A Low Signal-to-Noise Ratio DSSS Signal Acquisition Method Using Traversal Method to Eliminate Data Modulation

Abstract

Non-coherent data modulation will seriously influence the direct sequence spread spectrum (DSSS) signal's acquisition performance. This paper proposes an acquisition algorithm for DSSS signal using traversal method to eliminate non-coherent data modulation. First, dividing the received signal into different frequency intervals, then modifying the local code rates based on the central frequency points of each interval, to prevent the relative slip of received signal and local codes due to long-term integral. Correlating the local codes and each interval signal then putting them into the storage. Doing the FFT operation after eliminating non-coherent data modulation using traversal method then the acquisition result will be captured. This method can adapt to different modulation data rates and signal-to-noise ratios by modifying parameters. Theoretical analysis and simulation results show that the SNR of this paper’ method will higher than the conventional part correlation FFT method 3dB. For modulation data with a rate of 1kbps as an example, this algorithm can adapt to a signal-to-noise ratio of C/N0>44 dB.Hz. This algorithm has good prospects for engineering applications.