NGS Second Generation ASCII and Binary Orbit Formats and Associated Interpolation Studies

In 1985 the NGS introduced GPS orbit formats and weekly orbit products based on those formats. The products are very specific regarding contents, epoch interval, and arc length; however, the formats are general. The formats permit any start time, any epoch interval, any number of epochs, and any number of satellites. These formats also accommodate partial orbital data for one or more satellites. These formats come In ASCII and binary and comprise either position data or position and velocity data. Although these formats have been used for 6–7 years and have been well received by the GPS community, it was decided that they would be enhanced to include satellite clock information. The 1985 (first generation) orbital formats and products will continue to be valid.