sprintZ GPS track comparative tests

Evaluation around test track

We took an early prototype for a comparison test at a 400 m test track: we ran 4 laps with 3 different units: 

  • BLUE: our prototype: follows perfectly the track and reported an almost perfect distance at 1.59 km
  • RED: Strava app on a mobile phone: not bad on distance but pretty poor on track accuracy 
  • GREEN: a commercial unit that you can buy for about £80: rather poor

The test track used is located in an area with many surrounding building and the weather was pretty cloudy so the test was particularly demanding for any GPS device. In subsequent test, during touch games played in good weather and on pitches less surrounded by buildings, it must be said that the commercial unit was providing a much better signal. 

Another analysis of the data can be done by analysing in detail the data contained for one lap of each one of the device using the great free software “MapSphere GPS Track Editor”. You see the result in the graph below in which colour is proportional to the speed measured and arrows are used to connect each data sample. The brief analysis is:

  • 1st image: our prototype: not much too say, just what you want to see, the baseline
  • 2nd image: the commercial £80 unit: showing here the best one of the four laps, you can see many samples but a significant inaccuracy in matching the correct 400m lap. It also report speed varying much more than reality
  • 3rd image: the mobile phone: manages to close the loop but reported speed varies far too much and it shows 2 long arrows indicating that the position was not recorded for as much as 5-10 seconds at a time in these sections
  • 4th image: a garmin F220: sampling is too horrible to be useful for touch

Additional tests

Results of an additional tests will be posted here by the end of January.