Nomenclature ix xiii xv A Comparison neutral delay GPS and InSAR A.1 Spatial networks 82 113 161 162 163 173 190 194 197 199 204 220 226 Theory Single-point observation statistics Coherence and SNR Sources of decorrelation Integer phase ambiguities Influence and modeling of orbital errors Atmospheric signal: turbulence Atmospheric signal: stratification Error propagation and joint stochastic model 4.10 Conclusions Decomposition of the displacement vector Corner reflector experiments Groningen coherence estimation Cerro Prieto geothermal field Izmit earthquake Conclusions Theory Refractivity sensitivity analysis Ionospheric influence Water vapor mapping Combining amplitude and phase information Validation radar interferometry using Meteosat radiometry Spatial moisture distribution during CLARA 96 Conclusions Contributions of this research Recommendations Contents vii
Spaceborne radar interferometric delay measurements were used to infer high-resolution maps of integrated atmospheric water vapor, which can be readily related to meteorological phenomena. Maps of the water vapor distribution associated with a precipitating cloud, a partly precipitating cold front, and horizontal convective rolls reveal quantitative measures that are not observed with conventional methods, and suggest that such radar observations can be used for forecasting and to study atmospheric dynamics.
Abstract-In the permanent scatterer technique of synthetic aperture radar interferometry, there is a need for an efficient and reliable nonlinear parameter inversion algorithm that includes estimation of the phase cycle ambiguities. Present techniques make use of a direct search of the solution space, treating the observations as deterministic and equally weighted, and which do not yield an exact solution. Moreover, they do not describe the quality of the estimated parameters. Here, we use the integer least squares estimator, which has the highest probability of correct integer estimation for problems with a multivariate normal distribution. With this estimator, the propagated variance-covariance matrix of the estimated parameters can be obtained. We have adapted the LAMBDA method, part of an integer least squares estimator developed for the ambiguity resolution of carrier phase observations in global positioning systems, to the problem of permanent scatterers. Key elements of the proposed method are the introduction of pseudo-observations to regularize the system of equations, decorrelation of the ambiguities for an efficient estimation, and the combination of a bootstrap estimator with an integer least squares search to obtain the final integer estimates. The performance of the proposed algorithm is demonstrated using simulated and real data.Index Terms-Nonlinear parameter inversion, permanent scatterers, synthetic aperture radar (SAR) interferometry.
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