Then here's a report from my GPS (extracted with the work-in-progress program I'm writing), produced this morning:
Time (UTC): 11/03/2017 13:50:41 (mm/dd/yyyy hh:mm:ss)There are several interesting pieces of information in there beyond the location. First, there's the fact that 21 satellites were used to calculate the 4D fix (the four Ds are: latitude, longitude, altitude, and time). These satellites were part of three independent satellite systems: the US's Global Positioning System, The EU's Galileo, and Russia's GLONASS. The accuracy of the 4D fix improves as the number of satellites used goes up, and with 21 satellites that accuracy is darned good. Of most interest to me is the time accuracy, as that's what's synchronizing my NTP server. The GPS is reporting that its time signal is accurate to within 12 nanoseconds (that's 0.000000012 seconds). That will do just fine!
Latitude: 41.58308650 N
Longitude: 111.84003970 W
Altitude: 4868.373 feet
Motion: 0.007 mph at 0.000 degrees heading
Satellites: 21 (used for computing this fix)
Accuracy: time (12 ns), height (+/-2.169 feet), position (+/-1.654 feet), heading(+/-169.961 degrees), speed(+/-0.029 mph)
If you're wondering about that reported motion, first of all 0.007 mph is a very slow motion indeed: about one tenth of an inch (2 mm) per second. Most of us would not distinguish between that speed and motionless. :) But why isn't it zero? That reported speed is the result of a small amount of “noise” in the GPS fixes. From one fix to the next there is always a slight variation in the calculated location, even though the actual location isn't moving. That “fix noise” looks like some very slight motion to the GPS, as it is exactly what would happen if you actually were moving ever-so-slightly and there was no fix noise...