Research Of GPS Software Receiver Technology For Real-time Tracking

In recent years, GPS software receiver technology is a new technology in the field of satellitenavigation, the software receiver is the future direction of the satellite receiver because of itsflexibility and openness, and real-time tracking is a Key technologies, the real-time tracking of keytechnologies has important theoretical and practical value.Based on the requirements for real-time tracking, we researched and implemented thePLL-DLL joint tracking algorithm, then detailedly analysised the code tracking and carrier trackingin the tracking loop, in which the most time-consuming part are the local code generation,carriergeneration and six-way integral accumulate.With the methods of prestore and fine-tuning the local carrier and codes, their data are advancestored as a binary number system in accordance with permutations and combinations, look-up tabledirectly adopt these data in the tracking loop, have successfully eliminated the time-consuming ofthe carrier generation in every trace loop;In order to eliminat the time-consuming of six-way integral, we use a software correlatorefficient parallel algorithm which are used in CDMAsignal processing, in which the original plasticand floating-point are quantified as binary bits according to certain rules, so that individual 32-bitPC can store multiple data and multi-channel data can be parallel processed;In the optimization process, we use SSE instruction which can process multiple data in a singleinstruction, one calculation complete four floating-point, so this batch method also improves thespeed of the receiver tracking loop in GPS software.Finally, by using the real GPS measurement data for experiment show that: our softwarealgorithm is effective, and compared with the high-precision receiver, tracking the results meet theaccuracy requirements.