| The increasing detection demand for atmospheric information has made microwave radiometer becoming the main sensor to obtain the parameters of atmospheric information,which playing an important role in remote sensing detection of atmosphere,ocean,land and other fields by receiving atmospheric radiation signals and remote sensing information.The antenna module of the microwave radiometer is the primary structure of the radiometer and also an important part of receiving atmospheric radiation.The research on radiometer antenna has paid more attention on the signal reception under the ideal input,less on its connection with atmospheric radiation.However,as an important connector of radiometer and atmospheric radiation,antenna is not only the beginning of radiometer signal receiving,but also the ending of atmospheric radiation transmission.So it is necessary to analyze the signal reception of the antenna from the perspective of atmospheric radiation transmission,so that the radiometer and atmospheric radiation transmission can be studied as a whole.This thesis studies the influence of parabolic radiometer antenna on the reception of atmospheric radiation signal.Firstly,this thesis calculates the atmospheric radiation signal received by the front end of antenna,then designs the radiometer antenna and analyzes the changes of the radiation signal before and after receiving by antenna.The specific work is as follows:1.Calculation of atmospheric radiation transmission: analyzes the atmospheric radiation spectrum caused by the absorption of particle spectral lines,calculates the temperature-induced broadening caused by particle motion and pressure-induced broadening caused by particle collision,then derives the atmospheric radiation transmission equation and uses the PWR98 model to calculate the absorption coefficient,and finally constructs three-dimensional atmospheric environment data through the Fengyun satellite remote sensing data,and calculates the atmospheric radiation transmitting through vertical path and slant path.2.Design of radiometer antenna: analyzes the overall index of the radiometer and calculates the performance index of the antenna module according to the radiometer function,then designs the antenna scanning system and calculates the scanning angle through the range index of observation,finally calculates the main lobe of the antenna with the accuracy index of observation and designs the corresponding side lobe structure and pattern.3.Analysis of the influence of antenna parameters on the reception of atmospheric radiation: derives the method for calculating the signal reception of the antenna pattern and calculates the signal reception of the antenna in the ideal environment,then considers the reception of the actual radiometer antenna on atmospheric radiation and analyzes the influence of its main and side lobes on the signal reception,and lastly analyzes the impact of antenna parameter changes on the received data,and finds that the antenna observation frequency band and the main beam efficiency have the greatest impact on the signal reception.The research in this thesis can make atmospheric radiation transmission and radiometer as entirety,restore the input signal of radiometer more accurately,and provide certain theoretical support for the high-precision radiometer signal processing or antenna design in the future. |
PDF Full Text Request