Low Earth Orbit (LEO) as an Alternate Source for Position Navigation and Timing (PNT) in Airborne Aerospace Applications

Radio Frequency Interference (RFI) is a common threat to Global Navigation Satellite System (GNSS)-based Position, Navigation and Timing (PNT) solutions, as reported from various regions of the world including India. Low Earth Orbit (LEO) signals that currently are evolving can be considered as effective Signals of Opportunity (SoO) and as an alternate means for supporting positioning and navigation applications. In this paper, a comparison is performed by considering two different LEO constellations having large number of satellites, against the performance obtained using GNSS. Satellite geometry, the number of satellites available and the handovers are considered to arrive at the position errors in static and dynamic scenarios. The results indicate the feasibility of deploying LEO signals for PNT applications in the airborne aerospace domain. Additionally, a few key advantages and disadvantages of LEO-based positioning are also corroborated for practical applications.