Garmin InReach Mini 2 – 1.5 Hour Long Inaccurate GPS Location On Mont Albert

I’ve had that happen on my old Garmin GPS

Once, it told me I was going the other direction when I got to this road.  That didn’t make any sense so I ignored the GPS and went the right way.  Then it gradually came back to correct location.

I think this is just a property of GPS.  It’s usually good, but occasionally you just have to ignore it.

There is an age old analogy here.  For decades, we have taught medical people who are sitting at a desk reading charts, labs and looking at monitors.  If something doesn’t seem right, get off the chair and go actually look at the patient. A thousand years tried and true technique.  This electronic behavior is not unique to GPS units, watches or phones.  I have a whole closet full of units going back into the mid 90’s and they all do this on occasion. A healthy disrespect of electronic devices is being lost in today’s world. If the data is suspect, reboot. In the meantime, look around in the real world with compass and topo in hand.  Even with the amazing ability of the military hardware and software engineers, the F18 has a big red button that if the pilot suspects a disconnect from the computers and the real world, they press it and it reverts to the last software version.

Could be a lot of  things. But first thing to try is to turn it off and restart… just like when any computer goes crazy…

These last two remarks remind me of the true story of the saturation diver whose cable was severed on the bottom of the North Sea when his ship’s state of the art GPS auto-piloting software went bananas and drifted away. I think about 20 minutes were lost as the crew tried in vain to manually head back over his precise location in the storm.

They finally simply rebooted all the computers and the auto-pilot zoomed straight back on site. This story is recounted very well in the movie “Last Breath,” which I think is on Netflix.

I found this interesting. It was tracking perfectly, just bumped over due to the initial error. If it was this accurate in plotting its points all throughout, why would the points erroneously plotted be relative to when the course got wonky on the plateau? Just a random musing from a retired programmer who also needs a reboot.

OR… it was them thar goldurn Roosian or Chinese messing’ with our GPS satellites! ;o)

I’ll have to remember to restart the device when things feel off on the Garmin, although that’s not always always easy to spot in the moment.

@Mark L, I hadn’t noticed that the track has the same shape even while it’s too far West. Almost like the new points are being updated with a differential relative to the previous point. Maybe it gets a key point every now and then which then puts everything back on track.  This is very much a guess.

A few speculations on what might or might not have happened:

– Every GNSS device has different position update intervals. If the Apple Watch updated OK, then the inReach updated and got a wild position (or several) a few minutes later, the inReach might have tried averaging the wild position with following positions until they converged again. Not how I would have designed the software.

– Good old rare software bugs. Wouldn’t be surprised if an Apple Watch goes off-trail sometimes, too. Even your red line cuts across a corner for unknown reasons.

– The inReach and Apple Watch were listening to “all” GNSS systems after you set the inReach to Multi-GNSS. Apple Watch 7 & 8 specs say they listen to “GPS, GLONASS, Galileo, QZSS, and BeiDou,” and I haven’t stumbled across a setting to change that. So in broad terms, any system fudging, spoofing, or jamming should have affected both devices equally – except for the position update interval problem.

– There are other ways a GNSS device can mislead you.

As others have stated, maintaining spatial awareness and map & compass skills are still critical. Your situation reminds me of the old joke that someone with two watches never knows what time it is – because they never agree. Now its GNSS devices.

Just throw out the obviously incorrect Apple Watch track, and brag about your high-speed cliff climbing and descending skills :-)

— Rex

@Rex

– Good old rare software bugs. Wouldn’t be surprised if an Apple Watch goes off-trail sometimes, too. Even your red line cuts across a corner for unknown reasons.

That happened because this user forgot to un-pause his Apple Watch after taking a break. Unfortunately for me, I’m better at pausing than un-pausing.

Love the points about two DNSS devices and re-thinking my story telling about the trip route :)

Single event upsets (SEUs) occur in computer circuits when high-energy particles such as neutrons or muons from cosmic rays or gamma-rays strike the silicon used in microchips. This generates an electric charge that can change the internal voltage of nearby transistors… etc.