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iPhone 14 Pro comes with dual-frequency GPS (apple.com)
183 points by tosh on Sept 10, 2022 | hide | past | favorite | 197 comments


Xiaomi released a phone with dual frequency GNSS in 2018 (with the Broadcom BCM4775 chipset), and as far as I know most Android phones have had it since then, or maybe a bit later. If you want to see if your phone supports it, try GPSTest.

Garmin has recently released several watches with it as well, both their high end models and some more affordable ones. They also have an auto mode that switches it on or off depending on if the current environment needs it, to save power when you can have the same accuracy without it.

Personally, I find the accuracy and sensitivity of modern GNSS devices amazing. I remember when you had to wait maybe 10 minutes to acquire a fix, the accuracy was poor and maybe within 10 meters, and if you covered the receiver with clothing you would lose satellite fix. Now my phone gets a good position in a few seconds, I can see which side of the road I ran on, and even with my phone in my pocket I can often get a reasonably accurate track indoors.

https://www.androidauthority.com/dual-frequency-gps-878169/

https://play.google.com/store/apps/details?id=com.android.gp...


The speedup you are noticing is probably mostly due to assisted gps, where your phone gets a location using - partial gps information + wifi location + cell tower location all triangulated. Your eg early 2010 car gps unit didn't have any of the addition ways to speed up the location fix


Downloading the orbital parameters can be done via the internet rather than at the 50 bps that the satellites broadcast them at.


Also the challenge of old receivers was which Doppler shift frequency to listen on depending on if the target satellite is going towards or away. By knowing the rough location (from cell towers, known wifi AP’s etc), they can get an instant lock.


There are three things that lead to fast lock times for cell phones.

* Ephemeris and almanac data updated via the internet so the receiver doesn't have to wait for either and can immediately know what satellites to listen for and acquire.

* Precise clock via NTP so the receiver has a smaller solve space for its internal clock

* AGPS gives a very good position fix to further help with the initial clock and position solving


Apple has supported GNSS since the iPhone 8/X generation in 2017. This is about L5 GPS which I'm not sure how well this is supported in general ATM as its pretty new


GNSS is a generic term for satellite based positioning systems. It looks like you're referring to the iPhone adding Galileo support in the 8/X.

L5 support has been available in a number of devices for a couple of years now. Garmin was one of the first to use L5 in commercial devices, with their Fenix watches a while back.

The phone I'm currently using, the Pixel 6 Pro uses the L5 band. It's nice and I can definitely tell a difference, but it still struggles due to antenna size.

In my experience, for people doing significant outdoor stuff like backpacking, endurance running, etc, a positioning device from a solid company like Garmin is going to be a good bit better than an apple, Samsung, Google, etc device.


In my experience I find Apple tends not to add features that don’t meet a reliability or quality bar, which is why they’re usually not first movers on things like 4G or 5G.

I had an LG phone that was one of the first in 4G (at least on my carrier) and the thing ran so hot it was often painful to touch.


Nope, Apple is just late to the party here. Multi-frequency GPS has been completely reliable in competing devices for at least two generations.


The Apple Reality Distortion Field is clearly still strong.


It’s more a statement of how they operate IMO. I’ve watched them be extremely conservative over the years to see which ideas stick and wait until hardware has matured.

My HTC thunderbolt was one of the first “4G” phones, but was barely useable more than a few hours.

Yes, Apple has made some insane design constraints in the past (butterfly keyboards, the whole thin-ness thing), but their chip choices are usually pretty sound and grounded in reality.

*edit: I wanted to throw in how frustrating the lack of push email was for so long (and still kind of is), but I get it. From their standpoint, they control APNS & can use that for energy efficiency benefits to make a grandma-friendly device


I hear this claim a lot, especially by Apple brand enthusiasts, but is there really any data supporting this?

From my memory Apple is just often late to the party. Especially for 4G and LTE.


