GPS HDOP Errors

This graph is a count of the different HDOP errors.  I have used Unix CLI commands to extract the HDOP data from the text file, sort it, and then count the number of each HDOP error type.  This was collated from a small run of 3785 records(seconds) of GPS data and after the GPS unit had been up and running for quite some time.  Looking at the graph, if you said that a HDOP of 1 is equal to an error of around 5m, then a HDOP of 1.23 is equal to around 6.15m and if that accuracy was good enough for you, them around 76% of the data is equal or under that value.  See one of the other posted graphs that show how HDOP can change over time.