HF sky wave radar signals are subjected to a wide variety of distortion and contamination effects as they propagate through the ionosphere. Signal processing techniques designed to remove or at least mitigate these effects have been in use for some years, but they do not address the problem of simultaneous occurrence of multiple distortion mechanisms, which may reduce drastically the efficacy of the ameliorative processing. In this paper we present an algorithmic structure for a global optimum distortion correction scheme which can function under arbitrary combinations of signal corruption phenomena. The scheme is based on multiply recursive estimation of distortion parameters. Results from a prototype implementation of this scheme show substantial gains over traditional processing sequences. The new approach is expected to enhance the remote sensing capabilities of HF sky wave radars significantly. ¿ 1998 American Geophysical Union