second antenna element number threshold Q, the first antenna element number threshold P is less than the second antenna element number threshold Q, and M is less than N;

[0018] The first antenna element quantity threshold P corresponds to the first minimum demodulation threshold of the first synchronization signal, and the second antenna element quantity threshold Q corresponds to the second minimum demodulation threshold of the second ephemeris information.

[0019] Optionally, the GNSS function of the very small aperture terminal meets the functional degradation condition.

[0020] Optionally, the functional degradation condition includes at least one of the following conditions:

[0021] The GNSS function module of the very small aperture terminal is faulty or missing hardware.

[0022] The continuous fault duration of the very small aperture terminal losing GNSS signal exceeds the fault duration threshold.

[0023] The number of failures of the very small aperture terminal to reconnect to the GNSS signal is greater than the failure number threshold.

[0024] The positioning accuracy of the GNSS function module of the very small aperture terminal is lower than the positioning accuracy threshold.

[0025] The GNSS measurement period of the GNSS function module of the very small aperture terminal is greater than the GNSS measurement period threshold.

[0026] Optionally, the communication method further includes:

[0027] The direction of the second beam is determined based on the target positioning information and the first ephemeris information;

[0028] According to the direction of the second beam, the third beam is used to receive the third synchronization signal and the third ephemeris information of the third satellite;

[0029] Based on the third ephemeris information and the target positioning information, the third beam pointing and the first uplink time-frequency synchronization deviation for accessing the third satellite are determined;

[0030] Based on the first uplink time-frequency synchronization deviation and the third beam pointing, the fourth beam is used to access the third satellite;

[0031] Wherein, the beamwidth of the third beam is less than or equal to the beamwidth of the second beam, and the beamwidth of the fourth beam is less than or equal to the beamwidth of the second beam.

[0032] Optionally, the communication method further includes:

[0033] Based on the second ephemeris information and the target positioning information, the remaining visibility time of the second satellite is determined;

[0034] In response to the remaining visible time being greater than or equal to the satellite access time threshold, the fourth beam pointing and the second uplink time-frequency synchronization deviation for accessing the second satellite are determined based on the second ephemeris information and the target positioning information.

[0035] Based on the second uplink time-frequency synchronization deviation and the fourth beam pointing, the fifth beam is used to access the second satellite, and the beamwidth of the fifth beam is less than or equal to the beamwidth of the second beam.

[0036] Secondly, a communication system for a very small aperture terminal is provided, the communication system comprising an ephemeris acquisition module, an initial positioning determination module, and a target positioning determination module;

[0037] The ephemeris acquisition module is used to acquire first ephemeris information;

[0038] The initial positioning determination module is used to receive the first synchronization signal of the first satellite corresponding to the first ephemeris information with a first beam, and determine the initial positioning information of the very small aperture terminal based on the first synchronization signal and the first ephemeris information.

[0039] The target positioning and determination module is used to determine the direction of the first beam based on the initial positioning information and the first ephemeris information, and to receive the second synchronization signal and the second ephemeris information of the second satellite with the second beam according to the direction of the first beam.

[0040] Wherein, the beamwidth of the second beam is smaller than the beamwidth of the first beam;

[0041] The target positioning information of the very small aperture terminal is determined based on the second synchronization signal and the second ephemeris information.

[0042] Thirdly, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and for running on the processor, wherein the processor executes the computer program to implement the communication method of the very small aperture terminal as described in the first aspect.

[0043] Fourthly, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the communication method of the very small aperture terminal as described in the first party.

[0044] Fifthly, a computer program product is provided, comprising a computer program that, when executed by a processor, implements the communication method of the very small aperture terminal as described in the first aspect.

[0045] In a sixth aspect, a chip is provided, on which a computer program is stored, and when the computer program is executed by the chip, it implements the communication method of the very small aperture terminal as described in the first aspect.

[0046] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of this disclosure.

[0047] The positive advancements of this disclosure are as follows: Before completing its own positioning, the terminal does not need to rely on external auxiliary positioning data or perform time-consuming full-space beam scanning. This overcomes the shortcomings of existing technologies, such as low beam alignment efficiency and difficulty in quickly acquiring satellite signals with narrow beams when the terminal's location is unknown. It significantly improves positioning speed and accuracy, providing a reliable beam pointing and uplink synchronization reference for subsequent narrow-beam communication. In particular, it provides an effective alternative communication scheme when the terminal's GNSS function degrades, further enhancing the terminal's environmental adaptability and robustness. Attached Figure Description

[0048] Figure 1 A first flowchart of a communication method for a very small aperture terminal provided as an exemplary embodiment of this disclosure;

[0049] Figure 2 A second flowchart of a communication method for a very small aperture terminal provided as an exemplary embodiment of this disclosure;

[0050] Figure 3 A third flowchart of a communication method for a very small aperture terminal provided as an exemplary embodiment of this disclosure;

[0051] Figure 4 A schematic diagram of a communication system for a very small aperture terminal provided as an exemplary embodiment of this disclosure;

[0052] Figure 5 This is a hardware schematic diagram of an electronic device provided for an exemplary embodiment of the present disclosure. Detailed Implementation

[0053] The present disclosure is further illustrated below by way of embodiments, but the present disclosure is not limited to the scope of the embodiments described herein.

[0054] The prefixes such as "first" and "second" used in this disclosure are merely for distinguishing different descriptive objects and do not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes used to distinguish descriptive objects in this disclosure does not constitute a limitation on the described objects. The description of the described objects is given in the claims or the context of the embodiments, and should not be construed as an unnecessary limitation. Furthermore, in the description of this embodiment, unless otherwise stated, "multiple" means two or more.

[0055] Unlike the omnidirectional antennas of handheld terminals, VSMEs in the Ku / Ka bands are generally equipped with high-gain directional antennas (such as parabolic antennas or phased array antennas) to achieve high throughput. A directional antenna is an antenna that concentrates electromagnetic wave transmission / reception energy in one or several specific directions, with extremely weak energy in other directions. It achieves higher antenna gain by focusing signal energy and can also suppress interference from non-target directions, offering better security and anti-interference capabilities. However, it requires high beam pointing accuracy, with the beam precisely aligned with the satellite. VSMEs using parabolic antennas have only one beam and can only point to and track one satellite at a time. To reduce weight, power consumption, cost, and complexity, VSMEs using phased array antennas generally employ an HD-FDD (Half-Duplex Frequency Division Duplex) system and only support a single beam, allowing them to point to and track only one satellite simultaneously.

