The Design Of Three-dimension Attitude Sensor

In recent years, attitude measurement becomes increasing important in aviation, navigation and many other military fields. And it receives great attention in the function of attitude angle measurement. Although the attitude sensors applied in the national defense and military fields can achieve perfect accuracy and performance, the sensors is too expensive or bulky that limit its applications in civil products. In this paper, the low cost, high cost performance MEMS units are adopted to design the three-dimensional attitude sensor which can precisely measure the carrier’s attitude change in real time.This paper proceeds from the development of transducer technology, attentively designed the general frame of the project through analyzing the function and the application environment of the attitude sensor. After comparing the different schemes of the attitude sensor, we confirmed the final scheme of this project, which includes the three-axis magnetic resistance sensor HMC5883L and MPU-6050 that is constituted by the low-cost gyroscope and the accelerometer. And these components are constituted to measure the carrier’s angular velocity, the accelerated velocity and the magnetic component.The hardware design and software design of this project adopted the modular design principle, and finally realized the basic measurement of the carrier’s attitude change. The hardware design of this system includes the detailed circuits of every submodule, the signal filtering and circuit protection design. The software design of this system presents the design and debugging of the software. And the system data processing involves the error processing and the data fusion, While, the error processing plays a very important part in improving the measurement accuracy of the sensor. And this process covers the following procedures:first,analyze the characteristics of the inertial devices. Second, identify the error source of sensors by theoretical analysis and sensor calibration. Third, build the mathematical model between the error source and the measured value through sorting and analyzing the collected data of the system. The combination of the complementary filtering algorithm and the Kalman filtering algorithm applied in this system contributes to the precise measurement of the carrier’s angle change in real time.The test results indicated that the error of the low-cost and inertial components based three-dimensional attitude sensor designed in this project will not exceed 0.5°in static testing and 2°in dynamic testing. And the sensor has reached the required accuracy of the low-cost attitude sensor in the market. Consequently, the experiment results demonstrated that the scheme of this project is feasible, the mathematical model is correct and the data fusion algorithm is practical and effective.