Method for capturing, tracking and receiving Beidou signal of high-dynamic movement carrier

Abstract

The invention provides a method for capturing, tracking and receiving a Beidou signal of a high-dynamic movement carrier. Through the adoption of the method, a satellite signal can be quickly captured and tracked, the capturing time is shortened, the tracking reliability is ensured, and the signal loss is avoided. The method comprises the following steps: Step 1, capturing a satellite signal of the high-dynamic movement carrier, using repeated uncorrelated accumulation and Tong detection, and obtaining a rough carrier frequency and a pseudo code phase of a received signal; Step 2, using a second-order FLL (frequency locked loop) for tracking the received signal during initial tracking so as to obtain frequency tracking errors, and at the same time, selecting a frequency tracking error for feeding back and rectifying the output carrier wave frequency of a numerically controlled oscillator (NCO) of the FLL by an output selector; Step 3, when the frequency tracking error is smaller than a preset threshold, using a third-order PLL for tracking so as to obtain phase tracking errors, at the same time, selecting the phase tracking error for feeding back and rectifying the output phase of the numerically controlled oscillator (NCO) of the FLL by the output selector, and realizing accurate tracking; Step 4, when the phase tracking error of the third-order PLL is greater than the preset threshold, returning to the Step 2 to perform the second-order FLL tracking, and completing carrier tracking.

Description

technical field [0001] The invention relates to a Beidou signal acquisition, tracking and receiving method for a highly dynamic moving carrier, which belongs to the field of wireless communication. Background technique [0002] In the modern wireless communication system based on spread spectrum, the transmitter and the receiver are usually used for data transmission, the spread spectrum sequence is sent by the transmitter, and the boundary of the spread spectrum sequence is found and received by the receiver. For fixed or slow-moving terminals, the Doppler frequency shift and its changes are not easy to produce large frequency offsets, making it easier for the receiver to capture and track satellite signals. However, in a highly dynamic environment, the high speed of the carrier movement causes Doppler frequency shift, and the acceleration of the carrier movement causes changes in the Doppler frequency shift, resulting in frequency offset and offset changes in the received ...

AI Technical Summary

Problems solved by technology

The frequency locked loop directly tracks the carrier frequency, and outputs the Doppler frequency estimation error through the carrier frequency discriminator, which has better dynamic performance, but the tracking accuracy is lower than that of the phase locked loop.

The phase-locked loop directly tracks the carrier phase, and extracts the phase estimation error through the carrier phase detector. When the loop is closed and stable, it has high tracking accuracy, but the dynamic tracking ability of the phase-locked loop is poor.

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