N8UR's Ancient GPS and NTP StuffEverything on this page is several years out of date...
Here is an MP3 file which provides The Ultimate Explanation of Satellite Navigation (length 1 minute, 23 seconds, size 245kb, but worth it).
I've been experimenting with getting the Network Time Protocol (ntp) software working with a Linux computer and the TAPR Totally Accurate Clock/Motorola Oncore GPS receiver unit.
Here is a collection of NTP-related stuff that I've found useful. At present this is all based on NTP version 3-5.91, but I've just gotten an NTP version 4.0.99 system running, and hope to have info about that here Real Soon Now.
My house has a copse of tall trees to the immediate south. I was to see curious what effect the trees had on my GPS horizon, so I did a test using Stan Huntting's SAwatch program. Here are the results of my science fair experiment.