Second Data Collection Run - Satellite data vs. HDOP

This graph is just a graph displaying the second data run with possible Satellite counts and the number of satellites the GPS is actually using with a resultant distance error.  The distance error was worked out with using a HDOP error of 1 equalling a distance error of +/- 5m.  At around reading 1065, the large olive line spikes with a reading of +/-37.5m, when the usable satellite count gets down to 5.  A few seconds later the satellite count is back to 7 and the distance error has dropped back to +/- 5.6m.

The top coloured bar shows the different segments of readings that are spatially plotted on this GIS map.