Multi-band GPS signal tracking in a high dynamic maneuvering situation

In a GPS receiver, the goal of the signal tracking is to synchronize local generated code and carrier with the received signal. After a step of acquisition, the receiver tracks the shifting of the local code provoked by the movements of the receiver and satellites. In the future evolution of the GPS, the system will have several carrier frequencies, then it will be possible to have several tracking systems working simultaneously for a same satellite. We present in this article a detection method for the tracking of the future multi-band GPS signal. This method is applied to the localization of a vehicle which makes high dynamic maneuver. We define a MAP detection criterion to fuse the shifts discriminator detection achieved on multi carrier frequencies. This criterion is defined in the case when shifts are not necessary simultaneous and when there is a lack of information on one frequency provoked by the unlocking of the code tracking on one of the carrier. Indeed, there is a difference between the instants of shifts on the different carrier frequencies. This difference is due to the effect of ionospheric propagation. The experimentations achieved on synthetic GPS signals show the advantages of the method compared to the classical algorithm.