[0056] When the GNSS function of the Very Small Aperture Terminal is available, it obtains its own precise position information through the GNSS module, calculates the approximate satellite position at a certain moment based on the stored ephemeris information, and then determines the beam angle (such as azimuth and elevation angle) pointing to the satellite based on its own precise position information and the approximate satellite position. It controls the beam to point at the satellite at that angle and continuously tracks the satellite, and receives SSB and system messages (such as SIB1, SIB19, etc.) broadcast by the satellite.

[0057] Example 1

[0058] Figure 1 This flowchart illustrates a communication method for a very small aperture terminal provided as an exemplary embodiment of the present disclosure. The embodiment provides a communication method for a very small aperture terminal, the communication method comprising:

[0059] S101, Obtain the first ephemeris information;

[0060] Specifically, the first ephemeris information refers to the ephemeris data used by the Very Small Aperture Terminal (VSA) to preliminarily determine the satellite's spatial position and trajectory before obtaining accurate ephemeris information (such as the ephemeris information contained in SIB19).

[0061] In one embodiment, the first ephemeris information is pre-stored locally on the terminal. The very small aperture terminal periodically receives and stores broadcast ephemeris information from satellites during factory release or normal operation. When GNSS functionality degrades, the terminal can directly retrieve the most recently updated and saved ephemeris data from its local memory as the first ephemeris information.

[0062] In one embodiment, if the terminal maintains a terrestrial wireless network connection such as a cellular network or Wi-Fi, or a wired network such as fiber optic, before entering the GNSS function degradation state, it can download satellite ephemeris data through the terrestrial wireless network or wired network to obtain more real-time and reliable ephemeris information as the first ephemeris information.

[0063] S102. Receive the first synchronization signal of the first satellite corresponding to the first ephemeris information with the first beam, and determine the initial positioning information of the very small aperture terminal based on the first synchronization signal and the first ephemeris information.

[0064] Specifically, after acquiring the first ephemeris information, the very small aperture terminal uses this information to calculate the approximate spatial position of the first satellite at the current moment. The terminal controls its phased array antenna, activating M antenna elements to form a beamwidth of... Gain is The first beam, for example , i. Because the first beam has a wider beamwidth, even if the first beam is not precisely aligned with the first satellite, it can still be used for a period of time (assuming [...]). The system covers the actual location of the first satellite and continuously receives the first synchronization signal periodically transmitted by the first satellite.

[0065] The terminal receives a first synchronization signal periodically transmitted by a first satellite through the first beam, such as a synchronization signal block (SSB) in the 5G NR standard. The SSB signal is transmitted in a known time-frequency structure within a preset period T, for example, period T = 20ms.

[0066] During the reception process, the terminal measures the Time of Arrival (TOA) of each SSB signal and parses the frame index corresponding to its transmission time, and uses the first ephemeris information to determine the spatial position of the first satellite at each SSB transmission time.

[0067] Subsequently, the terminal adopted a single-satellite downlink time difference of arrival positioning method:

[0068] Assume the coordinates of the very small aperture end are ,exist At time i, the i-th SSB signal is received. The j-th SSB signal is received at time j. Based on the first ephemeris information, the satellite's position is calculated. and Rough position coordinates of time and Then the equation of the hyperboloid can be established:

[0069]

[0070] ;

[0071] Where c is the speed of light. The above equation has only three unknowns: the coordinates of the very small aperture endpoint. By establishing at least three hyperboloid equations and solving them jointly, the approximate coordinates of the very small aperture terminal can be obtained. This serves as the initial location information for the terminal.

[0072] The error magnitude of the initial positioning information is typically in the range of hundreds to thousands of meters, which is still insufficient to support precise alignment and tracking of extremely narrow beams. However, it can be used to determine the approximate beam angle pointing to the satellite, so as to switch to the second beam for more precise pointing and tracking.

[0073] In one embodiment, the terminal establishes a relationship between its position and the Doppler frequency shift by measuring the Doppler frequency offset of the first synchronization signal and utilizing the satellite's velocity vector from the first ephemeris information. Through multiple measurements, this equation is solved simultaneously to obtain the terminal's initial positioning information. For example:

[0074] The very small aperture terminal receives the i-th SSB signal and measures the downlink Doppler frequency offset. ,in Let i be the frequency point at which the UE receives the i-th SSB signal. The frequency point at which the satellite transmits the i-th SSB signal.

[0075] Based on the first ephemeris information, the satellite's position was calculated to be... Approximate location of time and rough speed Assume the position of the very small aperture end is... ,but Distance from the smallest aperture terminal to the satellite at any given time for:

[0076] ;

[0077] Unit direction vector from the very small aperture terminal to the satellite for:

[0078] ;

[0079] but,

[0080] ;

[0081] The above formula has only three unknowns: the position coordinates of the very small aperture end. By establishing at least three equations and solving them jointly, the approximate coordinates of the very small aperture terminal can be obtained. This serves as the initial location information for the terminal.

[0082] In one embodiment, the very small aperture terminal employs a single-satellite meridian positioning method, specifically:

[0083] The very small aperture terminal receives the i-th SSB signal and measures the downlink Doppler frequency offset. ,in Let i be the frequency point at which the UE receives the i-th SSB signal. The frequency point at which the satellite transmits the i-th SSB signal;

[0084] Calculate the radial velocity from the satellite to the UE. :

[0085] ;

[0086] Among them, the radial velocity It is negative when it is close to the terminal and positive when it is far from the terminal.

