Re: GPS Accuracy: Android versus iPhone

[Andy Burnelli]

sms wrote:

> I always wondered why my iPhone Xr's GPS was not as accurate as that on
> my Android devices. Now I know!
>
> <https://medium.com/@importanttech/we-tested-mobile-gps-gnss-accuracy-and-found-some-surprising-results-b9ec35873e2e>.
>
> Wish they would repeat this analysis on newer iPhones.

This thread topic is best leveraged among iPhone & satellite experts.

Notable conclusions...
The tested _iPhones suck at location accuracy_ when only GNSS is used.
The tested Android devices (Pixel & Galaxy) were far better in all ways.

*Often iPhones were more than an order of magnitude worse in accuracy!*
*Often iPhones are five times less accurate than Apple _claims_ they are*

Who knew Apple lied about location performance of the iPhone. (quote)
"*The iPhone XR overvalued its accuracy by 450%*"

Notable charts...
<https://miro.medium.com/max/720/1*6M1CWsA3IZ2M1i_Hja4umg.webp>
<https://miro.medium.com/max/720/1*psFQY8BD491lDufnmBk1jw.webp>
<https://miro.medium.com/max/720/1*eNRIxbWP6pwMKr2-LgOJdg.webp>
<https://miro.medium.com/max/720/1*PozyVyqG6vPEEAsxMe-R9A.webp>
<https://miro.medium.com/max/720/1*UqRd7xBpWV92uKC-43W2CA.webp>
<https://miro.medium.com/max/720/1*dzQUtNSHSZI2Me8yu6CZEg.webp>

I limited this summary to just a dozen key takeaways...
1. GNSS refers to a variety of satellite systems used across the globe.
These systems include GPS (US), GLONASS (Russia), Galileo (EU),
BeiDou (China), QZSS (Japan) and IRNSS (India).

2. Date: May 19th, 2020
Our next test will be in September 2020 (where is it?).

3. Why? We predict accidents with motorcyclists, cyclists & pedestrians.

4. Ultimate goal: Submeter accuracy. Not there yet.
But that's why typical achieved GNSS accuracy matters.

5. Half-inch accuracy using "Arrow Gold" Survey-Grade RTK Accuracy meter.
<https://eos-gnss.com/products/hardware/arrow-gold>

6. Five common phones were tested.
Apple iPhone XR
Apple iPhone 6 SE
Samsung Galaxy 10 Note+
Google Pixel 4
Samsung Core A2

7. All five phones were tested under two fundamental conditions (five).
a. The path taken by the phone (straight vs. curved)
b. Use case of the phone (in hand, in jacket, in pants)

8. In all cases, Apple iPhones seriously underperformed in accuracy.

9. In all cases, Apple lied about the accuracy of their iPhones.

10. Precision was 20% higher precision when moving compared to when still.

11. Accuracy was better on longer paths than on shorter paths.

12. Accuracy & precision is better with phone held stable in your hand
and a coat pocket is better than a swinging hand or pants pocket.

In summary, Apple lied like Apple _always_ lies, and the tested Android
phones outperformed the tested iPhones by an order of magnitude or more.

What else is new?
--
V yrsg gung ynfg yvar nf onvg sbe gur puvyq-yvxr vXbbxf gb srnfg hcba.

[Andy Burnelli]

VanguardLH wrote:

>> Wish they would repeat this analysis on newer iPhones.
>

> Even on my Android smartphone, I've had to reset GPS by deleting and
> re-downloading the A-GPS database.
> https://en.wikipedia.org/wiki/Assisted_GNSS

I admit, up front, I don't know a lot about GNSS and A-GPS, where folks
like nospam and Alan Browne know more than I ever will know about it
(mostly because, for me, it just works, so I don't need to do anything).

But to your specific point of manually re-loading the A-GPS database,
may I ask you "why"... or... more specifically... how do you know you need
to reload it?

What "evidence" or "telltale observation" tells you that you need to
reload the A-GPS database for a phone you've been using every day on GPS?

To be perfectly clear, I've _never_ "felt" the need to do that in all my
years with Android (and prior to that I used plenty of Garmin devices).

Even with the crappy iPads (which truly suck at radio hardware), I don't
feel the need to re-load the A-GPS database - so I wonder how you know
when you need to load it.

What observation do you use to determine you need to reload the A-GPS data?

NOTE: I repeat I know next to nothing about the A-GPS, so if the answer to
how you know you need to reload it is obvious, just state what it is for me.

