I only have my new Edge 820 (no other Bluetooth Garmin devices, my magnificent eTrex remains a loyal servant), but this may be true for any Garmin Edge…

Used my Edge 820 for the first time yesterday. All good, happy chappy. Or so I thought, until seeing where my Bluetooth-connected phone’s Strava app thought I had been. My ride took me to Ghana on the phone, max speed 17,500 mph! Constant systematic error, snail trail spot on shape-wise just not in the right place. The Garmin’s snail trail was fine, this wasn’t a GPS anomaly.

Some testing post-ride and this position error is linked to when my phone is connected to the Garmin Bluetooth. 100% repeatable on two different phones. Google Maps, etc all jump to an incorrect location. WTF.

Obviously now wondering if this is unique to me? Or a common ‘feature’?

Bizarre! Can’t say I’ve ever had to use Strava on my phone at the same time as my 820 though so never had this.

There was a firmware update out a few days ago (3.0) have you applied it yet?

EDIT: A quick Google (or indeed just looking at the option on your phone!) reveals that Location Services on the iPhone uses Bluetooth to help determine your location, so possibly that’s the culprit if the Garmin is sending it some dodgy data! Unfortunately there doesn’t seem to be a way of disabling just the Bluetooth component of LS.

Indeed. It was force of habit using Strava app. But it caught my attention, and more significantly all my phone photos are geotagged somewhere else in the world (unless I disable the BT connection). If you’ve not experienced that (and are using an iPhone), then it would be very useful to know.

Yes. Latest 3.00 firmware, and latest phones’ firmware. I’ve emailed Garmin, yet to get a response.

As you say, I’m thinking there’s an issue with the location in the Bluetooth BLE data (or how the phone is interpretting it), but there’s no way to disable BT use for location services in my phone.

It’s very bizarre!! Another ride today, in the very same place in Ghana (on the phone). As were my photos.

Finally remembered to check this on my ride in this morning. Yep, location of photos not reported correctly. Not quite as badly as yours (a town 50 miles away rather than another continent!) but wrong all the same.

Thanks. Seems a common theme for iPhone owners Garmin Forums thread discussing this issue

It’s a great device which also has its flaws (eg. hyper-sensitive touchscreen and poor battery life when navigating, too). Undecided whether to accept the faults in anticipation of firmware update fixes, or send it back for Garmin to check it over.

Was driving from Swinley to Cymcarn the other day, charging up my Garmin via my cigar lighter on the way (which obviously turns the 820 on and connected it to my phone – this is my only real bugbear with the 820). Tom-tom on iPhone started going mental! Fortunately I realised the problem straight away and quickly turned off bluetooth on the phone.

The touchscreen is annoying when it gets wet (e.g. sweat) however locking it solves the problem for me. Not experienced any battery issues although not used it much for navigating yet.

Yes, my edge 820 is doing the same with my iphone 6 – always end up in Ghana on the phone if the Edge is connected via bluetooth. Any response from Garmin?

Garmin haven’t offered much help yet (apart from initially saying they couldn’t replicate the problem).

https://forums.garmin.com/showthread.php?358788-Bluetooth-phone-connection-causing-large-systematic-errors-in-phone-s-GPS-position

https://forums.garmin.com/showthread.php?360528-Activities-get-transported-to-the-Guinea-Gulf-when-uploaded-to-strava

This is has been fixed (at least on my 820 with the 4.1 update!)

so is the Garmin 820 sending GPS data to strava on the phone via BT?

I would be really surprised if the phone was using GPS data over BT in preference to its own GPS. Normally what happens is the phone recognises a BT or Wifi device as being in a particular area and uses that not for precise position calculation but to know which satellites to start looking for so as to reduce the time to first fix. For example if it see’s a wifi AP with a particular SSID, it will look online to see if that SSID has been seen by another devc

Ghana is just north of 0 degress lat and 0 degress Lon (over the sea). Its possible that somewhere some one has cocked up their maths, most likely the Lat. I have done that a few times myself.

Some quick tests

turn the phone BT off, does the phones position improve?
turn the phone GPS off, does the phone still record a position?

I have a BLE sniffer but no 820, otherwise I could tell you exactly what was going on between the phone and the 820.

I would be really surprised if the phone was using GPS data over BT in preference to its own GPS

well, that’s not quite what was happening, because then the phone would display the correct position anyway! What seemed to be happening was that the BT connection from the Garmin was corrupting the GPS data somehow. (so if you turn off the BT connection on the phone, yes the GPS position on the phone becomes accurate again)

All sorted now though with the new update.

I think it’s due to corrupt GPS data. I had a ride to Russia and back once. In fact that’s the only time it’s happened in three years or so of using Garmin.