Research Of Measure Method And Key Technology For Spatial Absolute Radiance Calibration Primary Radiometer

Affected by launching process and space environment, the radiation scale of spatial irradiance calibration method cannot be traced to the international unit system(SI), the urgent requirement of spatial remote irradiance calibration accuracy cannot be satisfied. The sun is used as the calibration source, based on the spatial Absolute Radiometer Calibration Primary Radiometer(ARCPR), the detector calibration method significantly improves the space remote irradiance calibration accuracy. Meanwhile, the irradiance scale transfer link can be directly traced to SI. It is significant for establishing the independent space irradiance calibration standard, and improving the space remote irradiance calibration level for our country. ARCPR is a kind of cryogenic absolute radiometer, and works at 20 K. TSI cavity is used to measure total solar irradiance and used as the irradiance standard detector. Limited by measure period, the measure method of ground-based cryogenic radiometer is not applicable for on-orbit TSI cavity. It is necessary to research the measure method which is applicable for space cryogenic radiometer, shorten the measure period, and ensure the measure accuracy.Firstly, the ARCPR principle and prototype structure are introduced, the thermoelectric model of detector is investigated. The temperature dynamic responses of TSI cavity and heat sink are achieved by solving thermal equilibrium equation. The thermoelectric experiment in cryogenic vacuum environment is designed in order to verify the correctness of thermoelectric model. Meanwhile, the sensitivity and thermal time constant(τ) of detector are investigated. The theoretical analysis and experiment result illustrate that due to the temperature variation of heat sink, the temperature dynamic response of TSI cavity has a double exponential form. The relationship between equilibrium temperature and electrical power is nonlinearity. The investigation of thermoelectric model provides the theoretical basis and experimental evidence for measure method and heat sink temperature control research.In the second place, based on the investigation of TSI cavity temperature dynamic response model, the method of predicting equilibrium temperature and sensitivity dynamic correction is proposed. The key problem of applying high-precision rapid method is researched. The non-equivalent response time between optical and electrical power is proposed and measured. The reason of the temperature pulse production at the opening and closing shutter time is analyzed. The virtual experimental platform for investigating the experimental feature of measure method is developed. The method for temperature pulse compensation and equilibrium temperature prediction accuracy is investigated. The measure period is optimized to 6τ. Meanwhile, the comparison result of laser power measurement illustrates that the sensitivity non-linearity error is compensated by dynamic correction method. The investigation result illustrates that the method has the feature of short measure period and high measure accuracy.In the last part, the key technology research in the development of ARCPR principle prototype is introduced. Based on the measure chain of irradiance power, the uncertainty requirement of equivalent electrical power measure is analyzed. The influence quantities of equivalent electrical power measure are researched in detail. The resolution plan of high-precision measure for equivalent electrical power is proposed. The measure method of blackbody cavity absorptance is investigated. The average absorptance is used to represent the actual absorptance of blackbody cavity. Experimental result illustrates that the average absorptance of TSI cavity is 0.999928±0.000006. Meanwhile, the sloping bottom structure improves the absorptance uniformity of blackbody cavity. The TSI cavity can be the irradiance standard detector of ARCPR. The key technology investigation of high-precision thermal environment control is introduced. The control model is established. The control algorithm is designed. The key problem of high-precision thermal environment control is researched by experiment.