Saturday, January 4, 2014

More on Jake Berkowitz's "jaggies"

If you're following the Knik 200 GPS trackers, you may have noticed some erraticness in Jake Berkowitz's line in the race flow chart.  Here's an example:

(Jake is the purple line).  And if you've looked very closely at his track you may have noticed some oddness in the timestamps.  For example, readings 32 and 33 have timestamps 16 seconds apart but appear to claim that the distance covered during that 16 seconds was about .25 miles, which isn't possible (yes, Jake's got a very fast team, but not that fast).  After my last blog post I heard from Trackleaders with an explanation of what they're doing and why this looks odd.

They've been working on having one team carry two trackers, providing extra reliability (and hopefully accuracy) during events.  The Knik is the first time that they've experimented with using two different types of tracking devices, putting both a SPOT Gen 3 and a SPOT Trace on Jake's sled.  They're splicing the two data sources together into one data stream.  It appears to be the case that the Gen 3 and the Trace treat timestamps differently from one another and it's introduced some inconsistency into the times on the readings, which in turn has necessarily had some impacts on the race flow chart since the X axis is time.

Jake's location on the map is correct and the overall slope of the line is correct, and even with Jake's jaggies I think the chart remains the most useful tool Trackleaders provides for understanding how the race is unfolding.

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