US 12,032,075 B2
Satellite-based source of positioning system-independent position navigation and time
H. Stewart Cobb, Reston, VA (US); Mark Hargrove, Vienna Santa Clara, VA (US); Jerry Goetsch, Reston, VA (US); Gregory Gutt, Herndon, VA (US); Dan Higgins, Reston, VA (US); Pete Johnson, Reston, VA (US); Trevor Landon, Vienna, VA (US); David G. Lawrence, Santa Clara, CA (US); Michael L. O'Connor, Redwood City, CA (US); Mark Pedersen, Reston, VA (US); Rachel Schmalzried, San Jose, CA (US); and Francois Tremblay, Reston, VA (US)
Assigned to Satelles, Inc., Reston, VA (US)
Filed by Satelles, Inc., Reston, VA (US)
Filed on Dec. 21, 2021, as Appl. No. 17/557,716.
Prior Publication US 2023/0194727 A1, Jun. 22, 2023
Int. Cl. G01S 19/40 (2010.01); G01S 19/07 (2010.01); G01S 19/38 (2010.01)
CPC G01S 19/40 (2013.01) [G01S 19/07 (2013.01); G01S 19/073 (2019.08); G01S 19/38 (2013.01)] 26 Claims
OG exemplary drawing
 
1. A satellite system comprising:
two or more satellites configured to transmit position, navigation, and time (PNT) signals independent of a global positioning system or any other purpose-built PNT system, the two or more satellites linked such that a relative range and/or satellite timing is provided between the two or more satellites, and the two or more satellites each having a clock, the two or more satellites all in a same orbital region;
at least one ground monitoring station having a known location, the at least one ground monitoring station configured to receive the PNT signals of at least one of the two or more satellites;
a terrestrial source of precision timing; and
a processor configured to estimate, for each of the two or more satellites, a variation between the clock of the satellite and the precision timing source using the observations from the at least one ground monitoring station and the relative range and/or satellite timing without observations from any satellites outside of the same orbital region.