> I use the GPS Status app by MobiWIA Kft at:
> https://play.google.com/store/apps/details?id=com.eclipsim.gpsstatus2
> I paid $2.14 USD for the Pro version to get rid of the ads and get some
> additional features. Alas, when I try to go to the Google Play Store's
> page for the Pro version, it's not there anymore.

We've discussed this app at length Vanguard, and it's fine that you love it
but I would rather use the FOSS app that I have no evidence your developer
copied, except his app looks "suspiciously" similar in very many ways.

I have an _excellent_ memory Vanguard, so I remember EVERY claim you made
that I have no proof that your developer copied from the FOSS app.

But it's similar enough for me to recommend the FOSS SatStat app to others.
<https://gitlab.com/mvglasow/satstat>
<https://f-droid.org/packages/com.vonglasow.michael.satstat/>

Please don't argue (as you did long ago and I didn't forget anything)
unless you have something _new_ to bring to the table we didn't cover.

> https://mobiwia.com/gpsstatus/getpro/ has a Play Store link to
> https://play.google.com/store/apps/details?id=com.eclipsim.gpstoolbox.pro
> but that reports "requested URL was not found". No idea what happened
> to the Pro version.

Agree this URL I just tested is "not found" in the Google Play Store repo.
<https://play.google.com/store/apps/details?id=com.eclipsim.gpstoolbox.pro>

Since it's Android, and not iOS, the functionality to find and install old
apps is almost infinite (whereas iOS is crippled), so here's just one link
that purports to be the old app (best to pull it off an old phone though).
<https://www.rottlegacy.com/en/com-eclipsim-gpstoolbox-pro/>
<https://apkcombo.com/gps-status-pro-legacy-key/com.eclipsim.gpstoolbox.pro/>
<https://hola.org/access/apk/com.eclipsim.gpstoolbox.pro>
etc.

> I've not found GPS in smartphones to be very accurate. Yes, a guided
> missile wouldn't care about being off 2 to 4 meters (unless it's trying
> to fly through a window in a building) when it impacts and explodes,

My experience is different than yours, where I use GPS all the time for
backcountry hiking (e.g., Avenza Maps + USGS topographic maps) over here.

These free apps work on both my iPads and my Android phones for any map
that is a geoPDF map (which is most downloaded PDF maps nowadays).

*Avenza Maps* Offline Mapping by Avenza Systems Inc., In-app purchases
Free, ad free, 4.6 star, 72.6K reviews, 1M+ Downloads
<https://play.google.com/store/apps/details?id=com.Avenza>
<https://www.avenza.com/avenza-maps/>
<https://apps.apple.com/app/apple-store/id388424049>

*Paper Maps* by Abbro Inc, In-app purchases
Free, ad free, 5K+ Downloads
<https://play.google.com/store/apps/details?id=ca.abbro.androidmap>
<https://www.paper-maps.com/>
<https://apps.apple.com/app/nextmap/id1147385120>

What's nice for all the 256 US Parks is this app which works offline,
but it requires you to plan ahead & download tiles to use it offline.
*OuterSpatial* by OuterSpatial
free, ad free, requires gsf, rated 3.4 out of 113 reviews @ 10K+ Downloads
<https://play.google.com/store/apps/details?id=com.trailheadlabs.outerspatial>
<https://www.outerspatial.com/>
<https://apps.apple.com/us/app/outerspatial/id1254161962>

> but
> being off 12 meters when you return to a huge parking lot (e.g., Disney
> theme parks) makes it tough to find your car,
> and everyone else leaving
> the park at the same time using their key fobs to make their cars beep
> means a lot full of beeping cars.

Most people are dumb and stupid so what they would do is use Google Maps
on the Internet to find their car (it has a find-my-car feature built in).

Others are smarter and can figure out how to use the built-in find-my
parked car feature of FOSS offline maps such as the free OSMAnd~ app.
<https://f-droid.org/en/packages/net.osmand.plus/>
<https://github.com/osmandapp/OsmAnd>

It's free on F-Droid but not if you get the same app on Google Play Store.
*OsmAnd& Maps & GPS Offline by OsmAnd, In-app purchases
Free, ad free, 4.5 star, 153K reviews, 10M+ Downloads
<https://play.google.com/store/apps/details?id=net.osmand.plus>
The Google Play Store repo does have a free version; but I've never used it.
<https://play.google.com/store/apps/details?id=net.osmand>

The find-my-car feature is surprisingly useful, as it gives you
an offline map to your car and verbal directions using pathways.

