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How does GPS determine heading in 2017?
nickmarotta
0 Points
My question is how do GPS systems today determine what direction you are facing, also known as heading. The only two options that immediately come to mind are either with an electronic compass, or by looking at the previous "bread crumbs" coordinates and determining what direction you are going by looking at where you have been. I know most cell phones have compasses built in to them, but is that what is used? What about regular car mounted gps? Thanks!
Comments
Most (maybe all) Garmin automotive devices just use motion and don't have a magnetic compass. Under certain conditions, it can actually cause the heading to change when stopped (because of drift or false readings). Sometimes in 3D or track up navigation mode it will cause the map display to rotate. In North Up mode your vehicle icon will rotate.
We discussed this here at the time, I recall a thread where someone claimed you could see it in action if you drove around a parking lot and swerved from left to right. This person felt the vehicle orientation responded much faster than it could have using a satellite fix. I remember trying this with my own 3790 and not feeling like it was conclusive.
So I think the compass is there, but not clear under what circumstances it is actually used. A quick Google search found this reference to the compass on the Nuvi 2360. But IIRC, Garmin specifically mentioned the compass in the original press release when the 3790 was introduced.
gpstracklog.com/2011/02/garmin-nuvi-2360lmt-review.html
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"A couple of features unique to the 2360LMT (at least as far as 2xxx models go) are a screen that can rotate to portrait view and a tri-axial electronic compass. That latter feature may prove interesting for geocachers or folks planning to use it as a pedestrian navigator."
And as far as using it for geocaching ... pretty much worthless except for getting you to the nearest parking spot ... then I would switch to the Oregon to hike to the actual cache. That said, I will have to admit that I haven't been geocaching much since I replaced my 855 with the 3597, so maybe I should give it another try.
gpstracklog.com/2012/03/the-best-garmin-nuvis-for-pedestrian-navigation.html
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Here are all the nuvi models with a triaxial compass:
Garmin nuvi 2360LMT
Garmin nuvi 2360LT
Garmin nuvi 3450
Garmin nuvi 3450LM
Garmin nuvi 3490LMT
Garmin nuvi 3550LM
Garmin nuvi 3590LMT
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But there is still some ambiguity, see this thread: http://forums.gpsreview.net/discussion/25306/auto-gps-for-trail-riding
So I bet the nuvi triaxial compass went away with the demise of the pedestrian mode.
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With Urban Guidance users are able to integrate public transportation into their
route, complete with detailed itineraries of transit stops. The
new feature considers trains, trams, busses and water taxis when calculating
pedestrian routes. Users will be guided to a transit stop by foot and be able
to look up detailed information on what line to take and where to get off.