A Joint Code-Doppler Acquisition Algorithm for DSSS-MSK Signal Based on Compressed Sensing

The unavoidable Doppler offset significantly reduces the correlation peak for code acquisition of the direct sequence spread spectrum minimum shift keying (DSSS-MSK) signal in highly dynamic environment. To eliminate the severe influence caused by the Doppler offset, a novel joint code-Doppler acquisition method based on compressed sensing (CS) is proposed. This acquisition algorithm introduces CS to spread spectrum communication. A sparse dictionary is constructed based on the observed signal, which is then reconstructed in the sparse domain by orthogonal matching pursuit (OMP) to obtain the code delay and Doppler offset simultaneously. However, the computational complexity of this algorithm is very high over a wide searching range. To reduce the computational complexity and improve this algorithm further, a two-stage acquisition method is introduced. Simulation results show that the detection probability of the proposed method reaches 0.9 in a low signal to noise ratio (SNR) at a -20dB environment.