Research on Configuration of Tri-Satellites and Location Precision of TDOA

Tri-satellites geo-location using Time Difference of Arrival (TDOA) is an important passive location technique of high precision. It is necessary to further study the formation of tri-satellites to improve the performance of location. Based on the TDOA geo-location principle of tri-satellites,this paper deduced the analytical equation of error of latitude and longitude,put forward the mathematical formula of optimal tri-satellites configuration by means of least location root mean square error (RMSE),and analyzed the sensitivity of location error for the different tri-satellites configuration. Also discussed the design and maintenance of tri-satellites formulation,designed the tri-satellites formulation by the equations of Euler-Hill,according to the requirements of periodical stability and consistency of location error. All the simulations show that the location error is sensitive when the geocentric angle of corresponding triangular leg is less than about 0.3 degree,or the triangle is nearly colinear,and the isosceles right-angled triangle is optimal for the fixed length of triangle leg. The detailed design,put forward herein,is of little location error and favorable consistency,and is valuable for application.