Design Of Data Acquisition And Control Units For Meteorological Microwave Radiometer

By using microwave remote sensing technology,atmospheric parameters are retrieved by the radiation characteristics of water vapor and oxygen in the atmosphere.In the scheme,the microwave radiometer,using water vapor and oxygen absorption resonance,measures radiation respectively between 22GHz-30 GHz and 51GHz-60 GHz to get the inversion temperature profile,humidity profile and liquid water profile,and then to forecast the weather.Among them,the Kv band receiver mainly reflects the humidity distribution characteristics,while the V band receiver mainly reflects the temperature distribution characteristics.In this paper,an improved full power microwave radiometer scheme is adopted by studying the basic principle of microwave radiometer and comparing meteorological microwave radiometers at home and aboard.In addition,it is necessary to calibrate the parameters by the transmission equation of the full power microwave radiometer.Parameters are achieved by calibration.The scheme uses liquid nitrogen calibration and TIP calibration.At the same time,the periodic calibrations are added to the observation to calibrate parameters.In the system scheme,each receiver collects the 8 frequency points of the respective frequency band,and outputs 16 parallel voltages in real time.The data acquisition and control unit,through reasonable sequence,controls and collects the environment sensors,the internal temperatures of the receiver,the receiver voltages of outputs,the power supply voltages,then packages the data and transmits to the host computer in real time.This paper mainly completes the design of function flows in the microwave radiometer system,which includes 5 functional processes.The interface drivers are designed and implemented in each function.The upper and lower computer communication protocol is designed to facilitate the communication between the radiometer and the control computer by RS422.The most important indicators of the data acquisition and control unit are the accuracy and consistency of data collection.In this paper,analyze the accuracy and consistency of the data by the acquisition and control unit collecting to validate the receiver interface.In addition,through the communication with the host computer,verify the radiometer weather entering the specified function flow under the protocol command.The integral time of the receiver can be verified by the time interval of the data package received by the host computer and collected by oscilloscope.Based on the experimental results,software of radiometer is basically completed.