Satellite Positioning System And Error Analysis

The satellites location system can location without consideration in border, airspace, territorial sea and weather, it can reconnaissance in large acreage. Moreover, the velocity of satellite is faster than others; it can get information very convenience. All of this makes electronic reconnaissance by satellites location system very important. This paper makes detailed analysis in the low orbit single-satellite direction finding and position system, the low orbit dual-satellites passive location system by using TDOA and FDOA measurements, the low orbit triple satellites passive location system by using TDOA, and makes analysis about the factors in the satellites location system selection. This paper presents a location algorithm Based on WGS-84 Earth Model and a dynamic multidimensional scaling algorithm through modifying the classical MDS and using the TOA measurement, including the following:The single-satellite direction finding and position system is discussed, the main techniques of goniometry are analyzed, an algorithm is presented which locates ground emitter from space satellites and uses sphere recursion. The WGS-84 ellipsoid earth model was used to reduce the systemic error; as the simulation results shown, the location model has good performance if the height error is within some limits, the recursion algorithm converges rapidly and is effective, and the direction-finding error has large effects on the location error.The low orbit dual-satellites passive location system is discussed, the main factors which influence the precision of the location system are analyzed, The low orbit dual-satellites passive location method using TDOA (time difference of arrival) and FDOA (frequency difference of arrival) was studied , an algorithm is presented which locates ground emitter from space satellites and uses sphere recursion. The WGS-84 ellipsoid earth model was used to reduce the systemic error; a sphere recursion algorithm is discussed. As the simulation results shown, the location model has good performance if the height error is within some limits, the recursion algorithm converges rapidly and is effective, and the frequency measurement error has large effects on the location error. The low orbit triple satellites passive location system is discussed, the main factors which influence the precision of the location system are analyzed; the problem of locating a ground emitter passively using TDOA measurements of triple satellites is discussed. First, a location model for initialization is given. Then improve the emitter's precision by using the information of height, a new zero height constraint algorithm is proposed, At last, simulation results are presented. As the results shown, the location model has good performance if the emitter's height is no more than 200m; the recursion of the proposed algorithm converges rapidly and is effective.Present a dynamic multidimensional scaling algorithm through modifying the classical MDS which uses instantaneous measurement for each location. The proposed algorithm is simple and computationally efficient which allows real-time processing. It performs better when the number of measurement is more than five. Classical MDS is equal to the proposed algorithm when the number of measurement is only one.