Research On The Integrated Navigation System Based On SINS, Land-Based Navigation System And CNS

In order to improve the ability of satellite's autonomic survivorship,this thesis aims at low earth orbit satellite, studies on integrated navigation system consists of the strap-down inertial navigation system(SINS),the land-based navigation system and celestial navigation system(CNS). This integrated navigation system synthesizes the independence of SINS,the high precision of land-based navigation and CNS,the advantage of independence,reliabilities and so on,overcomes the disadvantage of single navigation. Moreover it can achieve a higher navigation accuracy,which has a far-reaching effect on the autonomic navigation of modern satellite. The main study of this paper as follows:Firstly, this paper analyses the principia of SINS system,establishes the mechanics layout of implementing the strap-down inertial navigation system on the former basic. On the basis of a set of boost-phase's real measurement data, the simulation of strap-down inertial navigation system was carried out,which verifies the accuracy and reliability of the inertial navigation system. However,we put forward the problem of the navigation system's error, which is inflicted by the inertial measurement element , will increase as time goes on. Accordingly,SINS have to combine with other navigation systems to provide navigation information with high precision.Secondly,this paper takes over the theory of land-based passive navigation system,analyses all kinds of element effect on the locating accuracy of land-based navigation during satellite navigation,makes out,to a great deal,locating accuracy of land-based navigation system depends on the geometric dilution of precision (GDOP) of the land-based station. It, using genetic algorithm,fast optimizes the distribution of navigation station to meet the demand of navigation which has higher requirement on navigation locating precision. In order to reduce the ground press,advance the survivability of land-based navigation,it gives out navigation schemes which consists of less than four land-based stations. On top,on the basis of implementing the strap-down inertial navigation system,it analyses the error source of land-based station deeply,establishes the error equation of SINS and land-based system,and the measurement equation of position and velocity , applies Kalman Filter technology , to realize the integrated navigation of SINS and land-based system , correcting the inertial navigation system's error , verifying the necessary of importing land-based navigation system.Lastly,the article analyze the theory of star-sensor navigation,adding the CNS system into the integrated navigation system using SINS and land-based system. It construct the state equation and measurement equation of the integrated navigation system in inertial coordinate system. Based on an absence feedback Kalman-Filtering,the dates from all of the sensors was integrated. Considering the characteristic that the SINS of measurement information is abundant and update frequently,it improves the accuracy of the navigation system through the way of using the measurement information to modify the error of the system. The problem that the updating of date from different navigation systems was asynchronous was analyzed. It was proved that the method of the integrated navigation system using SINS ,CNS and land-based system was provided with real-time character and fault-tolerance. The paper provided a new way of the integrated navigation for the space vehicle.