The GRIFFIN team is pleased to announce our first successful operational regional GPS RF Interference Space Domain Awareness (SDA) capability. This Aggregated Central Processing system is currently sampling a distributed network of five passive phased-array radar sensors deployed across mid-Victoria, Australia.

The work was conducted in conjunction with the US Space Force Innovations Hub SDA TAPLab Cohort 7 for the purpose of tracking and geolocating RFI (jamming / spoofing) “signals of opportunity” (SOO) originating from US SpaceOps test communications spacecraft.

During Cohort7, four additional GRIFFIN sensor stations were installed and integrated with our original Keilor Park (Melbourne Airport) site. These producing:

• Each sensor’s passive phased-array radar (yellow beam Angle of Arrival (AOA)) tracking the target LEO orbit.
• Multi-sensor centralised aggregation produces multiple Time Difference of Arrival (TDOA) hyperbolas also tracking the target LEO orbit (purple).
• The network of 4 sensors generates 4x AOA and 6x TDOA measurements for each time synchronised epoch.
• Extended Kalman Filter (EKF) multi-state filtering is used to produce high-accuracy LEO 3D ECEF positions and an orbital TLE.

The accuracy was excellent and will be further improved with changes to sensor geographic placements (improved GDOP). Cohort 8 will focus on optimised GDOP layouts, expanded sensor coverage, and including additional FDOA (Doppler) observations. We also look forward to collaborating with Space Protocol (AUS) and SpaceApp (US) to verify data accuracy for real-world system deployments.

As we prepare for large-scale regional operations (US, Australia, Pacific, Europe), these tests are strengthening our ability to deliver precise SA of any satellites transmitting RFI signals that can impact GPS performance.

We thank the US SDA TAP Lab team for their outstanding support and encouragement, and US SpaceOps for providing ongoing LEO satellite test SOOs.

Read More