Better précision Qstarz Q890 Ultra + nokia N95

I use a Qstarz - Receptor GPS Bluetooth Q890 Ultra compact with my N95 during kart race
My first test was awful because the gps was in my trouser pocket
Then I fix the GPS on my shoulder and I manage to get this KML file.
Does anyone managed to get better precision with this gps or an other.
here a link for the 16 lap of the race
Thank for your kml links

thank you to help me to optimise this
Image :
KML en zip
KML en directe


  • edited April 2009
    Thank you for posting that its fun to see others who use the software:

    By the way you might like to know that you can input a KML file directly into google maps like this:

    It looks like the GPS was NOT in 5Hz mode
    here is my KML if you want to compare
  • edited April 2009
    teckom77, your data is not bad at all for 1 Hz, taking in account the small scale of the circuit. A 5 hz receiver should smooth out some rough corners, but I doubt the general accuracy would be much better. You might try to install the receiver on top of your helmet though, for best satellite visibility.

    I guess there is no chance in getting the driving lines visible in such small circuit. The lap time accuracy should be rather OK already with the current data.

    PS. Can yo submit the track file please? (to )
  • edited April 2009
    MY GPS was at 5htz . I can see it the csv export, (I have a data line each 0,2 sec..).
    spec of BT-Q890 Products/BT-Q890.htm
    Dimitry thanks for the google maps link,. I try download your kml and it doesn t work, i have an XML file instead...
    I realy like to see other KML a 5htz to see the difference.
    One more think, if you see all the 22 laps one bye one you see form time to time 1 or 2 who have more than 1or 2 metter of difference between 2laps. I dont understand why this gap it s like all the data are wrong.
    How it is possible when you got 5 time perseconde the data from 8or 9 satellite...
  • Unfortunately GPS receivers (atleast these cheap consumer models) are not accurate enough for better data. You are lucky to have only 1-2 meter error, which equates only 0.05s -0.10s error in lap times, if you are going 80 km/h over the finish line.
  • edited April 2009
    At least,I think racechrono il a very good product but GPS are to slows to get real time information.
    I continue to use it to get my lap timing in realtime, it s fastess than waiting the data at the end of the race.
    i compare laptiming with race chrono and official laptiming and it s not so bad :
  • Thanks for the comparison table! Quite a bit of error between laps 64-65, maybe some glitch in the GPS reception. Usually the maximum error should be somewhere around 0.25 seconds. Maybe try to install the GPS receiver on your helmet, a lot of kart drivers have mentioned that working best for them.
  • As you can see her :
    The Gps is on my shoulder and i think his position is optimised
    Do you have any KML file to see what other GPS recever give
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