The help for persistent scatter (PS) states "The coherence estimate can be considered "reliable", for the PS identification, using 20 input acquisitions or more " This seems like an exceedingly high amount of inputs (in addition to the work required to focus all 20+ scenes). When I use only 7 input SLC's and click the "estimate precision' it yields: PRECISION (VELOCITY=1.37088 Height=1.5494e-014) Given this precision estimate, wouldn't only 7 interferograms as input be sufficient? The precision estimate for velocity is (according to the help) in mm so 1.37 mm precision seems extremely good. So to summarize, could I be confident with my results using only 7 interferograms as input or do I really need a minimum of 20?