If I had the chance to use a GPS device while racing on a track... what would I use? and would the data from it be of any use to help with track elevations?
Short answer is no, GPS blows at elevation values. I have been testing that years ago, doubt it would be any better today - and that was even with a decent GPS.
Is there another device (that can be carried while racing) that can give an idea of surface with not so much cost?
In my experience, standard GPS receiver cannot give accurate heigh (z-axis) information. I'm not sure if it's related to receivers itself or is standard civil signal from gps satellite somehow distorted. I have tried record GPS coords (with decent equipment) from two different tracks last year. Each time start and endpoint (same physical location on s/f line) z - coords differs 1 - 2 meters end of the lap. I'm not sure which technology land survey technicians uses (NOT laser scanning though) when they measure some road edges, but that data accuracy is normally 1 cm or less. Cheers!
Elevation reading on a GPS is a lot less accurate than a altimeter which measures height above sea level by barometric pressure. Both aren't very accurate relatively speaking. Taking pictures on a race track against an object to scale things would be a much more accurate way to record elevation changes, or even more accurate would be to have it surveyed by a professional. If someone is interested. http://www.xcmag.com/2011/07/gps-versus-barometric-altitude-the-definitive-answer/ Just gives you an idea of deviation of the two methods. For this application they wouldn't be very practical.
