Satellite navigation using long-term navigation information and autonomous orbit control

A navigation satellite comprising:

• a receive antenna adapted to receive ephemeris data from a ground station, wherein the ephemeris data corresponds to a nominal orbital path of the navigation satellite;
• a memory adapted to store the ephemeris data;
• a transmit antenna adapted to transmit the ephemeris data to a plurality of navigation devices;
• a plurality of propulsion actuators;
• and
• a processor adapted to:
• determine an actual orbital path of the navigation satellite,
• determine a deviation between the actual orbital path and the nominal orbital path, and
• command the propulsion actuators to adjust the actual orbital path to reduce the deviation between the actual orbital path and the nominal orbital path.

A navigation satellite comprising:

• means for determining a nominal orbital path of the navigation satellite;
• means for transmitting ephemeris data corresponding to the nominal orbital path from the navigation satellite to a plurality of navigation devices;
• means for determining an actual orbital path of the navigation satellite locally at the navigation satellite;
• means for determining a deviation between the actual orbital path and the nominal orbital path locally at the navigation satellite;
• and
• means for autonomously adjusting the actual orbital path locally at the navigation satellite to reduce the deviation between the actual orbital path and the nominal orbital path.