Research On Atmospheric Effects In Spaceborne Single-Pass SAR Interferometry

Single-pass SAR interferometry is a new generation of microwave remote sensing methodology which has been developed in recent years.As a new remote sensing for earth observation,single-pass SAR interferometry creates a new development field for spaceborne SAR Interferometry.At the same time,single-pass SAR interferometry provides more possibility to observe the earth surface in a high-precision and large-scale mode and supports the research of natural science.Single-pass InSAR system can overcome the impact of the various coherent sources which always exist in the traditional repeat-pass InSAR system.By using the high precision of baseline measurement technology,the measurment of baseline length can reach millimeter scale accuracy.Without time decorrelation,single-pass InSAR system can realize the observation in a high precise mode.In order to further improve the measurement accuracy of single-pass InSAR system and aim to attain the high-precision processing results,we research on the effects of signal propagation by troposphere and ionosphere.Moreover,an algorithm is proposed for compensating the effects of troposphere and ionosphere.The main work of this paper is organized as follows:Chapter ? is the introduction.The research background and the research significance of this paper are described.The development of single-pass SAR interferometry and the research on atmospheric effects are summarized.The content and structure of the whole paper is introduced.Chapter ? introduces the basic theory of atmospheric propagation effects for spaceborne SAR signals.We firstly analyzd the theory of troposphere on the SAR signal and the acquisition algorithm of tropospheric zenith delay.Then,the basic characteristics of ionospheric propagation and its influence on SAR signal are discussed.Chapter ? is dedicated to the influence of tropospheric effects in single-pass SAR interferometry and proposed the corresponding error compensation algorithm.Firstly,the tropospheric propagation model of single-pass SAR interferometry is established,and the error of InSAR measurement introduced by troposphere is quantitative analyzed.Then,we proposed a new algorithm used for compensating the tropospheric effects.This algorithm uses a prior tropospheric zenith delay,and can be directly used to deal with the products of InSAR.The algorithm has a well operational efficiency and high accuracy of compensation.Finally,two groups of experiments with different prior tropospheric zenith delay are used to deal with the InSAR simulation data,the results of the experiments verify the robustness and universality of tropospheric error compensation algorithm.In chapter ?,we studied the influence of ionospheric effects in single-pass SAR interferometry and proposed the corresponding error compensation algorithm.Firstly,the influence of ionospheric effects are discussed in the aspect of homogeneous ionosphere,the impact of spectral shift and TEC gradients.Then,an ionospheric error compensation algorithm for single-pass SAR interferometry is proposed.By using the prior ionospheric spatial TEC distribution,the algorithm can directly compensate the error of InSAR products in an operational manner.Finally,the results of the ionospheric compensation experiments show that the precision of InSAR products have been more improved by using the ionospheric error compensation algorithm.The compensation algorithm has a well application prospect for solving the ionospheric effects in low band radar system.In chapter ?,all achievement of the full work and the innovation of this paper are summarized.At the same time,we come up with some guidance for the next stage of work.The research in this paper has a great significance to the high accurate interferometric processing of the single-pass SAR interferometry,and also make contributions to the development of radar system with low bandwidth.Furthermore,our research provides some theoretical support and necessary technical exploration for the continuous development of the interdisciplinary fields in space remote sensing technology and atmospheric effects.