LOW BANDWIDTH METHOD FOR EPHEMERIS RECOVERY IN OVER-THE-AIR TRANSMISSION

摘要

A method and apparatus are disclosed for processing and transmitting precise orbit predictions of satellites in a Global Navigation Satellite System such as Navstar-GPS or a communication device such as Iridium which employs force models and curve fitting techniques so encode ephemerides, and particularly ephemerides of duration of a month, in order to minimize bandwidth requirements over-the-air and NVRAM storage requirements. The methods also apply to GNSS constellations such as Galileo or GLONASS.

主权项

1. A method for encoding an orbit prediction of a satellite over a period of time and having a start time T comprising:
selecting a reference ephemeris model Meph whose validity includes T; selecting a multi-day precise orbit prediction POP; fitting the initial velocity and empirical accelerations A0 of model Meph at T to the POP using force models while holding the initial position P0 from Meph at T fixed; determining a scalar along-track velocity correction va to the velocity of Meph at T relative to the fitted velocity and empirical accelerations A0; and encoding the empirical accelerations A0 and the scalar along-track velocity correction va.