Is this device available from a European supplier yet? Anyone got any idea if the data logging requires an iOS device or is there PC software available to download the logging data?
Mendelsohn (linked here: http://www.gps-laptimer.de/Compatibility.html) will be a supplier here in Europe. They do not have them on stock so far, but it will be a question of 1 or 2 weeks.
That paper refers to RTK, Real Time Kinematics. The position accuracy of RTK is on the order of two centimeters because the receivers use the signal phase from each satellite as well as the time information. Those receivers cost thousands of dollars and you need a base station receiver to determine local position and transmit the phase correction information to the mobile receivers. See for example the Racelogic VBOX DGNSS RTK Base Station ( http://www.velocitybox.co.uk/index.php/ ... n-rtk.html ). Inexpensive GPS receivers like the XGPS160 or the VBOX Sport aren't capable of RTK.
I used the Dual XGPS160 this weekend at an autocross and the effective update rate was 10 Hz in HLT. That's as good as I obtained with a VBOX Sport. With more satellites used, I think the altitude data was more accurate as well.
Maybe gplracerx can comment on this. As far as I see the negative comments (there are very positive too) are from aviation users - which is probably a different game.