Strange problem with GPS loggin

Hi, today I has done about 60 laps in karting.

So the first run (25 laps) it had a extreme good precised times, compared to Alfano (profesional chronometer) the fail is 0.05s +/-. In the Alfano my better lap was 1.10.88 and in racechrono 1.10.89. And had a very good data login from GPS.

The problem was in the second and third run, it recorded very bad, the precision was 0.5s - 1.0s I has done with 5Hz every time, so if I see the race line in the map the first run was very exact, but 2nd and 3rd very very bad. What can be the problem? The phone always I have in the pocket and the GPS don't move. The sky was clear all day


  • Yes, the accuracy correlates with how good the racing line looks in the "traveled route". So as you say, when the line was good, the accuracy was good as well. And when the line is mess, so is the accuracy.

    I can't say why the 2nd and 3rd runs were so bad, but it might be that your GPS is running out of battery, or maybe the hardware is failing. Try with different receiver if the problem persists.
  • I had charge the receiver about 1h before, and don't mark low battery. I will try another day, if it fail again, I would have to use the warranty :(

    Thanks for answer
  • I was thinking about this problem. I remember how I use this day... The first run I remember that I minimize to background the racechrono, and the 2nd and 3th no. So I remember too that at the end of 1st run I stoped first the GPS received before pause the racechrono, and I think that would be the problem, what you think?
  • Which phone do you have? I should not matter whether the app is in background or not. But I guess it will be easy to test next time you're on track.
  • 6210 Navigator.

    And what about stop first the GPS before pause session in racechrono?

    I will test in track, so I tested in car in route and I think work fine.
  • That should not matter.
  • Yesterday I tried again Racechrono and runs perfect, I don't stop session and off recieve, so I don't reproduce the error. I will try to reproduce the next day
  • i have had exact same problem recently whilst bike racing at cadwell park in uk. Weather was perfect and locked to 8 satellites but travelled route went long way out for several laps only. Presumed losing satellites as colour of line changed from green to orange. Sector times invalid as result too. This on nokia 5800 + qstarz extreme bt818 on 5 hz
  • Probably just lost satellites or bluetooth connection... where did you install the GPS receiver?
  • GPS receiver just in front of forks on fairing mount with clear view of sky. Phone mounted on top yoke. Worked superb without problems at donington in august, but occasional drifting at anglesey last month . Have latest version of software on phone. When i viewed travelled route then scrolled through the graph with No of satelites too it showed some of the 'wayward' lines were when still had 6,7 or 8 satelites. Some lines in the route were a very long way out of position and wrong direction (100 yds)
  • You might want to try the tail section if it is better there. I've heard some such reports.
Sign In or Register to comment.