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Why is AW2 GPS too generous with actual distance run?

L

Long Run Nick

macrumors regular
Original poster
Oct 4, 2016
156
118
Florida Panhandle
Excuse my ego, some street creds: have been running since 4/76 currently over 87,000 miles run(87,710 miles and counting). Have owned my Nike Edition for 1 year. Love the smart watch aspects, BUT, have found the GPS inaccurate compared to other GPS running watches. An example, a 9 mile run on a tried and true accurately measured course used for years, the AW shows 9.2 miles while my Garmin VVA 3 reflects 9 miles.
The over the actual distance has never been nearly correct. I feel for folks who rely on the watch and think they are going further and faster than they actually are. If you run a 10k certified course and at the 6 mile mark your watch shows 6.2- that changes the actual pace by quite a bit. Have run with a watch on both wrists, and switch from left to right. Same results. Always too generous with miles. I do like the audio info at each mile, but it normally results in reflecting a 15-20+ second faster pace per mile. For “serious”runners this is not acceptable. Heart rate tracks pretty close, but for an anal guy like me I am not sure why Apple can’t correct this, or maybe the 2 AW2’s I have owned were just flukes. Members views/ experiences appreciated. Thanks. Nick
 
I have run three marathons this year and the last one with the build in app - it was SPOT on the kilometer marks.. The earlier marathons with the Nike app was all over the place. Not accurate as you said and even worse: crashing on me.

The build in is the fastest, most precise and reliable way to use the AW as a serious runner IMO
 
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I’d say there’s a few issues....

The GPS isn’t 100% accurate in measuring your route. If you check your workout, the line isn’t following your route perfectly and those differences may contribute to what your seeing.

On the certified route, how would that be measured? (I’m not a runner) I’m guessing it’s the shortest measurement of that course, ie taking the inside of each corner to minimise distance? I’m guessing you can really run a bit further than 10k when doing even a certified course, if the route is wider than single file.
 
KrisLord said:
I’d say there’s a few issues....

The GPS isn’t 100% accurate in measuring your route. If you check your workout, the line isn’t following your route perfectly and those differences may contribute to what your seeing.

On the certified route, how would that be measured? (I’m not a runner) I’m guessing it’s the shortest measurement of that course, ie taking the inside of each corner to minimise distance? I’m guessing you can really run a bit further than 10k when doing even a certified course, if the route is wider than single file.
Click to expand...

You are correct. My issue is I have used more GPS running devices over the years, numerous Garmin’s, Polar, Samsung, Times, etc and as much as I like the AW the distances are just overly generous. xDKP has presented some info that may be helpful and will try the native run app.
You,would think with all the mileage I have run over the last 4+ decades I would be able to figure out distance, HR, and pace without a watch..
 
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KrisLord said:
I’d say there’s a few issues....

The GPS isn’t 100% accurate in measuring your route. If you check your workout, the line isn’t following your route perfectly and those differences may contribute to what your seeing.

On the certified route, how would that be measured? (I’m not a runner) I’m guessing it’s the shortest measurement of that course, ie taking the inside of each corner to minimise distance? I’m guessing you can really run a bit further than 10k when doing even a certified course, if the route is wider than single file.
Click to expand...

I’m a race director and former collegiate coach and certified courses are measured with a wheel—not GPS. Because GPS is just a series of back-and-forth pings between the device and a satellite, frankly, no GPS can be said to be 100% accurate. And yes, a wheel-measured course turns on the inside-most tangent. In all the longer races I’ve run (9+ miles) I’m over the advertised distance due to weaving or poor tangent running.

As to the Apple Watch, i have the new Series 3 with LTE and it matches up with my old Garmin mile markers as well as the marked distances on this paved park path I run on frequently. I’m very happy with it.
 
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I run several 5ks on my trail, it’s an out and back run. Every official race ends up being exactly 3.1 miles on my watch. I run the same course at least 3 times a week and always turn around at the same spot and it’s always 3.1 miles on my watch.

