integration of BR2 and GPS

[ElectronSpeed]

I have a customer with both a BR2 and a GPS receiver.

We would like to use the BR2 for start/finish and the GPS for split times (and even I2 segment times if reasonable). If this is not possible, what are the most realistic alternatives?

One approach that I took was to try to use GPS only data and match up the beacon and GPS start/stop location. I ran the car one session with the BR2 running the show but logging lat and long. I then turned on the GPS based lap detection and set a detection radius of 100 ft. I looked at the first session data and found a point 100 ft past the beacon and entered that point as the beacon point. I expected the lap data from the BR2 and the GPS system to overlay. The GPS data is offset early by around 80 feet. I have attached a picture with the first session highlighted at approx. 100 feet after the beacon and two sessions of GPS based data overlayed. What did I do wrong?

Tips appreciated.

thanks,

[JamieA]

There is currently no way to use main beacon on BR2 and splits on GPS.

You will need to do either all GPS or all BR2 based beacons.

GPS based lap times, from testing, are very accurate, so I really don't see a reason not to use them.

I understand your issue with the position of the beacon, but haven't tried to back to back it with a BR2.

Can you tell me what the lat and lon were that you entered. The lat and lon of the beacon position the first time, then what you changed it to, and what the lat and lon were on the second beacon. I would like to see if the beacon moved as expected.

Kepp in mind, all GPS' have an element of drift, which wont generally effect lap times, but could effect the exact placement of the beacon.

regards

-Jamie

[ElectronSpeed]

JA:>GPS based lap times, from testing, are very accurate, so I really don't see a reason not to use them.

If I can't reasonably overlay the GPS based data with beacon based data it greatly reduces its value.

JA:>Can you tell me what the lat and lon were that you entered. The lat and lon of the beacon position the first time, then what you changed it to, and what the lat and lon were on the second beacon.

Lat and long entered (this number was determined by looking at the recorded lat and long at a lap distance of 100 feet from the recorded lap start based on the BR2) (see picture): 36.5686553, -79.2075940

Lat and long at BR2 reported beacon (not used in my proposed method of determining beacon location but pulled from the data today): 36.5685970, -79.2079076

Lat and long "you changed it to": ?

Lat and long "on the second beacon": ?

What I tried to do:

Run the car in the first session with a BR2 triggering lap times, the tires calculating lap distance, and the GPS receiver reporting lat and long to be logged. I looked at the data (knowing that I was going to set the detection radius at 100 feet) to find the lat and long for a spot 100 ft after the desired lap trigger location (the BR2 trigger location). I entered the 100 radius and the start/stop location for the GPS based lap detection. The result was the GPS laps triggering about 80ft early.

Thanks for your thoughts.

[DarrenR]

Hi Electron,

Can i ask why you didn't set the GPS coordinats to the lat/long of the very start of the lap, at the same point as the BR2 beacon? The detection radius is only there to allow for wide tracks where a small radius wouldn't cover if you were on the edge past the point. Saying that, changing the radius shouldn't move the beacon point.

So where you set the lat/long to 100ft away from the BR2 beacon and it's triggering 80ft away this is actually only an error of 20ft as i understand it? 20ft could be accounted for by drift.

Please explain (or send logging in) if i have misunderstood.

Regards,