The Research Of Tree Height Inversion Based On Spaceborne Pol-InSAR

By the fusion of traditional techniques,Polarimetric SAR Interferometry(Pol-In SAR)has the technical advantages of both In SAR and PolSAR,which makes it a hotspot in the research of remote sensing.Since Pol-InSAR can accomplish the tasks left by InSAR and PolSAR,it has a promising prospect in various applications.Based on the existing foundation of relevant research,this thesis carry out researches on the tree height inversion technique through spaceborne Pol-InSAR.Corresponding research results are demonstrated as well.Primarily,in order to reduce the impact of time decoherence in traditional repeat-pass Pol-InSAR measuring mode,this thesis imports the real-time flying strategy of satellite formation based on the developing tendency of international satellite systems.Through the mathematical modeling of orbit configurations,this thesis realizes the orbit design of HELIX,Cartwheel and Pendulum formation modes.By STK simulations,the validity of designed results are verified.The tree height inversion algorithm based on the optimal coherent decomposition is presented in the second part of this thesis.Considering that this algorithm is vulnerable to phase noise,a hybrid adaptive and iterative filter based on the mode and median methods is bring up to improve the retrieval accuracy.By constructing the adaptive and iterative relationship between the filtering window size and the shortest sub-interval of searching range,this filter can efficiently reduce the influence of local phase noise on the interferometric fringe.Simulated and real data are respectively processed to prove the correctness of this algorithm.The three-stage algorithm based on RVoG model is introduced in the last part of this thesis.Through the process of simulated data,it is not hard to find that when the azimuth gradient remains unchanged,the precision of tree height inversion deteriorates with the increase of range gradient.By introducing a fresh parameter,traditional RVoG model can be modified in terms of range gradient.Meanwhile,due to the change of scatter model,volume coherence coefficient need to be re-deduced.Based on the improvements above,the same data are processed again under the same condition.The simulation results showsthat the precisions of inversion under different range gradients are all within reasonable range.