Enhanced Acquisition and Signal Tracking using a P/Y code TIDGET-PLUS Architecture Activity

NAVSYS have previously developed a low cost, low power GPS sensor, the TIDGET which adopts a client/server architecture to sample and buffer "windows" of GPS data for processing at a remote workstation. Many of the advantages of this approach can be realized with a "TIDGET-PLUS" architecture where the buffered data is processed at the receiver. Since the TIDGET front-end is only powered on while the data window is being collected, this architecture results in a significant savings in power consumption. Under this contract, NAVSYS will develop a P/Y code version of the TIDGET-PLUS. An enhanced rapid acquisition alogirthm is proposed that also provides improved signal detection. Preliminary results ahve shown that this algorithm will provide equivalent performance to 15,000 parallel Correlator channels. A commercial DSP chip is available that can support direct P/Y code acquisition in near real-time, without resorting to expensive, power consuming atomic references. The performance of the code and carrier tracking loops can also be improved by taking advantage of the "post-test" nature of the signal processing to embed the code and carrier tracking functions in the EKF used for navigation. This will allow better tracking performance down to lower signal thresholds than conventional single channel tracking algorithms.