I've been doing some tests with a self-written application that uses the GPS to report locations and plot them on a map. One of the things I've noticed is that the coordinates seem to be more accurate when the interval at which they are gathered is smaller. In general, when reporting every 10 or 15 seconds the coordinates seem to correlate more with the actual position at that time, whereas when reporting every 30 or 60 seconds they seem to be less accurate.
This is even true for a non-moving phone. If I put it down in my backyard and leave it to gather 10 coordinates, once every 10 seconds, I seem to get coordinates that are less spread out and actually are a pretty good indication of the actual location. When gathering 10 coordinates, once every minute, I get a lot less accurate measurements.
Is there any hard evidence to suggest that gathering coordinates at a small interval is more accurate? Or is what I am seeing just coincidence?