The result for 17 laps, tested on Ales[FR] track :
Most importantly, the average precision is 0.03 seconds
. Very impressive!
If I remember correctly, in his documentation aol say : better +-0.15sec with GPS 5hz.
How do I located the magnetic strip : a magnetic sensor plugged to GPS button during 40 laps.
From there, I have defined the M point, this position indicate a new start/finish line in RaceChrono.
Details of GPS points identified by the magnetic sensor
GPS time is accurate to 0.2s (5 Hz) and my average speed in this area is 144kph. This gives a possible distance error of 144 x 1000 x 0.2 / 3600 = 8 meters. It is approaching 8,9m. That is why I have located the point M at the beginning of the detection area.
You can download the spreadsheet
that comes from these calculations. Also contains the 40 GPS points identified by the magnetic sensor and more things ...
Here you have two bin RaceChrono files
of this session, also added nmea original file in zip archive file. And here, you can download "track.bin"
which contains as start/finish line the GPS position of the magnetic strip.
I made this on a motorcycle, the GPS is attached to the rear (mounted on duck tail), as it is well clear of everything, including me the driver.
Track is dry, wind is very low, sky is blue and the temperatures are between 18 and 29 Â°C. Weather is perfect !
I completed 68 full laps during the day, I started the track at 9:26, I left at 17:40 (local time, for UTC time remove 2hours).