The Key Technique Research Of The Design Of Low Power And High Sensitive GPS Reciver

With the development of the GPS and relative technologies, theapplication of the GPS has spread from traditional professional filed suchas military and measurement field to ordinary civilian field. In this process,the high sensitivity and low power technique which are the key point of theportable civilian receiver have become a hot topic. This paper aimed at thegeneral vehicle and hand-held application. By the analysis of the vehicle’sdynamics and satellite signal’s characteristics, we obtained the followingresults (based on the theoretical analysis and simulation):(1) Through the combination of the Viterbi and FFT algorithm, thispaper realized the carrier frequency estimation and signal tracking of weakGPS signal. Simulation results show that, when the dynamic of the carrieris less than0.3g (max acceleration of ordinary car), the tracking sensitivityof the algorithm is13dB Hz.(2) Completed an adaptive tracking loop which is suited for highsensitive receiver based on state machine. The state machine includesfrequency locked loop, phase locked loop, week signal tracking andreacquisition when loop unlocked. In order to realize the equalization ofthe performance and power consumption, it can take proper trackingmethod according to the GPS signal strength and carrier dynamic.(3) Reduced the power consumption from two aspects: channelprocessor design and algorithm design. The former mainly refers to thebaseband circuit design; the latter mainly refers to intermittent work. It canturn off part of the receiver to reduce the power consumption when theposition is not needed; turn on the whole receiver to output the positionwhen the position is needed. Simulation results showed that, theintermittent work can reduce the power consumption by90%(ideally) when the signal strength is larger than25dB Hz and the carrier dynamicis smaller than1g.This paper included high sensitive tracking, adaptive tracking loopsuited for high sensitivity receiver and low power receiver design. It issignificant for the design of low power and high sensitivity civilian GPSreceiver.