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By rikur_
#1739797
Has anyone else had issues with GPS interference and smartphones / smartwatches?

Over recent months, I've been getting relatively frequent GPS dropping in both cars (happened occasionally before, but now more regularly), and with Nexus 7 whilst flying (which never happened previously). Initially I dismissed it as coincidence .... but working back through 'what's changed' it seems to correlate with when I got a new smartphone and smartwatch.

I know the theory that this could be the cause, but has anyone else had similar issues?
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By flybymike
#1739892
I bought a new mini iPad 5 recently together with a protective cover.
Flying with the cover on I had regular drop outs. I removed it.
No further problems. I assume it was blocking the signal to the aerial.
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By Sooty25
#1739924
If you can, try turning off EGNOS. Witnessed instability last year, cured by disabling EGNOS.
rikur_ liked this
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By Sooty25
#1740359
are the drop outs often enough to be predictable?
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By rikur_
#1740426
Sooty25 wrote:are the drop outs often enough to be predictable?

not quite - albeit there is a bit of a pattern and some more regular 'drop spots'.
when driving it appears to be worse when I've got the family in the car (worth noting this is in two different cars), and generally it will drop the GPS at a roundabout or significant change of direction manoeuvre (not all roundabouts, and not always, but there's a bit of a correlation)

when flying it's not happened often enough to derive a pattern - and I wasn't doing anything noteworthy at the times it went (at 4000ft over open countryside)

my hunch is 4G, WiFi or bluetooth interference (family in the car = 4 x mobile phone, 4 x smartwatches). As far as I'm aware, all the watches pair with the phones via Bluetooth so (there shouldn't be any WiFi active), and I thought the low power and frequency hoping nature of bluetooth made it less likely to interfere with other things than WiFi .... so perhaps it points to 4G. Which on reflection, all the 'drop spots' are quite remote, so where 4G is likely to be shouting loudest to be heard.

Paul_Sengupta wrote:The Nexus 7 doesn't have EGNOS. Or do you mean on the device which may be causing the interference?

What about any chargers in use?

No chargers in use
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By Sooty25
#1740506
Install a GPS monitoring App and look at the GPS count and signal strengths. My gut feeling is the GPS receiver in the Nexus is crapping out.
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By rikur_
#1740525
Sooty25 wrote:Install a GPS monitoring App and look at the GPS count and signal strengths. My gut feeling is the GPS receiver in the Nexus is crapping out.

I've used GPS test in the past on the Nexus (when I had issues with PilotAware Wifi interfering with GPS) ..... but ideally I need to find one that logs in the background.
Options for debugging in the car are somewhat limited, so helpful in a way that the issue is now affecting the Nexus too.

flybymike wrote:Do you really need 4G when flying?

Not really - but this started off as an issue whilst driving that I've noticed has also* started affecting Nexus when flying (* it might just be coincidence). Putting phones in airplane mode whilst driving might be more of an issue.
The 4G theory gives me something to try.
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By Sooty25
#1740526
rikur_ wrote:Over recent months, I've been getting relatively frequent GPS dropping in both cars (happened occasionally before, but now more regularly), and with Nexus 7 whilst flying (which never happened previously). Initially I dismissed it as coincidence .... but working back through 'what's changed' it seems to correlate with when I got a new smartphone and smartwatch.



Just so we are clear, is the Nexus being used in the cars and flight, or is this different GPS receivers?
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By rikur_
#1740529
Multiple different GPS receivers.
I first started noticing it in two different cars using their built in satnav systems.
Initially I thought it might be some degradation of GPS coverage, or local interference. Seemed too much of a coincidence for both cars to develop a fault at the same time.
I then noticed it during flying using the Nexus 7 which has previously been flawless for years.
That's when I started to wonder if it was me - or more likely, something I was carrying - and the theory that the problem started when I upgraded my phone/watch.
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By Sooty25
#1740547
sorry, I mis-understood, I thought The Nexus was being used in all three.

What you could try is,

Set the Nexus up working somewhere clear of everything, say in the garden.

Get a GPS APP running so you can see GPS count and strengths.

Then, walk your phone and smartwatch towards the Nexus and see if they have any affect whatsoever on the Nexus GPS states.
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By rikur_
#1740559
Sooty25 wrote:What you could try is,
.....

In the middle of the garden with just GPS and GLONASS enabled, 16 satellites in view - toggling between 14 - 16, showing 3m 3D accuracy.

Place phone and watch either side of the Nexus ..... no step change, still toggling between 14 - 16 satellites.

Switch off WiFi (to force phone to use 4G) - no difference

Start downloading a file (to force some 4G data) - drops to 12 - 14 satellites

Remove phone and watch from the Nexus ...... remains at 12 - 14 satellites

Looks like some impact, but if there is, not much greater than the ambient noise.

My local 4G cell site is in the 800MHz range (band 20) ... clearly there are quite a range of different 4G bands, and it might be that others are having a more noticeable impact.

I hadn't thought about 4G being the cause when I started this thread, but certainly gives me something to test with/without
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By Sooty25
#1740583
the App I use is "GPS Test"

https://play.google.com/store/apps/details?id=com.chartcross.gpstest&hl=en

One of its pages is as follows,
Image

This shows the individual signal strengths of each GPS being received. Try the test using a display like that.
You've established that you are seeing 2 satellites drop out as a result of 4G, what you might see with this screen is that all 14 satellites are being attenuated. In a different location, antenna shielding may be causing a lower initial signal strength, causing a much higher number of satellites to drop out when 4G interferes.
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By rikur_
#1740613
Sooty25 wrote:the App I use is "GPS Test"

same here - indeed using that same screen
it started raining, so I stopped for today
I've got a theory to investigate and an app to use, albeit I suspect I might need to drive to some of the drop spots and see what 4G band is in use there :-)

albeit, what I actually do about it in the end I'm not sure!