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Model 3 GPS position error in tunnel

sabf

Member
Aug 8, 2019
5
159
Melbourne
I’ve had my model 3 for a few weeks now and have noticed that it can’t seem to track my location properly in tunnels. Of course GPS won’t work, but I assume the Tesla uses a gyro or something because the map position keeps updating in the tunnel, but it starts to drift and accumulate more and more error over several minutes.

This would not be much of a problem if the only loss is the moving map accuracy, but the Tesla gets quite upset and will screech and stop using autopilot because it thinks that the car is driving diagonally through some local road instead of in the Burnley tunnel with an 80kph speed limit :)

5C02862F-99DF-4BC9-B028-BC765E0D3EE2.jpeg

Has anyone else had this issue?
 

stedes

Member
May 23, 2019
136
171
Sydney, NSW
I’ve had my model 3 for a few weeks now and have noticed that it can’t seem to track my location properly in tunnels. Of course GPS won’t work, but I assume the Tesla uses a gyro or something because the map position keeps updating in the tunnel, but it starts to drift and accumulate more and more error over several minutes.

This would not be much of a problem if the only loss is the moving map accuracy, but the Tesla gets quite upset and will screech and stop using autopilot because it thinks that the car is driving diagonally through some local road instead of in the Burnley tunnel with an 80kph speed limit :)

View attachment 467026

Has anyone else had this issue?

It works fine in both Lane Cove and Harbour tunnels in Sydney...
 

Rockford

Member
Jun 16, 2018
69
39
BOTANY
Sydney M5 Tunnel is the bad. Mine tends to put me about 50M either side of the tunnel, would never use the Autopilot in such a situation. It doesn't seem to snap to streets or anything but if you have Navigation running it will go a bit crazy.
 

meloccom

Moderator Aus/NZ
Supporting Member
Feb 11, 2008
2,438
1,391
Sydney Australia
I had a problem with my MCU about a year ago and part of the repair was to replace the “Gyro Board” so it is replaceable as a separate part on Model S so almost certainly on Model 3 too.
Now that it’s repaired I still have some drift through tunnels but it’s only a few meters off whe I exit the M5 tunnel.
 

tessiestraya

Member
Oct 2, 2019
190
232
Melbourne, Australia
  • Informative
Reactions: Hairyman

ajdelange

Active Member
Dec 10, 2018
1,077
638
Virginia/Quebec
I’ve had my model 3 for a few weeks now and have noticed that it can’t seem to track my location properly in tunnels. Of course GPS won’t work, but I assume the Tesla uses a gyro or something because the map position keeps updating in the tunnel, but it starts to drift and accumulate more and more error over several minutes.

This can get complicated fast but in general the car estimates its position from its previous location estimate and from its knowledge of where the road is (map data) and then corrects that from GPS/Glonass readings. This is why in many cars the navigation display will show you traveling on the road it thinks you should be on even though you have driven off it onto a road that isn't shown on the map.

If GPS is lost then the system cannot correct its position estimates but if it knows the lay of the road it can continue to update position (note that it can get speed data from the speedometer) pretty well. I'd guess that it isn't working well because of a problem in the map database.
 

MP3Mike

Well-Known Member
Feb 1, 2016
16,553
38,931
Oregon
OpenStreetMap's isn't the source of data for the map itself. That's Google Maps.
The only thing that they use with OSM, as far as I know, is speed limits.

I thought the OSM was used for the navigation as well. (Just that the route planned with OSM is laid over the top of the Google Maps that are displayed.
 
  • Informative
Reactions: raynewman

spidey

Member
Aug 15, 2019
91
229
Melbourne
I was intrigued by how well my model 3 maps worked in the Mullum Mullum tunnel in Melbourne the other day, showed my progress through the tunnel quite accurately. Then I remembered there is a GPS beacon device to assist GPS in tunnels - which perhaps is installed in that particular tunnel. OR - it might simply be Assisted GPS (A-GPS) from the Telstra Mobile coverage in the tunnel. Either way it seems to do it really well.

No idea, but if it works in one tunnel and not in others, I'd blame the tunnel :-/ (if the tunnel also has poor Telstra mobile coverage, then the could well be it).
 

spidey

Member
Aug 15, 2019
91
229
Melbourne
Sydney M5 Tunnel is the bad. Mine tends to put me about 50M either side of the tunnel, would never use the Autopilot in such a situation. It doesn't seem to snap to streets or anything but if you have Navigation running it will go a bit crazy.

Autopilot doesn't use GPS for lane positioning or driving etc etc. Elon has been very clear in the past that using GPS to keep the car on the road and in it's lane etc etc basic driving is an insane idea and should never be done. It's purely using it's own sensors - Sight, Radar and Ultrasonics. So even if no GPS signal Autopilot should be able to stick to lanes and avoid other cars perfectly well.

Only thing would be without GPS I presume it wouldn't be able to 'navigate on autopilot' (ie. decide when to change lanes, take offramp etc etc to get you to your destination.
 

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