Now when I do Intervals on a local high school track the gps is off, way off. I’m finished my .25,.5, .75 or 1 mile on my watch way before I actually make it around the track, the more laps the worse it is. It’s so off that I now use a stopwatch when doing intervals.
 
Resqu2 said:
I run several 5ks on my trail, it’s an out and back run. Every official race ends up being exactly 3.1 miles on my watch. I run the same course at least 3 times a week and always turn around at the same spot and it’s always 3.1 miles on my watch.

Now when I do Intervals on a local high school track the gps is off, way off. I’m finished my .25,.5, .75 or 1 mile on my watch way before I actually make it around the track, the more laps the worse it is. It’s so off that I now use a stopwatch when doing intervals.
Click to expand...

All GPS is way off on a track. Because of its oval shape, the way the watch (whether it be Apple, Garmin, or what have you) communicates by bouncing a signal back and forth is a recipe for inaccuracy on a circle shape. Any GPS route—no matter the device—is actually just a series of straight lines connecting each point where the signal bounced back and forth. I too use a regular Timex for track workouts. Frankly, I think it’s better anyway, because you teach yourself how to pace without relying on the pace readout from a watch.
 
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I have AW0, and usually go out with my iPhone, which provides GPS. 2.4 mile runs are routinely listed as 3.1. No idea why.
 
My initial thought on posting was to simply comment on my experience comparing the AW2 GPS distance to my Garmin- wearing both watches- one on each arm, same course, same time. Some feedback got wrapped up on course measurement and racing. I have run over 500 races and have directed and use a calibrated wheel to measure courses so I am aware of the route when running. Anyways, the best input was trying the native workout app and not using the Nike app. Also, the comment on GPS accuracy on a track is spot on.
For over 20 years, prior to all the tech/GPS/HR, etc I ran with a base Casio Watch. What is interesting to me is overall average running times at races I compete in seems in general to have gotten slower. Back in the early 80’s I would run 10K’s in the 36-37 minutes and not place in the top 3 of runners 40-44. I see some races in my area now that time like that would win the race:). So much for tech.
Hey get fit, keep running. Closing in on 75 and still running 40-50 miles a week, all be it, a hell of a lot slower.
Nick
 
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Long Run Nick said:
My initial thought on posting was to simply comment on my experience comparing the AW2 GPS distance to my Garmin- wearing both watches- one on each arm, same course, same time. Some feedback got wrapped up on course measurement and racing. I have run over 500 races and have directed and use a calibrated wheel to measure courses so I am aware of the route when running. Anyways, the best input was trying the native workout app and not using the Nike app. Also, the comment on GPS accuracy on a track is spot on.
For over 20 years, prior to all the tech/GPS/HR, etc I ran with a base Casio Watch. What is interesting to me is overall average running times at races I compete in seems in general to have gotten slower. Back in the early 80’s I would run 10K’s in the 36-37 minutes and not place in the top 3 of runners 40-44. I see some races in my area now that time like that would win the race:). So much for tech.
Hey get fit, keep running. Closing in on 75 and still running 40-50 miles a week, all be it, a hell of a lot slower.
Nick
Click to expand...

Amazing - I run around 100-150 km’s per month so not even close to your level. I take my hat off to you sir
 
Long Run Nick said:
My initial thought on posting was to simply comment on my experience comparing the AW2 GPS distance to my Garmin- wearing both watches- one on each arm, same course, same time. Some feedback got wrapped up on course measurement and racing. I have run over 500 races and have directed and use a calibrated wheel to measure courses so I am aware of the route when running. Anyways, the best input was trying the native workout app and not using the Nike app. Also, the comment on GPS accuracy on a track is spot on.
For over 20 years, prior to all the tech/GPS/HR, etc I ran with a base Casio Watch. What is interesting to me is overall average running times at races I compete in seems in general to have gotten slower. Back in the early 80’s I would run 10K’s in the 36-37 minutes and not place in the top 3 of runners 40-44. I see some races in my area now that time like that would win the race:). So much for tech.
Hey get fit, keep running. Closing in on 75 and still running 40-50 miles a week, all be it, a hell of a lot slower.
Nick
Click to expand...

