If you use GPS you need to be aware of the sample rate/frequency measured in Hertz (hz). Basically this will tell you how many times per second it will take/record a positional reading, and so for a more accurate reading you want a high number of reading as it will be taking more readings per second. When walking etc this doesn't really matter but the difference becomes more important the faster you go. At 30 mph there will be 8.8 feet between each sample with a 5Hz system, whilst a 10Hz system will only have 4.4 feet between readings. Take this up to 200mph and we are talking 58.67 and 29.33 feet respectively. Or in other words GPS systems, especially cheap bluetooth ones, can be pretty crap for lap times Of course my maths may be wrong but I think the above numbers are correct.
"Or in other words GPS systems, especially cheap bluetooth ones, can be pretty crap for lap times" Is your's a bluetooth model Jay?
With my aim came a disc to download the "race studio" whatever that is but because i have an apple it won't work.. Really like the idea of sharing data though..
Nope, it's the very accurate and 'Bitchin' AIM Solo! AiM Sports - The World Leader in Data Acquisition
get a better GPS system then.for track stuff needs to be at least 10hz (thats what aim's are),once locked on runs off about 7-9 sats (tells you how many it's locked onto).when it records data,you can alter the rate,upto 100hz on some chanels (if logging off the ECU) i know the solo is accurate to within a metre or so,you can see this when you overlay the track trace onto google earth
Matt,dont bother downloading that disc as it will have an out of date software.i'll get the info together and send you a link for an up to date download.
I don't really want to get into a debate about this so I'll just show what the Ordinance Survey say about gps accuracy in the UK. "Accuracies using a single GPS receiver Positional accuracy with a single receiver, to civilian users approximately equals 5m to 10m, 95% of the time, and the height accuracy is generally 15m to 20m 95% of the time. Military users receive a more accurate coded signal from the satellites." If your'e happy to believe yours is accurate to 1 metre who am I to piss on your parade.
All the clever cut and paste above aside.... We've checked my hm dash, and jase's aim solo lap timer against tsl timing transponders (I think most would agree they are considered accurate as they recortd most Motorsport timing in uk).... Guess what, they are pretty much cock on. 0.1 of a second ish.... Good enough for me. But will do some proper checks as a test - be interesting to see just how accurate they are
