The Electrical Design Of Fast Electricity Substitution Absolute Radiometer Of High Accuracy And High Sensitivity

It is of great significance for meteorological analysis to measure the solar spectrum radiation of high accuracy and monitor it in a long time. In order to fill up the blank in the field of space solar spectrum radiation measurement of our country, the research of critical technology in solar spectrum radiation absolute measurement has been conducted in the third period innovation project of Chinese Academy of Science. A new Electrical Substitution Radiometer (ESR) is developed in order to tackle the key problem in preliminary stage for solar spectrum radiation measurement in satellite "FY" and "Kuafu". The electrical design of fast electricity substitution absolute radiometer of high accuracy and high sensitivity has been carried out without modifying the mechanical structure of ESR. The main research aspects discussed in the paper are as follows:1. The operational principle of SIARS and the working process of ESR were grasped, and the electrical substitute process in ESR was analysed and demonstrated. Via theoretical analysis, some improvements were applied to the primary working process.2. All the methods for detection of weak signals at present were compared. According to the characteristic of ESR, a digital phase-sensitive demodulation (DPSD) method is adopted. The basic technology of this method had been grasped and its relative theories were introduced and validated by simulation.3. According to the requirement, the design scheme of the system was completed, and it had been confirmed feasible by deep research. According to the scheme, the design in terms of software and hardware were completed and the performance of the system was tested by experiments.In the paper, the direct digital frequency synthesis (DDS) technology was adopted to generate a sinusoidal carrier signal. The sinusoidal carrier signal was modulated by ESR. The export signals of ESR were amplified by precise preposition amplifier, and then collected by the data collection system. The electrical performance of the high accuracy electrical substitute radiometer which adopted the digital phase-sensitive demodulation (DPSD) technology is excellent, and it can fulfill the target requirement. It is of great significance for solar spectrum measurement on satellite "FY" and "Kuafu".