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Assisted GPS (A-GPS) has been developed to provide greatly improved capabilities, helping GPS work better and faster in almost any location. Offering a detailed look at all the technical aspects and underpinnings of A-GPS, this unique book places emphasis on practical implementation. The book reviews standard GPS design, helping you understand why GPS requires assistance in the first place. You discover how A-GPS enables the computing of a position from navigation satellites in the absence of precise time – a topic not covered in any other book. Moreover, you learn how to design and analyze a high sensitivity GPS receiver and determine the achievable sensitivity. The book provides detailed worksheets that show how to compute, analyze, and improve the processing gain from the input signal at the antenna to the signal after the correlators.

RTK stands for “Real Time Kinematic”. GPS RTK receivers provide real time position at centimeter level accuracy, on moving vehicles. If GPS is a fifty-watt bulb and Differential-GPS a spotlight, then RTK is a laser. RTK uses the inherent properties of the microwave satellite signals to measure positions one hundred times more accurately than most Differential GPS receivers. This paper presents a breakthrough in global positioning technology, since RTK can now be done in environments where it was previously impossible. Until now RTK has relied upon dual frequency signals from the GPS system. Both frequencies were needed to get the extra measurements needed for RTK to work. We can now get the extra measurements from another GPS-like system, GLONASS. This gives us dual-system RTK. Dual-system RTK has the advantage that there are more satellites in view, so that we now have RTK operating in environments where it would not work before.