惯性导航系统（Inertial Navigation System, INS）在工作中不需要外界信息，不易受到环境等的影响，在军民等领域具有广泛应用。采用自由转子陀螺仪的空间稳定惯性导航系统可以充分发挥陀螺仪的高精度潜力，保证系统长时间工作的稳定性，具有较大的发展空间。为保持导航系统的精度，通常在系统回路中加入校正网络，使临界稳定的惯性导航系统变为一个渐近稳定的系统，这种方法被称为阻尼技术。本文从抑制导航系统周期性振荡误差、保证导航精度的角度出发，针对空间稳定惯性导航系统的阻尼技术进行了研究。（1）简述了空间稳定系统的组成和工作原理，并对空间稳定系统的误差组成和误差方程进行了详细的推导分析，给出了系统机械编排框图和误差模型框图，介绍了如何对空间稳定系统进行阻尼的传统方案；（2）分析了传统水平阻尼网络的阻尼原理，并对目前广泛应用于惯导系统的几种阻尼网络进行了详细的研究，分析了各种误差源对不同阻尼网络造成的影响，并对其高低频特性进行对比，由此得出互补滤波阻尼网络阻尼效果较好，尤其是对于高低频参考速度误差的抑制能力均较强的结论。最后建立了MATLAB模型，并对该模型的正确性以及理论分析的正确性进行了验证；（3）对互补滤波阻尼网络的误差特性进行了详细的分析，随后针对船舶工作在外水平阻尼情况下参考速度误差对导航精度影响较大的问题，探究了参考速度误差组成及其对系统精度造成的影响，设计了基于参考速度误差变化量的变阻尼系统，并设计了模糊控制器避免系统的阻尼状态频繁切换，采用超调抑制模块抑制系统阻尼切换造成的超调误差；（4）利用Visual C++ 6.0软件编写了惯性导航系统的仿真程序，并利用MFC技术设计了人机交互界面，进而实现仿真参数的实时设置与结果的实时显示。最后采用海上实际数据进行实验，验证了本文提出的基于参考速度误差变化量的变阻尼系统的优越性。

Inertial navigation system (INS) does not need to interact with the outside world, is not easy to be affected by the external environment, and has good concealment. It is a completely autonomous navigation system, which is widely used in civil, military and other fields. The space-stable INS using a free-rotor gyroscope can give full play to the high-precision potential of the gyroscope, realize the long-term stable operation of the inertial navigation system, and has a large development space. In order to ensure the accuracy of INS, a correction network is usually added to the system loop to turn the critically stable system into an asymptotically stable system. This method is called damping technology. This paper studies the damping technology of space-stable INS from the perspective of suppressing the periodic oscillation error of the navigation system.(1) The composition and working principle of the space-stable INS are introduced. The error composition and equations of the space-stable INS are analyzed. The block diagram of the mechanical arrangement of the system and the block diagram of the error model are given. In addition, the traditional scheme of how to dampen the space-stable INS is proposed.(2) The damping principle of the traditional horizontal damping network is analyzed, and several damping networks which were widely used in INSs are studied in detail. Then this paper analyses the influence of various error sources on different damping networks, including their high and low frequency characteristics. By comparison, it is concluded that the damping effect of the damping network based on complementary filtering is the best. And this paper establishes a simulation model using Simulink of MATLAB to verify the analysis above.(3) The error characteristics of complementary filter damping network are analyzed in detail, then aiming at the problem that the reference velocity error has a greater impact on the navigation accuracy when the ship is working on the external horizontal damping status, the composition of the reference velocity error and its impact on the system accuracy are analyzed. Then this paper designs a variable damping system based on the variation of reference velocity error, then a fuzzy controller is designed to avoid the frequent switching of damping state, and the overshoot suppression module is used to suppress the overshoot error caused by the switching of system damping state.(4) A simulation program of inertial navigation system based on MFC technology is programmed by using Visual C++ 6.0, and a visual user interface is designed, so as to realize the real-time parameter setting and result display. The simulation results based on real sea test data verifies the superiority of the variable damping system based on the variation of reference velocity error.