The Doppler Positioning Technology of Iridium-Next and Oneweb Fusion Constellation

With the advancement of technology, the Global Navigation Satellite System (GNSS) faces increasing challenges. In response to various disruptions or weakening of GNSS navigation satellite signals, and when the visibility of navigation satellites does not meet the requirements for pseudorange positioning in complex positioning environments, there is growing attention towards the use of Low Earth Orbit Satellites (LEO) for positioning. This study focuses on the establishment of a fused LEO satellite constellation using the Iridium-next constellation and some Oneweb satellites as examples. Considering the non-cooperative nature of LEO satellites, an instantaneous doppler positioning model is developed. Two-Line Element (TLE) parameters are utilized as the orbit prediction model to obtain doppler shift information and receiver clock drift, enabling doppler positioning of LEO satellites.