Study On The Technique Of Interferometric Synthetic Aperture Radar Imaging

AbstractThe concept of Interferometric Synthetic ApertUre Radar (InSAR or IFSAR) wasfirst proPOsed by L. C. Graham in l974. It is a new radar imaging tecboquedeveloPed from SAR. Cwhed fOrWar the merit of SAR, InSAR can create highresolution DEM or accomplish change detection, such as slow-moving targetS orsubtle shift of the eall's surface, over the illuminaed scene. Despite itS attractivepossibilities, no distinct progress was made in about ten years that followed, becauseof itS severe reqUirement on the raw data paiL It is both the huge amoun of raw dataachieved by vedous SPacebome SAR systenis after l990's which satisfy the requeSt,and the wide and latent aPplications of InSAR in many areas of military civil andscientific researches, that makes InSAR one of the most active field in Radar andRemOte Sensing nowadays.In this dissertation, the signal processing of DEM imaging is syStematicallystUdied, using the actual tWo-pass raw data of X-SAR by SIR-C/X-SAR. GraSingtheory and fmding out a method to accomplish DEM are our focal POints. Mainaspects include principle of DEM imaging, comPOsition of signal processingprocedure, and the fiilfilling of each links of ffos procedure. Special Stress is laid onthe illuStration to make basic conceptS and principles accUrae, c1ear and easy tounderStand. hogement of chaPters and sechons are basically according with theprocedure of DEM imaging.ChaPter One presents some fundamental ideas of InSW reviews itS historysummarizes itS current state, and predicts itS improving trend.ChaPter Two details three problems: the rationale of DEM imaging, irnportanquality factors, and procedure of signal processing.ChaPter Thre illndes the formation of the raw dare and most paramCters weused for the imaging processing.ChaPter Four discusses the problem of SLC imaging of SAR, including rangeand azimuth comPressions, Doppler paramcters eshmation, ndgration and focusing,and phase preserving.ChaPter Five is about the prefiltering problem fOr coherence enhancing. WaVe-nUInbers shift. shift frequency eStirnation, design of the prefilting filters in eachdimension of range and chuth, geograPhic decorrelation, and their affechon on theresolutions of DEM in range and chuth are Studied.-IIl-Chapter Six relates to the registration problem. Selection of control-points, generation of displace-vectors, and interpolation of the slave image are discussed for both pixel registration and sub-pixel registration.Chapter Seven studies the problems of achieving the phase difference that reflects elevation and noise reducing of phase fringe. Estimation and compensation of the flat terrain's fringe, statistics of phase noise, and methods to reduce noise are included.Chapter Eight deals with the 2-D phase unwrapping, the topographic scale of factor, and the orthorecticfication. A brief survey of 2-D phase unwrapping, theory and practical algorithms of the above problems are provided in detail. Our result, the DEM, is also shown in this chapter.New ideas and creative jobs we have done are also explained in the above chapters. They are:a.A new explanation of DEM's principle that relates phase difference with elevation directly.b.A new comprehension of the critical baseline and a simple deriving of critical baseline based on this new comprehension.c.A phase preserving focusing method for SAR imaging based on the near range estimation.d.A new illustration of preflltering principle based on analysis of the return of a single frequent emitting signal.e.A new coherence index that is more suitable for InSAR.f.An improved method for sub-pixel registration.g.A weighted pivoting mean method and a robust weighted filtering method for noise reducing of phase fringe.h.A nonlinear least square 2-D phase unwrapping method, which uses the second difference of phase difference.i.Derivation of the topographic scale of factor from the difference of incident angles.Last, in the Conclusio...