Software-Aided Sequential Multi-Tap Correlator for Fast Acquisition

The requirement for GPS receivers with low Time To First Fix (TTFF) is increasing with the deployment of new standards like E911. Mean Acquisition Time (MAT) determines the TTFF in GPS receivers. In this paper we analyze a scheme called Sequential Muti-Tap correlator, which reduces MAT by an order of magnitude compared to a serial search correlator, without increasing the hardware significantly. The Sequential Multi-Tap (SMT) correlator is compared with other fast acquisition schemes with respect to various benchmark parameters like MAT, gate density, TTFF etc. and shown to outperform other approaches in a standard GPS receiver application. The SMT correlator scheme tends to be a potential candidate for low gate count and low power IP integrations.