Biggles wrote:A GPS is never 100% accurate, and cannot be. At best, it is a very good guide! Dilution of Signal — the time it takes for the position to be related to the satellite, the satellite to process the signal then correlate position and send it back to earth means there are variations in accuracy (often BIG variations), ...
Hi Biggles, either you're confused about how a GPS works or I'm not understanding you. A GPS doesn’t communicate with satellites - it is a receiver only, not a transmitter. Have a look at
https://spaceplace.nasa.gov/gps/en/Dilution of Signal? Are you referring to (geometric) dilution of position? which is concerned with the (very small) variances in calculated position that can occur as a result of the positions of the 4 (or more) satellites needed for the GPS to calculate it's position. eg if all satellites are well west of the GPS vs evenly distributed around the GPS (eg N, E, W & overhead).
What does 100% accurate mean? We're bushwalkers - how accurate do you need? To the nearest few metres is more than sufficient & a GPS delivers that in all but extreme locations (in narrow gorges, bottom of cliffs etc).
Edit : sorry, rolv, didn't see your post.