[0087] when At that time, UE calculates and The difference in distance between the UE and the satellite at any given time :

[0088] ;

[0089] Based on the first ephemeris information, the satellite's position was calculated. and Rough position coordinates of time and ;

[0090] Establish the equation of the hyperboloid:

[0091] ;

[0092] The above formula has only three unknowns: the position coordinates of the very small aperture end. By establishing at least three hyperboloid equations and solving them jointly, the approximate coordinates of the very small aperture terminal can be obtained. This serves as the initial location information for the terminal.

[0093] In one embodiment, because the first beam has a wide beamwidth, the terminal's first beam may simultaneously cover two or more different satellites, allowing the terminal to simultaneously receive and identify first synchronization signals from different satellites. Using the different satellite positions provided by the first ephemeris information, the terminal's initial positioning information is obtained based on the aforementioned positioning method. In scenarios with good inter-satellite geometry, this can provide positioning accuracy superior to that of a single satellite.

[0094] In one embodiment, a wide-beam coarse positioning method is employed. For example, the terminal estimates the distance to the satellite by measuring the average received power of the first synchronization signal, using the known position and transmit power of the first satellite based on the first ephemeris information, and combining this with a wireless propagation loss model. Initial positioning information is obtained by measuring the average received power at multiple times and combining this with the satellite position information at multiple times. Alternatively, the first beam is synthesized from multiple sub-beams. The terminal roughly estimates the angle (such as azimuth and elevation) of the satellite relative to the beam direction by comparing the amplitude and phase of the received signals from each sub-beam, and then reverse-engineers the initial positioning information.

[0095] S103. Determine the direction of the first beam based on the initial positioning information and the first ephemeris information, and receive the second synchronization signal and the second ephemeris information of the second satellite with the second beam according to the direction of the first beam.

[0096] Wherein, the beamwidth of the second beam is smaller than the beamwidth of the first beam;

[0097] Specifically, the terminal uses the initial positioning information obtained in step S102 and the orbital parameters of the second satellite in the first ephemeris information obtained in step S101 to calculate the current spatial position of the second satellite. Based on the geometric relationship between the initial positioning information and the current spatial position of the second satellite, the terminal calculates the beam pointing angle pointing to the second satellite, including the elevation angle and azimuth angle, which is defined as the first beam pointing. Since both the initial positioning information and the first ephemeris information have certain errors, the calculated first beam pointing is an approximation, but its accuracy is sufficient to allow the second beam, with its narrower beamwidth, to cover the actual position of the second satellite.

[0098] The terminal controls its phased array antenna, activating N antenna elements to replace the first beam formed by the previously activated M antenna elements. The newly formed second beam has a narrower beamwidth and higher antenna gain; for example, the beamwidth is narrowed from 33.9° to 12.7°, and the antenna gain is increased from 12.5dBi to 21dBi. The terminal sets the pointing center of the second beam to the direction of the determined first beam.

[0099] The terminal receives downlink signals from the second satellite via the second beam. Due to the higher antenna gain of the second beam, the terminal can successfully detect and parse the second synchronization signal and system messages broadcast by the second satellite, such as SIB19, and extract the second ephemeris information from SIB19. The accuracy of this second ephemeris information is significantly higher than that of the first ephemeris information, providing the necessary high-precision satellite position and velocity data for subsequent accurate target positioning.

[0100] In one embodiment, if the terminal finds that the expected signal strength of the second satellite is insufficient to be reliably captured by the second beam while pointing and tracking the second satellite through the second beam, the terminal may perform a small-range beam scan, for example, scanning in 1° increments within ±3° of the calculated pointing range, until the second synchronization signal is successfully captured.

[0101] In one implementation, if the first satellite in step S102 still meets the reception conditions, such as sufficient remaining visibility time and sufficient signal strength, then switching to other satellites is not necessary. The terminal calculates the first beam pointing to the first satellite based on the initial positioning information and the first ephemeris information, and receives the second synchronization signal and the second ephemeris information of the first satellite with the second beam according to the first beam pointing, so as to reduce handover overhead.

[0102] S104. Determine the target positioning information of the very small aperture terminal based on the second synchronization signal and the second ephemeris information.

[0103] Specifically, the terminal uses the precise orbital parameters from the second ephemeris information to calculate the precise spatial position of the second satellite at each transmission time of the second synchronization signal. Simultaneously, the terminal measures the arrival time or Doppler frequency offset of each second synchronization signal and uses a positioning algorithm similar to step S102 to recalculate its own position, obtaining its target positioning information. Because the accuracy of the second ephemeris information is significantly higher than that of the first ephemeris information, and the second beam gain is higher with better signal reception quality, the accuracy of the obtained target positioning information far exceeds that of the initial positioning information. The error can typically be reduced to within tens of meters, which is sufficient to support subsequent precise pointing and tracking of the satellite with a narrow beam, as well as the accurate calculation of uplink time-frequency synchronization deviation.

[0104] In this scheme, the terminal does not need to rely on external auxiliary positioning data or perform time-consuming full-space beam scanning before completing its own positioning. This overcomes the shortcomings of existing technologies, such as low beam alignment efficiency when the terminal's location is unknown and difficulty in quickly acquiring satellite signals with narrow beams. It significantly improves positioning speed and accuracy, providing a precise and reliable beam pointing and uplink synchronization reference for subsequent narrow-beam communication. In particular, it provides an effective alternative positioning and communication scheme when the terminal's GNSS function degrades, further enhancing the terminal's environmental adaptability and robustness.

[0105] As one possible implementation, the very small aperture terminal includes a phased array antenna, which includes S antenna elements;

[0106] The very small aperture terminal generates the first beam by activating M of the S antenna elements, and the very small aperture terminal generates the second beam by activating N of the S antenna elements.

[0107] Where S, M, and N are all positive integers, M is greater than or equal to the first antenna element number threshold P, N is greater than or equal to the second antenna element number threshold Q, the first antenna element number threshold P is less than the second antenna element number threshold Q, and M is less than N;

[0108] The first antenna element quantity threshold P corresponds to the first minimum demodulation threshold of the first synchronization signal, and the second antenna element quantity threshold Q corresponds to the second minimum demodulation threshold of the second ephemeris information.

