I just did a 20 km ride and the Garmin 130 added about 14km to the ride. Weird. It started normally then after about 30 seconds the speed when blank as if it lost the gps signal. Then came back on within a few seconds. The track when I downloaded it looked like Some drunken bird had flown around with it. Is GPS subject to magnetic storms causing poor tracking? I thought GPS was immune to that.
GPS receivers are getting signals [electromagnetic waves] that are very precisely timed to generate a position based on the geometry of the satellites used and the distance from each satellite to the receiver. So anything that will impact electromagnetic waves in that frequency band will affect GPS positions you see. Any sort of atmospheric phenomenon that's disrupting GPS signals would affect a wide swath of users on the ground so you'd hear a lot of grumbling. You can have localized issues under power lines, under tree canopies or near tall buildings. Consumer GPS units are [relatively] cheap/basic electronic devices. They can glitch/fail/error without needing anything external to happen.
And just like that it’s working fine again this morning. I’ve had a Garmin of some sort since they came out and I’ve never had an error like this one. Dropped signals were common with my first 105(?) unit but they have improved the accuracy a lot since then. Mostly too complex for what I’m wanting but the 130 I have now has been very good for a few years now. If this anomaly is the first indication of the unit failing, I may go without.
Don't think I've seen quite your issue, but I typically track my rides with my phone. I will sometimes get anomalous tracks, like a half mile line straight out and back that registers at like 60 mph, to a place I never went. Can't speak for Garmin, but it hasn't been a degradation, more like occasional blips.
Does it need a firmware update? My Edge updates automatically as required through Garmin Connect but you may or may not have that feature turned on.
Also related to updates, previously I had a Garmin Fenix watch and at one point it had what was effectively a bad (out of date) lookup table for the signals Vik mentioned. Again, a firmware update and a full reset and it returned to proper function.
I think a reset, followed by an update check, followed by a full wipeout/restart is how I would proceed to get it running again.
Posted by: mrbrett
Does it need a firmware update? My Edge updates automatically as required through Garmin Connect but you may or may not have that feature turned on.
Also related to updates, previously I had a Garmin Fenix watch and at one point it had what was effectively a bad (out of date) lookup table for the signals Vik mentioned. Again, a firmware update and a full reset and it returned to proper function.
I think a reset, followed by an update check, followed by a full wipeout/restart is how I would proceed to get it running again.
I checked the updates. It’s turned on and indicates that it’s all up to date. And it’s back to normal for now. Good advice though. If it happens again I’ll wipe it clean and reset everything.
This one from a bike park day was particularly egregious.
Pretty solid average speed. Nice work!
just got a new iphone and my first test ride with TrailForks resulted in a excessively wiggly yellow line up Mtn Hwy and all the trails I rode down from there. The yellow wiggle did not deviate more than 15 m from map lines on the TrailForks app, unlike my old phone which had straighter lines but my track could be parallel but off the mapped trail by 50 m. Three significant trails were not picked-up/recorded as ridden, but some little poodle path stuff that previously wouldn't get picked up did get recorded. I checked all the location and battery settings on my new phone and nothing was incorrect
Posted by: taprider
just got a new iphone and my first test ride with TrailForks resulted in a excessively wiggly yellow line up Mtn Hwy and all the trails I rode down from there. The yellow wiggle did not deviate more than 15 m from map lines on the TrailForks app, unlike my old phone which had straighter lines but my track could be parallel but off the mapped trail by 50 m. Three significant trails were not picked-up/recorded as ridden, but some little poodle path stuff that previously wouldn't get picked up did get recorded. I checked all the location and battery settings on my new phone and nothing was incorrect
I’ve always found the phone based GPS systems to be inaccurate. So much so that a friend of mine asked about the new trail I had recorded on Strava that crossed the Cheakamus river in a new spot. The Garmin based tracks were always much more accurate as of late.
Posted by: UFO
This one from a bike park day was particularly egregious.
That is some fast there boy. Print it and frame it for the shop wall to show your grandkids some day.
Posted by: andy-eunson
Posted by: taprider
just got a new iphone and my first test ride with TrailForks resulted in a excessively wiggly yellow line up Mtn Hwy and all the trails I rode down from there. The yellow wiggle did not deviate more than 15 m from map lines on the TrailForks app, unlike my old phone which had straighter lines but my track could be parallel but off the mapped trail by 50 m. Three significant trails were not picked-up/recorded as ridden, but some little poodle path stuff that previously wouldn't get picked up did get recorded. I checked all the location and battery settings on my new phone and nothing was incorrect
I’ve always found the phone based GPS systems to be inaccurate. So much so that a friend of mine asked about the new trail I had recorded on Strava that crossed the Cheakamus river in a new spot. The Garmin based tracks were always much more accurate as of late.
Phone probably works a lot better on your handlebars. Pocket no bueno.
Posted by: andy-eunson
That is some fast there boy. Print it and frame it for the shop wall to show your grandkids some day.
I have a good day job that I enjoy. The world cup DH guys should be thankful for that
Posted by: andy-eunson
Posted by: taprider
I checked all the location and battery settings on my new phone and nothing was incorrect
I’ve always found the phone based GPS systems to be inaccurate.
These days, phone location services rely heavily on Wi-Fi to figure out where they are. When that isn't available, GPS is the fallback, and that typically isn't great because the GPS antenna performance is often sacrificed so as to not interfere with the Wi-Fi and wireless antennae, and it is located to perform best when holding the phone upright. That's why they work better when mounted on handlebars.
Even a low-end GPS unit will have a much better antenna and signal reception.
As for GPS glitches, they just sort of happen every once in awhile. Here's one from my Lezyne unit on a road ride a few weeks ago when I was heading north.
GPS glitches are inherent to how the system works. I've had them from time to time with all the devices I've used.
I find that it helps to allow some time for the device to get a good signal before you start your activity. Best to stand in an open area (i.e. not under tree or close to high buildings etc.). Only start moving once the device locks on to the satellites. During the activity, best to have the device as unobstructed as possible (i.e. not in your shorts pocket).
Most of the issues I've had with funky GPS tracks that look like I was drunk were when I didn't have the patience and started before getting a good signal. This was often the case when I started right outside our high apartment building in North Van.
I'm usually not too bothered when a recorded track is inaccurate but when I absolutely want to have a good track for future rides I use redundant devices (watch + phone).
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