DSP Implementation And Optimization Of GPS Receiver Based On Software-defined Radio

Satellite Navigation System as a wireless communication system which is less disturbed by ground factors is more and more widely used in various fields, such as Satellite Phone, Ship and Vehicle Navigation,Precision Timing and other areas, so the system is attached seriously by National Defense Sectors and Scientific Research Institutions of many countries recently. The U.S.GPS system is a leader in technology currently, to study on it as a premise for many countries to develop their own navigation systems and its compatibility.Based on Software-defined Radio theory, a global positioning system (GPS) receiver is achieved upon DSP as core chip in this paper, which is called GPS sofeware receiver. Software-defined Radio is a theory that the signal digital process is moved as close as possible to the antenna while the wireless communication capabilities as much as possible are achieved on the high-speed digital signal processor (DSP) by a software way, it is a typical DSP wireless communication project,which has high flexibility and openness.RF front-end and signal processing section of GPS navigation receiver based on the traditional A-SIC (Application specific integrated circuit) structure are implemented by the dedicated chips, known as the hardware receiver. The signal processing unit of Hardware receiver is implemented by the dedicated chips, it is difficult to change the corresponding parameters or new algorithms because of the fixed designs on chips. The software receiver based on Software-defined Radio can adapt to different needs of the navigation signal processing algorithms and all kinds of navigation simulation.It becomes an active direction on GPS receiver research The current U.S.GPS is a leader in technology.China is also making great efforts to implement own Beidou program, to join the European Union's Galileo program, hoping to improve Chinese satellite navigation and its compatibility. The Study on the GPS software receiver implementation can provides a wealth of assessment and verification platforms for Chinese satellite navigation research. Firstly, the principle of GPS and the key technologies of GPS receiver modules are described in the paper,which provides a theoretical basis for the DSP implementation of GPS Software Receiver.And then the whole design program is illustrated, including the selection of hardware platform and the whole software design process,which focusing on the software implementation of each GPS receiver modules and algorithm optimization on DSP platform. The DSP platform storage management, the local signal generation module and the key modules of baseband process are included in the sofeware design.At last,the DSP-based software optimization methods and processes are summed up in the paper. The proposed design and optimization programs provided in this paper, which according to the baseband signal processing for real-time requirements and the characteristics of the hardware platform, are verified by result analysis obtained from Matlab and CCS tools.This paper describes not only the GPS software receiver implementations based on the Software-defined Radio technology, but also summed up software optimization processes and methods of Software-defined Radio systems based on DSP platform,and There is certain reference value for Software-defined Radio systems development.