[0109] Specifically, the very small aperture terminal employs a phased array antenna, which comprises S antenna elements, for example, S=1024. Assuming each antenna element has a gain of 3dBi and the spacing between antenna elements is... ,in The wavelength is specified, and the antenna noise temperature is 180K. The terminal can dynamically control the beamwidth and antenna gain by adjusting the number of activated antenna elements, thereby meeting the reception requirements of different signals. For example, when all antenna elements of the phased array antenna are activated, the gain is 33dBi and the beamwidth is 3.2°. When some antenna elements of the phased array antenna are activated, such as activating only 3×3 antenna elements, the gain is 12.5dBi and the beamwidth is 33.9°; if only 8×8 antenna elements are activated, the gain is 21dBi and the beamwidth is 12.7°.

[0110] The terminal presets a first antenna element number threshold P and a second antenna element number threshold Q based on two different signal reception requirements.

[0111] The first synchronization signal has a low first minimum demodulation threshold, for example, the minimum demodulation threshold of SSB in 5G NR is -125 dBm. Through link budget analysis, when M antenna elements are activated, and M is greater than or equal to P (e.g., P=9), the receiving antenna gain of the formed first beam is sufficient to overcome link loss and meet the minimum demodulation requirements of SSB. Therefore, P=9 is the minimum number of antenna elements required for the terminal to successfully receive and resolve the first synchronization signal. In one embodiment, the terminal activates M=9 elements (i.e., 3×3 antenna elements) in the initial stage, forming a first beam with a beamwidth of approximately 33.9° and a receiving gain of approximately 12.5 dBi.

[0112] The second ephemeris information has a higher second minimum demodulation threshold. For example, the minimum demodulation threshold for SIB19 carrying precise ephemeris information is -116.5 dBm, which is typically about 8.5 dB higher than the first minimum demodulation threshold of SSB. Therefore, to meet this higher demodulation threshold requirement, the terminal needs to activate more antenna elements. Through link budget analysis, when N antenna elements are activated, and N is greater than or equal to Q (e.g., Q=64), the receiving antenna gain of the formed second beam is sufficient to successfully resolve the precise ephemeris in SIB19; for example, the total gain of the second beam is 21 dBi. Therefore, Q=64 is the minimum number of antenna elements that the terminal needs to activate to successfully receive and resolve the second ephemeris information. In one embodiment, after completing initial positioning, the terminal activates N=64 elements (i.e., 8×8 antenna elements) to form a second beam with a beamwidth of approximately 12.7° and a gain of approximately 21 dBi. Since Q > P, the beamwidth of this second beam is smaller than the beamwidth of the first beam.

[0113] In practice, the terminal can dynamically select and activate more antenna elements based on real-time measured signal strength, while meeting the minimum threshold, to obtain additional link margin, improve reception robustness, and enable this solution to flexibly adapt to different channel conditions and satellite transmission power.

[0114] In this scheme, the terminal dynamically activates different numbers of antenna elements according to signal reception requirements, ensuring the optimal match between beamwidth and signal reception sensitivity. This avoids the problems of insufficient gain due to excessively wide beamwidth, which prevents the demodulation of high-threshold signals, or difficulty in acquisition due to excessively narrow beamwidth. While ensuring rapid acquisition capability, it provides reliable channel conditions for the acquisition of high-precision ephemeris information, thereby improving the signal reception efficiency and success rate of the terminal in multi-level positioning processes.

[0115] In another implementation, the very small aperture terminal uses a first beam to receive SSB signals and SIB19. Because the first beam has a wider beamwidth, the very small aperture terminal does not need to point its beam normal towards the first satellite, and can receive signals for a period of time (assuming...). The system continuously receives SSB signals and SIB19 signals transmitted by the satellite. Assuming the minimum demodulation threshold for SSB is -125 dBm and for SIB19 is -116.5 dBm, a difference of approximately 8.5 dB, the first satellite's equivalent isotropically radiated power (EIRP) when transmitting SIB19 should be at least 8.5 dBW higher than its EIRP when transmitting SSB. For example, if the EIRP for SSB transmission is 25 dBW, the EIRP for SIB19 transmission should be increased to over 33.5 dBW. Through this power enhancement on the satellite side, the SIB19's received signal-to-noise ratio under wide beamwidth can also reach the demodulation threshold. Based on the received SSB signals and the SIB19 carrying precise ephemeris information, the very small aperture terminal uses a positioning algorithm similar to step S102 to recalculate its position and obtain its target positioning information.

[0116] As one possible approach, the GNSS functionality of the very small aperture terminal meets the functional degradation conditions.

[0117] Specifically, the GNSS function of a very small aperture terminal (VSA) is considered to have malfunctioned or degraded in performance due to an abnormality in the terminal's built-in GNSS positioning function, resulting in its inability to provide reliable positioning information that meets the accuracy requirements for subsequent beam alignment and uplink synchronization. This is assessed and triggered in real time by the terminal's internal GNSS status monitoring module. Once the malfunction condition is determined to be met, the terminal automatically switches from the conventional GNSS positioning mode to the communication method described in this embodiment.

[0118] In this solution, the continuity and reliability of terminal communication are ensured by intelligently switching to an alternative communication mode in a timely manner when GNSS performance is insufficient.

[0119] As one possible approach, the functional degradation condition includes at least one of the following conditions:

[0120] The GNSS function module of the very small aperture terminal is faulty or missing hardware.

[0121] Specifically, the terminal periodically sends query commands to the GNSS receiver through its internal GNSS status monitoring module. If there is no response after a preset number of queries (such as three consecutive times), a hardware error code is returned, or the GNSS hardware device is not recognized in the terminal firmware, it is determined that the GNSS function module is faulty or the hardware is missing.

[0122] The continuous fault duration of the very small aperture terminal losing GNSS signal exceeds the fault duration threshold.

[0123] Specifically, the terminal continuously monitors the validity of the GNSS positioning results. If all subsequent positioning attempts fail after the last valid positioning output, a timer is started. If the accumulated timer time exceeds a preset fault duration threshold (e.g., 30 seconds), and no successful positioning occurs during this period, the condition is considered met. The fault duration threshold can be adjusted based on the satellite orbital altitude and the terminal's speed; for example, 30 seconds is preferred for low Earth orbit satellite scenarios, while it can be relaxed to 120 seconds for geostationary orbit satellite scenarios.

