The Design and Development of a Geostationary Synthetic Thinned ApertureRadiometer.

[摘要] The Precipitation and All-Weather Temperature and Humidity (PATH) mission outlined in the National Research Council decadal survey for launch in 2016-2020 recommends a microwave array spectrometer as the instrument payload.A design for the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is presented that fulfils all but one of the mission requirements – integration time – and options are available to meet this requirement.A technological roadmap exists for the development of the key hardware components to minimize size and power requirements, especially with respect to the receiver and digital correlator design. The fabrication of the instrument demonstrator, GeoSTAR-D, contributed significantly to the hardware development (receivers, antennas, correlators) and provided a test-bed to verify the theoretical understanding of a two-dimensional Synthetic Thinned Aperture Radiometry (STAR).Measurements in the anechoic chamber provided a boresight phase calibration and verified that the antenna patterns closely matched the theoretical model.Field deployment of the instrument with an engineered Earth disk target allowed for generation of GEO like measurements and calibration validation.A theoretical based image retrieval algorithm was implemented and combined with various models to account for the sky aliases and minimize the target discontinuities.Images generated after sky alias removal and Gibbs mitigation had residual errors of less than 2%.A high resolution Earth disk model is generated from existing publically available datasets, appropriate geophysical parameter models and a full radiative transfer model.The model allows for the generation of un-physically realizable scenes to determine the impact of individual geophysical parameters on the observed brightness temperature.The realistic brightness temperature images are then evaluated with a GeoSTAR-like instrument simulator to investigate the effectiveness of apodization, spatial frequency information content and various processing algorithms.At the temperature sounding channels, sufficient contrast is available even at the largest baselines.The recommended retrieval algorithm performs well even when based on imperfect input models.

[发布机构] University of Michigan

[效力级别] Remote Sensing

[关键词] Microwave Radiometry;Remote Sensing;Synthetic Aperture Reconstruction;Electrical Engineering;Atmospheric;Oceanic and Space Sciences;Engineering;Science;Electrical Engineering & Atmospheric, Oceanic & Space Sci