For finding my car without needing maps, I've recently started using:
*GPS Waypoint Finder* by keuwlsoft
free, ad free, gsf free, 3.9 star, 1.35K reviews, 100K+ Downloads
<https://play.google.com/store/apps/details?id=com.keuwl.gpswaypoints>
Which will point to your car and tell you what the distance to it is
(and it even autocorrects for how you hold the phone & declination).

> I've tried several "find your car" apps, and settled on ParKing
> (https://play.google.com/store/apps/details?id=il.talent.parking.premium)
> which uses GPS to record where you parked, and where you are to lead you
> back to your car. Sometimes it shows my car within about 4 meters of
> where it is, but sometimes I'm off by a row, or two, in the parking lot
> using the app to find my car. I have it configured to use a Bluetooth
> disconnect to know when I parked (my BT goes off when the ignition is
> turned off). It's better than walking out the wrong side of the Mall of
> America to an entirely wrong lot, and then wondering where the hell is
> your car.

There are plenty of free find-my-parked-car apps on both platforms,
some of which (as I recall) use bluetooth to figure out when
you are parked so that you only need to use the app when looking for it.

*Parked Car* by Myroslav Kolodii
Free, ad free, requires GSF, 4.4 star, 179 reviews, 10K+Downloads
<https://play.google.com/store/apps/details?id=com.unagit.parkedcar>

*Car Location* by DigitalBox Studios
Free, ad free, requires GSF, not rated, not reviewed, 500+Downloads
<https://play.google.com/store/apps/details?id=com.carparking.location>

*Find my parked car* by Aurum App
Free, has ads, requires GSF, 4.6 star, 32.7K reviews, 1M+ Downloads
<https://play.google.com/store/apps/details?id=it.carfind>

The problem I have with _all_ those apps is the sneaky move they perform.
*Do you know if there is a way to permanently disable precise location?*
<https://groups.google.com/g/comp.mobile.android/c/ggawmi_4tAc>

In essence, any location app that employs Google GSF spyware can (& does)
make sneaky non-Android-native calls to turn on your GPS radios such as:
Google Location Accuracy = assisted_gps_enabled
Wi-Fi scanning = wifi_scan_always_enabled
Bluetooth scanning = ble_scan_always_enabled
Because they all (if they have GSF spyware linked in) seem to ask for:
android.permission.ACCESS_BACKGROUND_LOCATION
android.permission.ACCESS_COURSE_LOCATION
android.permission.ACCESS_FINE_LOCATION

It would take someoen more intelligent than I am to figure out how to
automatically turn all those off, although adb should be able to do it.
C:\> adb shell pm grant <sample.package.id> android.permission.<PERMISSION_NAME>
C:\> adb shell pm revoke <sample.package.id> android.permission.<PERMISSION_NAME>

The problem isn't removing the permissions; the problem is figuring out
how to make the app work _after_ the permissions have been removed.

If anyone on this newsgroup is smart enough to do that, please say how.
--
Posted out of the goodness of my heart to disseminate useful information
which, in this case, is to expound on the many aspects of Vanguard's post.

Nyfb, n gba bs onvg jnf yrsg sbe gur vtabenag vXbbxf gb cbhapr hcba,
yvxr terrql zvpr whfg jnvgvat gb trg gur onvg va gur tyhr genc.

[Andy Burnelli]

nospam wrote:

>> Even on my Android smartphone, I've had to reset GPS by deleting and
>> re-downloading the A-GPS database.
>

> that happens automatically whenever it's stale.

I agree with nospam that for Vanguard to manually load the A-GPS
information, he would likely need to have a reason to do so.

>> I've not found GPS in smartphones to be very accurate.
>

> then you need a better smartphone.

I'm curious if he's using GPS every day, what might be an observation he
might make that tells him that he needs to re-download the A-GPS database?

>> Yes, a guided
>> missile wouldn't care about being off 2 to 4 meters (unless it's trying

>> to fly through a window in a building) when it impacts and explodes, but

>> being off 12 meters when you return to a huge parking lot (e.g., Disney
>> theme parks) makes it tough to find your car, and everyone else leaving
>> the park at the same time using their key fobs to make their cars beep
>> means a lot full of beeping cars.
>

> it should be much better than 12m, but even with that, 12m is close
> enough to be able to find the correct vehicle.

I agree that when you're looking for your own car, being close enough
should be good enough to find it, as your memory will be jogged even if
it's a common white Tesla Model Y hiding in the huge Costco parking lot.

Some of the free find-my-car apps I previously listed also have a
parking-meter alarm feature, which can warn you when time is almost up.

These find-my-parked-car apps are certainly enticing to most people...