[0124] The number of failures of the very small aperture terminal to reconnect to the GNSS signal is greater than the failure number threshold.

[0125] Specifically, after a GNSS signal loss exceeds a short sub-threshold (e.g., 10 seconds), the terminal can actively trigger the GNSS module's reacquisition process. Each reconnection attempt that times out or returns an invalid result is counted as a failure. Reconnection includes resetting the module, re-downloading ephemeris, re-searching for and locking onto satellites, and completing a positioning calculation. This condition is met when the number of consecutive failures exceeds a preset failure threshold (e.g., 5 times). This allows the terminal to quickly abandon invalid retries in weak signal areas.

[0126] The positioning accuracy of the GNSS function module of the very small aperture terminal is lower than the positioning accuracy threshold.

[0127] Specifically, the terminal extracts estimated position error indicators, such as horizontal position error (HPE), from the GNSS positioning results. If the HPE values ​​of three or more consecutive positioning outputs exceed a preset positioning accuracy threshold (e.g., 100 meters), then this condition is met. Even if the terminal can output coordinates, insufficient accuracy cannot support subsequent precise alignment of narrow beams and uplink time-frequency deviation calculation. Therefore, an alternative communication scheme needs to be activated to obtain higher-precision target positioning information.

[0128] The GNSS measurement period of the GNSS function module of the very small aperture terminal is greater than the GNSS measurement period threshold.

[0129] Specifically, the terminal records the time interval between two consecutive valid GNSS positioning outputs. If the latest three consecutive time intervals all exceed a preset measurement cycle threshold (e.g., 10 seconds), then this condition is considered met. For example, in a scenario where a low-Earth orbit satellite moves at approximately 7 km / s, the satellite's position can change by up to 70 km within 10 seconds. Using outdated positioning information would lead to unacceptable errors in beam pointing calculations. Therefore, an alternative communication scheme needs to be activated to obtain more accurate target positioning information.

[0130] The above five conditions can be triggered independently or in combination. Once the terminal determines that at least one condition is met, it considers the GNSS function of the very small aperture terminal to meet the functional degradation conditions, thereby activating the communication scheme of this embodiment.

[0131] This solution improves the positioning availability and access success rate of terminals in various complex environments by intelligently detecting GNSS status and flexibly enabling alternative solutions.

[0132] As a feasible approach, such as Figure 2 As shown, the communication method further includes:

[0133] S1051. Determine the direction of the second beam based on the target positioning information and the first ephemeris information;

[0134] Specifically, after obtaining the target positioning information, the terminal enters the access preparation phase. Based on the target positioning information and the coarse orbital parameters of the third satellite in the first ephemeris information, the terminal calculates the direction of the second beam pointing to the third satellite. The first ephemeris information is the original coarse ephemeris obtained by the terminal in step S101, or the orbital description of the third satellite in its subsequent updated version.

[0135] The terminal controls the phased array antenna to activate L antenna elements, where L is greater than or equal to the number of elements N that form the second beam. The beamwidth of the formed third beam is less than or equal to the beamwidth of the second beam, for example, the beamwidth of the third beam is about 6°. The pointing center of the third beam is set to the pointing direction of the second beam.

[0136] S1052. Receive the third synchronization signal and third ephemeris information of the third satellite using the third beam according to the direction of the second beam;

[0137] Wherein, the beamwidth of the third beam is less than or equal to the beamwidth of the second beam, and the receiving gain of the third beam is greater than or equal to the receiving gain of the second beam.

[0138] Specifically, through the high receiving gain of the third beam, the terminal successfully received the third synchronization signal and third ephemeris information broadcast by the third satellite. For example, the third synchronization signal... Such as the synchronization signal block (SSB) Third ephemeris information, such as SIB19, includes precise ephemeris information for the third satellite.

[0139] The third synchronization signal can be a broadcast signal with the same or similar structure as the first synchronization signal and the second synchronization signal.

[0140] S1053. Based on the third ephemeris information and the target positioning information, determine the third beam pointing and the first uplink time-frequency synchronization deviation for accessing the third satellite;

[0141] Specifically, after obtaining the third ephemeris information, the terminal extracts the precise orbital elements or position and velocity vector of the third satellite from this information. Based on the third ephemeris information and known target positioning information, the pointing of the third beam and the first uplink time-frequency synchronization deviation are calculated.

[0142] For example, by utilizing the geometric relationship between the current position and the precise position of the third satellite, the direction of the third beam pointing towards the third satellite can be calculated. Since both the target positioning information and the third ephemeris information are high-precision data, the error of this third beam pointing is extremely small, and it can be directly used for alignment and tracking of ultra-high gain narrow beams.

[0143] The first uplink time-frequency synchronization deviation is composed of the TA deviation value and the frequency pre-compensation value. The first uplink time-frequency synchronization deviation of the terminal is calculated by using the geometric relationship between the current position and the precise position of the third satellite. Its accuracy is sufficient to be directly applied to the random access process based on orthogonal frequency division multiplexing (OFDM) to reduce the retransmission probability and access delay.

[0144] In one embodiment, if the third satellite received by the third beam is the same satellite as the second satellite in step S103, the step of receiving ephemeris information again is omitted. The third ephemeris information is used as the obtained second ephemeris information, and the third beam pointing and the first uplink time-frequency synchronization deviation are calculated in combination with the target positioning information.

[0145] S1054. Based on the first uplink time-frequency synchronization deviation and the third beam pointing, the fourth beam is used to access the third satellite;

[0146] Wherein, the beamwidth of the fourth beam is less than or equal to the beamwidth of the second beam, and the receiving gain of the fourth beam is greater than or equal to the receiving gain of the second beam.

