121–130 of 153 posts
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Well, when I’m driving in Kyiv, and there is an air raid alert, usually my car navigation starts to derp, and after a few minutes it thinks that it’s suddenly in Lima, Peru. Not that I mind too much, I know how to get around without navigation.
GPS jamming for incoming drones?
As one of the commenters pointed out, altitude. A geostationary orbit is ~26,000 miles. Dollars to donuts, that's where it is.
Context is confusing because we arrive in the middle of a story arc, at a point where an unrelated tech snafu happens. The story arc is about a lost airtag that is living it's secret life in Mexico. The link is for a post where Apple decides the distance to it's location in Mexico is greater than the circumference of the Earth.
GPS has an altitude component so maybe it thinks either the AirTag or the tracking phone is really high up?
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I wonder if it's using a compass and odometry (distance) with dead reckoning. A strange choice when GPS is available, but it would account for the map moving in the car's direction and it not changing locations when it moved without rolling (ferry).
Almost certainly. GPS is not only easily jammed, but easily spoofed. If the car believed GPS instead of its own eyes, so to speak, then there’s significant potential that you’d see glitches more often. It could also be something of a safety risk when using its self-driving capabilities.
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GPS has an altitude component so maybe it thinks either the AirTag or the tracking phone is really high up?
Nah, the altitude component is less than a rounding error at the scales involved.
Maybe they are running into https://en.wikipedia.org/wiki/Coastline_paradox
While we're on the subject of maps-related bugs, I was recently borrowing a new Tesla Model Y and took it on a RORO ferry. After the crossing, the car’s GPS was convinced I was still at the port where I had departed from. I restarted it a couple of times, but nothing. I drove off using Waze on my phone instead of the car's navigation. The map on the car kept moving relative to the direction I was driving, so the navi…
A practical issue is that GPS can be spoofed relatively easily. If autonomous driving became a thing, and ubiquitous, with vehicles that prioritized remote over local consistency, then a single GPS spoof could cause some interesting things to happen. This is probably a concern that does drive decisions, at least to a degree. It creates a weird scenario where you kind of need to trust GPS, but you simultaneously also…
The Phenom 300 jet can't fly straight without a valid GPS signal: https://news.ycombinator.com/item?id=12519629
Every swept-wing jet has a tendancy to enter a positive feedback loop of rolling and yawing, called a dutch roll, when flying at altitude, so even when not using autopilot, an active system is needed to fly straight and level. If the Phenom 300 doesn't have a valid GPS signal, that system fails.
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That's no excuse for disbelieving GPS for extended periods of time. Google Maps gets it right: it tried to keep you on road, but only for a few tens of seconds. After that, if you are in the middle of uncharted territory, it'll show the marker there. (This is probably because Google Maps can be used for walking/biking too)
> That's no excuse for disbelieving GPS for extended periods of time. You've got it backwards. I was explaining why GPS should take priority over mapping data. Not the other way around.
I’ve had that bug a few times. I think it’s related to some roads being closed and/ or under reconstruction. I’ve seen this happen multiple times on the same route, and it always fixed itself after I passed the construction site.
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My guess would be: 1. Car entered ferry, loses GPS 2. Car entered dead reconning mode used for tunnels and such 3. Car left ferry, acquired GPS Then either: 4a. Location via dead reconning vasty disagreed with GPS because the car doesn't know about the ferry's movements, triggering some kind of failsafe. Or: 4b. There's just a plain old bug in the condition to switch back to GPS and maybe people haven't noticed becau…
It probably doesn't do dead reckoning even in tunnels And maybe the system sucks to get the GPS almanac if badly desynced