基于内嵌微小型惯性测量单元的浮标定位方法研究

Making use of the one-off buoys to compensate the navigation and positioning error of the underwater inertial navigation system is an effective way to solve the contradictions between the long-term and concealment of the submersible underwater vehicle. However, the movement of the buoy relative to the sea is generally determined through its underwater motion equation without power, which can lead to large errors in the complex sea areas. Moreover, the attitude of the buyo on the surface of the sea can't be determined through the traditional method.To this end, the project have sought to build the MEMS based micro IMU, embedding which into the buoy to record the accleration and angle rate inforamtion of the vehicle. Performancing the forword and backword navigation algorithm on the accleration and angle rate inforamtion to determine the buoy's trajectory which can be used to compensate the errors between the buoy in the sea surface and the underwater vehicle. The dynamic model of the buoy under the surface has also been studied, which can be used as the integrated information for the MIMU copuattion. Meanwhile, some dynamic filtering algorithms with high precision and robustness have been developped to determined the position and attitude of the buoy. The methodology proposed in this project can reduce the relative error of the actual location of the buoy location and the submersible caused by the ocean currents, the motion state of of submersible vehicle and other factors, thus improve the accuracy of the vehicle's position. Moreover, the methodology can provide a more accurate position reference for correction and readjustment of the underwater vehicle, with a significant military benefits.

利用内嵌卫星接收模块的抛弃式浮标在海面接收卫星信号获取浮标位置信息对潜器惯导累积误差进行修正是解决潜器水下航行长期性与隐蔽性矛盾的有效方法。然而目前应用的抛弃式浮标自潜器发射出至运动到水面完成卫星定位过程位置误差一般通过其水下无动力运动方程来确定，这在复杂海域条件下存在较大误差。为此，本课题提出在现有浮标腔体内加装低成本的微惯性测量单元（MIMU）的方案，对浮标水下短时定位技术展开研究。首先根据浮标运动位置误差信息不需要实时处理的特点，提出了基于逆向导航解算技术的水下短时定位方法；其次研究了结合海流数据库的浮标水下运动无动力数学模型，并将其与MIMU解算信息进行融合以进一步提高浮标的定位解算精度；同时针对所研究的内容设计相应的精度高、鲁棒性强的动态滤波算法。该方法能够减小因洋流、水下运载体和浮标运动等因素引起的相对误差，提高浮标的位置解算精度。从而为潜器惯导系统校正提供更为精确的修正信息。

由于潜艇抛弃式浮标在海况较为恶劣的情况下存在较大定位误差，从而影响对潜艇位置的修正精度。针对该问题，本项目利用微小型惯性测量单元（MIMU）体积小，价格低，短时定位精度适中的特点，提出了在浮标腔体内加装MIMU的方案，深入研究与项目特点紧密结合的正逆向导航解算、快速初始对准、直接式组合导航标定等，力图从算法角度，在不显著增加系统成本前提下，达到提高浮标定位精度的目标。.（1）根据本课题实际应用中对浮标内MIMU测量信息解算处理的实时性要求不是很高的特点，将MIMU的采样数据当作一组时间序列看待，提出了逆向导航的浮标定位方法，通过利用浮标在水面上较为精确的导航信息，使得相应的逆向导航过程有更精确的初始值，进而提高其解算精度。.（2）研究了适用于低精度惯导系统的快速惯性系初始对准方法。本项目借鉴现有惯性系初始对准坐标系分解的思想，提出了一种基于姿态估计的惯性系初始对准方法，在进行姿态确定的同时实现了陀螺常值漂移的估计补偿。同时结合基于矢量观测的观测方程的特点推导了一种基于四元数的伪观测线性方程，从而可以直接应用线性卡尔曼滤波进行状态估计，降低了算法计算量。.（3）为了对浮标内嵌MIMU中加速度计常值零偏进行建模估计补偿，利用海面上接收到的卫星信息和MIMU进行组合导航。针对浮标在海面上受较大风浪干扰的实际应用特点，提出了基于惯导基本方程的直接式组合导航方法，该方法能够有效处理外界干扰及MIMU自身较大器件误差所引起的非线性和鲁棒问题。为了进一步抑制海平面风浪干扰带来的量测信息不确定性，在无味卡尔曼滤波框架内引入了基于Huber方法的鲁棒算法，进一步提高了滤波精度。.（4）针对研究方案中所涉及的基于姿态估计的惯性系初始对准方法以及基于惯导基本方程的直接式组合导航方法，研究了相应的非线性滤波算法。对其在姿态估计问题中所涉及的一系列问题，如四元数规范性约束以及抗野值干扰的鲁棒性处理，展开改进研究，提出适用于本项目研究内容实际特点的改进算法。

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