Harry's GPS Suite Forum

I was testing the Speedo display on a "course" I defined on a local highway. I would have the Timer display active when I crossed the starting line and then change to the Speedo. The average speed displayed was about 40mph and my true average was around 60mph on my first run yesterday. Today, on my second run, Speedo showed an impressive average speed of 162mph. Again, my true average was a more modest 60mph. The current speed displayed was always correct. Using an iPhone 4s without any extra devices.

I realize you can reset the average speed, but I did not try that in my tests.

Is this a case of user error/ignorance or is something amiss in the Speedo display?

Deven

Average speed calculation is a fragile process using GPS. Wrong speeds typically result from bad GPS quality generating invalid distance driven values. If for example there is one fix off to the left by 100 meters and back for then next one, LapTimer would add 100m plus 100m to the distance travelled - generating a too high avg. speed. This could be improved by applying a better distance calculation, but currently isn't. So what you need to do is taking care you have good GPS reception (like always). In case avg. speed is off, tap the field to reset.

Harry