SINS+GPS Integrated Navigation System Designing Based On MEMS Intertial Device And The Input Signal Processing

This thesis focuses on how to design a SINS+GPS integrated navigation system by using MEMS inertial devices, and how to analyze input signal of inertial device (gyroscope) on this navigation system. In addition, the effect of using IIR digital low-pass filter deal ing with input signal of inertial devices is also presented.At the beginning, the development of navigation system and inertial device in recent years is introduced. The advantage of SINS+GPS integrated navigation system based on MEMS inertial device is described, the ideas of how to design this kind of system are discussed.The advantages of designing the whole system under the principal of modular design are figured out by describing the function of navigation system. By analyzing requi rement of system, pr ice and quality of products sold on market, MEMS gyroscope (LCG-50), accelerometer (1221J) and GPS module (OEM4-G2L) are chosen for this system.In hardware design part, how to chose appropriate chips and design suitable circuits of signal processing module (based on FPGA-EP2C20 and MCU-C8051F064), central processing module(base on DSP-TMS320C6713), communication module and power supply module are discussed. It also describes some rules about how to design reliable PCB board.In software design, mixed-programming are chosen for this system. By using both C language and assembly language, not only the efficiency of develop are increased but also the flexibility and efficiency of system are improved. This thesis shows program Flow chart of DSP and MCU, and emphasizes program detail of how to operate peripheral components (ROM, DS18B20). Interrupt service program and BOOTLOADER of DSP are also included in this paper.After building the whole system, the result of testing is good enough for fulfill all the requirements of this system, such as measurement, navigation, communication, self test and simulation test.Focus is also put on how to process the input signal. Based on the developed navigation system, output data of MEMS gyroscope is been calibrated and collected both on static mode and on dynamic mode. By using MATLAB software, IIR Butterworth low-pass filter with different cut-off frequencies for dealing with gyroscope signal are constructed by analyzing data frequency spectrum. In this paper, it is described that using ALLAN variance, which is the common method of representing random shift error of inertial device, to analyze original signal data and filtered signal data. Random shift error of MEMS gyroscope (LCG-50) is consisted of Angle random walk, Bias instability and Rate random walk. Value of these three errors is calculated. By analyzing, the lower the cut-off frequency of IIR digital filter is, the better the effect of smoothing signal and highlighting real signal is. At the same time, the delay cost by filter can be ignored. But the filter has no effect on reducing the random drift error of MEMS gyroscope (LCG50).It is a good beginning for further analysis of how to reduce random drift error of MEMS Inertial device, how to modify SINS+GPS intergraded navigation algorithms and how to improve system usability by designing a SINS+GPS intergraded navigation system based on MEMS inertial device.