[0147] Specifically, after completing the calculation, the terminal controls the phased array antenna to activate K antenna elements, where K ≥ the number of elements N forming the second beam, and the beamwidth of the formed fourth beam is less than or equal to the beamwidth of the second beam. In one possible implementation, K = S, meaning the terminal controls the phased array antenna to activate all S antenna elements, and the beamwidth of the formed fourth beam is less than or equal to the beamwidth of the second beam. For example, the beamwidth of the fourth beam is approximately 3.2°, the receiving gain is approximately 33 dBi, and the pointing center of the fourth beam is set to the pointing direction of the third beam.

[0148] When transmitting uplink signals, the terminal actively applies a first uplink time-frequency synchronization deviation, that is, sets the uplink timing advance to the TA value corresponding to the distance and sets the uplink carrier frequency pre-compensation index to Doppler frequency shift. The terminal transmits the Physical Random Access Channel (PRACH) to the third satellite through the fourth beam. Based on the precise pre-compensation of all beam direction, timing, and frequency parameters, the PRACH and subsequent uplink signals are successfully detected and responded to by the satellite, and the terminal completes the entire random access process, establishing an efficient communication link with the third satellite. In this scheme, by progressively narrowing the beamwidth and precisely pre-compensating for the uplink time-frequency deviation, the success rate and efficiency of narrow-beam random access are improved, access latency is reduced, and a reliable link foundation is provided for high-speed data transmission.

[0149] As a feasible approach, such as Figure 3 As shown, the communication method further includes:

[0150] S1061. Based on the second ephemeris information and the target positioning information, determine the remaining visibility time of the second satellite;

[0151] Specifically, after obtaining the target positioning information, the terminal does not immediately initiate access. Instead, it first calculates the remaining visible time of the second satellite relative to the terminal's position based on the second ephemeris information and target positioning information obtained in step S104.

[0152] The terminal uses precise orbital parameters (such as Kepler elements) from the second satellite's ephemeris information, combined with the known current epoch, to predict the second satellite's spatial position sequence over the next few minutes using an orbital extrapolation algorithm. Simultaneously, using its own target positioning position as a reference point, the terminal calculates the satellite's elevation angle relative to the terminal at each predicted time.

[0153] The terminal presets a minimum effective communication angle threshold. (For example The elevation angle threshold needs to consider the impact of factors such as increased atmospheric attenuation, exacerbated multipath effects, and terrain obstruction on the quality of narrow-beam communication at low elevation angles. The terminal starts from the current moment... Begin searching backwards to determine the last one that satisfies the condition. The moment Then the remaining visible time of the second satellite .

[0154] S1062. In response to the remaining visible time being greater than or equal to the satellite access time threshold, the fourth beam pointing and the second uplink time-frequency synchronization deviation for accessing the second satellite are determined based on the second ephemeris information and the target positioning information.

[0155] Specifically, the terminal will calculate the remaining viewing time. With preset satellite access time threshold Comparisons, such as satellite access time thresholds For 30 seconds. If If this is the case, the second satellite still has enough time within the current overpass cycle to complete a full random access and data transmission process, thus determining that the terminal can directly access the second satellite.

[0156] Based on the target positioning information and the precise position and velocity of the second satellite in the second ephemeris information, the terminal calculates the fourth beam pointing and the second uplink time-frequency synchronization deviation.

[0157] if If the terminal does not choose to access the second satellite, it will switch to other processes, such as switching to the third satellite for access as described in steps S1051 to S1054, to ensure continuous communication.

[0158] S1063. Based on the second uplink time-frequency synchronization deviation and the fourth beam pointing, the fifth beam is used to access the second satellite, wherein the beamwidth of the fifth beam is less than or equal to the beamwidth of the second beam.

[0159] Specifically, after completing precise beam pointing and uplink time-frequency synchronization deviation calculations, the terminal executes the access procedure. The terminal controls its phased array antenna to activate H antenna elements, where H is greater than or equal to the number of elements N forming the second beam, and the beamwidth of the formed fifth beam is less than or equal to the beamwidth of the second beam. In one possible implementation, H=S, meaning the terminal controls the phased array antenna to activate all S antenna elements, and the beamwidth of the formed fourth beam is less than or equal to the beamwidth of the second beam, for example, the beamwidth of the fourth beam is approximately 3.2°, the receiving gain is approximately 33dBi, and the pointing center of the fifth beam is set to the pointing direction of the fourth beam.

[0160] During uplink transmission, the terminal applies a second uplink time-frequency synchronization deviation, including an appropriate timing advance (TA) value and an uplink frequency pre-compensation value. It then sends a random access PRACH to the second satellite via the fifth beam. After the satellite responds with a random access response, the terminal completes the subsequent connection establishment process, formally accesses the second satellite, and utilizes the narrow beam for high-throughput data transmission.

[0161] In this solution, by introducing a remaining visible time judgment mechanism, the inefficiency of needing to switch immediately after access due to insufficient remaining visible time is avoided. At the same time, the accurate ephemeris of the second satellite is fully utilized, eliminating the latency and signaling overhead of additional ephemeris acquisition required for switching to the third satellite. This improves access efficiency and optimizes the utilization of overall communication resources while ensuring access reliability.

[0162] The very small aperture terminal communication method provided in this embodiment utilizes a wide beam to quickly acquire satellite synchronization signals and combines them with preset ephemeris information to obtain initial positioning. It then gradually switches to a narrower beam to obtain more accurate ephemeris and target positioning information, ultimately achieving precise access to the target satellite with a narrow beam. Furthermore, it introduces a multi-level beam hardware multiplexing mechanism and intelligent access decision-making based on remaining visible time, reducing complexity and signaling overhead while avoiding unnecessary satellite switching and optimizing system resource utilization. This enhances the environmental adaptability and communication robustness of the satellite communication terminal under adverse conditions such as GNSS degradation and signal obstruction.

[0163] Example 2

[0164] Corresponding to the aforementioned embodiments of the communication method for very small aperture terminals, this disclosure also provides embodiments of the communication system for very small aperture terminals.

[0165] Figure 4 This is a schematic diagram of a communication system for a very small aperture terminal provided as an exemplary embodiment of the present disclosure. This embodiment provides a communication system 100 for a very small aperture terminal, which includes an ephemeris acquisition module 110, an initial positioning determination module 120, and a target positioning determination module 130.