Garmin only recently introduced dual-frequency GNSS in some versions of their Fenix 7 watches, and have since added it to some cheaper models like the Forerunner 255. The first watch with L1+L5 was the Coros Vertix 2 from last year, so it's still quite new in watches.

Qualcomm has had it since the Snapdragon 855 though, so basically every flagship Android phone since 2019.

https://support.garmin.com/en-IE/marine/faq/9NWiPDU4gM0JWMfd...


I'm not sure what you're talking about. GNSS is just a generic term for a "global navigation satellite system."


Wow you're right, GPSTest on my 2019 Oneplus 7 shows L5 GPS satellites, in addition to L1 GPS, GLONASS, Michibiki, and dual-band Galileo.


Does the Android OS and apps like Google maps actually use multiple frequencies to get a position fix? I have friends with Samsung phones supporting dual frequency gps yet the GPS accuracy doesn't seem any better than single frequency devices.


It's transparent to the apps, it's included in all GPS (or technically GNSS) locations. GPSTest has a built in accuracy test mode where to can measure your phones location accuracy. Read more about that here: https://barbeau.medium.com/measuring-gnss-accuracy-on-androi...

I noticed a huge difference when I switched from my older phone to my current with dual frequency, and I usually log runs, walks, and bike rides so it's easy to compare the tracks. But maybe my old phone was just bad, my Garmin watch uses single frequency and it's usually quite good anyway. I've seen a few reviews of new Garmin watches and there dual frequency seems to make a small and not always noticeable difference.


They might not notice a huge difference depending on where they use location services. The real accuracy advantage of dual-frequency GPS only become apparent in degraded signal environments, such as next to tall buildings (multipath signal reflections) and under tree canopies. With a clear view of the sky, regular GPS is already quite accurate (especially if the device also supports other GNSS constellations).


How long ago was that? I never remember it taking more than a minute or so to get a good fix with GPS devices. I'm talking about Garmin devices.


The first GPS device I used didn't have any built in maps, only a breadcrumb trail on a monochrome LCD display. It used AA batteries and it was before selective availability was turned off, so accuracy was quite poor compared to today. Late -90s, so around 25 years ago now. If I recall correctly it was a Garmin 38.


Garmin devices have supported downloading satellite ephemeris data from the Internet for several product generations. This greatly accelerates getting a GPS fix. Some models will also get an approximate location via Bluetooth from a paired cell phone.

Long fix times are still an issue today with cameras that lack connectivity.


I had a Garmin Forerunner (I can’t remember the number, 425 maybe?) circa 2007. IIRC it was one of the earliest on-wrist GPS devices Garmin did. Most of the time it would only take a minute. There would be occasions where it took much much longer. Increasingly so by the time I retired in 2018.


[flagged]


It interesting how Apple has been able to stay ahead while often being a step or two behind from a technological standpoint (in some areas at least). I think it goes to show how important it is to have things work in a very seamless way.


Many tech products are still sold on feature lists. Few people care any more.

This great (short and funny) internal video from Microsoft was supposed to be a wake up call, but nothing really changed: https://www.youtube.com/watch?v=EUXnJraKM3k

The fact that Apple doesn't really play that game seems to drive some people wild.


The real player in this space is Nintendo, which specifically uses commodity hardware in its devices to drive down costs and to my knowledge does not sell consoles at loss the way that MS or Sony do or have done in the past.

As I once heard it described, Nintendo is fine to laugh about being a second-rate console all the way to the bank, because while MS and Sony fight out expensive battles to be people’s first consoles, the second console is usually Nintendo.


Apple has always been “behind” on some aspects and “ahead” on others. It boils down to the fact that they have their own priorities, which are different from what Android OEMs like to emphasise, which are also different from what people on Teh Interwebz like to go on about.


> stay ahead while often being a step or two behind

Yeah, good advertising can make even those sentences a valid statement.


You dropped “from a technological standpoint” from the parent comment. Removing words from a sentence changes the meaning.


