5 ms·
High-power, and ideally authenticated, alternatives to space-based GNSS are desperately needed, given the sharp uptick in jamming and spoofing incidents in many
by lxgr 2y ago
High-power, and ideally authenticated, alternatives to space-based GNSS are desperately needed, given the sharp uptick in jamming and spoofing incidents in many places.
In a true "end of history" moment, the US and other NATO members discontinued both of their ground-based systems (which are inherently harder to jam due to their much higher transmission power, since transmitters are not power limited) – Omega in the late 1990s and Loran-C in the early 2010s – in favor of GPS, while Russia kept their equivalent functional, and China completed an eLoran network last year.
Add to that the FAA's reduction of their ground-based VOR/DME station network that lets planes navigate when GPS is unavailable...
GPS jamming, and much more concerningly spoofing, will probably quickly come within reach of non-nation-states and smaller groups of all kinds, and ultimately individual actors, and that can't possibly end well for civil aviation if robust countermeasures don't become available very soon.
- mindcrime 2y agoGPS jamming, and much more concerningly spoofing, will probably quickly come within reach of non-nation-states and smaller groups of all kinds, and ultimately individual actors It may already be so: https://hal.science/hal-03456365v1 https://hal.science/hal-03456365v1
- jeffbee 2y agoA university of Texas research group demonstrated more than ten years ago that they could spoof GPS in the vicinity of an automatically navigating UAV, and force it to land at a point of their choosing. This has been within the reach of garage hackers for a long time.
- Scoundreller 2y agoNow the UAV needs to track where the signal is coming from. “Hey, this isn’t coming from the sky, what gives”
- touisteur 2y agoGets trickier when you're using dGPS. And you need at least 2 antennas/receivers to know direction of arrival. Beamforming in the direction(s) of the expected satellite(s) seems to help a lot with e.g. starlink. But you'll need a phased array and a beamformer.
- typewithrhythm 2y agoYou can't really beat a jammer, sure you can compete for power output, but there is no real stopping it. Aircraft and military positioning concepts are evolving towards more map and dead reckoning, lessening the benefit of GPS jamming.
- zinekeller 2y agoThe reason that dead reckoning was inaccurate was because of clock and vector inaccuracies. Looking at the advances in clockpieces and gyroscopes (both of these has benefitted over the optical revolution) over the years, I am not shocked that dead reckoning is back in vogue.
- cameldrv 2y agoDead reckoning is also inaccurate due to unknown winds. Even if you take off with the best available forecast, it’s often wrong by 5mph+. After three hours your position is off by 15 miles. That’s not remotely good enough for most aviation purposes.
- t0mas88 2y agoDead reckoning based on heading and time alone, but if you have a good INS it's not affected by wind only by accuracy of the gyroscopes/sensors. Current systems drift by about 0.5 miles per hour. And that's normal commercial grade systems, I'm sure the military has an option for better systems if they need them.
- deleted 2y ago[deleted]
- zinekeller 2y agoAs t0mas88 said, you don't rely on the measured speed of the aircraft/ship, you rely on gyroscopes (which are much more resistant to external factors), and both clocks and gyroscopes have improved signifcantly (clocks are now better than cesium atoms - read about atomic clocks) and so are gyroscopes (again, optical gyroscopes that are miles better than mechanical ones).