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Apple Maps claims it's 29,905 miles away

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Re: Apple Maps claims it's 29,905 miles away

#91

Post by testing22321 »

monerozcash wrote: post #21

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…

My farming GPS does this every time I ship it with my vehicle to a new continent.

I always figured it has some code to get a quick location, and it assumes that location is very close to the last time it got a sat lock.

I just ignore it for the first day, then it comes good.

Re: Apple Maps claims it's 29,905 miles away

#92

Post by mjlee »

raverbashing wrote: post #70
bragr wrote: post #34

Earlier quoted context omitted.

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

I swapped out the satnav in a 2008 Honda for a modern unit and the car had a “speed pulse” wire. I looked it up and that wire is used for dead reckoning.

Re: Apple Maps claims it's 29,905 miles away

#93

Post by CamperBob2 »

malfist wrote: post #90
kijin wrote: post #36

Earlier quoted context omitted.

My dad used to have a crappy aftermarket GPS in his car that did the same thing. It would get lost dozens of miles away, and then hundreds of miles away. The explanation I found online at the time was that a GPS receiver needs to download data about the exact orbits of all GPS satellites from time to time. Satellites slowly lose altitude and change their orbits. Up-to-date information is constantly broadcasted by eve…

_deleted incorrect statement_

Well, that's certainly not the case. Each satellite transmits a low-precision almanac to the receiver that helps it lock onto the others, as well as a higher-resolution ephemeris that provides the necessary pseudorange accuracy for that particular SV.

But it's true that neither of those factors accounts for miles of error. That has to come down to either poor sky coverage/signal strength, poor software, or (more likely) both.

Re: Apple Maps claims it's 29,905 miles away

#94

Post by malfist »

somenameforme wrote: post #47
monerozcash wrote: post #21

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…

If it becomes common place, spoofing is easy to counter. Directionality and parallax of the signal is enough to figure out the true signal, all it requires is an additional antenna.

This won't prevent jamming, that requires a different mechanism, but spoofing should be prevented.

Re: Apple Maps claims it's 29,905 miles away

#95

Post by malfist »

CamperBob2 wrote: post #93
malfist wrote: post #90

Earlier quoted context omitted.

_deleted incorrect statement_

Well, that's certainly not the case. Each satellite transmits a low-precision almanac to the receiver that helps it lock onto the others, as well as a higher-resolution ephemeris that provides the necessary pseudorange accuracy for that particular SV. But it's true that neither of those factors accounts for miles of error. That has to come down to either poor sky coverage/signal strength, poor software, or (more like…

You are correct, there's several words of data at the end of the packet that is a low precision almanac

Re: Apple Maps claims it's 29,905 miles away

#96

Post by [deleted] »

malfist wrote: post #90
kijin wrote: post #36

Earlier quoted context omitted.

My dad used to have a crappy aftermarket GPS in his car that did the same thing. It would get lost dozens of miles away, and then hundreds of miles away. The explanation I found online at the time was that a GPS receiver needs to download data about the exact orbits of all GPS satellites from time to time. Satellites slowly lose altitude and change their orbits. Up-to-date information is constantly broadcasted by eve…

_deleted incorrect statement_

[deleted]

Re: Apple Maps claims it's 29,905 miles away

#97

Post by hnlmorg »

theamk wrote: post #44
hnlmorg wrote: post #42

Earlier quoted context omitted.

The problem is that roads are continually being built and maps aren’t always as quick to be updated. There are also private paths that aren’t public roads but are still intended for vehicles.

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.

Re: Apple Maps claims it's 29,905 miles away

#98

Post by WarOnPrivacy »

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.

Re: Apple Maps claims it's 29,905 miles away

#99

Post by FireBeyond »

Maps has gone backwards on CarPlay, too. Hysteresis is completely broken - I stop at a traffic light and the map will jump back and forth between two resolutions, often once a second, which is extremely distracting.

I also love that Find My says my partner was "last seen" at home "8,912 days ago".

Apple just doesn't give as much of a shit any more.

Re: Apple Maps claims it's 29,905 miles away

#100

Post by stefan_ »

murkt wrote: post #86
theamk wrote: post #44

Earlier quoted context omitted.

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)

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.

It does teleport to Peru but it also fast-forwards time to about a year into the future, which caused my car to think its overdue for that oil change. It even synced that back to the headquarters and I got an email asking me to take it to service.. (and arriving there on the wrong side of the Dnieper, I just decided to wait it out)

Wish we could put it into a manual mode where you just reset it's position once and then it updates based on wheel encoders & snapping to roads.

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