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Author Topic: ios find my iphone app - accuracy  (Read 3844 times)

Weaver

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ios find my iphone app - accuracy
« on: March 04, 2019, 08:51:18 AM »

I often use the “find my iphone” app, mainly in order to find my wife who will be attached to her iphone usually or her ipad too. She doesn't stray more than a hundred metres of so away. If I'm in bad pain for example and need to summon some help, I can use the app's feature where it will trigger a remote pinging noise on the target machine. This is a life saver, metaphorically speaking, thus far anyway.

I'm wondering if there might be any trickery I could do to increase the accuracy of the location of an iDevice in the map?

It clearly uses mobile phone network cells, but i'm thinking that it picks up wireless lans too. Isn't there some message that one sees somewhere in an iOS device that says that turning on bluetooth improves location services? not sure how.

i'm thinking that in the case of my wife at home her iphone is located by this system relative to my waps maybe? i have two waps currently and a third waiting to be set up. they are i suspect not very helpful to location service as they are very close together. there's an upstairs one and a downstairs one as things are just now and one is very roughly not too far off being vertically above the another.

i wonder if the system would be aided if there are two waps say if would it then be able to triangulate? i don't know whether or not it can get the distance from each?

anyway, that creates the possibility that one could improve location accuracy on the map by having more waps and by repositioning them spaced out in a certain way. if it can't do triangulation then any intelligent positioning might be down to venn diagram like overlaps maybe?

I can't reposition the waps that i have now though.

i wonder if there is anything else that I can use, including the mysterious bluetooth.

anything that i could do without too much hassle that would aid the location accuracy, that would be helpful, as the positioning can all be a bit all over the place on the map sometimes, so that i can't work out whether Mrs Weaver is inside or outside even.
if my beloved is feeding her two donkeys then i know that she won't be able to necessarily pick up a message or a call for help so quickly, and she might need the remote loud ping feature to be able to even hear me.
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sevenlayermuddle

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Re: ios find my iphone app - accuracy
« Reply #1 on: March 04, 2019, 09:59:18 AM »

iOS is meant to use whatever it can at any given moment for location, being cells, Waps, Bluetooth, or GPS.

WiFi does support time of flight in some measure.   My iMac uses it in deciding whether to allow my watch to unlock it, based on actual distance (8 feet, I think), rather than assuming anything about signal strength.   Car manufacturers with their flawed keyless entry systems, that are easily spoofed by signal boosters, could learn from that, but that would be another thread.

But I do not know whether iOS location uses time of flight to ascertain Wap distances.    Another recent thread, we speculated that iOS might need at least two consistent Waps within earshot, before trusting location, as a single Wap might have moved since its location was last known. Just speculation though, I’ve never seen anything definitive pubslished by Apple.

Iphone should be able to use GPS, which would obviously trump WiFi or cell towers for accuracy.   But for some reason it has been spectacularly unreliable for the past few iOS versions.    When tracking better half, her location can be several miles adrift, even in open air under a clear blue sky.    It’ll suddenly improve (accurate to feet) if she unlocks her phone, but that should not be necessary.

I have tried long and hard to figure out a way of getting around that GPS bug of last paragraph, so I can track her properly, but never succeeded.   It used to work and my old iPhone 5c, stuck at iOS 10, seems much more reliable.
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Weaver

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Re: ios find my iphone app - accuracy
« Reply #2 on: March 04, 2019, 08:42:22 PM »

My beloved’s iPhone is sometimes shown at an implausible place, down on the road to the east of the house. That is testing the res of the system tho, as we are not talking large distances, the whole area under consideration here is only a couple of hundred metres radius or so. But anyway, in such a situation I have literally pinged the IPv4 address of her iPhone’s WLAN interface and if that doesn’t work, the address of her 4G NIC. Both are static routable addresses. The idea is to wake the phone up. I do get the feeling that this can help a bit.

What I don’t know is whether the devices located have to themselves reply, report in, and give their own coordinates, or whether some central system has some cached info, or whether other local devices report on MAC addresses of known devices.

I was wondering what bluetooth’s role is in all this.

I also wondered about beacons and iBeacons whatever they are called, which announce stuff. They might or might not have known coordinates. I wondered if they were relevant or could even assist.

This snooping is of course with my beloved’s agreement. We can locate each other. It’s just rather  one-sided in that I myself never move more than ~8m.
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sevenlayermuddle

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Re: ios find my iphone app - accuracy
« Reply #3 on: March 04, 2019, 10:55:07 PM »

Caching does happen, though seems to be also updated with a realtime device communication.   If I check better half’s location it will typically show a dot on the map accompanied by the time it was last updated, eg “47 min ago”.      After a few moments, it will usually change to “now”, and the dot on the map may also change.   

Bluetooth uses nearby iBeacons for location.  My understanding, which may be wrong, is that rather than geographic coordinates, the beacon simply tells a device within (say)  a supermarket that owns the beacon, that the device is near the Deli counter, so a corresponding App may spam the owner with ads for speciality cheeses.  As said though, unsure of my facts on iBeacons.

Per location of actual Waps, maybe beacons too, I believe that to be crowd sourced.   Eg, Some unrelated phone, which already knows its location from GPS, can update the databases when it spots a Wap.   Thus the location of the Wap is stored and can be used to locate subsequent devices that don’t have GPS, or can’t see enough satellites.

Emphasise repeatedly though, above is not authoritative, just my understanding.    Google knows more than I do, if you have time to ask. :)
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Weaver

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Re: ios find my iphone app - accuracy
« Reply #4 on: March 04, 2019, 11:44:39 PM »

Is there any way I could gain any advantage from beacons - parking them at strategic points more widely spaced out around the place ?
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