Research On ISLs Allocation Method In GNSS

Constellation autonomous navigation is an important future developmentdirection in the global navigation satellite system, the establishment and maintenanceof ranging and communication link is the basis of constellation autonomousnavigation, and inter-satellite link network design is an important part to realize theinter-satellite links. This background, from the actual demand of the inter-satelliteranging and communication, the navigation constellationsn link networking strategyhas made a primary study.The main research contents are including four parts:(1) In view of the current GPS ISL system no longer meet the future navigationsystem, in the background of the new navigation system, according to the periodicityand finite state of satellite constellation, this study proposed a system of ranging andcommunication between satellites.(2) The topology of24MEO+3GEO+3IGSO hybrid constellation was analyzedthrough the Satellite Tool Kit (STK) and MATLAB, including the elevation, azimuth,distance and visibility of MEO-MEO links and GEO/IGSO-MEO links.(3)Due to the limit of the number of satellite antenna, in order to realize theinter-satellite ranging and inter-satellite communication, how to effectively allocateantenna resources to build inter-satellite link is one of the key problem of GNSSsatellite network design. This paper presents a satellite link design method, which isaming at minimizing position dilution of precision and communication link cost. Thenetwork based on design method not only can meet the requirements of the satelliteautonomous orbit determination, but also ensure optimal communication cost andnetwork connectivity.(4) On the premise of MEO built chain with adjacent satellites on the sameorbital plane and satellites on other orbital planes at the same time, calculating PDOP,selecting the link with the minimum PDOP value, it decreases complexity of linkallocation. When PDOP value is less than3, firstly selecting the minimumcommunication cost links to connect, finally satellites achieved minimum value of thePDOP and the satellite network communication cost minimization in the samenetwork topology.The simulation results show that the elevation range should be between -65°~-35°, the optimum range should cover-70°~-20°and azimuth should cover0°~360°, and the information of link elevation, azimuth and distance has certainreference meaning for antenna design，and when the PDOP value of single satellite isless than3and the entire constellation communication delay is about9seconds, at thesame time, it reduces the number of ISL switching. GNSS satellite network designmethod in this paper is feasible, it has certain practical value and applicationprospect.