Real-Time Kinematic Absolute and Relative Velocity Estimation of Geostationary Satellites in Formation Using IRNSS Observables

The Indian Regional Navigation Satellite System, under development at ISRO, is an emerging regional navigation satellite technology with three geostationary and four geosynchronous satellites. Subsequently, four more geosynchronous satellites will be added to increase the coverage and also to improve the dilution of precision. This paper describes the techniques of kinematic absolute and relative velocity estimation of geostationary satellites in formation. The Doppler range measurements are used to estimate the absolute velocity. The relative velocity estimation is carried out using the between-receiver single-difference carrier phase measurement. The receiver clock bias drift modelling and estimation is also carried out in a highly dynamic environment along with simulation results.