Compressed sensing-based multi-period direct-spread MSK signal two-dimensional joint acquisition method

Abstract

The invention discloses a compressed sensing-based multi-period direct-spread MSK signal two-dimensional joint acquisition method. According to the method, A / D sampling is performed on received intermediate-frequency direct-spread signals; after passing through a receiving and converting filter, sampled signals are converted into approximate direct-spread BPSK signals; the approximate direct-spread BPSK signals are subjected to down-conversion and low-pass filtering, so that direct-spread DSSH complex baseband signals are obtained; a sample point sequence of M symbol periods is selected from the signals so as to be adopted as an observation sequence, and local pseudo-codes are adopted to construct a joint sparse matrix; and an orthogonal matching pursuit algorithm is used to reconstruct compressed sensing signals, so that pseudo-code phase difference and Doppler frequency offset can be captured. The method of the invention has the advantages of simultaneous completion of pseudo code phase and Doppler frequency offset capture, large search range, high estimation precision, small error, and the like. The method of the invention is a novel two-dimensional capture method, is suitable for a high-dynamic low-signal to noise ratio application environment and has a high practical value.

Description

technical field [0001] The invention belongs to the technical field of digital communication, and relates to intermediate frequency all-digital reception and pseudo code and Doppler frequency offset capture of a spread spectrum communication system, specifically, a two-dimensional joint capture of multi-period direct spread MSK signals based on compressed sensing method. Background technique [0002] At present, BPSK and QPSK modulation methods are mostly used in spread spectrum systems, but these two modulation methods cannot be applied to the application fields with severe nonlinear distortion, Doppler frequency shift and multipath fading. The direct spread MSK communication system has the advantages of low interception of the spread spectrum system, multi-user random site selection capability, strong anti-interference performance, constant envelope of the MSK signal, high spectrum utilization, energy concentration, fast sidelobe attenuation, and band With the advantages ...

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Problems solved by technology

However, most of these methods are difficult to strike a balance between the Doppler estimation range and the estimation error

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