Ephemeris Message for the Next Generation SBAS

Abstract

The next generation SBAS Satellite-Based Augmentation System being discussed for international standardization is likely allowed to be transmitted from non-geostationary satellites as well as geostationary satellites. However, it is found that the clock correction parameters in the SBAS ephemeris message of the latest draft standards do not have enough dynamic range for non-geostationary satellites. The author has investigated a revision of the message to solve this point by adjustment of the number of bits for each ephemeris parameter and here reports the discussion.