Calculation of the ETA
I have a question about the data field ‘ETA’.
I love this function, I used it for trail running on my Garmin Fenix 3 over 10 years ago.
The time that is displayed is unfortunately not quite realistic at the beginning. I know it takes a while for a system to display a target time, but after 10 km it should be the case.
Funnily enough, the finish time was only relatively correct with a deviation of +/- 5 minutes after the first climb of about 3 kilometres, but by then I was already running 15 kilometres.
Before that, the planned finish time was at a pace of I would roughly say 23-25 KM/h purely mathematically. The funny thing is that my average speed after 10 kilometres was around 21-22 km/h.
So how is the ETA calculated?
Maybe Hammerhead can say something about this?
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Hi Markus, Just to explain how it works: during the first hour of the ride, we use a weighted average of your current speed and 15 MPH. After that, it switches to a weighted average of your speed over the last hour and your total ride average. That’s why the ETA might not feel realistic early on, but usually gets more accurate as the ride goes on. Our team plans to improve this calculation in future updates to make it even more reliable. Thanks again for your feedback.
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@Bhagyashree:
Thanks for explaining how the ETA is calculated.
A start calculation with 15 mph, regardless of bike/route type and ascent/descent seems not very sophisticated. And 15 mph are to much for me (old man on MTB rides through forrest and trails).
If you would use the average speed of the latest rides or a setup parameter instead it would become more realistic, especially for me, I'm usually doing round trips with similar elevation profile.
I would like to use the ETA for a decision whether I can do a route in time e.g. before a date or before sunset. Therefore I need a reasonable ETA at route start. With the current 15 mph start calculation, the result is far off and useless for me.
For long term, you should develop a ETA calculation, which considers the bike type (MTB, gravel, race), the route type (trail, road) and the elevation profile and personal fitness.
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I’m having the exact same bug on my Karoo!
Just yesterday
it showed 5.58 km remaining at 08:26, with an ETA of 08:28... basically expecting me to pedal my e-MTB at 170 km/h!It’s completely absurd for a modern flagship GPS. Resetting and updating the software didn't change a thing, so it's definitely a core flaw in Hammerhead’s routing algorithm. Really hope they wake up and fix this ASAP.
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Update: I unlinked the e-bike speed sensor and tested pure GPS speed, but the bug is still there!
Here is exact pattern: at start, the ETA is realistic. After about 6-7 minutes, the algorithm completely breaks down and drops the ETA to just a few minutes, even with 20 km left. From that point on, it simply adds 1 minute to the ETA for every real minute that passes until the destination.
This proves it’s 100% a core software bug in Hammerhead's calculation engine, completely independent of external sensors.
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