Design And Implementation Of GPS Receiver Test Signal Source

With the extensive application of Global Positioning System both in military and civil fields,users pay more attention to the GPS receiver with higher performance. This thesis concentrates onthe design and implementation of GPS receiver test signal source based on USB2.0interfacetechnology, the output signal is able to provide a better environment in which GPS receiver can beresearched and estimated.(1) According to the idea of data recording and playback as well as taking the advantage ofUSB in data transmission, the structural frame of GPS receiver test signal source is designedwhich can be divided into GPS signal acquisition module and USB data playback modulefunctionally, mainly including RF front-end, USB interface, GPS IF data transmission andprocessing part.(2) During the development of USB interface, USB protocol and the slave FIFO mode ofCY7C68013are discussed. Then the design of USB interface hardware both in signal acquisitionand data playback are detailed described. The firmware program is designed in the integrateddevelopment environment of μ Vision2as well as the host computer procedure in Visual C++6.0.And the data transmission between the PC and peripheral is implemented both in the parts ofsignal acquisition and USB data playback.(3) The acquired GPS data is transmitted back to the data playback side by the unit of GPSIF data transmission and processing. And the interpolation principle is employed to deal withsignal outputted by the USB the data playback. After integer times interposing and low passfiltering, the GPS IF analog signal can be generated through the digital-to-analog converter.(4) The module of GPS signal acquisition and USB data playback are both estimatedcombined with USB firmware and the host computer procedure. Then the generated signal istested by the Superstar and OEMSTAR receiver. And the performance of the signal resource isanalyzed by comparing the positioning results of GPS real signal and the generated signal.According to the test results of GPS receiver the system is verified to be feasible and valid.