[Talk-GB] mapping tunnels

Mark Williams mark.666 at blueyonder.co.uk
Tue Oct 2 22:05:43 BST 2007


My car (Fiat Stilo) uses wheel rotation data to calculate turns & distance.
It goes horribly wrong if you reverse round a corner while it's getting 
a GPS lock, but works well in tunnels. For what that's worth...
Unfortunately there's no way to save tracks (I haven't tried opening the 
box!) & it does a 'lock to Navtech map' so it's no use for OSM & I drive 
with 2 sat-nav devices. Isn't that sad..

Mark

tim wrote:
> Navigating whilst driving through tunnels can be helped by reading the
> cars computer, connecting to its OBD / ECU - you can get at least rpm
> and speed, along with a whole load of other stuff - You can also tie
> into the indicator lights (useful if there's a junction underground)
>
>
> Its what the navtech vans use when they go underground (with a gyroscope)
>
> On 9/28/07, Robert (Jamie) Munro <rjmunro at arjam.net> wrote:
>   
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>> Robert (Jamie) Munro wrote:
>>     
>>> Thom Shannon wrote:
>>>       
>>>> actually ASN looks a bit smarter than that.
>>>>         
>>>> Here's another crazy idea. Use a video camera close to the road (I have
>>>> a bullet cam that can be mounted on a car) then pattern match the images
>>>> to track motion (like an optical mouse does) then combine that with a
>>>> trace from a digital compass. Then by taking gps readings at either end
>>>> of the tunnel you can calibrate those traces to counter cumulative
>>>> error. You should then be able to get a really accurate trace.
>>>>         
>>> You might be better off using a ordinary forwards facing camera, and
>>> match-mover software (like boujou) that the use in movie effects to work
>>> out the camera movement and add virtual elements. There seems to be a
>>> free match-mover (camera tracker) package at
>>> http://digilab.uni-hannover.de/docs/manual.html
>>> that's probably worth a try.
>>>       
>> Sorry, that should be
>>
>> http://www.digilab.uni-hannover.de/docs/manual.html
>>
>>     






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