基于激光测速仪的惯导系统行进间初始对准技术研究
Research on in-motion initial alignment technology of Inertial Navigation system based on laser Doppler Velocimeter

Abstract

激光多普勒测速仪(Laser Doppler Velocimeter,LDV)具有测速精度高、动态响应快等优点,有望取代里程计,与捷联惯性导航系统(Strapdown Inertial Navigation System,SINS)组成高精度陆用组合导航系统。目前陆用组合导航系统几乎都是采用静基座对准这一初始对准方式,这将极大的影响载体的机动性,并制约军事行动中快速反应与精确打击能力,因此如何利用外部传感器辅助SINS完成行进间对准成为组合导航领域的一个研究热点。本文针对LDV/SINS组合导航系统的行进间对准方法展开研究,旨在提高行进间对准的精度、速度以及鲁棒性。本文的主要研究内容包括如下几个方面:(1)LDV在线标定技术。提出了一种基于位置观测的高鲁棒性标定方法以提高LDV的测速精度,进而提高行进间对准的精度。两组车载实验证明了所提标定方法的精度和鲁棒性,在传感器输出正常时,两组实验的最大航迹推算水平位置误差小于总里程的0.04%,在LDV和全球定位系统(Global Positioning System,GPS)输出存在异常值时,两组实验的最大航迹推算水平位置误差小于总里程的0.06%。(2)行进间对准模型的改进。在行进间对准的过程模型和测量模型中加入LDV的刻度系数误差和安装角误差,以提高行进间对准的精度。(3)行进间对准滤波算法的改进。对无迹四元数估计法(Unscented Quaternion Estimator,USQUE)进行了平方根处理,以保证数值的稳定性和协方差矩阵的正定性。对测量噪声协方差矩阵进行自适应处理,以提高行进间对准的精度、速度和鲁棒性。利用滤波中的后验测量残差信息提出了一种双增益结构来加快行进间对准的速度。提出了一种自适应H∞滤波方法来提高行进间对准的鲁棒性。两组车载实验表明,所提行进间粗对准方案较其他对比方案拥有更优的对准性能,两组车载实验的航向角误差在300s粗对准过程结束后分别小于0.03°和0.09°。

Due to its high velocity measurement accuracy and fast dynamic response, the laser Doppler velocimeter (LDV) is anticipated to replace the odometer, forming a high-precision land integrated navigation system with the strapdown inertial navigation system (SINS). Currently, nearly all land integrated navigation systems utilize the initial alignment method of static base alignment, significantly affecting vehicle mobility and limiting rapid response and precision attack capabilities in military operations. Utilizing external sensors to aid SINS in achieving in-motion alignment has become a research hotspot in the field of integrated navigation. This paper studies the in-motion alignment method of the LDV/SINS integrated navigation system to improve the accuracy, speed, and robustness of in-motion alignment. The main research contents presented in this thesis are as follows:
(1) Online Calibration Method of LDV: A highly robust calibration method based on position observation is proposed to improve the velocity measurement accuracy of LDV, and subsequently enhance the accuracy of in-motion alignment. Two groups of vehicle tests verify the accuracy and robustness of the proposed calibration method. When the sensor output is normal, the maximum horizontal position error in both test groups is less than 0.04% of the total mileage. When the LDV and Global Positioning System (GPS) outputs contain outliers, the maximum horizontal position error in both test groups is less than 0.06% of the total mileage.
(2) Model Improvement of In-motion Alignment: The scale factor error and installation angle errors are incorporated into the process and measurement models of in-motion alignment, improving alignment accuracy.
(3) Filtering Algorithm Improvement of In-motion Alignment: The square root of the Unscented Quaternion Estimator (USQUE) is processed to ensure numerical stability and the positive definiteness of the covariance matrix. The measurement noise covariance matrix is adaptively processed to improve the accuracy, speed, and robustness of in-motion alignment. A double gain structure is proposed to expedite in-motion alignment using the posterior measurement residual information in the filter. An adaptive H-infinity filtering method is introduced to enhance the robustness of in-motion alignment. Two groups of vehicle tests demonstrate that the alignment performance of the proposed in-motion coarse alignment scheme surpasses that of the comparison scheme, with heading angle errors in the two test groups being less than 0.03° and 0.09°, respectively, after the 300-second coarse alignment process.

Keywords

• 激光多普勒测速仪(Laser Doppler velocimeter)
• 捷联惯性导航系统(Strapdown inertial navigation system)
• 行进间对准(In-motion alignment)
• 在线标定(Online calibration)

Recommended citation: 向志毅. 基于激光测速仪的惯导系统行进间初始对准技术研究[D].国防科技大学,2021.
Z. Xiang, "Research on in-motion initial alignment technology of Inertial Navigation system based on laser Doppler Velocimeter (in Chinese)," MEng. thesis, National University of Defense Technology., 2021.