Mobile phones and sat-nav's

Questions or advice on GPS, mapping software, CB's, Sat phones etc

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Brian-reynolds
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Mobile phones and sat-nav's

Postby Brian-reynolds » Mon Mar 09, 2020 10:49 am

Just a quick ask here....

I think, maybe last April, at the AO show there was an ex-Army navigator chap that gave a lecture on why mobile phones do not (very loose term) have a GPS fitted....

He gave a very interesting lecture and I am sure some of you also attended?

Can any of you remember what his name was please? I suppose I could ask Tom, but thought I would ask here first......

TIA, B.

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Re: Mobile phones and sat-nav's

Postby crinklystarfish » Mon Mar 09, 2020 3:23 pm

Bri,

Was it this seminar?

11:00-12:00 Room 3 Mike & Sue Wood
Survival without Satnav – navigation for the nervous?

As per personal discussion, I'm curious to know what was said as I'm almost certain all smartphones as we now know them have built-in satellite receiving hardware (just like a 'regular' satnav device) and do not require any network assistance, extrapolation or other functionality to act as a navigation device.

Of course, they can be set to have cell / wifi networks (allegedly) enhance the GPS function (AGPS), but it's not necessary.

As before, we went all the way round the Balkans last year with my Android phone and Maps.me with all data and cell services well-and-truly disabled. I can't for the life of me see how this would be possible if the phone didn't have standard GPS receiving hardware fitted.

If it turns out there is some other black art at work, I'm totally open to learning.

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Re: Mobile phones and sat-nav's

Postby NeilandPat » Mon Mar 09, 2020 5:22 pm

Steve, I am certain you are correct.

Sorry Brian


We have had our smart phones and tablets in the middle of nowhere, literally maybe 200km from civilisation.

No phone signal or internet or any cell device at all.

Location on the phone and tablets works a treat, so I think they must have a real gps receiver in them.

The tablets aren't phone or SIM equipped so it must be gps.

Neil

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Re: Mobile phones and sat-nav's

Postby crinklystarfish » Mon Mar 09, 2020 5:51 pm

I know it's the case that position can be fixed with cell networks only, and that some tracking apps like Polar Steps can purportedly be made to work by pinging regular cell masts and no reliance on GPS or GLONASS receivers.

Older phones were heavily dependant on General Packet Radio Services (GPRS) but for current satellite-based positioning this just isn't required. I can only think there's was some misinformation or lack of clarity at the seminar.

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Re: Mobile phones and sat-nav's

Postby Brian-reynolds » Mon Mar 09, 2020 9:54 pm

crinklystarfish wrote:Bri,

Was it this seminar?

11:00-12:00 Room 3 Mike & Sue Wood
Survival without Satnav – navigation for the nervous?



That's the seminar, now I wonder if we can find the actual notes, or a copy of what was said.

In my intro, I said
"why mobile phones do not (very loose term) have a GPS fitted...."
It would seem the bit (very loose term) was not very well written by me, as that is what I meant, a very loose term, by that I was not saying they do NOT have a GPS chip, they just do not have the complete chipset, as discussed in the above seminar, so that was why I was asking if we could find out exactly what the chap was saying as it was very interesting, then let him discuss his reasons.

On my smartphone I did about a mile stood next to my kettle waiting for it to boil... I also walked about 5 miles according to my mobile, whereas my Garmin Oregon 300 antique said it was actually 3.5 miles.....

Steve has explained to me why he thinks the smartphone is indicating a conflicting distance, but I am still interested in what Mike Wood said in his original lecture.

Anyone have a copy?

I can't attend another lecture he may give, as I have no intentions of going to another AO show, which is a shame......

Did Mark Hadley attend this lecture? He may be able to explain what was actually said...

B.

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Re: Mobile phones and sat-nav's

Postby crinklystarfish » Tue Mar 10, 2020 6:18 am

To clarify, I think what might have been happening was that Brian had his phone set in Assisted GPS (AGPS) mode and in the case of the 'kettle incident' was stood in a fully enclosed steel-clad barn.

I suspect the phone was struggling to fix position using satellites so was also pinging cell masts to try to extrapolate a position from packet data.

Likewise, though, a steel barn is not the best place to pick up cell data.

I'm guessing, then, that the phone was constantly faced with conflicting data as it tried to gain enough information to get beyond trying to approximate a location to a point where it could fix the actual location (next to the kettle).

All this time Brian had a tracking function running in some mapping software.

[Speculation] Because the phone was approximating positions and therefore constantly switching from one approximate location to another, the mapping software tracked each approximate positional 'jump' as if it was an actual movement on the ground instead of just standing next to a kettle. [/Speculation]

My suggested solution was to turn AGPS off and wait for a proper fix just using satellites.

I hope the notes from the seminar can be discovered as I'm curious to know what the bloke was trying (without much success, it seems) to get across. If indeed he said smartphones "...have a GPS chip, they just do not have the complete chipset" then that's fine and dandy. I guess he might have been trying to say that the hardware / firmware wasn't as sophisticated as some dedicated satnav devices, but who's surprised?

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Re: Mobile phones and sat-nav's

Postby Brian-reynolds » Tue Mar 10, 2020 10:48 am

Just to clarify what was said above...

I was not in the barn at the time of making a cuppa, I was in the carpark at Bubwith on the old rail track.

Plus it was the same rail track the I took the measurements with the Garmin Oregon alongside the mobile.

Obviously you are quite right about being in the barn when playing when you were here, but I think it does the same when outside as well, but I will need to check that......

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Re: Mobile phones and sat-nav's

Postby crinklystarfish » Tue Mar 10, 2020 11:53 am

I'd guess it's the same issue, though, ie the phone unable to fix position by satellite so repeatedly approximating via the cell network.

Turning AGPS off and using just the inbuilt satellite receiver should sort it. That way, you'll either have no positional fix at all, or a full fix; with none of the 'jumping' and artificial track logging in between.

That's my best guess, anyway.

FWIW I've previously used my Android phone together with the Strava app in pure GPS (ie not AGPS) mode to log run / bike sessions all over the place and it's always logged tracks accurately enough. Not to say it hasn't occasionally lost satellites and 'straight-lined' or thrown the odd wobble, but I've never seen the 'jumping' effect and, essentially, it's been cock on.

I more often than not these days use a very simple Polar wrist-worn heart rate monitor / GPS logger to log training sessions and races. I'd say it's no more stable or accurate than my phone but it is much more convenient and functional.

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Re: Mobile phones and sat-nav's

Postby crinklystarfish » Tue Mar 10, 2020 12:09 pm

Should probably add - I think the idea behind AGPS is that it'll very helpfully pick up the slack in cities where satellites may be lost behind tall buildings but where cell-signals are strong and Wi-fi networks abundant. It's undoubtedly brilliant for hipsters to track themselves whilst talking about manscaping in barista bars.

When out and about in rural areas I currently consider it simply pointless and battery-sapping.

That may change as the world rushes headlong into 5G. What could go wrong?

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Re: Mobile phones and sat-nav's

Postby Brian-reynolds » Tue Mar 10, 2020 8:28 pm

crinklystarfish wrote:That may change as the world rushes headlong into 5G. What could go wrong?


5G doesn't work in the rain.....


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