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Gizmo555

macrumors newbie
Original poster
Aug 19, 2018
3
0
Bristol, UK
Hi

I’ve previously used my Garmin Fenix 3 to record Go Kart races I compete in. GPS accuracy has been spot on with all data points accurately following the track layout.

With my AW I’ve found that the level of accuracy is inferior by a large amount. GPS points jump all over the place and outside of the track layout by a large amount.

Speeds are up to 60mph.
I’ve been using outdoor cycling activity to record the race.

It’s been ok on bike rides at slower speeds.

Any thoughts?
Do I have a problem with my watch?

Perhaps GPS update rate just isn’t fast enough to let this work properly. I think with the Garmin there is some control over the rate.

Thanks

Mark
 

oeagleo

macrumors 6502a
Feb 5, 2016
712
417
West Jordan, Utah
Garmin will give you 1 second recording, at best. Going 60 MPH, that means you move 88 feet per second, and depending on how many, and how strong the sat signals are, that's a long distance to keep a track, given the best GPS standard is +/- 15 feet. I don't think the GPS in the watch, (or even the Fenix 5x I have) are made to track activities going that fast, I don't know for sure though.
 

Gizmo555

macrumors newbie
Original poster
Aug 19, 2018
3
0
Bristol, UK
Here’s the GPS plot from the Fenix F3

C6C273C4-6C60-4FD6-9363-2831ECB5EB6D.jpeg


And from the AW S3 (all be it a different circuit)

AF0C1B12-47BB-4BCE-B674-2E1AF748C676.jpeg


Definitely some difference.

Thanks

Mark
 

tony_glasgow

macrumors member
Jul 16, 2015
67
32
UK
I've just had a look a a GPX file from one of my runs recorded on an Apple Watch. GPS data comes in around every 2-3 seconds (and that's with a good signal) so looks like its just not suitable as oeagleo says.
 

ftaok

macrumors 603
Jan 23, 2002
6,483
1,569
East Coast
Do you have your iPhone with you when you're racing? Perhaps the GPS polling rate is higher when you're using the iPhone's GPS.
 

Julien

macrumors G4
Jun 30, 2007
11,835
5,430
Atlanta
What app do you use for racing? Are there car route recording apps with the proper algorithms/data smoothing?
 

Gizmo555

macrumors newbie
Original poster
Aug 19, 2018
3
0
Bristol, UK
I don’t carry my phone whilst racing so restricted to gps accuracy of the watch. I suspect the refresh rate is different by activity type and until Apple give some control over custom activities I’m stuck with it.
I guess the rate is to deal with battery life whereas the Fenix doesn’t have an issue using a faster refresh rate vs battery life.
I may try carrying the phone at the next race in Sept to see if that makes a difference to the rate.

In terms of Apps I don’t use any on the watch/phone. My Garmin VIRB Ultra 30 Camera films everything and has GPS, accelerometer etc built in so the video output can have all that data as an overlay. Newer higher end GoPro now have onboard sensors as well.
I haven’t looked to see if that produces a file which could be imported into Apple Health?

Thanks

Mark
 
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