Antenna pattern correction for microwave radiometry utilizing a priori knowledge based on projection onto convex sets method

The APC is the powerful technique for obtaining a precise data of microwave-radiation, though the pattern correction is much more sensitive to the footprint changes and additive noise. It is necessary to reduce the instability that is called 'ill-posed problem in inverse problem', therefore an iterative algorithm for APC based on the Projection Onto Convex Sets (POCS) method is proposed and shows its advantages in the APC by several numerical experiments based on the parametric data of the Advanced Microwave Scanning Radiometer (AMSR) of the ADvanced Earth Observing Satellite-II (ADEOS-II) which is planned to be launched in 1998. The proposed algorithm uses a priori knowledge to provide the convergence of the manifold including the solution iteratively. In this work, the changes in the footprints or the point-spread functions of AMSR along the orbit of the satellite (ADEOS-II) and the constraints in non-negative and smoothness conditions on brightness-temperature are introduced into the APC process as the a priori knowledge.