System and method for efficient broadcast of satellite constellation ephemeris information

A method for broadcasting satellite ephemeris data for a constellation of a plurality of satellites comprising:

• characterizing each of a set of orbital parameters for each of the plurality of satellites as a function x(t) of a plurality of terms including a constant, a linear function of time and a number of harmonics, wherein each set of orbital parameters collectively reflects a position of the respective satellite as a function of time (t),
• classifying each of the plurality of terms for each orbital parameter in one of a plurality of information classes, wherein each information class is subject to a respective update frequency for the respective terms classified therein, and wherein each of the plurality of terms for each orbital parameter is classified based on a rate of change over time (t) of the term;
• determining an updated value for each of the terms of each frequency class based on the respective update frequency for the frequency class;
• and
• broadcasting, by each of the plurality of satellites of the constellation, a current value for each of the terms of each frequency class at a frequency relative to the respective update frequency for the frequency class in order for a user terminal to determine a position of the respective satellite at a time (t).