PB Performance Tools sometimes gives errorneus lap times for .VBO exports from RaceChrono

Hi there!

I was finally able to test out RaceChrono on-track, and while it seems to work really well all by itself, I'm having some problems when exporting the data to .vbo and analyzing it within the PerformanceBox software.

The timing results calculated by the PB software are very different from what RaceChrono puts out. It seems, the PB software is putting out much lower times than RaceChrono.

For example: I exported "all laps", opened the file in PB, set a start/finish line and ran lap timing. PB is then putting out a fastest lap of 1:43.0, while Racechrono recorded a fastest of 1:44.54. In fact, pretty much all lap times are lower in PB than what RaceChrono recorded.

The same thing happens when exporting single laps. The fastest lap of 1:44.54 is calculated as a 1:43.0 within the PB software. A second fastest of 1:44.96 comes out as a 1:43.6 within the PB software.

Those are rather large differences and I wonder if there's anything wrong with the export or am I doing something wrong?

Thx again for a great piece of software, though. :)


  • edited June 2008
    What kind of GPS are you using? 1 Hz or 5 Hz?

    The Performance Tools lap time calculation does not work for 1 Hz, since it is a bit 'stupid' and does not interpolate. Hence this is not RaceChrono issue, but Peformance Tools issue. For 5 Hz you should get lap times within 0.2s to those calculated with RaceChrono, if the start/finish line is at same position.

    You can try the I2M Danas software to have 'more intelligent' lap time calculation than Performance Tools.

    If you can, please send me the \RaceChrono\Sessions\*-nmea.txt file for this session you are trying to export to tracks(at)racechrono.com, so I can take a look.
  • Hi aol, thx for the quick answer.

    I'm using a 5Hz GPS mouse. After some further testing it seems, the PB lap time calculations get closer to the RaceChrono output when using "repaired" files (PB always complains about drop outs). Around +-0.2 seconds does indeed seem to be the margin now.

    So it might have been a bit stupid from me to try and use the unrepaired data, but it looked okay in the graphs. Sorry, I'm still trying to get to grips with the software.

    I do however have some other issues when comparing laps from my first turn to laps from the second turn. The graphs don't seem to be in sync then, which might have to do with a poor GPS signal on the second run, but I'm not sure, as later laps (when the GPS signal should have been fine) are also off compared to the first session. So, the nmea-file is on the way.

    I did have a play with the DANA software, however, and that does indeed seem to work perfectly.

    Thx again,

  • edited June 2008
    All right, so it was an issue with the drop outs, and it was fixed by 'Tools > File repair'.

    I'm starting to believe the performance tools is not programmed too well... :-) I also changed the thread topic so people having these issues can find the solution.
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