"soxinbox" wrote

In non aviation GPSs, at least the older ones, there really is a
limitation on speed. These units receive the signals from satellites one
at a time. You have to receive 4 satellites in order to calculate a 3
dimensional position. If you are traveling extremely fast, than the
signals from each satellite are received at different physical positions.
This makes it hard for the GPS to resolve your position.

My son has a Palm Pilot V that has the GPS receiver plugged into the
expansion port. On a737, I was able to hold it up to a window, and get
altitude and speed locks, no problem, showing 540 MPH.
--
Jim in NC