GPS discrepancy - AiM
#31
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I had lots of trouble with my AIM Solo DL at COTA recognizing start/finish on the smartycam, and when I looked at the GPS data it was off by hundreds of feet. Lots of 20min laps
TexasRS printed out some nice 11x17 laminated COTA maps with reference lines from his VBOX on them - turned out perfect. Great teaching tool.
I'm not sure if people know this but Racelogic (company behind the Video VBOX) makes some of the world most accurate GPS data acquisition devices for automotive engineers.
For the first time I have been able to compare lines via overlays. Could never do this with AIM, Traqmate, or G2X.
TexasRS printed out some nice 11x17 laminated COTA maps with reference lines from his VBOX on them - turned out perfect. Great teaching tool.
I'm not sure if people know this but Racelogic (company behind the Video VBOX) makes some of the world most accurate GPS data acquisition devices for automotive engineers.
For the first time I have been able to compare lines via overlays. Could never do this with AIM, Traqmate, or G2X.
Yes, his export method, although far less work than doing that in AiM, works great and the visualization of the line data is very good. Race-Keeper offers an easy export to Google Earth, too. The best, hands down, is MoTeC's RaceGrade 20Hz system, however... Always more, bigger, better and faster!
Julian Thomas, the founder and principal of Racelogic, started his company in 1992 to build GPS simulators for calibrating military equipment. That's all they did until he started autocrossing and decided to build the Performance Box, then went circuit racing, got a coach and built the VVB in 2010! So yes, they know their GPS!
Considering AiM doesn't even offer a single lap export (and I have never seen any successful RacePak GPS info), the Traqmate is fine for in-session comparison.
I agree though, VVB knocks it out of the park with their quick and easy line analysis. That's why they're the second most popular system I sell. And, the reason why nearly every client I work with at the track gets a loaner for our engagement. It's the fastest way for me to find what we need to work on...
I will say that comparisons between AiM HW generated laps using the latest firmware on properly set up equipment is fine.
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Last edited by ProCoach; 01-21-2016 at 09:04 AM.
#32
Here's an excerpt of a description of the GPS tech in the Video VBOX:
"Velocity and heading data are calculated from Doppler Shift in the GPS carrier signal, providing users with unparalleled accuracy. For example, over 10 tests between two light barriers placed exactly 1000m apart, the VBOX will report a distance within ±2-3cm, on every test, and the average comes out to within less than 1cm. Impressive for a device using satellites 18,000kms away!".
"Velocity and heading data are calculated from Doppler Shift in the GPS carrier signal, providing users with unparalleled accuracy. For example, over 10 tests between two light barriers placed exactly 1000m apart, the VBOX will report a distance within ±2-3cm, on every test, and the average comes out to within less than 1cm. Impressive for a device using satellites 18,000kms away!".
#33
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I can't fine tune braking performance with purely GPS calculated accelerometer readings alone (the VVBOX has no internal electromechanical accelerometers) and if you have a GPS "hiccup," that lap is compromised because it can't reconcile lap distance and cannot be compared with another "good" lap, anymore.
You pay your money and you make your choice.
#34
Sure, but what I mean is that they go and explain in detail how impressive their GPS system is, whilst AiM or MoTeC are maybe using the same technology but don't explain it, because they have 100 other selling points.
#35
That's both a blessing and a curse.
I can't fine tune braking performance with purely GPS calculated accelerometer readings alone (the VVBOX has no internal electromechanical accelerometers) and if you have a GPS "hiccup," that lap is compromised because it can't reconcile lap distance and cannot be compared with another "good" lap, anymore.
You pay your money and you make your choice.
I can't fine tune braking performance with purely GPS calculated accelerometer readings alone (the VVBOX has no internal electromechanical accelerometers) and if you have a GPS "hiccup," that lap is compromised because it can't reconcile lap distance and cannot be compared with another "good" lap, anymore.
You pay your money and you make your choice.
#36
Maybe, but I sold my Aim system because the Vbox was better for my needs, and it was two things 1) Comparative (Video + Overlays + data histograms), and 2) GPS accuracy. I'm not a racer so my needs are different.
#37
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I don't buy that.
To do better in track days and DE's, you want to objectively grade best execution of fundamental skills.
To race better, you need to leverage more of the capability of the car than the other people you're racing with, by best execution of fundamental skills...
It's all about how you assimilate information. There are so many ways to slice and dice the information that we are lucky to have so many good ways to collect and display it!
To do better in track days and DE's, you want to objectively grade best execution of fundamental skills.
To race better, you need to leverage more of the capability of the car than the other people you're racing with, by best execution of fundamental skills...
It's all about how you assimilate information. There are so many ways to slice and dice the information that we are lucky to have so many good ways to collect and display it!
#38
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OK, so I decided to try out the nifty new ability of exporting individual laps in RS2 to KML. I outputted a lap from a session I drove in my SO's car, to one she drove so that I could go over line with her. I've attached two images here, both showing our lines on the back straight at TWS where we should have very similar lines. You will note that I zoomed in a lot more in RS2 to see the difference in gps coordinates than I did in Google Earth. You will also note that the relative location of the laps is not the same. And yes, in both images the red line is my session and the blue line is her session. Same car, same day, same AIM Solo. It appears to me that there is an issue with export of GPS coordinates. This REALLY REALLY REALLY needs to be fixed.
#40
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#41
#42
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#43
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I'm pretty sure that the GPS data is fine. It's the export that is fubar.
#44
Vbox uses WAAS, and EGNOS in europe.
Here is a good summary
http://extension.missouri.edu/p/wq452
....on precision agriculture, but it applies here
Way more detail here:
https://en.wikipedia.org/wiki/Error_...tioning_System