IRNSS Orbit Determination and Broadcast Ephemeris Assessment

Kurzfassung

The Indian Regional Navigation Satellite System (IRNSS) is an emerging satellite based navigation system offering an independent positioning and timing service over India and neighboring regions. Based on satellite laser ranging data collected by selected stations of the International Laser Ranging Service (ILRS) precise orbits have been determined for the first pair of inclined geosynchronous satellites (IRNSS-1A/B). These orbits are used to assess the quality of the IRNSS navigation messages. A Signal-in-Space Range Error (SISRE) at the five meter level is confirmed, which is consistent with the accuracy assess-ment given in the message itself. Even though the current 3 satellite constellation does not yet support standalone navigation, the results offer a first indication of the navi-gation quality that can be expected by future users in the area.