Design And Implementation Of Navigation Signal Ground Enhancement System Based On NI 5645R

The global navigation satellite system(GNSS)is widely used in various fields,and at the same time,some shortcomings of the satellite navigation system are more and more concerned.The navigation signal transmission distance is far away,and very vulnerable to occlusion and interference,influence of ionospheric and tropospheric delay and vertical positioning accuracy is not enough.These reasons make the satellite navigation system can't meet the requirements of some special precision positioning and weak signal applications.In order to improve the performance of the navigation system and expand the application scenario,this paper designs and implements a navigation signal ground augmentation system platform.This paper,based on the GPS signal structure,completed the detailed design of the ground enhanced signal format,and got a multi carrier flexible navigation enhanced signal format.We build a set of radio hardware platform based on PXI system software by using NI's equipment,which includes PXIe-1075 chassis,PXIe-8135 real-time embedded controller and PXIe-5645 R vector signal transceiver.The navigation signal ground enhanced platform on the basis of the hardware platform,using LabVIEW FPGA efficient programming language.In the device built-in Xilinx Virtex-6 FPGA to completed the entire digital IF baseband signal generation and processing.The system consists of signal enhancement generation platform and signal enhancement receiving verification platform.The control parameters of the enhanced signal transmission and reception are controlled by two sets of visual PC software.The signal enhancement generation platform generates baseband digital signal in FPGA,and the final navigation augmentation signal is generated by quadrature up conversion by DA conversion.Signal enhancement receiver platform to let the signal under the quadrature down conversion and then the AD conversion,and finally receiving and storing digital signals.In this paper,each performance index of navigation signal enhancement platform is tested.At last,the MATLAB software is used to PN code acquisition and to track the navigation data for the stored data.In this way,the validity of the system is verified,and the design requirements are achieved.The idea of software radio is used for signal enhancement platform.The method has strong flexibility and for different requirements,can be applied to the same hardware platform.The whole development is based on LabVIEW FPGA,the graphical programming method greatly simplifies the I/O connection and data communication tasks,to a large extent,improve the design efficiency,reduce the design difficulty and shorten the design cycle.