Satellite signal carrier synchronization method and system

Abstract

The invention discloses a satellite signal carrier synchronization method and system. The method comprises the steps of carrying out frequency mixing filtering on a received carrier signal, and obtaining a sampling signal; calculating an in-phase component and an orthogonal component based on the sampling signal; capturing and compensating the carrier frequency offset based on the two components, and achieving first synchronization of carriers; mixing and filtering the carrier signal by using a double-layer phase-locked loop, extracting carrier frequency and phase information for the first time, and compensating carrier frequency offset and phase offset for the first time according to the information to obtain a carrier signal after the first time of compensation; and carrying out frequency mixing and filtering on the carrier signal by using a double-layer phase-locked loop, extracting carrier frequency and phase information for the second time, compensating the carrier frequency offset and phase offset for the second time according to the information, obtaining the carrier signal after the second time compensation, completing phase tracking of the carrier signal, and achieving second synchronization of the carriers.

Description

technical field [0001] The invention relates to a satellite signal carrier synchronization method and system, and relates to the fields of satellite navigation, satellite communication, wireless communication applications and the like. Background technique [0002] In recent years, high dynamics are prevalent in satellite communications, aerospace measurement and control, and navigation systems. In the satellite communication system, with the rapid development of satellite communication technology, the mobile communication between constellations composed of space vehicles (communication satellites, navigation satellites, deep space probes, etc.) and between satellites and ground has attracted more and more attention; Due to the high-speed movement of the satellite constellation relative to the ground and the high-speed movement between the constellations, the sending and receiving parties are under high dynamic communication conditions, which manifests as serious time-select...

AI Technical Summary

Problems solved by technology

[0004] In a high dynamic application environment, the high-speed relative motion between the communication parties will often introduce a large Doppler frequency offset and its high-order change rate on the carrier frequency of the signal received by the receiver; in order to adapt to the high dynamic environment, the medium and low The loop bandwidth of the carrier tracking loop of a dynamic receiver must be widened to capture and track the Doppler frequency offset and its rate of change of the received signal. However, the increase of the loop bandwidth will inevitably lead to a decrease in the carrier tracking accuracy. Especially when the tracking loop is in a communication environment with low signal-to-noise ratio, the introduction of noise may even cause the carrier tracking loop to lose lock

[0005] There are two major technical difficulties in carrier synchronization in a highly dynamic environment; one is the relatively large absolute frequency offset. Puler frequency deviation, which brings serious challenges to the design of the receiver

The emergence of a large frequency offset forces the receiver to widen the front-end bandwidth so that the useful signal can completely enter the post-stage signal processing module; The ratio drops significantly, which brings great challenges to the subsequent synchronization and demodulation modules; at the same time, in the acquisition module, a larger frequency offset range also means a larger frequency search interval, and an excessively large search interval may cause receiver hardware resources Practical engineering problems such as shortage

[0006] Another technical difficulty in a highly dynamic environment is that there is a large frequency change rate; in the actual space, the relative motion speed of the communication carrier often changes drastically, which makes the corresponding Doppler frequency deviation also produce drastic fluctuations, that is, there is a large frequency change rate; compared with the frequency offset, a high frequency change rate has a stronger impact on the communication system; it not only requires the receiver synchronization module to give a relatively accurate The estimated value requires the carrier tracking system to have a very high dynamic tracking capability, and to be able to give an accurate estimated value in real time under the condition of rapid changes in carrier frequency and phase, which brings severe challenges to the acquisition and tracking modules in carrier synchronization. the test

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