An Applied Research Of Nios And FPGA In Inertial Navigation Unit Test

For the requirement of measuring the output of multiple signals in the test of inertial navigation unit.This article designs a dual-mode testing system of inertial navigation unit based on FPGA and NIOS.This system can count the48ports pluses outputted by4inertial navigation unit and receive RS-422serial port data of8ports outputted by8inertial navigation unit,the collected data will be uploaded to a controlling computer by USB Bus,and processed,displayed by the computer.First of all,the thesis introduces inertial navigation system, inertial navigation unit test technology and research status of the data acquisition of inertial navigation unit at home and abroad, then discusses the main research contents and the design schemes of this system,and makes a comparison of the different design scheme,finally a hardware design scheme is determined to use the FPGA and USB.FPGA controls the data collection,USB achieves the high speed data transmission,a upper computer application program is designed to process the data.The system design contains hardware design and software design.The hardware circuit takes the EP3C16Q240C8FPGA chip of Cyclone III which is made from Altera company and CY7C68013USB chip made from Cypress company as its core;The program of digital filtering module and48pulse counters module will be wrote in FPGA using Verilog. A Nios II soft-core with8UART module will be set up in FPGA based on SOPC idea to control data collection of pluses and serial port,the collected data will be uploaded to a controlling computer through a USB chip.The software design include lower computer program,USB firmware program and upper computer application program.The lower computer program is programmed in NIOS for the purpose of switching mode,collecting data of pulse and serial port,uploading data to the upper computer by USB Bus.The USB firmware program is used to control USB chip,upload the data in FIFO to upper computer and transmit commands between the upper computer and lower machine.The upper computer application program which designs MFC interface is developed by VC++6.0,this program can receive, save,calculate and display the data that uploaded by the USB FIFO.Eventually,the test system is debugged,the debugged process and testing result are given out,the error of the received data is analyzed. The experimental results indicate that the testing system could measure the48ports pulse outputted by the inertial navigation unit and receive8ports RS-422serial port data accurately,the system can work stably in a very long time.This design reduces complexity of the acquisition circuit,raises measurement efficiency of inertial navigation unit,and promotes the reliability and stability of the acquisition system,it can be used as a new equipment of inertial navigation unit test.