A GPS beginners guide/mannual help you know more about GPS:

what is gps
what is Differential GPS (DGPS)?
What is aGPS?
what is gps wass(gps wass definition)
how does gps wass work
GPS receivers accuracy comparison
GPS chipset comparison
GPS receiver drawbacks
what is GPS Utility
how to install gps utility
how to use GPS unit
New GPS Receiver Initialization
GPS power supply and GPS battery capabilities
GPS no signal problem