Liked the spirit of gargin's 'GPS for the poor' ,if not the practicalities. How about an inertial system that takes data from the speed + distance your wheels rotate and the direction the wheels point in? I know airborne Inertial systems lose accuracy over time, but you wouldnt get things like varible air speed and air presure to throw you off. continental drift could be a problem, but hey, no ones perfect ;) Dont know if it would be any cheaper than a low end GPS though. The moving map would have to be on an LCD, but smallish ones seen to be used on cheap digital camera etc.
-- tacit, Dec 02 2005

Most automotive GPS systems also use accelerometers to calculate the instantaneous position delta between the slower GPS fixes. This is how the realtime moving maps are driven.
-- bristolz, Dec 02 2005


Ah. Did'nt know that Bristolz. Bang goes my (first) idea. I guess that also answers the question on how much cheaper it would be...not a lot.
-- tacit, Dec 02 2005


The Chinese made a purely mechanical compass ages ago. It was a small cart with two wheels and a pointer on top. As the wheels turned ad different rates, the pointer would keep pointing the same way by means of gears inside.
-- discontinuuity, Dec 03 2005



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