Originally Posted by
futurama
"Stand-alone single-frequency GNSS receivers ... estimate velocity either by differencing two consecutive positions ... or by using Doppler measurements related to user-satellite motion. The former approach is the most simple to implement, but it has a meter per second-level of accuracy due to the dependence on pseudorange-based position accuracy.
In contrast, Doppler frequency shifts of the received signal produced by user-satellite relative motion enables velocity accuracy of a few centimeters per second." --
GNSS Solutions
"GPS and other global navigation satellite systems use the Doppler shift of the received carrier frequencies to determine the velocity of a moving receiver.
Doppler-derived velocity is far more accurate than that obtained by simply differencing two position estimates." --
GPS World
"With respect to the receiver, of course, the satellite is always in motion, but the receiver may be in motion in another sense, in kinematic GPS. It may be on a moving platform, like a vehicle.
The ability to determine instantaneous velocity of a moving vehicle has always been one of the primary applications of GPS and it is aided by the Doppler shifted frequency of a satellite signal.In other words, if the platform is moving, there is a relationship between the Doppler shift nominally from the satellite and the change based upon the movement of the vehicle on which the receiver finds itself." --
GPS and GNSS for Geospatial Professionals
Thanks for the links, the last one is part of a comprehensive introduction to GPS (hit 'up' at bottom of page) that covers a lot of things that I have 'picked up here and there' cursory knowledge of, in a way that ties it all together. In other words there goes a few more hours learning things that I have no practical use for.
