Limits on the Resolution of Closely Spaced Multipath Signals

Fundamental resolution limits of multipath replicas are presented. The results are not based on any specific resolution technique and therefore hold for any method. The resolution limit is a function of signal to noise ratio, signal waveform and the resolution success rate. As a specific example we consider the resolution of a radar chirp signal. We compare the limit with empirical results obtained by employing the Akaike Information Criterion and the Minimum Description Length criterion for model order selection.