Research On Algorithm Of Missile Attitude Measurement Based On MIMU

Missile-borne inertial attitude measurement unit is a core component of the inertial guidance system. Because the missile-borne device works in harshest environment and narrow space, the inertial attitude measurement unit should be characteristic of micro-structure, low-power, and low-cost. Adding the number of samples can improve cone error composition in the traditional equivalent rotating vector algorithm, but it also increase calculated amount, and affect real-time. So the algorithm which can improve the accuracy of cone error compensation should be designed, meanwhile the algorithm can reduce calculated amount. The main content of this article is as follows:(1)Knowledge about attitude computation in theory of inertial guidance system is elaborated, and equivalent rotating vector algorithm should be regarded as the basis of algorithm of missile attitude measurement.(2)The missile attitude measurement unit based on MEMS gyro sensor in designed, the core components of the system such as MEMS gyro sensor, A/D converter, microprocessor are analyzed, besides, the module function of power, signal filter, A/D voltage reference and serial communication is explained.(3)An experiment on the calibrating of MEMS gyro is done by using the turntable, the cross coupled coefficient of installation error, and the zero bias of gyro and the scale factor are calibrated.(4)An algorithm that make three attitude angle change in the range of-180°to 180°be designed, and the problem that angle hop at singular point be solved in the process of all attitude change.(5)Three kinds of algorithms of cone error composition based on traditional equivalent rotating vector three-sample algorithm are put forward in this paper. Angular increment is extracted via Trapezoidal-Simpson and Lagrange’s interpolation-Simpson respectively in the first two algorithms, the third is put forward based on the first two, rotation vector is calculated via angular rate in the third algorithm, and something optimized is did, the advantage of the algorithm in the aspect of calculated amount and drift error is verified.The attitude algorithms are simulated by using MATLAB simulation. The results showed that the algorithm in this paper restrains the hop of attitude angle at singular point, so that full attitude change is achieved. Besides, the three algorithms of cone error composition are compared by simulation, and the advantage of the algorithm in the aspect of precision is verified.