But what I find disturbing is how rude & ignorant most people are who
habitually put on the Google Maps Suicide Vest - which harms everyone.
*Remember where you parked with Google Maps*
<https://blog.google/products/maps/remember-where-you-parked-google-maps/>

These rude people ignorantly trade their convenience for your privacy.

When they could have used their brains instead, by using an app
that doesn't hurt everyone around you, in addition to yourself.

In terms of the privacy of the people around you, to use Google Maps with
the default settings is to wear a suicide vest which harms everyone around
you in that it uploads _their_ private information to Google Servers
without you obtaining any permission whatsoever from those people around
you.

What gives you the right to upload their unique GPS location and unique
identifier to their home router, for example, just because you drove by?

[NY]

"Andy Burnelli" <sp...@nospam.com> wrote in message
news:tqn6bn$10ob$1...@gioia.aioe.org...

> VanguardLH wrote:
>
>>> Wish they would repeat this analysis on newer iPhones.
>>
>> Even on my Android smartphone, I've had to reset GPS by deleting and
>> re-downloading the A-GPS database.
>> https://en.wikipedia.org/wiki/Assisted_GNSS
>
> I admit, up front, I don't know a lot about GNSS and A-GPS, where folks
> like nospam and Alan Browne know more than I ever will know about it
> (mostly because, for me, it just works, so I don't need to do anything).
>
> But to your specific point of manually re-loading the A-GPS database, may
> I ask you "why"... or... more specifically... how do you know you need
> to reload it?
>
> What "evidence" or "telltale observation" tells you that you need to
> reload the A-GPS database for a phone you've been using every day on GPS?

There are various parameters that can affect GPS accuracy:

- how often a reading is taken or recorded: some apps which record to GPX
file (or whatever) can be set to read a new point from the GPS device in the
phone at one of several intervals - eg one reading per second, one reading
every 5 seconds, 10 seconds etc (the more often you read a point, the
quicker the battery loses charge); some apps don't record a new point to
file (even if they poll more frequently) if you have moved less than a
configurable distance since the last reading

- A-GPS can make a difference: I tend to reload if a) the phone is taking a
long time to get its first reading after GPS has previously been turned off
and the phone has moved a significant distance since the last reading, b) if
the track is displaced sideways from the road that you are following (note
that some map overlays are not always perfectly correct, so it may be that
the phone is right and the map is wrong!)

- location of phone: in a pocket or bag, or inside a train (or other
mostly-metal vehicle) can give much less accurate readings - maybe no
readings at all on some trains :-(

I use OutdoorActive (the successor to the much better ViewRanger which was
bought up and then killed off) and/or Outdoor Map Navigator, on Android 8
phone, having bought the (UK) Ordnance Survey maps at 1:50,000 and 1:25,000
scale. OMN is good because the maps are all stored on the phone, whereas
OutdoorActive only caches maps close to where the phone is currently, so if
you lose mobile internet you may find that the maps don't download as you
are travelling on a journey.

I've got them configured to take a reading every second, and to take a
reading every foot or metre (I forget which). Viewranger had a useful
"units" setting which used miles and mph for distances and speeds, but used
metres for heights above sea level (since OS maps have contours and spot
heights in metres). A nice bit of mixed-units for the half-and-half people
in the UK ;-)

I've also used a small app called SpeedView speedometer which is mainly a
way of displaying your speed, but it does have the ability to log your
position periodically (seems to be fixed at one reading every two seconds)
and it records your true GPS speed each time, which is less "noisy" than
calculating your speed from (distance moved since last reading) / (time
since last reading), because using the "delta" method any error in location
reading will translate to an error in speed so you get a lot of spikes and
bizarre readings.


My wife has an iPad and its results tend to be more variable: sometimes it
follows roads better than my Android phone, and sometimes it is terrible or
loses GPS altogether (freezes) at critical times like approaching a junction
where it's useful to know "how far till I reach the junction?". She bought a
new iPad when the old one started to run slow and wouldn't allow more than
one web page to be open at once in its browser. Sadly we didn't realise than
Apple are sneaky: unless you pay extra for the version that has mobile phone
connectivity (which we wouldn't need) they don't give you a GPS receiver, so
we're investigating getting an external GPS receiver that connects by
Bluetooth for times when we would use the new iPad (larger screen) for
navigating in the car. I wouldn't have guessed that no 3G receiver would
also mean no GPS receiver: we were not best pleased that a horrendously
expensive device (compared with an Android equivalent) would be lacking a
"must-have" device like GPS.