Improvement of Intersatellite Measurements Scheduling to Refine the Accuracy of the Ephemerides of Modern and Prospective GLONASS Orbital Segments

Abstract

The information technology developed by the authors to ensure the possibility of operation without downloading information by the ground control complex while improving the accuracy of the ephemerides of the existing global navigation satellite systems (GLONASS) midaltitude segment and its promising additions is described. Achieving the stated goals within the framework of the technology under discussion involves the formation of precise ephemerides by solving the following interrelated tasks: improving the accuracy of determining and predicting the ephemerides of navigation satellites in the inertial coordinate system; improvement of methods and algorithms for forecasting and updating the evolution of the Earth’s rotation parameters onboard satellites; and precise synchronization of onboard clocks. The primary attention is paid to the first of the listed tasks, i.e., prediction and refinement of the ephemerides of navigation satellites in the inertial coordinate system, including in the mode of operation of satellite constellations without updating the ephemerides-temporal information. As a base for its solution, it is proposed to use advanced onboard hardware for intersatellite measurements. The basic limitations related to the implementation of intersatellite measurements and their subsequent processing for both midaltitude and advanced space segments of the GLONASS are discussed. The results of the design-ballistic analysis and processing of real and simulated measurements, as well as the preliminary characteristics of the accuracy of the ephemerides estimates obtained in this case onboard, are presented.