The Need

Positioning, navigation, and timing (PNT) resilience is increasingly critical as GNSS vulnerabilities become more apparent in contested, denied, or degraded environments. Low Earth orbit (LEO) communication satellites offer a promising alternative PNT source, but their utility is limited by poorly known or non-public ephemerides. Existing approaches either require short baselines, tight synchronization, or strong assumptions about satellite states, preventing scalable, high-accuracy LEO-based PNT deployment.

The Technology

OSU engineers have developed a reference-network-based ephemeris error correction framework for non-cooperative LEO satellites. A reference receiver with known position estimates compact ephemeris error parameters for each observed satellite and transmits these corrections asynchronously to remote users. The rover applies the corrections to its LEO-derived ranging measurements, enabling accurate PNT over long baselines without direct satellite cooperation or precise prior orbit knowledge.

Commercial Applications

• GNSS-denied or degraded navigation for autonomous vehicles and UAVs
• Resilient PNT solutions for defense and public safety users

Benefits/Advantages

• Long-baseline operation: Effective over hundreds of kilometers, reducing infrastructure density
• Non-cooperative compatibility: Works with existing LEO constellations without satellite modification
• Asynchronous corrections: No tight time synchronization required between reference and user
• Meter-level accuracy: Demonstrated significant improvement over uncorrected LEO ephemerides