Data acquisition

I use a data logger from Track Systems called Traqmate. It's not the most popular and it's not the most deluxe, but as a first-timer, it suits my needs. The system is composed of the sensor unit which has the accelerometers and brains in it, an external GPS antenna, and a display unit (which doubles as the data storage device). It also includes PC software for analyzing the sessions, so you can see all the braking, speeds, segment times, etc. The whole system is about $1000.

In my car, the sensor unit (the size of a small paperback) is stashed inside the center console below the radio head unit. There's a somewhat friendly access panel to that area on the passenger side. The GPS antenna is hidden underneath the dash board at the bottom center of the windshield.

The only thing visible in the setup is the display unit, which is attached with Velcro just forward of the shifter. The unit can be quickly unplugged and then connected to a PC using a USB cable. The PC software then recognizes the unit and transfers the data files from the display unit to the PC. Depending on the sampling rates used, this can take up to a couple minutes per session.

The system's ultra easy to use. Turn it on, start recording, and press a button at the start/finish line is. When you record the session, you (obviously) only get a recording of where the car was on the track and the applied forces over time. What you don't get is a map of the actual track. It's not a big deal, but if you really want to see where you're driving relative to the pavement, here's what you can do.

Next time there are low-speed parade laps, go out with the data logger turned on. Do a lap driving at the absolute left edge of the pavement all the way around. Trace that edge a bit beyond where you started just to be sure you got it all. Then move to the other side of the track and do the same thing for just over one complete lap. Don't relocate your GPS sensor or hang it out the window to try to catch the actual pavement edge (since you won't do that during your sessions). With this method, you're creating an approximate map of the track on which you'll later overlay your session data. But that session data assumes that the car has no width and this track map you're creating will actually be one car width narrower than the physical pavement. When you overlay the data, you see the relative position of your car on the track.

The low-speed session that maps the track can be imported into the Traqmate PC software (called Traqview) and chopped/trimmed to create the track map. Another technique would be to trace the track from a satellite view and then massage the data into some acceptable format. Note that your position dot wouldn't ever get to the very edges of the pavement and you have to hope that the satellite coordinates are exactly the same as your data logger's.

The Traqview PC software (even the new version) is pretty imperfect (they all are). But it does work and there's a lot to be learned from the data.