Design Of Small-Size Attitude Measurement Systems Based On MEMS Inertial Devices

Attitude measurement is the basis for motion control, and it's an important research direction of navigation. The common methods of attitude measurement include inertial measurement technology, satellite navigation and positioning, electronic compass and astronomical measurements, Their measurement accuracy, stability, autonomy, continuity and the work environment requirements are different,in different applications, their strengths and weaknesses should be differently treated, among them the inertial measurement technology has high autonomy, not easily affected by environmental, so it has a broad application space.MEMS (microelectromechanical systems) technology is a new science, which is rapid developed in recent decades and based on precision instruments technology, It included multiple micro-sensors, signal processing, communications interface and power supply in a micro-electro-mechanical system. The main advantages of MEMS are small size, low cost, high reliability and large-scale advantages. With the accuracy improvement of MEMS inertial devices, the inertial measurement systems research based on MEMS inertial measurement devices become a hotspots of navigation technology applications. In abroad, the MEMS inertial devices has begun to apply in weapons and made good effects. This paper combined with practical project, conducted a study on small-scale inertial attitude measurement systems based on MEMS devices as the goal of Small size, low weight, low cost, low power consumptionThis paper mainly carried out studies from the following two aspects: the hardware platform design and algorithm optimization program. The main contents include: Firstly, described the common methods of attitude measurement and their applications features, introduces MEMS and micro inertial technology development condition, considering the practical project, the article determined the inertial measurement scheme; Secondly, in connection with the current research of inertial measurement, analysed a variety of inertial measurement algorithm process, designed the system's algorithm implementations and electrical structure; Thirdly, chose Analog Devices'MEMS production ADIS16350 as the inertial measurement unit, a navigation computer based on Cyclone series FPGA chip EP1C12Q240I7 and a NIOS II platform for program operation had been designed; Fourth, analysed the error of IMU(Inertial measurement Unit), established the IMU's error model of both Uniaxial and triaxial, calibrated the error model parameters.By using Allan variance,we analyzed the random noise of Gyro. Separately using digital low-pass filter, kalman filter and wavelet denoising methods processed the sensors signal, Compared the results of every methods, and chosed kalman filter in the real system; Fifth, improved the attitude initial alignment accuracy by design a modified alignment, which is accorded to the sensor performance. And achieved dynamic correction of attitude angle by presented sufficient conditions, realized combination of attitude measurement. Finally, no error input simulation, noise input simulation and semi-physical simulation were done, to verify correctness of the algorithm, Then, carried out static and dynamic testing and performance analysis on the real system.Through experiment test, the results show that the small-size attitude measurement systems was reasonable designed,both the software and hardware works well, system realized the design goal.