The Development Of Embedded GPS Receiver System

This article has researched to the FPGA-based GPS receiver. We have studied the following points:First, we analyze the GPS receiver hardware, software and its work mechanism which is starting from the GPS receiver system functions. Proposing the GPS receiver system implementations based on GP2015 RF chip and FPGA-specific programmable chip according to the functional requirements of GPS receiver system. We discussed the feasibility of GP2015 GPS receiver for specific RF chip RF front-end, and calculate the RF front-end module to use low-noise pre-amplifier gain. According to the requirements of signal processing module and application processing module, we summed up the implementation of receiver system software requirements and capabilities, and divid different operating frequency requirements of the receiver system software in various tasks. We summed up the viable working mechanism for the receiver of quick start and search the satelliten to the situation that the receiver should handle multiple satellites and invisible satellite signals.Second, we design a specific implementations based on GP2015 for requirements of GPS receiver RF Front-End. It is detailed account of the RF amplifier and filter circuit, 175.42MHz filter circuit, 35.42MHz filter circuit, clock circuit design and implementation details. Finally, we completed the development of GPS receiver RF front-end board, it meet the design requirements through testing.Thrid, we proposed a correlator implementation that meet the requirements of GPS receiver signal processing functions. Designed to achieve at the same time epoch of 12-channel simultaneous extraction method of the original observations to make processing more satellite signals the same time, the local reception to meet the processing requirements of the positioning receiver. DDS based on the principle described in detail the carrier NCO, code NCO, carrier phase, carrier weeks, code phase, code NCO phase, code sliding module epoch counter module, the relevant points accumulated module, when the base module and other parts of the design and implementation To achieve 12-channel correlator, described the design of the correlator registers, bus interface design and implementation. Finally finished the Device.GPS receivers in home-made hardware platform to complete the relevant device testing and validation, the development of related devices with GPS acquisition, tracking program to track the GPS signal acquisition processing, visualization of satellite acquisition and tracking correctly, indicating that the correlator designed and implemented to meet the requirements. The design is completed based on the relevant modules and RF front-end GPS receiver structures and machine commissioning, the receiver can work correctly.