Estimation Oftdoaand Research On Three-satellite Locationalgorithms

The passive location system itself does not emit electromagnetic wave, completely work passively. It has the advantages for longer distance and more passive covert receiver not easily be found than active pisition. It plays a important role of improving the system in the power of the war environment.Among the existing passive location methods, the method based on time difference of arrival(TDOA)location estimation, which is less computation, higher positioning accuracy, but also easy to implement real-time systems, is the common method of passive location. This method uses multiple distributions of receivers at different positions in space reconnaissancing emitter signal, measuring signal arrival time difference. The time difference corresponds to the space stations of a group focused on two-surface. The multiple sets of double-surface intersection is the location of radiation source. TDOA location technology system is adapt to the signal forms broad, and has high positioning accuracy compared to the traditional test. It has been widely used in the field of electronic surveillance field. Above all, the passive TDOA location positioning technology and the theoretical of three-satellite algorithms is analysised and simulatied. Quantitative results and relevant conclusions have been drawn in depth research of various factors which affect the precision,First, three-satellite location technology, particularly the theory of the time difference location technology and its basic principles are researched. WGS-84 earth surface coordinate system has been used to accurate model, avoiding the introduction of significant systematic errors of using spherical model. Secondly, the key technologies and time difference measuring method are analyzed. The fourth order cumulant-based least mean square time difference estimate (FOC-LMSTDE) algorithm has been used to estimate the time difference. And the impact factors of estimation error have been researched through test simulation. Then the relevant conclusions are drawn.Finally, a three-satellite passive TDOA location model is established. The existing TDOA location algorithm is analysised. Least squares iterative algorithm is used to locate. And the impact factors of location error are researched through analysis and experimental simulation. Then conclusions are drawn.