The servo system of the self‐propelled anti‐aircraft artillery has the possibility of fail‐ures .While w orking in the emergency state ,it has the problems of slow reaction ,low preci‐sion and large error for lead .To solve these problems ,the dynamic cursor circuit was proposed to use for producing the video frequency with a dynamic cursor .Thus ,the target data and the lead of artillery could be calculated in real time ,so as to control the position of the dynamic cursor .The video frequency signal was shown on the display screen and projected to the reticle surface of the sight lens ,enabling the dynamic cursor in the field of view .T herefore ,it could guide the user to aim manually and to slew the artillery to the lead position rapidly while work‐ing in the emergency state .The use of the dynamic cursor in the sight lens could reduce the op‐erational difficulty and improve the slew rate ,facilitating to grasp the fighting chance and in‐crease the probability of hitting .This device was tested with a type of self‐propelled anti‐air‐craft artillery .The results show that it fulfills its intended functions and can attain the prede‐termined effect .

The design of optical window on a spherical shell in electro-optical systems is introduced. The comparison between conventional design and solid modeling by UG is made by an example of IR window. The former adopts the method of iterative trying,and the latter acquires the correct size and location of the optical window from UG solid modeling and space geometry transform,the latter is more visualized and theoretical sound. According to the optical features and engineering limitations,the installation of the optical window is determined.