Study On Passive Radar Location System Using CDMA Communicational Signal As External Illuminator

With the rapid development of the communication standards, CDMA mechanism has been the main stream of the cellular mobile communication system. It is feasible to use CDMA base stations, which have been constructed in dense distribution and broad coverage throughout the whole country, as external illuminators to detect and locate flying targets moving in low altitude. At first, the history of the cellular communication is introduced. The structure of the CDMA system, the key channel coding techniques, the composing and characteristics of the CDMA down-link signal are analyzed. Then, a signal processing scheme of the passive radar location system using CDMA communicational signal as illuminators is proposed, which is mainly composed of adaptive clutter cancellation, Range and Doppler processing, location parameters extraction and data fusion. The feasibility of this scheme is demonstrated by simulation. At the same time, the discernment of the target after processed by different cancelling algorithms is contrasted. At last, the location precision improvement via data fusion of the multiple stations is analyzed and the various affecting elements of the location error are discussed. The mean square error of the location system is analyzed. The influential factor of the location precision improvement of the multiple stations is demonstrated by geometrical deduction. The GDOP analysis of location via distance summation is conducted under the situation of multiple transmission stations and an algorithm to alleviate the influence of GDOP is introduced. Simulation experiences give some reference to the optimal configuration of base stations and data fusion of location parameters adopting a set of reliability weighs.