Slow Speed (purple display) in Tunnels

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Mighty Malc
Posts: 56
Joined: Wed Apr 22, 2015 3:43 am

Slow Speed (purple display) in Tunnels

Post by Mighty Malc »

I rode Garda Lake Loop part 4 for the 1st time this morning.
In many of the tunnels (at least 8 times by my rough count) the speedometer display went purple and my speed was shown as about 4 km per hour for long periods of a minute or two (not the odd second). As I came out of the tunnel it went back to the usual display colour with genuine speeds (30-50 km per hour depending on the tunnel). So the effect seemed closely linked to being in the tunnel or not being in the tunnel.

Some of the tunnels were empty of traffic, so its not as if the route needed to be filmed slowly leading to a purple display. I am guessing the problem was something to do with losing the GPS signal in the tunnels so distances and speeds were recorded too small. Supporting this theory, the website has the course length at about 36 km (matching the corresponding website profile). whereas the profile shown in the VeloReality App is 26.8 km so it looks like up to 9 km of the course might be missing - lost in the tunnels due to GPS issues?

My reported average speed (correctly matching distance travelled with time) was quite impacted by the forced stretches at 4 km per hour. For a relatively flat course like Garda I would have expected say 32 km per hour, certainly 30+, whereas it was reported as 26.4 km per hour over a period just under an hour. So the slow stretches were taken account of. I guess this is good because consistent, but feels irritating when riding long purple stretches.

If it is GPS problems in the tunnels leading to camera speed deemed too low as ~4 km per hour and tunnels being correspondingly short, is it possible to simultaneously scale camera speeds and hence tunnel length to recover the 'missing' tunnel bits?

I guess this may be too difficult - but thought I would ask!
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admin
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Re: Slow Speed (purple display) in Tunnels

Post by admin »

Yes it is a problem with GPS signals in tunnels and also GPS device still trying to deduce something. We might find some solution that is more graceful then the current one for such situations but we do not consider it showstopper so some other tasks might take precedence
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Mighty Malc
Posts: 56
Joined: Wed Apr 22, 2015 3:43 am

Re: Slow Speed (purple display) in Tunnels

Post by Mighty Malc »

Rode this again yesterday with the new option to turn off Virtual Brake.
Really enjoyed the ride, travelling at a sensible speed in the tunnels now. I think the video jumped a bit to keep up, but inside the dark tunnel it was hardly noticeable from a visual point of view.
So thanks for offering the Virtual Brake option - a great success in this case.

I actually 'raced' my previous slow performance. Yesterday I was still recovering from a cold and consequently very slow. I could not match my previous performance until we got to a tunnel section where the forced Virtual Brake slowed him down so much I caught up rapidly and dropped him. This happened repeatedly as he caught me once through the tunnel - and was dare-I-say-it very satisfying.
It did make me wonder if an option to replay past performances with a choosable % multiplier (both faster and slower) for their speed would be worth considering? Or of supplying pacers travelling at selectable fixed wattage?
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