一种适用于SINS动基座初始对准的新算法

在运载体运动情况下,提出了一种适用于捷联惯导系统(SINS)初始对准的新算法,该算法以惯性空间为过渡参考基准,即建立了初始时刻惯性坐标系(i₀系)和初始时刻捷联惯组惯性坐标系(i_b0系)两个惯性坐标系。将捷联惯组坐标系(b系)与导航坐标系(n系)之间的初始对准姿态矩阵的实现分解为三步骤:(1)通过地理位置和初始对准时间求解i₀系至n系的变换矩阵;(2)通过惯导比力方程变形,引入测速仪速度辅助,求解从i_b0系至i₀系的常值变换矩阵;(3)使用姿态更新算法实时计算b相对于i_b0系的变换矩阵。最后,载车运动环境下的初始对准试验结果表明航向角对准精度达到了0.1°(1σ)。

New initial alignment algorithm for SINS On moving base

On the moving base,a new initial alignment algorithm for strapdown inertial navigation system(SINS) is proposed.In this algorithm,two special inertial frames,the initial-time inertial frame(i₀ frame) and the initial-time SINS body inertial frame(i_b0 frame),are defined and are selected as transition reference frames.The calculation of initial alignment direction cosine matrix(DCM) between SINS body frame(b frame) and navigation reference frame(n frame) is expanded into three parts:(1) the DCM between i₀ frame and n frame is easily obtained via local geographical coordinates and initial alignment time;(2) by expressing SINS specific force equation in b frame and by the aid of external velocity log,the constant DCM from i_b0 frame to i₀ frame is achieved;(3) attitude updating using gyro samples gets the DCM between b frame and i_b0 frame.In the end,some vehicular tests are carried out on the moving base and the accuracy of azimuth reaches about 0.1°(1σ).