Fused Low-Earth-Orbit GNSS

Traditional Global Navigation Satellite System (GNSS) immunity to interference may be approaching a practical performance ceiling. Greater gains are possible outside traditional GNSS orbits and spectrum. from low Earth orbit (LEO) has long been viewed as promising but expensive, requiring large constellations for rapid navigation solutions. The recent emergence of commercial broadband LEO mega-constellations invites study on dual-purposing these both communications-their primary mission-and secondary positioning, navigation, timing (PNT) service. Operating at shorter wavelengths than GNSS, would permit highly directive, relatively compact receiver antennas. PNT-specific on-orbit resources not required: the transmitters, antennas, clocks, spectrum hosting network suffice PNT. Non-cooperative use signals PNT is an option, cooperation with constellation operator (“fusion” its communications mission) eases burden tracking dense, low-altitude ground enables produce single-epoch stand-alone This paper proposes such cooperative concept, termed fused GNSS. Viability hinges opportunity cost, or mission imposes operator. assessed in terms time-space-bandwidth product energy budget. It shown that near-instantaneous-fix service over ±60° latitude (covering 99.8% world's population) positioning superior pseudoranging cost less 1.6% downlink capacity largest new constellations, SpaceX's Starlink. allocation comparable adding one user consuming 5.7 Mbps each cell.