Ahead in what? Money they fleeced from US market? Core fanbase satisfaction? I don't think they were technologically ahead in anything in a decade or so. Unless you count inventing new charging ports and removing headphone jack or discovering that screen can have notches and customers still buy it.


unless you count the fast mobile chip year over year for the last decade, developed and designed in-house


Are they leapfrogging their competition or just keeping pace with the first place going alternatively to Apple and Android chips every generation where simply the newest chip is the fastest?


When was the last time a Qualcomm (let alone an Exynos or Kirin etc) was faster than the Ax of that year? I can't even remember. Any ideas?


I don't know, but assuming the answer is never I got response to my original question.

Apple is ahead in the amount of money they fleeced from US market, core fanbase satisfaction and CPU speeds.

That's not nothing.


But things are better when they’re from Apple.

A random example is Apple TV vs any Smart TV.

I just bought a flagship Sony A95K smart television. It has everything, it ticks every checkbox, but the software is basically trash. Low effort garbage that should have failed QA the second you see any part of it.

It is 1080p upscaled to 4K, so it’s blurry!!! Even with my worsening vision I can see the fuzzy edges and it makes my eyes hurt.

It’s too dark so that in a bright room it is borderline invisible.

It isn’t color managed, which means the better the TV panel, the more garish it looks. On this QD-OLED panel it looks stupid bad.

The second you switch to the Apple TV you instantly realise why they’re the biggest company on earth. It’s beautiful! It’s crisp, fluid 4K with correct colors and brightness. Such simple things to get right.

Google (Android TV) and Sony just… couldn’t be bothered to any of that properly.

They threw some features in the and called it a day.


I think you should check out google tv on the latest 4k version. Your review is almost like a sarcastic example of a lazy pro apple review. Some crap tv ui like that sony apparently is does not really say much about apple competitors. Apple is great at some things, but they aren't the only good thing.


What are you talking about!? I have the latest Google TV operating system on the latest flagship Sony television, a model released just months ago! The Google TV OS on the latest available version.

There is no excuse for Google & Sony being so obviously inferior.

The difference between the two is night and day, not some "fanboyism". Switch inputs to the Apple TV and you instantly think "wow!" unless legally blind. Switch back and it's instant disappointment.

Dark oversaturated 1080p upscaled and blurry versus razor sharp native 4K with subtle hues is something anyone can recognise as a clear difference.

The downvotes on my original comment and your response is very telling.

Let me ask you: Have you actually sat down and compared the two? As in, plugged in an Apple TV 4K into an Android TV and switched back and forth?

Or are you just assuming I'm a "fanboy" and have a preference based on nothing more than tribalism?


Article about what dual-frequency GPS is: https://www.zdnet.com/article/what-is-l5-precision-dual-freq...

It says that GPS has added a new band (L5) that works better indoors. Combining it with traditional L1 gives better results. L5 is not fully deployed.


My Google Pixel 6 can already do this. I can see L5 and L1 GPS satellites at the same time right now. I can also see a lot of other systems ones.


It's not just the pixel 6, it goes clear back to the pixel 4, galaxy s20, and many more.

A totally excellent list of supported and tested devices is at the latter part of this article.

https://barbeau.medium.com/tl-dr-dual-frequency-gnss-on-andr...


I'm sure once L5 has an actual complete deployment it will be used by even more devices.


How is the positioning accuracy outdoors?

My iPhone 13 is rather disappointing in this regard. Even in my garden, with a clear sky, Maps.app will show my location at least 5 m off my actual position.


5m is within the design spec of L1 GPS, so you’re getting it as designed. GPS was never designed to be mm level accurate. The new L5 frequency aims for 30cm accuracy.


It is possible on quite a few modern Android phones to access raw receiver data and do post-processing using a rinet file to get mm-level accuracy. It's a little over my head since this isn't my industry. One of Google's more obscure Android apps to be used with it: https://play.google.com/store/apps/details?id=com.google.and...

GPSTest also carries some logging functionality to do the same: https://github.com/barbeau/gpstest


> GPS was never designed to be mm level accurate

Kind of. Consumer/public GPS was never to be that accurate. Galileo for example, has the following accuracy: 1 metre (public), 1 cm (encrypted)

I'm sure the same applies to other systems too.


