Earth radiation array sensing system

摘要

A sensing cavity is directed towards the radiation to be measured. An identical reference cavity is directed towards a heat sink which is maintained at a constant temperature. An electric heater and a temperature sensor are mounted on both the sensing cavity and the reference cavity. The temperature sensors are connected to a bridge which is powered only when an observation is made. The heater on the sensing cavity is controlled by bridge imbalance to equalize the temperature of the two cavities. The heater power is then a direct measure of the difference in the power entering the sensing cavity and the power entering the reference cavity. By knowing the power entering the reference cavity, the power entering the sensing cavity can be calculated. The two cavities are mounted together to a common heat sink and have a directly associated preamplifier circuit included in the modular mounting. A plurality of such sensors is used to obtain radiance measurements in many directions simultaneously.