Research On The Key Technologies Of GPS Software Receiver Signal Processing

Global positioning system (GPS) is applied to a wide range of applications, such as geomatics, navigation and guidance, mobile commerce. As the GPS application market grows, the stringent requirements necessitate in-depth research on GPS related technology. Development time and cost are the two most important factors in this research. GPS software receiver consists of RF signal acquisition and IF digital signal acquisition, tracking, positioning. Because most parts of GPS software receiver are based on software implementation, it can provide a low-cost and flexible way to speed up development. Therefore, GPS software receiver is a very important research trend of GPS technology research.This paper focuses on GPS software receiver signal acquisition, processing and GPS/INS ultra tight coupling navigation algorithm research which is used for high dynamic positioning. Specifically as following:1. The GPS software receiver's peripheral signal acquisition circuit will be discussed thoroughly. A SuperStar II OEM receiver is modified, then GP2015 RF signal processing will be analyzed, other signal preprocessing module will also be introduced.2. A rapid acquisition method for weak GPS signal processing will be proposed. A new rapid serial search and FFTsearch acquisition method is presented based on C/A code's own correlation characteristics. In the same precision, this method can improve the speed of computation and reduce the time of computation greatly to ensure the real time of weak signal processing.3. Software Implementation of IF digital signal tracking loop. Based on phase lock loop (PLL) analysis, complete software implementation of code tracking loop and carrier tracking loop in tracking phase. Then analyze demodulation of IF signal, bit synchronization, pseudorange solution of GPS software receiver. 4. GPS/INS ultra tight coupling navigation algorithm will be proposed to improve high dynamic positioning accuracy and robustness. Firstly, introduces two normal GPS/INS coupling navigation algorithms. Then proposes a GPS/INS ultra tight coupling navigation algorithm, analyze GPS signal acquisition, tracking and doppler frequency shift resolution with INS ancillary information.This paper completes the software implementation of GPS software receiver signal acquisition, processing and proposes a fundamental GPS/INS ultra tight coupling navigation algorithm. It's helpful for one who is willing to further study GPS software receiver signal processing.