Research Of K Band Ground-based Radiometer System

The atmospheric temperature and humidity profiles are important meteorological parameters,and real-time detection of them is of great significance for weather forecasting,artificial rainfall and flight safety.At present,the main detection methods include radiosonde balloons,satellite remote sensing and ground-based radiometer,etc.Among these methods,the ground-based microwave radiometer is used to detect the characteristics of the target by passively receiving the microwave radiation.Compared to other methods,the ground-based microwave radiometer makes up for the poor performance of the satellite-based radiometer on the bottom of the troposphere and the shortcomings of low resolution and low time resolution of radiosonde balloons.Besides,the ground-based radiometer has the advantages of low maintenance cost,reliable operation,continual observation,high accuracy and working independently.Since the end of the last century,the technique of detecting atmospheric humidity and temperature profiles of ground radiometers has developed a lot and become matured.It has gradually become a means of providing business data services and has been widely used in meteorological observation and weather forecast.The research and use of ground radiometer in China is relatively backward over the years.Although development has been made for many years and achievements has come out,because of the lack of mature ground radiometer products for atmospheric detection,there is still a big gap between domestic and foreign countries.Although domestic researchers have done a lot of research on the use and retrieval on ground radiometer,they only did them from the perspective of the principle of exploration and academic research and didn’t form a system for the system and hardware development.Therefore,the development of ground-based microwave radiometer detection system is imminent and has a broad application prospects in China.The purpose of this thesis is to study the K-band ground-based microwave radiometer system.The main work of this thesis is as follows:(1)Present a dual-band ground-based radiometer system based on lens antenna.The system has the advantages of high performance,high integration,low weight and low power consumption,etc.Based on this scheme,the thesis develops a K-band microwave-direct-detection radiometer system.The key technology,receiver index and calibration method are also measured and analyzed.(2)In order to analyze and correct the noise injection of the system,a transfer model based on scattering parameters of network is built up in this thesis.Then this thesis provides a lot of experimental data to verify reasonability of the noise injection correction method.(3)Develop a display and control software based on the radiometer system.The software has features such as providing human-computer interaction interface,sending commands to the lower computer through the serial port according to the user’s instructions,receiving the remote sensing data packet transmitted from the lower computer,converting system electrical signal sampling measurements to data products.Meanwhile,the software can realize functions such as processing,displaying,transmitting,distributing,archiving and storing of all levels of data products.