BOC (n, n) modulation signal fast capture method

Abstract

The invention provides a BOC (n, n) modulation signal fast capture method. Multi-stage down-conversion, amplification and filtering are carried out on useful navigation signals in the band, to obtainan analog intermediate frequency BOC (n, n) signal, a low-speed clock CLK1 drives a signal preprocessing module to preprocess the intermediate frequency BOC (n, n) signal, sampling values of IF, QF and the CLoc are read by using a high-speed clock CLK2, partial matching filtering is carried out, the high-speed clock CLK2 is used for driving, a correlation value obtained in the round is subjected to P times of L-point all-phase FFT, the high-speed clock CLK2 is used for driving, and whether a signal is captured or not is judged according to the capture result and BOC (n, n) signal characteristics. According to the method, whether the signal is captured or not can be effectively judged by judging the characteristics of the relationship among the three peak values, spectrum leakage caused bysampling data truncation is reduced, and the signal processing efficiency is effectively improved.

Description

technical field [0001] The invention belongs to the technical field of satellite navigation signal processing, and in particular relates to a navigation signal acquisition method Background technique [0002] The Global Navigation Satellite System (GNSS) provides users with all-weather, high-precision, high-continuity, and high-reliability navigation services on a global scale, and is widely used in various fields such as national defense construction and national economy. With the continuous construction and development of the global satellite navigation system, the types of signals emitted by each satellite navigation system in the same frequency band are increasing, and the limited spectrum resources are becoming more and more crowded. [0003] In order to make more effective use of limited spectrum resources and increase the compatibility and interoperability between satellite navigation systems, the new navigation system adopts binary offset carrier (Binary Offset Carri...

AI Technical Summary

Problems solved by technology

[0004] Compared with the traditional BPSK signal, the BOC(n,n) signal has a long pseudo-code period and a large capture search range. The traditional partially matched filter (PMF) combined with the fast Fourier transform (FFT) time-frequency domain fully parallel capture method, although the capture speed Fast, but takes up a lot of computing resources, and the spectrum leakage caused by asynchronous sampling makes the capture sensitivity worse

In addition, there are multiple correlation peaks in the autocorrelation function of the BOC(n,n) signal, resulting in capture ambiguity and easy to cause false capture

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