基于低轨卫星信关站转发的双星定位算法研究OA

With the rapid and vigorous development of low Earth orbit(LEO)communication constella-tions,the integration technology of communication and navigation has ushered in new historical develop-ment opportunities.Aiming at the problems such as limited number of satellites and insufficient cover-age multiplicity in the initial stage of LEO constellation construction,a dual-satellite positioning algo-rithm based on the forwarding of LEO satellite gateway stations is proposed.This algorithm introduces ground gateway stations and constructs a closed-loop communication by utilizing the two-way communica-tion characteristics of satellite-station and satellite-terminal links,which in principle eliminates clock de-viation.With the assistance of altimeters,elevation information is obtained based on the similar ellip-soid model to increase the number of observations,and finally completes the terminal position calculation based on the extended Kalman filter(EKF).Three simulation scenarios are constructed and analyzed.Compared with the shortest distance(SD)principle of gateway stations and the least-squares method,the three-dimensional positioning accuracy of the proposed minimum position dilution of precision(mPDOP)method is improved by 48.05%and 45.21%,respectively.Compared with the dual-satellite positioning method without gateway stations,the positioning accuracy of this method is improved by 46.50%.Fur-ther,to address the problem of a sharp increase in PDOP caused by the rapid movement of LEO satel-lites,a periodic satellite switching(PSS)strategy is proposed.The simulation results show that the posi-tioning accuracy of the proposed method can reach 7.52 m,better than the 7.59 m accuracy of Beidou po-sitioning.