I don't really see the strategic importance of 1 meter Vs 1 cm positioning... Is the enemy missile going to miss the bunker because it hit 1 meter off? Or the enemy built their airport 1 meter wonky because they didn't have access to 1 cm level accuracy?


GPS might have been a military invention, but its uses reaches further out today. I think the purpose of Galileo's encrypted GPS is not to prevent military strikes against European nations, but to be able to offer more precision as a commercial service, making a profit.

Basically, companies who use GPS for measurements or what have you, can pay money and get access to improved accuracy.


Right.

1m vs 1cm is not a big deal for a rideshare driver. On the other hand, if two bridge spans meet in the middle and are 1m misaligned, that’s a huge problem.


Because the EU notionally (at least for now) is not a military alliance, Galileo does not have a military application. The slot where you would put a military encrypted mode instead has the "Public Regulated Service" to be used by authorized government bodies which might well in practice be military.

As the US found, in practice such services are largely useless, they sound cool, but in practice COTS (Commercial Off The Shelf) dominates. The $50 device you see on Amazon has better features than the $500 military product your supplier offers. When you ask the Amazon supplier can sell you 1-1000, with 48 hour delivery but your military supplier quotes 6-12 months with batches of 500.

Can the enemy jam your $50 Amazon special? Maybe. But in a hot war zone, unlike for an annoying neighbour, jamming isn't necessarily an effective strategy because it involves transmitting radio signals, which makes you a target.


The EU is a military alliance. There has been a mutual defense clause since 2009. So far it's not clear whether members will actually fulfill that obligation.

https://www.euronews.com/my-europe/2022/06/07/like-nato-the-...


But since GPS is a broadcast service, there is no way to offer encrypted service widely (ie. To a random app which pays for better GPS accuracy) without someone decapping/exploiting a chip in the phone and leaking the rolling encryption key via a web service for everyone.


Should be possible. Encrypted DVB-S providers can also lock/unlock single smartcards.


And it is pretty common that said smartcards get 'cracked', and then they have to reissue new cards to all viewers and switch to a new master crypto key. If even one legacy card remained in use, then attackers could use that card to dump the key used for the video stream and publish it online.


It's usually not that simple. Yes there is card sharing, but you need to have the card active for that. But card sharing is not "cracking" obviously. Also, you don't store the "master key" on the card, obviously.


It’s needed for things like site surveying and construction.

https://www.takeoffpros.com/2019/07/31/gps-surveying-explain...


Military stuff can be moving, sometimes quickly, so more accuracy at one point in the trajectory could result in more accuracy later on


Uhh, for hunter killer drones trying to minimize collateral damage using exclusively impact weapons (like what was used against the ISIS dude who was recently killed), that difference really, really matters.


Have you considered that the underlying map may be out? I remember (non-academic) researching this and looking through past Google Earth imagery and its about a 2 metre error.


When I compare Apple Maps and Google Maps, both show me in the same spot relative to the aerial imagery. Could of course be, that both apps are off. I think it's more likely it's the GPS accuracy.

I know that regular GPS is not super accurate. But my impression was, that chipsets which support Galileo in addition to GPS, would be more accurate than 5-10 m.


I live in a building. From my window I can see 28 satellites and I have a 2m precision radius.


How do you check what satellites you can see?



That's right, I use that app :)


For a moment, I thought L5 refers to Lagrange point 5 and L5 GPS to a new GPS sattelite located there for some reason.


For Android users, there's an interesting article about dual-frequency GPS at https://barbeau.medium.com/dual-frequency-gnss-on-android-de... (source: https://github.com/barbeau/gpstest/blob/master/FAQ.md#does-g...).


So my 2 year old Android device already had a feature that was only now implemented by Apple in their top of the line products. Neat.

