In order to protect the infrared earth sensor of FengYun No.1C and No.3 weather satellite's from sun radiation

a kind of protecting system of vision field is developed

and its merit and demerit

measuring method and calibration algorithms of peak value are studied.The disturbance to the infrared earth sensor by sun radiation is analyzed and two methods for protecting the vision field of infrared earth sensor are compared. A new covering non-scanning mechanical system

named sun sensor is developed

a kind of valid metrical device is designed to determine vision field range of sun sensor

and to deduce the academic formula of signal measurement. A calibration scheme for sun sensor's signal peak value according to theoretics of atmosphere radiation is provided. The running result of FengYun No.1C weather satellite in orbit shows that the sun sensor can protect infrared earth sensor effectively. The conclution is that the sun sensor can be successfully used to measure satellite gesture and also can be used in the infrared earth sensor of FengYun No.3 weather satellite's in future.