1、 第1期 熊 智等 : 基于北斗雙星定位輔助的 SAR INS 組合導航系統研究 93 Research of SAR INS Integrated Navigation System Aided by BeiDou Double Star Position XIONG Zhi , LENG Xue2fei , LIU Jian2ye (Navigation Research Center , Nanjing University of Aeronautics & Astronautics , Nanjing 210016 , China Abstract :Because of th

2、e images matching position in SAR INS BeiDou integrated navigation system needing the unequal matching calculation time , and the output of BeiDou position system having time delay , which resulted in different steps and delay characters of measurement output. So , The integrated filtering with the

3、common federated kalman filtering algorithms couldn t get high degree of accuracy for the problem. The paper analyzed the work process in SAR INS BeiDou integrated navigation system , and utilized kalman filtering theory to design the integrated filtering scheme based on federated filtering theory f

4、or solving the prob 2 lem of different steps measurement information. And then , the paper gave the algorithm of solving the measurement delay , thus the information fusion problem of the SAR INS BeiDou integrated navigation system can be good do. With the analysis of the covari 2 ance , the results

5、 have verified the feasibility of this scheme presented in the paper , and shown important reference value from the 2 ory to the application of SAR INS BeiDou integrated navigation system. Key words : Federated filtering ; Measurement different step ; Measurement delay ; Information fusion ; Kalman

6、filtering ( 上接第 57 頁 Optimization of the Distribution Geometry of Stations Based on the System of Orbit Determining by Use of Rate Data LIU Ji2ying , ZHU J u2bo , LIU Ye , HU Zeng2hui (College of Science , NUDT , Changsha 410073 , China Abstract : In the system of orbit determining by use of rate da

7、ta , the relationship between the accuracy of the estimation and the distribution geometry of stations was different from the one in conventional system which was based on measurements of rang and rang rate. In this paper , we began with the principle of orbit determining by use of rate data , analy

8、sed how the distribution geometry impact the accuracy of the estimation , and utilized the genetic algorithm to optimize the distribution geometry in two backgrounds , one was the unconstrained search in certain space , and the other was the search in some given stations. In the de 2 sign of genetic algorithm , we considered the selection of different fitness functions and the robustness of the algorithm and so on. The simulation indicates that the effect of optimization is evident. Key words : Orbit determining by use of rate data ; Error propagation ; Genetic algorithm ; D