what are the sources of errors in sattelite positioning?

Question

in engineering

Answer 1

I use gps a lot in surveying and I think it's mostly error in time factors since the whole thing is based on the calc's involving when and where the satellites were when you took a shot. i don't think it's a equipment error unless you count the physics involved in the process. I'm not a scientist, but I've noticed some inconsistencies in measurements...not feet, but certainly inches, especially vertically. When we develop a control point for a site, we shoot it several times and sometimes on another day and average all the individual shots (after taking out the weird ones) to get decent accuracy. This is not using the new phone system, we use local monuments and a second base station.

Answer 2

The biggest sources of errors are in the GPS units themselves not using high enough resolution for mathematical units in calculations. Any time you deal with decimal values in digital computers there will always be round off errors.

Here is a good article that explains it:
http://docs.sun.com/source/806-3568/ncg_goldberg.html

Answer 3

Decay of orbit, weather, solar flares, etc.

GPS satellites contain a catalog of positioning that is constantly being updated using fixed ground units as reference.

Answer 4

time precision