You are awesome! And although I’m not as old, I’ve noticed the same thing about race times getting slower. I know a lot of runners, but not that many who really try to be competitive. That’s the joy of it for me!
 
I notice essentially the same thing with my AW3 - tracks are generally a little long compared to my previous Garmins, usually by .1-.3 of a mile over ~8-10 miles. So far I can't say for certain one is right and one is wrong, as they both seem to be consistent in their own way. That said, I have much more experience to trust that the Garmin's are consistent so the jury is still out for me with the AW. I do love running with the same watch I wear the rest of the day though, and appreciate having cellular connectivity on the go.
 
I was having problems with inconsistency between my series 2 vs. the iphone's GPS. The aw was overstating distance by up to 15%.

After a little research, I fixed the problem but I'm not sure which remedy actually worked. I tried two things and afterwards the watch was super on compared to the phone. Note that the phone was pretty accurate compared to a 5 Mile certified course (5.06 vs 5).

Anyways I did an unpaid/repair. Also, I made sure that I had the right settings checked on (Settings>privacy>location services>Motion calibration & distances)

After that, the watch and phone were dead on
 
Resqu2 said:
I run several 5ks on my trail, it’s an out and back run. Every official race ends up being exactly 3.1 miles on my watch. I run the same course at least 3 times a week and always turn around at the same spot and it’s always 3.1 miles on my watch.
Click to expand...

My results are similar to yours. I run a 5K loop around my house. I've only ever measured it using apps on my phone (Nike, Strava, etc) and google mapped it, but it's always showed up as 3.1 miles, and when I run it with my apple watch, it always comes back as 3.1 miles. It's never off at all.

For those that are seeing overly generous distances, I'd be curious to know if your extra distance increases proportionally to the length of your run. If it's off by 5% over 9 miles is it also off by 5% over 5 miles and 15 miles. My guess is that the difference in distance is during the initial mile or so of the run, due to the auto-start of the GPS feature. Possibly the area you are running in doesn't get as good of a satellite lock at the beginning of the run, and so that section of the run is off, but once it locks, it's as reliable as any other GPS watch. Just a guess, and since we can't see what's going on with the GPS, it's hard to say for sure.
 
mk313 said:
My results are similar to yours. I run a 5K loop around my house. I've only ever measured it using apps on my phone (Nike, Strava, etc) and google mapped it, but it's always showed up as 3.1 miles, and when I run it with my apple watch, it always comes back as 3.1 miles. It's never off at all.

For those that are seeing overly generous distances, I'd be curious to know if your extra distance increases proportionally to the length of your run. If it's off by 5% over 9 miles is it also off by 5% over 5 miles and 15 miles. My guess is that the difference in distance is during the initial mile or so of the run, due to the auto-start of the GPS feature. Possibly the area you are running in doesn't get as good of a satellite lock at the beginning of the run, and so that section of the run is off, but once it locks, it's as reliable as any other GPS watch. Just a guess, and since we can't see what's going on with the GPS, it's hard to say for sure.
Click to expand...

I would have to take a bit more closer look, because most of the routes that I run that are repetitive are in the 6-10 mile range. Usually when I run longer than that I start to vary more so have less to compare with my old Garmin tracks, but my feeling is that it's not just a matter of being off at the beginning. If I compare the tracks made by the AW with those made by the Garmin over the same terrain, the Garmin track is much smoother, and more accurately follows the route I actually took. For this reason I think the AW is truly off by a bit more than the Garmin, but given that it's on the order of 0.1-0.3 miles in 10 it's not a big enough discrepancy for me to generally care too much.
 
Abstract said:
For those who have inaccurate readings, are hills involved??

Just curious if that makes a difference. I’ve never used a GPS for running before. Have never run with my phone.
Click to expand...

In my case the track is flat but an earlier poster explained why the track is so far off. My trail is wooded and mostly flat and is 100% accurate.
 
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