为了满足先进航空目标指示装备对视轴速度平稳性误差的设计需求，提出了一种基于扰动估计与补偿理论的控制算法。设计了一种改进扩张状态观测器以减小高阶观测器的相位延迟，提高视轴控制精度。对改进的控制算法进行了阶跃响应和速度稳定两部分实验，并与传统PID算法进行了比较。通过分析阶跃实验结果可得，该控制算法在不同的闭环控制带宽下，均能达到更短的稳定时间和更低的超调量，在35 Hz的闭环带宽下，相比PID算法的稳定时间减少了49.1%、超调量降低了88.4%，系统动态性能提升明显；速度稳定实验结果表明，该控制算法对幅值为1°、频率为2.5 Hz以内的不同扰动的抑制能力显著提高，视轴的速度误差均控制在0.1 (°)/s以内，扰动残值均小于0.1 (°)/s。该控制算法满足先进目标指示装备的设计需求，对提高系统动态性能和视轴速度平稳性具有较高的实用价值。

A control algorithm based on disturbance estimation and compensation theory was proposed in order to meet the design requirement of apparent axis velocity stationary-error in advanced airborne target indication equipment. An improved extended state observer (ESO) was designed to reduce the phase delay of the high order observer and to improve the control accuracy of the line of sight (LOS). The step response and velocity stability capability of the improved control algorithm were tested in the experiment, and were compared with the classical control algorithm. By analyzing the step experiment results, it can be seen that the designed control algorithm can achieve shorter stability time and lower overshoot under different closed-loop control bandwidth. Under the closed-loop bandwidth of 35 Hz, the stability time of PID algorithm was reduced by 49.1% and the overshoot was reduced by 88.4%, and the dynamic performance of the system was significantly improved. The velocity stability experimental results show that the designed control algorithm can significantly improve the rejection capability of different disturbances of amplitude of 1° and frequency within 2.5 Hz, the velocity error of the LOS was controlled within 0.1(°)/s, and the disturbance residuals were less than 0.1(°)/s. The designed control algorithm meets the design requirements of advanced target indication equipment and has high practical value for improving the dynamic performance of the system and the velocity stability of the LOS.