GPS tracking offset

[Gil]

Hi all,

did anyone see if the GPS tracking is actually on the road?
In my case, the tracking is not aligned over the road. sometimes it's way off.

See screenshot:

 

[jokiin]

generally a sign of poor signal

 

[WA3PNT]

My GPS Track is dead on in the Thinkware Dashcam VIewer.
This is true for my F770 and my two F50s.

RodeoGeorge

 

[jokiin]

My GPS Track is dead on in the Thinkware Dashcam VIewer.
This is true for my F770 and my two F50s.

RodeoGeorge

I don't know of any common complaint of this issue, external influences are a possible cause, other electronics, athermic windscreen etc

 

[flip9]

I checked mine, and it looks accurate when the maps is at default zoom, but when you start to zoom in the error becomes much more apparent.

So i compared the same clip with the SG cam and the SG cam is much more accurate, it can even pick up which side of the lane i am in. I guess it helps to have it GPS unit mounted externally.

Also if there's heaps of buildings and trees around it reduces the accuracy of the GPS. Even my Garmin goes crazy driving in the city with high rise buildings.

 

[jokiin]

I guess it helps to have it GPS unit mounted externally..

it does help avoid interference issues

 

[gpb]

First off, GPS has inherent inaccuracy. About 8 meters radius I believe for any given location fix. Typically GPS devices will "smooth" the readings and can lead to a track that seems to be offset from the maps. Some GPS devices will "snap" this track to roads to hide this inaccuracy, others don't.

Second - be careful of assumptions that the road maps are an accurate representation and that mismatch from the GPS location is the GPS's fault. Both the GPS location *and* most maps representations are based on approximations of the fact that our planet isn't perfectly spherical. When you grab a couple different approximations of the oblate spheroid we live on and try to match them up, guess what happens... stuff doesn't always perfectly line up.

Lastly... Does it matter? Common sense says you were on the road not driving through the building. Video evidence will support that as well.

 

[jokiin]

First off, GPS has inherent inaccuracy. About 8 meters radius I believe for any given location fix. .

2 meters at best

 

[Gil]

First off, GPS has inherent inaccuracy. About 8 meters radius I believe for any given location fix. Typically GPS devices will "smooth" the readings and can lead to a track that seems to be offset from the maps. Some GPS devices will "snap" this track to roads to hide this inaccuracy, others don't.

Second - be careful of assumptions that the road maps are an accurate representation and that mismatch from the GPS location is the GPS's fault. Both the GPS location *and* most maps representations are based on approximations of the fact that our planet isn't perfectly spherical. When you grab a couple different approximations of the oblate spheroid we live on and try to match them up, guess what happens... stuff doesn't always perfectly line up.

Lastly... Does it matter? Common sense says you were on the road not driving through the building. Video evidence will support that as well.

Thanks for the info.

Sent from my A0001 using Tapatalk

 

[gpb]

2 meters at best

Yep and almost 8 meters at worst. http://www.gps.gov/systems/gps/performance/accuracy/

Since the poster was concerned with a bad track I'd lean more towards worst case than best case, but you're welcome to do whatever you want.

 

[jokiin]

Yep and almost 8 meters at worst. http://www.gps.gov/systems/gps/performance/accuracy/
.

up to 500 meters if you're in China, even more if anywhere near a military installation

Since the poster was concerned with a bad track I'd lean more towards worst case than best case, but you're welcome to do whatever you want.

the more satellites you're connected to the more accurate it gets, not because they get more accurate but because it can start averaging all the data to work out the most likely position you're in, when it's off as much as it was for him that would indicate poor signal, not many satellites, or some type of interference which was impacting signal, the software also plays a part in how well it can interpret the data, not sure how advanced the Thinkware playback software is in that respect but that's something that Registrator Viewer is quite good at

 

[Ralph2]

Does it show the same offset in other viewers?

 

[jokiin]

Does it show the same offset in other viewers?

not sure there are many other options for this model

 

[Gil]

Does it show the same offset in other viewers?

It does.
Same offset on one viewer I tested.