Research Of Synchronization Acquisition For The Direct Sequence Spread Spectrum Signals On Noise Suppression

Direct Sequence Spread Spectrum(DSSS) communications technology is a new system for anti-jamming and confidentiality communications of more. This technology has a strong ability to concealment, anti-jamming, anti-detection, anti-wiretapping and anti-lateral. The anti-fading, particularly anti-frequency selection of its is a good performance with location capabilities. So that can enable CDMA. Therefore, it is widely used in mobile communications, satellite communications, and military secret communications.With the continuous development of DSSS communication technology, the form of signals is more colorful BOC modulation signal is added an carrier modulation based on the traditional PSK modulated signal that make its spectrum divisiving, reducing the mutual interference between the signals. The main peak of correlation function which is steeper can improve the positioning accuracy and multipath resolution. However, the vice peaks of the autocorrelation function also presents a challenge to the synchronization acquisition method, especially in terms of noise immunity.Therefore, the composition of direct sequence spread spectrum communication system is in-depth studied in this paper, also the DSSS signal characteristics and existing synchronization acquisition method and abroad. And analyzes the advantages and disadvantages of the existing methods on acquisition, as provided the foundation to propose the new methods of noise suppress synchronous acquisition on the DSSS signals.Further, aimed to acquisition ambiguity problem of the BOC and its derivative signals which is caused by vice peak of correlation function, focusing on method of the autocorrelation function reconstruction. According to the reconstruction model designed local auxiliary signal, and referenced on the original algorithm, then proposed the elimination of the dual peak matching algorithm and second-compensation quadratic correlation method. By the performance of these two algorithms analysis, we can draw that the two new algorithms eliminated the effect of vice peaks is quite obvious. The main-vice peak ratio is got larger and noise suppression of system is improved. The width of the main peak can be Narrowed to improve the navigation efficiency and the acquisition accuracy. The efficiency of the algorithm can be improved by a secondary compensation on Doppler to save time. The acquisition can be completed quickly and accurately by proposing the two new algorithms to improve the system noise immunity.