惯性测量系统火箭橇试验一维运动约束方法

A Constrained Method for One-dimension Motion of Inertial Measurement System Based on Rocket Sled Testing

火箭橇试验由于其大过载、高动态等特点,能够为惯性测量系统的性能测试和精度评估提供测量数据及试验验证等。在进行火箭橇试验时,火箭橇体的运动应为一维直线运动。但在实际情形中,由于惯性测量系统误差影响,橇体的实际轨迹为三维轨迹,导致导航解算结果存在较大误差。针对上述问题,提出一种将惯性测量系统火箭橇试验三维运动约束为精确的一维运动的方法。首先建立火箭橇橇体的姿态角误差、速度误差和位移误差模型,并将其作为系统状态量;其次,采用卡尔曼滤波器对系统状态量进行开环估计和零速修正补偿,最终使得橇体在侧向和高度方向上的位置和速度补偿到近似为零。试验导航结果表明,经过一维运动约束方法处理后的X轴位移误差明显减小,且经修正补偿后的Y轴和Z轴的位移误差已减小到1 cm左右,实现了火箭橇试验运动一维化的处理。

The rocket sled test technology of inertial system is an effective method to verify the error model of inertial system in a complex environment and evaluate its error model accuracy under the condition of large overload and high dynamic.In theory,the rocket sled moves along X axis which is a straight line and its velocity error and position error of Y axis and Z axis should be zero.However,the actual motion of rocket sled is a three-dimensional motion because of initial alignment error,inertial device error and external environmental conditions,and those errors will result in navigation solution error.To solve the problem,a constrained method for one-dimension motion of inertial measurement system is proposed based on rocket sled testing.First,system state equation and measurement equation are built,and its state values are estimated by kalman filter and compensated by zero velocity update method.In final,the velocity and position in Y axis and Z axis direction are corrected until they are close to zero.Testing results show that position error in Y axis and Z axis direction is reduced to 1cm after the estimation and compensation.