Luttrell S P, September 1987, The complex point spread function of the RSRE SAR, RSRE technical report (Malvern, UK), 4079
Super-resolution of SAR data requires that the complex point spread function (PSF) of the SAR be accurately known. We propose and implement a method of measuring the PSF which uses existing SAR images of targets as raw data. We find that in addition to the expected distortions of the azimuth response which arise from swing of the antenna and from artefacts of motion compensation processing, there are extensive and unexpected distortions of the range response. Most importantly the range response does not obey the principle of superposition (i.e. it is non-linear), and so SAR PSF calibration must be conducted with care. We estimate the complex SAR PSF when a bright target is present.