Research On Technology Of Direct P Code Acpuisition

The Global Positioning System is a precision satellite positioning system, which has a complete theoretical system and broad application prospects and good market prospects. The research of GPS (Global Position System) system has an important significance to improve our own satellite navigation and positioning system.Traditionally, GPS P-Code (Precision Code)acquisition depends on handover from C/A code(Coarse/Acquisition Code). But the C/A code has low anti-interference ability, when C/A code is not available, it is no longer possible to acquire GPS P-Code through handover from C/A code. In order to ensure the GPS system has a higher anti-interference ability, direct acquisition of the GPS P-code is desirable. The difficulty of the direct GPS P-Code acquisition is the extremely long one-week period of P-Code.The paper has done some research on current GPS P code directly capture program and studied the direct P code capture method based on FFT method and the direct P code capture method based on direct average method and the direct P code capture method based on XFAST method as well as the direct P code capture method based on XFAST method plus direct average method. And then gives the corresponding MATLAB simulation results. In this paper we describe a new overlap method in frequency domain to facilitate hardware design of fast direct P-Code acquisition. It decreases the hardware resource requirement and has some economic significances. Finally, use the Cyclone III EP3C120F80C8chip to complete the direct P code capture method based on FFT method and the direct P code capture method based on XFAST method plus direct average method. Then give some descriptions of the important module and the results of the system simulation.