[0166] The ephemeris acquisition module 110 is used to acquire first ephemeris information;

[0167] The initial positioning determination module 120 is used to receive the first synchronization signal of the first satellite corresponding to the first ephemeris information with a first beam, and determine the initial positioning information of the very small aperture terminal based on the first synchronization signal and the first ephemeris information.

[0168] The target positioning and determination module 130 is used to determine the first beam direction based on the initial positioning information and the first ephemeris information, and to receive the second synchronization signal and the second ephemeris information of the second satellite with the second beam according to the first beam direction;

[0169] Wherein, the beamwidth of the second beam is smaller than the beamwidth of the first beam;

[0170] The target positioning information of the very small aperture terminal is determined based on the second synchronization signal and the second ephemeris information.

[0171] As one possible implementation, the very small aperture terminal includes a phased array antenna, which includes S antenna elements;

[0172] The very small aperture terminal generates the first beam by activating M of the S antenna elements, and the very small aperture terminal generates the second beam by activating N of the S antenna elements.

[0173] Where S, M, and N are all positive integers, M is greater than or equal to the first antenna element number threshold P, N is greater than or equal to the second antenna element number threshold Q, the first antenna element number threshold P is less than the second antenna element number threshold Q, and M is less than N;

[0174] The first antenna element quantity threshold P corresponds to the first minimum demodulation threshold of the first synchronization signal, and the second antenna element quantity threshold Q corresponds to the second minimum demodulation threshold of the second ephemeris information.

[0175] As one possible approach, the GNSS functionality of the very small aperture terminal meets the functional degradation conditions.

[0176] As one possible approach, the functional degradation condition includes at least one of the following conditions:

[0177] The GNSS function module of the very small aperture terminal is faulty or missing hardware.

[0178] The continuous fault duration of the very small aperture terminal losing GNSS signal exceeds the fault duration threshold.

[0179] The number of failures of the very small aperture terminal to reconnect to the GNSS signal is greater than the failure number threshold.

[0180] The positioning accuracy of the GNSS function module of the very small aperture terminal is lower than the positioning accuracy threshold.

[0181] The GNSS measurement period of the GNSS function module of the very small aperture terminal is greater than the GNSS measurement period threshold.

[0182] As one possible implementation, the communication system further includes a satellite access module, which comprises a pointing determination unit, a signal determination unit, a compensation determination unit, and a signal access unit.

[0183] A pointing determination unit is used to determine the pointing of the second beam based on the target positioning information and the first ephemeris information;

[0184] The signal determination unit is used to receive the third synchronization signal and third ephemeris information of the third satellite using the third beam according to the direction of the second beam;

[0185] The compensation determination unit is used to determine the third beam pointing and the first uplink time-frequency synchronization deviation of accessing the third satellite based on the third ephemeris information and the target positioning information;

[0186] The signal access unit is used to access the third satellite with a fourth beam based on the first uplink time-frequency synchronization deviation and the third beam pointing.

[0187] Wherein, the beamwidth of the third beam is less than or equal to the beamwidth of the second beam, and the beamwidth of the fourth beam is less than or equal to the beamwidth of the second beam.

[0188] As one possible implementation, the communication system also includes a visual time calculation module and a satellite access module:

[0189] The visible time calculation module is used to determine the remaining visible time of the second satellite based on the second ephemeris information and the target positioning information;

[0190] The satellite access module is used to determine the fourth beam pointing and the second uplink time-frequency synchronization deviation for accessing the second satellite based on the second ephemeris information and the target positioning information when the remaining visible time is greater than or equal to the satellite access time threshold.

[0191] Based on the second uplink time-frequency synchronization deviation and the fourth beam pointing, the fifth beam is used to access the second satellite, and the beamwidth of the fifth beam is less than or equal to the beamwidth of the second beam.

[0192] For the system embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this disclosure according to actual needs.

[0193] Example 3

[0194] Figure 5 This is a schematic diagram of the structure of an electronic device according to an example embodiment of the present disclosure. The electronic device includes a memory, a processor, and a computer program stored in the memory and used to run on the processor. When the processor executes the computer program, it implements the communication method of the very small aperture terminal described in any of the above embodiments. Figure 5 The electronic device 90 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments disclosed herein.

[0195] like Figure 5 As shown, the electronic device 90 can be manifested as a general-purpose computing device, such as a server device. The components of the electronic device 90 may include, but are not limited to: at least one processor 91, at least one memory 92, and a bus 93 connecting different system components (including memory 92 and processor 91).

[0196] Bus 93 includes a data bus, an address bus, and a control bus.

[0197] The memory 92 may include volatile memory, such as random access memory (RAM) 921 and / or cache memory 922, and may further include read-only memory (ROM) 923.

[0198] The memory 92 may also include a program tool 925 (or utility) having a set (at least one) program module 924, such program module 924 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0199] The processor 91 executes various functional applications and data processing by running computer programs stored in the memory 92, such as the communication method of the very small aperture terminal provided in any of the above embodiments.

[0200] Electronic device 90 can also communicate with one or more external devices 94 (e.g., keyboard, pointing device, etc.). This communication can be performed via input / output (I / O) interface 95. Furthermore, electronic device 90 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 96. Figure 5 As shown, network adapter 96 communicates with other modules of electronic device 90 via bus 93. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with electronic device 90, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems.

[0201] It should be noted that although several units / modules or sub-units / modules of the electronic device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functions of one unit / module described above can be further divided and embodied by multiple units / modules.

[0202] Example 4

[0203] This disclosure also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the communication method of the very small aperture terminal provided in any of the above embodiments.

[0204] The readable storage medium may be more specifically adopted, including but not limited to: portable disk, hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0205] Example 5

[0206] This disclosure also provides a computer program product, including a computer program that, when executed by a processor, implements the communication method of the very small aperture terminal described in any of the preceding embodiments.

[0207] The program code for executing the computer program product of this disclosure can be written in any combination of one or more programming languages, and the program code can be executed entirely on a user device, partially on a user device, as a stand-alone software package, partially on a user device and partially on a remote device, or entirely on a remote device.

