Performance evaluation of a regional navigation satellite system in low earth orbit

RegionAl coveRage gdop opTimized sEgMented posItioning System is a conceptual navigation satellite constellation design in Low-Earth Orbit (LEO), which produces relatively long coverage durations, while optimizing the Geometric Dilution of Precision. This study examines the constellation performance with respect to an aerial moving receiver. We determine the receiver’s position by using the trilateration method and velocity by using doppler estimation, and improve the accuracy thereof by using an Extended Kalman Filter (EKF). We suggest a solution for the trilateration initialization problem, which arises for LEO navigation satellites, by averaging the Earth projection of all the satellites within sight. This study examines two scenarios, one wherein the EKF’s dynamic model matches the reference dynamic model, and another with a model mismatch. The results include the trilateration and doppler estimation errors, whose medians are about 10 m, and 10 cm/sec, respectively. When the dynamic model is approximated, the EKF reduces the errors by half. When the dynamic model is fully known, the position and velocity errors are reduced by one order of magnitude.