Exploiting Starlink Leo for PNT
8 days ago
- #Starlink
- #PNT
- #LEO
- The article discusses the urgent need for alternative Positioning, Navigation, and Timing (PNT) technologies due to increasing GNSS jamming and spoofing attacks.
- LEO (Low Earth Orbit) satellites are highlighted as a promising alternative for PNT due to their abundance, favorable dilution of precision, and higher signal power compared to GNSS.
- Four categories of LEO PNT are identified: dedicated LEO constellations, GNSS augmentation, dual-purposing LEO satellites, and opportunistic use of LEO signals.
- The article focuses on exploiting Starlink's LEO downlink signals for PNT, despite Starlink not being designed for PNT services.
- Challenges include undisclosed signal structures, poorly known ephemerides, and unresolved timing errors, which are addressed through novel algorithms.
- A Starlink PNT software-defined receiver (SDR) architecture is presented, capable of extracting Doppler and pseudorange observables.
- An approach to correct LEO ephemerides and timing errors via a reference receiver is described, enabling long baseline corrections with low bandwidth.
- Experimental results show a stationary receiver achieving 2-meter accuracy in 20 seconds and a ground vehicle navigating with meter-level accuracy over 3 km using Starlink signals.
- The article details the structure of Starlink's OFDM beacon and its advantages for PNT, including improved delay and Doppler resolution.
- A reference network design for wide-coverage LEO ephemeris error correction is proposed, featuring sparse reference stations across the U.S.
- Two experimental validations are presented: stationary positioning with carrier phase measurements and LEO-aided IMU navigation with Doppler measurements.
- The conclusion emphasizes the potential of Starlink signals for PNT and calls for discussions on integrity, availability, and continuity for practical use.