Does anyone have personal experience of how dual-frequency improves GPS? As I'm not really using GPS a lot, I'm not sure I noticed a difference from my previous devices (I live in EU, so also no high rise skyscrapers here)


I doesn't matter if your device had it for 99999 years and is therefore 'way cooler', what matters is how far along the GPS satellites are, and at this stage there isn't even one complete deployment, it's still being deployed.


You don't need every satellite to be broadcasting the L5 signal to benefit. In fact there's probably diminishing returns, you really only need to receive one L5 signal to do ionosphere correction


Ha, if only. No, a satellite broadcasting L5 only gives you ionospheric corrections for that satellite.

Otherwise what would be the point? WAAS already gives ionospheric corrections for a course grid. If you could just assume that the ionospheric delay was constant across the sky, you wouldn’t need L5 at all.


It doesn't matter how little you need if there are big gaps in availability. Granted, having prepared hardware and sometimes-coverage is great, but the buck has got to stop somewhere.


my 1999 honda civic has a feature that my Porsche 911 doesn't have. doesn't mean my Porsche 911 is a worse car


I wouldn't bother trying to reason on this.

I'm an Android developer, but use an iPhone. I've noticed some Android users really need their wins against Apple. It's almost like a Linux user trying to convince you how awesome and slicker the dev experience is, vs how bloated and slow your Macbook is: the point isn't to inform you, it's to reassure themselves.


I don't know which rock you're living under but Apple users do this way way more often to validate their purchase.


Ok.


Clearly it's a worse car WRT to that feature.

Besides the high price of iPhones, this metaphor doesn't go very far.


I think people are simply surprised that Apple is just now getting around to this, given that it's been a common feature in high end Android phones for quite a while now. OP did not say that Apple phones were worse, you inferred that.


adding in a "...only now implemented by Apple in their top of the line..." and a sarcastic "Neat." right after that sentence make it pretty clear what the poster was implying


That does not imply that on the whole Apple phones aren't good phones. Just that it's surprising they haven't implemented this bog standard feature.


I really don't care that you already had this feature.


Android has copy and paste before iOS but you wouldn’t want to brag about it just because. It didn’t work well at all till iOS came out with their implementation


I had a Symbian phone back then. It had copy and paste. Nothing to brag about because it was such a normal feature.


Great point, Android's swipe-able keyboard was VERY good before Apple copied it. Brag about that because it was good, not "just because."


yep, everytime Apple makes a feature actually useable, all the android people come out furious.

my guess is android people also use windows, and are used to constant blue screens, malware, and random crashes.


> my guess is android people also use windows, and are used to constant blue screens, malware, and random crashes.

Have you just woken up from a coma you fell into back in the 90s?


Yep, it's been days since 0days were exploited by malware in OSX. I still keep using it for some reason. Wish it would work with Android the way my linux boxes do! Even Win11 has some crapware that links it to my phone, sigh.


"Neat" but if it isn't even noticeable to you, the end user, then perhaps that's why Apple waited. After all, it would require die space, antenna and power.


Crowd-sourced list of Android phones that support dual-frequency GPS: https://docs.google.com/spreadsheets/d/1jXtRCoEnnFNWj6_oFlVW...


Semi-related: https://wiki.openstreetmap.org/wiki/GPS_device_reviews#Summa...

Though the table could use an update, I've tried to add new devices I got my hands on because (conversely) I'd like to know the accuracy of a device before buying it with mapping in mind.

What I found interesting is that

> As of 2021, some recent smartphones claim to support Galileo but in fact do not work with it. This includes the Fairphone 3 and 3+; Motorola Moto G Power and Moto G30. On the other hand, the Xiaomi Mi A2 Lite does not claim Galileo support (including on the manufacturer's own page), yet it works. The Samsung S10e is also confirmed to work.

The spec sheet doesn't always match reality unfortunately (or, for Xiaomi, fortunately!).


Are there any phones that average readings from GPS, GLONASS, and GALILEO together for better accuracy?


