Fpga-based Regional Location Technology Research

The paper is about Tiny-Pseudo-Satellite system which is a beforehand project of some department.This system is made up of four synchronous receiving stations in the same connected networks,the four receiving stations can mensurate the position of moving objects in the air,eradiation chips are loaded on these objects.The paper is a research on Software Receiver based on FPGA.The paper firstly introduces some concepts about Software Receiver,such as spread spectrum communication,composition and production of signal from Tiny-Pseudo-Satellite, ranging technology,tiny Tiny-Pseudo-Satellite,positioning principle,correlation capture and tracking.According to traditional design.Correlator that the core of receiver is completed by special chip.For example,the GP2021 and GP4020 of Zarlink Company.In the design of this paper, radio frequency(RF) department and A/D module are still structured by hardware,but the intermediate frequency(IF) signal into FPGA from down conversion,The mission of correlation capturing signals is completed by FPGA.The paper mainly introduces design and simulation of function modules based on FPGA,such as symbol synchronization,carrier NCO,production of C/A code,FIFO memory circuit,capture and tracking modules.Get the differences between matched filtering capture and FFT concurrent capture which is suitable to software receiver by comparing.The design of receiver involving model selection of FPGA,design of peripheral circuit,RF circuit.Result of the paper shows that the software scheme of FFT capture is viable,the advantages are low design cost,universal structure,flexible function,convenient improvement and upgrade.