Pilot frequency information and satellite ephemeris joint Doppler frequency shift estimation and compensation method

Abstract

The invention provides a pilot frequency information and satellite ephemeris joint Doppler frequency shift estimation and compensation method which includes the steps: a receiving pilot frequency signals from a low-orbit satellite by a ground terminal k; b acquiring satellite ephemeris data of the latest time tk, the frequency and the phase of carrier waves and the frequency and the phase of pseudo codes based on the pilot frequency signals by the ground terminal k; c calculating Doppler frequency shift between the ground terminal k and the low-orbit satellite based on satellite ephemeris information of the pilot frequency signals corresponding to the latest time tk, the frequency and the phase of the carrier waves and the frequency and the phase of the pseudo codes; d adjusting the frequency of the pseudo codes and the frequency of the carrier waves based on the Doppler frequency shift, and performing Doppler compensation when uplink signals are transmitted. The Doppler frequency shift is estimated and compensated by a high-precision pilot frequency method with small calculated amount, and the Doppler frequency shift is preferentially estimated and compensated by a high-precision orbit ephemeris method when the terminal suddenly cannot receive the pilot frequency signals due to reasons such as blocking of tall buildings.

Description

technical field [0001] The invention relates to the field of satellite communication, especially the field of low-orbit satellite communication, in particular to a Doppler frequency shift estimation and compensation method for joint pilot information and satellite ephemeris. Background technique [0002] In the field of low-orbit satellite communication, when the ground terminal and the satellite communicate, due to the relatively high-speed motion between the two, a large relative radial velocity is generated, which will cause the uplink and downlink signals of the satellite-ground communication system to appear large and time-varying. Dynamic characteristics such as frequency offset, especially for highly dynamic terminals, this change is more drastic. The Doppler effect will seriously affect the performance of the communication system, causing the carrier frequency of the signal on the communication link and the chip rate of the spread spectrum pseudo code to deviate to v...

AI Technical Summary

Problems solved by technology

However, due to the irregularity of the dynamic changes of the terminal and the influence and neglect of objective conditions, the Doppler estimation and compensation algorithms often have the problem of low precision. Some Doppler frequency shift estimation and compensation algorithms with high precision The amount of calculation is generally very large, which will limit the improvement of the performance of the entire communication system

In addition, the special communication environment is rarely considered when performing Doppler compensation

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