Study On Multi-Station Passive TDOA Location And FDOA Velocity Determination System

With the rapid development of modern electronic technology, the technology is more and more important to deal with the active radar. The passive radar is very important to improve the survivability of the system in the electronic warfare environment, which has become an important part of modern integrated air defense system. However, the passive radar can achieve the positioning and speed measurement accuracy is not high, mainly applied to the target tracking.But it is difficult to meet the requirements of high precision guidance system. High precision target radiation source location and velocity information can be directly used for precision strike against enemy weapons platform, guide the anti radiation weapon attack. By using multi-station receiving target radiation signal, it can enhance the power range of the reconnaissance receiver platform.The detection ability of the low detectable target and improve the accuracy of target location, which has strong anti-interference ability and anti stealth ability. Therefore, how to improve the accuracy of passive radar system has become a hot spot. So the study of the multi-station passive time difference frequency differential positioning and velocity measurement system is of great significance in the electronic countermeasure.This paper studies the passive time difference and frequency difference location system,including the time difference frequency offset estimation, the joint estimation, the arrival time difference and Doppler frequency shift. Firstly, the background and significance of the research on the multi-station passive time difference positioning and velocity measurement system is described. Then, the paper describes the basic principle of the time difference location and frequency differential velocity measurement, which provides a theoretical basis for the time difference and frequency difference velocity measurement.Because of the great influence of high accuracy parameter estimation on the accuracy and speed of measurement, two classical methods are analyzed and the classical method of Doppler frequency difference is studied. At the same time, it gives the model of the multi-station passive time difference frequency offset, the system structure and the algorithm flow. Because of the relative motion between the radiation source and the observation station, the received signal is not only containing the delay components, but also contains the frequency offset. In order to accurately measure the two components, the fast time difference estimation based on the mutual ambiguity function is proposed. Then the time difference location algorithm and the frequency difference velocity measurement algorithm are studied. Not only the nonlinear method and linear method, the two common methods for solving the problem of time difference location are given by this paper.Moreover, a new method of time difference location is proposed, which is based on semi definite relaxation. The method has the advantages of high precision and global convergence. Then based on the Doppler frequency difference, the target velocity is measured, and the difference between the Doppler frequency shift relative to different stations is achieved by using the target motion. Finally, the feasibility and efficiency of the algorithm are verified by the simulation and comparison of the related algorithms, and the main factors that affect the system accuracy are analyzed according to the simulation results. Overall, with the continuous development of electronic technology, the subject is worthy of further study.