What’s New: Several new papers showing how to use communications satellites to derive PNT.
Why It’s Important:
- There are lots of comms satellites up there
- They are in Low Earth Orbit, verses Medium Earth Orbit for GPS/GNSS, so signals are much stronger, and possibly penetrate buildings, are harder to jam, etc.
- They use different frequencies which adds to robustness.
- Accuracies aren’t as good as GPS, but usable for many applications.
What to Know:
- Many/most communication satellite constellations use GPS for timing. Those are a good augmentations for GPS, but wouldn’t work as a backup.
- Folks have been working on this for a while, Prof Todd Humphrey’s at Univ of Texas being one of the earliest and most well known,
PNT as a Service (PNTasS) Solution Benefits
Presentation by Alison Brown, President & CEO Navsys to National PNT Advisory Board, 3 May 2023
This algorithm can make satellite signals act like GPS
Alternative could be more reliable, safer than current system
(Blog editor’s note: “Alternative” as used here could be misleading as many/most satellites don’t have their own clock systems and rely on GPS for timing. So you could use instead of GPS, but not without GPS working in the background.)
Researchers have developed an algorithm that can “eavesdrop” on any signal from a satellite and use it to locate any point on Earth, much like GPS. The study represents the first time an algorithm was able to exploit signals broadcast by multi-constellation low Earth orbit satellite (LEO) satellites, namely Starlink, OneWeb, Orbcomm and Iridium.
Researchers found that by listening to the signals of eight LEO satellites for about 10 minutes, their algorithm could achieve unprecedented accuracy in locating a stationary receiver on the ground and was able to converge on it with an error of only about 5.8 meters.