锚泊状态下大型舰船惯导系统初始对准方法研究

For the large combat ships, anchoring is the most common situation case for carrier aircraft takeoff and landing. Because of the ship under the situation of anchoring, it is suffered by wind force, hydrodynamic, sea current force, anchor chain force and variety of dynamic interferences, which cause the ship doing swaying and heaving movement and makes INS (Inertial Navigation System) initial alignment become extremely complex. GPS, log and other auxiliary equipment also lost the advantages of accurate measurement.So traditional methods of self-alignment and combined-alignment become not applicable due to these factors. Based on the accurate modeling of anchoring ship movement, we can make an real time prediction of the information of ship motion, and that provides baseline information for initial alignment of the ship INS. Based on the above, the initial alignment of ship INS can be regarded as a random closed-loop control system, and it is possible to find a new method of initial alignment of ship INS under anchoring condition. The study mainly consists of: theoretical analysis and modeling techniques of ship kinetic characteristics under anchoring condition; techniques of Initial alignment of ship INS dynamic interference; techniques of Kalman filtering precision alignment based on the random closed-loop control. The study will have some theoretical and practical significance on aircraft carrier's INS alignment undering anchoring condition.

为了有利于舰载飞机的起降，大型作战舰艇启航前通常处于锚泊状态，锚泊状态下，舰船受到风力、水动力、海流力以及锚链力等多种动态干扰而作"偏荡运动"，使惯导系统的初始对准变得极其复杂，GPS、计程仪等辅助设备也失去了对速度信息准确测量的优势，导致传统的自对准方法和组合对准方法已经不适用。通过对锚泊船运动精确建模，能够实时预测舰船的运动信息，从而能够为舰船惯导系统初始对准提供基准信息。本课题以此为出发点，将惯导系统初始对准作为一个随机闭环控制系统，致力于寻找一种惯导系统初始对准的新方法，以解决锚泊状态下舰船惯导系统对准难的问题。主要研究内容包括：锚泊状态下舰船运动特性分析与建模方法；惯导系统抗动态干扰初始对准方法；基于随机闭环控制的Kalman滤波精对准方法。本项目的研究成果对实现锚泊状态下大型舰船惯导系统初始对准具有一定的理论和工程意义。

锚泊状态下，舰船受到风动力、水动力和锚链力等多种因素的影响而做“偏荡运动”，使捷联惯导系统的初始对准变得及其复杂，GPS、计程仪等辅助设备也失去了对速度信息准确测量的优势。传统的自对准方法是将船体的偏荡运动视为高频干扰，通过滤波的方法从中提取出地球自转角速率等信息进行自对准，这种方法得到的基准信息不够准确。惯性系下传统的解析法粗对准能够达到水平精度10’，航向精度30’的精度，可以满足精对准的需要。精对准采用对锚泊船进行运动建模预测运动信息的方法，通过采用MMG法对锚泊船偏荡运动的建模，将锚泊船的受力分为水动力、风动力和锚链力等几部分，通过对这几种力的分别建模，可以实时地预测舰船的运动信息，从而能够为舰船的捷联惯导系统初始对准提供基准信息。通过建模得到基准信息之后，再通过构建一个随机闭环控制系统，随机闭环控制系统由受控对象，卡尔曼滤波器和反馈控制律构成，其中卡尔曼滤波器采取速度加角速度的传递对准方法，达到将运动建模的基准信息传递给捷联惯导系统的目的。仿真结果表明，这种方法能够有效提高对准精度，在经过20min的精对准后，对准精度为水平误差角优于1.8’，航向误差角优于3’。