Service Efficiency Analysis Of Auxiliary Navigation Constellation System

With the development of user demand in the direction of high quality and diversification,the major satellite navigation countries and regions are starting to carry out the research and development and verification of new technologies and planning the construction of a new generation of navigation systems in order to improve the performance and competitiveness of navigation systems.Leo navigation satellite constellation has the advantages of high flexibility,low cost and fast convergence of PPP positioning services,which can complement each other with GNSS.In order to verify the auxiliary capability of Leo navigation constellation in the case of partial or complete failure of Beidou satellite system(BDS),the constellation design,the establishment of evaluation system and the service performance of the integrated system are studied in this paper.First of all,the design task of low-orbit navigation constellation configuration for large latitude cross-domain is completed.Combined with the idea of multiple coverage band design and the Walker constellation design method,a low orbit constellation design method under a certain coverage threshold is proposed.compared with the traditional coverage band design method,this method can obviously simplify the constellation configuration for large latitude cross-domain target regions.The orthogonal scheme set is obtained by horizontal division according to the main design parameters,which provides the data basis for the research of the evaluation system.In addition,in order to improve the credibility and reliability of orbit parameters,the constraints of common ground trajectory,quasi-regression orbit,term perturbation long-term effect and atmospheric resistance perturbation on satellite orbit are considered in orbit design.the collision interference detection of the design scheme is carried out on the basis of the analysis of the spatial topology of the constellation configuration.Then,a dynamic evaluation system of service effectiveness of Leo satellite navigation system is established.The time series of service efficiency considering the damage state of navigation constellation is obtained by using ADC evaluation model,and the comprehensive efficiency value of the scheme is obtained by combining the grey correlation method.In addition,on the basis of considering the changes of time and object state,the entropy method is used to obtain the adaptive weight of the system capability index.Through the sensitivity test of the evaluation model,it is found that,compared with the equal weight of each capability index,the evaluation model obtained by entropy weight method has a certain improvement in scheme differentiation.Finally,the constellation design scheme is optimized and the auxiliary enhancement of Leo navigation constellation is analyzed.The single satellite development cost and launch cost of Leo navigation satellite are obtained by analogy estimation,and then the cost estimation model of the whole constellation scheme is obtained.The orthogonal exploratory optimization design is carried out by using the utility comparison as the target value,and the auxiliary ability of the optimized scheme to BDS is verified at the same time.Through the analysis of the simulation data,it is found that the low-orbit navigation constellation can significantly improve the service performance and flexibility of BDS,and when the damage degree of BDS is mild,only starting the sub-constellation of loworbit navigation constellation can improve the overall system performance.