[0208] Regarding the modules / units included in the various devices and products described in the above embodiments, they can be software modules / units, hardware modules / units, or a combination of both. For example, for various devices and products applied to or integrated into a chip, all of their modules / units can be implemented using hardware methods such as circuits, or at least some modules / units can be implemented using software programs that run on a processor integrated within the chip, while the remaining (if any) modules / units can be implemented using hardware methods such as circuits; for various devices and products applied to or integrated into a chip module, all of their modules / units can be implemented using hardware methods such as circuits, and different modules / units can be located in the same component (e.g., chip, circuit module, etc.) or different components of the chip module, or at least some modules / units can be implemented using hardware methods such as circuits. The components can be implemented using software programs that run on the processor integrated within the chip module. The remaining (if any) modules / units can be implemented using hardware methods such as circuits. For various devices and products applied to or integrated into the terminal, each of its components / units can be implemented using hardware methods such as circuits. Different modules / units can be located in the same component (e.g., chip, circuit module, etc.) or in different components within the terminal. Alternatively, at least some modules / units can be implemented using software programs that run on the processor integrated within the terminal, while the remaining (if any) modules / units can be implemented using hardware methods such as circuits.

[0209] While specific embodiments of this disclosure have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this disclosure is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this disclosure, but all such changes and modifications fall within the scope of protection of this disclosure.

Claims

1. A communication method for a very small aperture terminal, characterized in that, The communication method includes: Obtain first ephemeris information; The first synchronization signal of the first satellite corresponding to the first ephemeris information is received with the first beam, and the initial positioning information of the very small aperture terminal is determined based on the first synchronization signal and the first ephemeris information. Based on the initial positioning information and the first ephemeris information, the first beam direction is determined, and the second synchronization signal and second ephemeris information of the second satellite are received with the second beam according to the first beam direction; Wherein, the beamwidth of the second beam is smaller than the beamwidth of the first beam; The target positioning information of the very small aperture terminal is determined based on the second synchronization signal and the second ephemeris information.

2. The communication method for a very small aperture terminal according to claim 1, characterized in that, The very small aperture terminal includes a phased array antenna, and the phased array antenna includes S antenna elements; The very small aperture terminal generates the first beam by activating M of the S antenna elements, and the very small aperture terminal generates the second beam by activating N of the S antenna elements. Where S, M, and N are all positive integers, M is greater than or equal to the first antenna element number threshold P, N is greater than or equal to the second antenna element number threshold Q, the first antenna element number threshold P is less than the second antenna element number threshold Q, and M is less than N; The first antenna element quantity threshold P corresponds to the first minimum demodulation threshold of the first synchronization signal, and the second antenna element quantity threshold Q corresponds to the second minimum demodulation threshold of the second ephemeris information.

3. The communication method for a very small aperture terminal according to claim 1, characterized in that, The GNSS function of the very small aperture terminal meets the conditions for functional degradation.

4. The communication method for a very small aperture terminal according to claim 3, characterized in that, The functional degradation condition includes at least one of the following conditions: The GNSS function module of the very small aperture terminal is faulty or missing hardware. The continuous fault duration of the very small aperture terminal losing GNSS signal exceeds the fault duration threshold. The number of failures of the very small aperture terminal to reconnect to the GNSS signal is greater than the failure number threshold. The positioning accuracy of the GNSS function module of the very small aperture terminal is lower than the positioning accuracy threshold. The GNSS measurement period of the GNSS function module of the very small aperture terminal is greater than the GNSS measurement period threshold.

5. The communication method of the very small aperture terminal according to any one of claims 1 to 4, characterized in that, The communication method further includes: The direction of the second beam is determined based on the target positioning information and the first ephemeris information; According to the direction of the second beam, the third beam is used to receive the third synchronization signal and the third ephemeris information of the third satellite; Based on the third ephemeris information and the target positioning information, the third beam pointing and the first uplink time-frequency synchronization deviation for accessing the third satellite are determined; Based on the first uplink time-frequency synchronization deviation and the third beam pointing, the fourth beam is used to access the third satellite; Wherein, the beamwidth of the third beam is less than or equal to the beamwidth of the second beam, and the beamwidth of the fourth beam is less than or equal to the beamwidth of the second beam.

6. The communication method of the very small aperture terminal according to any one of claims 1 to 4, characterized in that, The communication method further includes: Based on the second ephemeris information and the target positioning information, the remaining visibility time of the second satellite is determined; In response to the remaining visible time being greater than or equal to the satellite access time threshold, the fourth beam pointing and the second uplink time-frequency synchronization deviation for accessing the second satellite are determined based on the second ephemeris information and the target positioning information. Based on the second uplink time-frequency synchronization deviation and the fourth beam pointing, the fifth beam is used to access the second satellite, and the beamwidth of the fifth beam is less than or equal to the beamwidth of the second beam.

7. A communication system for a very small aperture terminal, characterized in that, The communication system includes an ephemeris acquisition module, an initial positioning determination module, and a target positioning determination module; The ephemeris acquisition module is used to acquire first ephemeris information; The initial positioning determination module is used to receive the first synchronization signal of the first satellite corresponding to the first ephemeris information with a first beam, and determine the initial positioning information of the very small aperture terminal based on the first synchronization signal and the first ephemeris information. The target positioning and determination module is used to determine the direction of the first beam based on the initial positioning information and the first ephemeris information, and to receive the second synchronization signal and the second ephemeris information of the second satellite with the second beam according to the direction of the first beam. Wherein, the beamwidth of the second beam is smaller than the beamwidth of the first beam; The target positioning information of the very small aperture terminal is determined based on the second synchronization signal and the second ephemeris information.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and for running on the processor, characterized in that, When the processor executes the computer program, it implements the communication method of the very small aperture terminal as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the communication method of the very small aperture terminal as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the communication method of the very small aperture terminal as described in any one of claims 1 to 6.

11. A chip, characterized in that, The chip stores a computer program, which, when executed by the chip, implements the communication method of the very small aperture terminal as described in any one of claims 1 to 6.

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