quote:Originally posted by magnetite
quote:Originally posted by oplopanax
People think the devices are more accurate than they are. 99% of the GPS units I've used report the 50% confidence interval, which is misleading. This project lets you compare the precision across devices, and under different environmental conditions.
For instance, the people flying UAVs keep claiming that they are accurate to within a metre, which is clearly not true, and you can see it for yourself.
Any conclusions you make based on this study would only be applicable to consumer grade units. Though I suppose that is the purpose.
Using a base station and a dual frequency GPS receiver absolute accuracies of 0.5 metre at 95% confidence level are regularly achieved on UAV projects. This thing http://www.aibotix.com/id-3d-laser-scanner.html
for example, doesn't rely on a $400 Garmin unit for positional data. Accuracies of several mm are acheivable with stationary survey grade units. We've done GPS surveys accurate enough to measure ground subsidence of several cm and the effect of plate tectonics on the positions of survey hubs over the course of a few years.
Edit - for hiking or finding a road spur, trailhead etc. I've never cared if my GPS was out by 15 metres as it doesn't need to be any better than that to know where I am.