Feed link synchronous switching method in low-orbit constellation satellite communication system

Abstract

The invention discloses a feed link synchronous switching method in a low-orbit constellation satellite communication system, and the method specifically comprises the steps that a global positioning time service system achieves the synchronization of clock sources of an operation control system, a low-orbit satellite, a source gateway station A and a target gateway station B; the operation control system comprehensively plans a satellite feed link switching plan table according to information such as ephemeris data, the health state and load condition of the gateway station, feed interference avoidance and weather, and issues the plan table to the gateway station and the satellite; the gateway station system calculates transmission delay and relative Doppler frequency offset according to ephemeris data, adjusts signal receiving and transmitting timing and frequency of the gateway station, and meanwhile adjusts antenna pointing to wait for a satellite to enter a view field; and the gateway station system captures a satellite, calculates transmission delay and relative Doppler frequency offset in real time according to satellite ephemeris data, and adjusts signal receiving and transmitting timing and frequency of a gateway station in real time. According to the invention, the service interruption caused by feed link switching is reduced, and the consistency of the characteristics of the signals from the satellite to the user terminal is ensured.

Description

technical field [0001] The invention belongs to the technical field of satellite communication, in particular to a method for synchronous switching of feeder links in a low-orbit constellation satellite communication system. Background technique [0002] 1. Low-orbit constellation satellite communication system [0003] The low-orbit constellation satellite communication system is a satellite communication system that transmits signals through the low-orbit constellation. At present, the low-orbit constellation satellite communication systems under construction or completed in the world mainly include starlink, O3B, OneWeb, Telesat, etc. In my country, there are mainly systems such as Hongyun and Hongyan. Generally speaking, the low-orbit constellation satellite communication system consists of three parts: the space segment, the ground segment, and the application segment, such as figure 1 Shown: [0004] (1) space segment [0005] The space segment consists of a conste...

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Problems solved by technology

Patent CN 201910782564.8 discloses a feeding link, user equipment switching method, equipment and device belonging to the satellite, adopts a typical asynchronous switching mechanism of the feeding link, and does not make any adjustments to the gateway station during the switching process, so the feeding link After the electrical link is switched, a large number of satellite terminals cause signaling congestion due to uplink synchronization

Patent CN202010105732.2 discloses a terminal reselection method and device for feeder link switching. When the satellite is about to switch feeder links, the link information of the target gateway station is broadcast to the terminal users in advance. After the feeder link is switched, the terminal adjusts the synchronization parameters according to the link information of the target gateway station, so as to achieve resynchronization with the network side, and the system implementation is complicated.

Patent CN 201910675491.2 discloses a satellite cross-gateway feeder link switching method based on user switching restrictions and unloading. When the satellite is about to switch the feeder link, the user is offloaded to the adjacent satellite, thereby avoiding the feeder link. After the switchover, a large number of satellite terminals cause signaling congestion due to uplink synchronization, but this may cause a burden on adjacent satellite resources. When the adjacent satellite resources are insufficient, the terminal cannot normally switch to the adjacent satellite and the communication is interrupted.

[0016] To sum up, the existing published documents belong to the asynchronous switching mechanism of the satellite feeder link, which requires the terminal to perform uplink and downlink resynchronization according to the target gateway station information provided by the network side. In order to ensure the probability of successful resynchronization of the terminal, the system needs to broadcast Sufficiently accurate information increases the complexity of terminal equipment implementation and the network burden. At the same time, during the uplink resynchronization process of a large number of terminals, ranging is often required, resulting in signaling processing congestion in the gateway system.

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