| With the development of airborne weather radar, it dominates the application markets ofmilitary and civil use. The weather radar detects targets by launching electromagnetic wavesignals on fixed time and simultaneously receiving the echo signals. While the ground cluttersseriously affects the recognition of weather echoes, especially in the case of airborne weather radar,the research of ground clutter suppression has become a active topic in the field of weather radarsignal processing. Starting from weather radar equation, we research the characteristics ofmeteorological targets and ground clutter, and then the simulation model is given. Several methodsof ground clutter suppression are investigated in detail. The major work of this dissertation is asfollows:In chapter1, the development of airborne weather radar is introduced and the researchbackground and current situation of ground clutter suppression are firstly reviewed, then wemake a brief introduce to this thesis.In chapter2, we analyze the characteristics of meteorological targets and ground clutter, andthen study the amplitude model and power spectrum model of them. The echo models of cloudand ground clutter are investigated by using the weather radar equation. The randomness of echosignal is simulated with the help of zero memory nonlinearity method which provides basic toolsfor clutter suppression.In chapter3, a clutter suppression method based on multi-sweep is proposed and theilluminated area of ground clutter under the airborne weather radar is analyzed. An echo mapwithout clutter is given through multiple scanning under different elevation angle of the radarbeam. Finally the simulation results are given.In chapter4, we suppress the ground clutter by the GMAP method. The effects of cluttersuppressing are displayed under the ground based weather radar as well as airborne weather radarsituation.In chapter5, a clutter suppression method based on sum and difference beam is discussed.According to the difference of the position and angle between the meteorology and clutter, theground clutter is suppressed while the meteorological information is preserved using the sum anddifference beam algorithm under airborne weather radar. At last we discuss the usefulness of themethod and its applicable condition.In chapter6, this thesis is concluded and further work is also pointed out. |
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