POCS-based blind array processing in incoherent microwave radiometric image reconstruction

A microwave scanning radiometer is the powerful equipment for obtaining precise data of microwave-radiation however the spatial resolution is larger than many of the objects of interest within the image. If the exact antenna directional pattern and the orbit of the satellite can be known, the image reconstruction can be done exactly. Actually, it is difficult to know the antenna directional pattern or the point spread function (PSF) of the imaging system exactly because the directional pattern of the antenna is changed in space due to thermal stress, mechanical stress or vibrations. Under such a condition, the image reconstruction process is much more sensitive to the PSF changes and additive noise. It is necessary to reduce the instability that is called the 'ill-posed problem in inverse problem'. Therefore, a new blind array processing algorithm based on a conjugate gradient-projection onto convex sets (CG-POCS) for signal recovery and image reconstruction in an incoherent signal is proposed. Its advantages are shown by numerical experiments based on the parametric data of the Advanced Microwave Scanning Radiometer (AMSR) of the Advanced Earth Observing Satellite-II (ADEOS-II).