A fast tracking algorithm in GPS software receiver

The increase of storage and computing performance in embedded mobile platforms has provided better opportunities for the development of portable GPS software receiver. However, due to a large number of complex calculations in baseband operations, the real-time software receiver is still the biggest challenge, and in the baseband operations of the receiver, the largest time-consuming part is the satellite signal tracking period. In this paper, based on the practical application model and with the purpose of improving the initial positioning efficiency in the receiver, an initial section of the navigation data will be preprocessed to determine the ID of frames, then appropriate strategy will be formulated to handle the next navigation data. The frames that are not involved in the initial positioning will be dropped, therefore, the navigation data that will be processed has been reduced significantly. Finally, the initial positioning efficiency will be improved to reduce TTFF(Time To First Fix). Because our method is starting from the original data sources in the tracking loop to reduce the amount of data and computing, it could greatly reduce the TTFF. The empirical results demonstrate the expectation clearly, and this algorithm has improved initial positioning efficiency and reduced tracking operations significantly. Most importantly, it provides a solid foundation for real- time embedded platform.