Moreover,the models of zenith blind zone for polar coordinates stabilized platform were presented and the reason of this type of zenith blind zone was analyzed.

Factors affecting the zenith blind spot of an altitude-azimuth optoelectronic telescope;

Practice of getting across the roof leakage area during the end session of mining in mechanized coal face;

Calculation and analysis design for blind area of photoelectric transformation system in transmission detection lnstrument for visual range;

Blind Area of Application and Research of Educational Technology——Education of Disabilities;

The two-axes infrared horizon is an absolute detection methodology which avoids blind areas that occur with the single infrared horizon technique.

A discussion about dead zone of double-slits eccentric photorefractor;

Explore and Study of the dead zone of mobile communication;

Then three conventional methods to solve dead zones of mobile communication, namely redesigning base stand, installing repeater and increasing new base stand, were analyzed and compared.