A Research On The Electronic System Of A New Four-passage Solar Total Irradiance Monitor

The energy of the earth all source from the sun radiation directly or indirectly. The sun radiation is the main item in global energy income and outcome, which affects the stability, convection and chemical process. People need precise sun radiation data to forecast the mid-term and the long term worldwide weather condition. It is extremely important for human beings and the whole nature to monitor the sun radiation, clarify its changing process, understand its mechanism and predict the global environment changes.We used four absolute radiometers as the core part of the instrument. Electrical heating power kept the temperature of the cavity constant. When the shutter in front of the precision aperture is periodically opened, reduce the heating power to replace the power of the additional optical radiation. And when the shutter is closed, the heating power again maintained the temperature. The changed electrical heating power and the changed optical radiation power were equivalent substitution, and therefore precise measurement of irradiance could be achieved.This instrument used a redundant design with four cone cavities to measure the radiation in turns, to monitor the trend of decay in the main cavity, so that the measurement accuracy could be improved. Phase-sensitive detection technology will be used to suppress the sensitivity of the instrument to the radiation heat background and the fluctuation of temperature varies with time, to get a higher accuracy and lower noise. Combining optical and mechanical structure designation, a new electric alternative radiometer will complete a high precision measurement of the sun radiation.