Strava speeds

[si_c]

Well, I tend to think that maybe the more expensive phones will have better hardware = more reliable, but that's just a hunch.

They all use the same basic chipset, differentiation comes mostly from the camera, screen, storage space and processor speed.

Very little between cheap and expensive phones really.

 

[r04DiE]

They all use the same basic chipset, differentiation comes mostly from the camera, screen, storage space and processor speed.

Very little between cheap and expensive phones really.

Thank you for that, interesting, and someting that I have wondered about. But could a better processor / more RAM increase the reliability of the GPS in any way?

 

[si_c]

Thank you for that, interesting, and someting that I have wondered about. But could a better processor / more RAM increase the reliability of the GPS in any way?

It's unlikely, they all use assisted GPS to improve accuracy, the problem is likely IMO to be the relatively slow polling speed of phones compared to a dedicated GPS device, probably to conserve battery. Quite happy to be corrected if wrong though.

 

[r04DiE]

It's unlikely, they all use assisted GPS to improve accuracy, the problem is likely IMO to be the relatively slow polling speed of phones compared to a dedicated GPS device, probably to conserve battery. Quite happy to be corrected if wrong though.

Thanks for the info

 

[Dogtrousers]

That average speed differential is surprising. They both calculate average speed by dividing total distance travelled by moving time. Is your Garmin set up to pause when you stop but phone isn't? Otherwise it must be that the Garmin is recording a lot more distance than the iPhone. My Garmin is pretty accurate so I guess yours is too which would mean it is the iPhone that is inaccurate (assuming you ride at 14 mph that would be a 7% error which is a lot)

Top speeds tend to be quite accurate. I notice that the Garmin goes a bit wonky when I'm in a heavily wooded area; speed drops as it struggles to find the GPS but the average corrects itself when it finds a good signal

"Moving average" is a moveable feast. Different devices and websites will give you different figures. I think this is because different algorithms will be used to determine what is moving and what is stopped (remember a stopped device will still seem to dither about). Also sample rates will probably affect it. That's why "moving average" is such a dubious measure. You can only compare like-with-like. For example my Garmin will always give a different value at the end of a ride to what RWGPS will give me once I've uploaded it. "Moving average" thus isn't really a speed, you shouldn't put miles or kilometres per hour after it. It's just a "fastness index".

It's unlikely, they all use assisted GPS to improve accuracy, the problem is likely IMO to be the relatively slow polling speed of phones compared to a dedicated GPS device, probably to conserve battery. Quite happy to be corrected if wrong though.

I'm not 100% sure, but I think A-GPS assists with time to first fix (speeds up downloads from the satellites) but once you have that fix it doesn't improve accuracy.

 

[si_c]

I'm not 100% sure, but I think A-GPS assists with time to first fix (speeds up downloads from the satellites) but once you have that fix it doesn't improve accuracy.

You could well be right. Android does however use additional information to assist in location services, including cell tower location/strength and WiFi hotspot location and strength, so it's not entirely a moot point. No idea regarding crapple i-thingies .

 

[Arjimlad]

Hurrah for the information above !

I have noticed that most of my PRs were set years ago when I was using a phone app for Strava. Now the Garmin is in service it's unusual for me to bust any of those even though I am of course sleeker and more athletic.

 

[HLaB]

Strava speeds are completely garbage IME. IIRC for RL on the flat it had me doing 52mph, just before and just after was 25mph, so I know what's more likely ;-)

I've also seen stupidly short down hill segments clocking folk at 200+mph. Me thinks thats garbage too ;-)

 

[Kajjal]

The accuracy assuming your device is a decent enough one depends how often it updates your position while you are riding. Some have an adaptive approach which can mean as little as once every 30 seconds, my edge 500 is set to update every second which makes it accurate enough for speed and distance.

 

[T.M.H.N.E.T]

The accuracy assuming your device is a decent enough one depends how often it updates your position while you are riding. Some have an adaptive approach which can mean as little as once every 30 seconds, my edge 500 is set to update every second which makes it accurate enough for speed and distance.

Data recording setting that has nothing to do with gps, it changes the amount of data that is recorded and this is reflected in file size.

 

[lazybloke]

GPS receivers and antennae come in all manner of price points and accuracies. Dual system ones that use both the US and Russian (Glonass?) systems are much more accurate than traditional US-only systems.
The European Galileo system will be better than any other system (when finished) but you'll always have best accuracy when using multiple systems. Especially under foliage and in so-called urban canyons.

If you zoom in closely to maps on strava you can see if the gps track has any glitches (which can result in odd speeds). Similarly the speedbtrack should be "smooth" with no weird spikes. Zoom in really tightly by dragging a selection on the analysis profile diagram to see see your detailed speed for that selection.