Research On The Key Technology Of Automous Navigation For Navigation Satellite

Under normal circumstances, the navigation message is the satellite ephemeris injection for navigation satellites on certain time intervals from the ground control station. If not properly ground systems for a long time on the Notes precise ephemeris, satellite ephemeris and can not self-update, then the navigation system will lose its effectiveness up. Therefore, autonomous navigation satellite navigation technology came into being. This technology is not used on the ground in real-time injection system precision ephemeris, and through two-way ranging and data exchange between the star, then go through a filtering process, continued use of inter-satellite observations corrected ephemeris information from satellite autonomous complete functional satellite orbit determination and punctual in order to achieve a satellite navigation system can not support the case of the ground can still provide some precision navigation capabilities over time. In normal times, this technique can be used in case of limited inter-satellite observation station location data to improve the accuracy of satellite orbit determination, provide more excellent navigation performance; in wartime, can enhance the protection of navigation satellite systems. This is the practical significance and academic value of the research lies.This article discusses the research observation system among the stars, study the inter-satellite observation data preprocessing methods, the election Star Scheme minimize GDOP value based autonomous navigation based on the Kalman filter algorithm and the ground as well as in-orbit testing program and results.First, because the inter-satellite observations and satellite links are inextricably linked, or, we can say that the establishment of a part in the inter-satellite link function in the satellite observation time. Therefore, the research for the study of inter-satellite link between the satellite observations are of a great significance. Inter-satellite observation system contains a lot of content, there are two points which is a prerequisite of significance, one is to select the observation band, and the second is based on flooding mechanism or peer mechanism. There is a certain degree later this discussion and summary.There are two, for inter-satellite ranging epoch imputed method is mainly based on a polynomial fitting method, this method of sampling precision is higher, but the small amount of calculation, and the other one is based on the dynamics of imputed method that large amount of computation, but the accuracy of the sampling requirements are lower. In this paper, inter-satellite ranging data were imputed epoch data and reduce computational improvement work, the method of polynomial fitting joint dynamics and replace the traditional series expansion and Lagrange interpolation method.From navigation satellite navigation receiver to determine the geometry of the positioning accuracy of the final representation of the geometric factor and the product of pseudo-range error factor. In general, the geometric factor called satellite / user set layout associated GDOP. Because it is in the form of the product, so the GDOP value error is a result of its location in the form of the product of amplification, so during the positioning solver, try to choose a smaller GDOP satellite portfolio position solution. Existing satellite selection methods: the best method selected stars, quasi-optimal satellite selection method, geometry optimization and fuzzy satellite selection method. In this paper, the formula for the ground GDOP values extended to spaceborne receivers, and re-derive the minimum GDOP value achieved in the inter-satellite Scene formula, based on this constellation of 24/3/1 were selected in WALKER Research Star program. The simulation results of a minimum of satellites(four satellites) optimal selection scheme based on satellite GDOP values.Finally, in this mode the Kalman filtering process, and finally obtain the track error 60 days after correction of about 8 m. Use filtering technology, in the absence of ground updated ephemeris, raising the forecast accuracy of satellite orbits.