Research And Implementation Of Pseudo - Code Fast Acquisition Technology Based On Array Antenna

The Direct Sequence Spread Spectrum system based Array Antennas(DSSS-AA) is studied in this paper for the advantages of Low Possibility of Intercept(LPI), interference rejection and high resolution in distance.Also, DSSS-AA can solve the problem of Muti Access Interfence(MAI) via forming a spatial filter to present max gain in the azimuth of signal of interested and min gain in the azimuth of signal of which is not interested. The acquisition of Pseudo-Noise (PN) code and Digital Beamforming(DBF) are the most important technologies of DSSS-AA.The mean acquisition time is a statistical description of the capblity of compution and successful synchronization of the systems.These parameters especially the mean acquisition time have been studied under different signal-to-niose ratio(SNR),signal-to-interference and niose ratio(SINR) and array location error in this paper.At first,the theories of acquisition technologies of DSSS-AA are introduced.The detect possibility and the mean acquisition time of Two-Dimension Search method (TDSM)and Joint Spatial and Delay Acquisition method(JSDAM) have been both analyzed.A method to optimiz the mean acquisition time by optimiz space divisition has been proposed in the paper.The results under fixed beamforming and Minimize Variable and Distortion Response(MVDR) beamforming are present by simulations.Second,the performance of acquisition capability of JSDAM based NLMS under strong interference have been simulated and analyzed.A improved method of JSDAM based Maximize-SINR have been proposed in the paper.The simulation show that the improved method have better performance under strong interference. Simultaneity,a implement method of Inversed QR Decompose-Recursive Least Squares(IQRD-RLS) of JSDAM based Maximize-SINR is illuminated.The performances of numerical stability properties and convergence properties have been showed in the paper.At last,a DSSS-AA system is designed to illuminate those exhibition acquisition performances.The analyzed methods of TDSM and JSDAM based NLMS and Maximize-SINR have implemented in the system.The detect capabilities of those methods have been illuminated by experiments.The results showed that the analyzed methods have good performance of acquisition.