Most phones since 2013 or so for GLONASS, and most after 2017 or so for GALILEO, at least in the US. These constellations needed US approval to be allowed as supplemental data, and it still requires an initial lock to GPS before feeding them in. GLONASS is only one of the constellations not broadcasting a civilian second band.

Additionally, Beidou is still banned and blocked in firmware while in US even though the satellites are broadcasting, since this constellation lacks US approval (partially because the other constellations are 1-way systems broadcasting to receiver and Beidou is a two-way system, that can be used for tracking and likely emergency response). Here's some slides about BeiDou's technical details, specifically note the 2-way messaging since all anyone's been talking about is Spacex/Globalstar: https://www.gps.gov/cgsic/meetings/2020/geng.pdf


Does GNSS chipsets in phones really support two way communication? Sounds like something that would need specialized antennas and high output power, not exactly something that can be hidden at least.

Galileo also supports or maybe will support emergency beacons from the ground.

https://www.esa.int/Applications/Navigation/Galileo/Galileo_...


> it still requires an initial lock to GPS before feeding them in

Is there any technical reason, or is it just protectionism? (as in, no GPS lock? No lock at all, even if Galileo and Glonass are 100% fine!)

> Beidou is still banned and blocked in firmware while in US even though the satellites are broadcasting, since this constellation lacks US approval

Is it legal to use a Xiaomi phone in Wifi only mode with Beidou GNSS?

> Here's some slides about BeiDou's technical details, specifically note the 2-way messaging

Super interesting, ty! I see interesting details like "Horizontally positioning accuracy is about 1.5m" so it should be better than GPS! Also, it supports 300k SMS/h with a coverage over Japan, India and Thailand!

I would love to play with Beidou!


> Is there any technical reason, or is it just protectionism? (as in, no GPS lock? No lock at all, even if Galileo and Glonass are 100% fine!)

No technical reason. It's a mixture of both legitimate concern for public safety (they are newer constellations with a shorter reliability track record) and the uh, more political concerns over privacy and national security.

I wouldn't be surprised if China does the inverse considering their motivations for developing BeiDou were first and foremost to stop the US jamming the GPS receivers on their missiles. My immediate thought with the decay of US/Russia relations was that it might be a good idea to throw a switch to disable GLONASS in case they start transmitting bogus signals. My assumption is with the 'GPS first' policy, the receiver shouldn't mix in less accurate data, but without documentation I'm not sure.

Personally I'm all for having options and I have come to respect Galileo for being civilian system, rather than a military system. More than anything I want the choice to be able to enable and disable whatever constellations I want and not deal with the bullshit that is Qualcomm's undocumented GNSS receiver firmware.

> Is it legal to use a Xiaomi phone in Wifi only mode with Beidou GNSS?

It's legal to use if it doesn't transmit on someone else's licensed spectrum. It's illegal to sell in the US as a navigation receiver (EDIT: without it being disabled in firmware). But you are free to do whatever you want with captured signals with only a very few restrictions (like sniffing cordless phone bands). I've even sniffed pager networks so I could track COVID cases coming in, afaik it's only illegal if I share what I see.

> I would love to play with Beidou!

Same. I told a GPS launch commander I'd like to play with their system and he got incredibly butthurt. I told him to stop being a bitch and either make the US system better or stop excluding civvies from using it to its fullest potential. There's no commercial alternatives in the US as all commercial satellite projects get heavily subsidized by the US military and they don't want competitors.


> It's legal to use if it doesn't transmit on someone else's licensed spectrum

Great then! I only want to listen, to study the performance of the different networks when non-technical limitations are removed.

> No technical reason

Then it's exactly what I thought: protectionism.

I'll try to get my hands on some devices and play with them - or mod existing ones if possible!

> More than anything I want the choice to be able to enable and disable whatever constellations I want and not deal with the bullshit that is Qualcomm's undocumented GNSS receiver firmware

Let's get in touch by email, I want to explore the GNSS firmware to allow "everything and the kitchensync"!


They do more than just average the systems - they can use information from one to get a lock on satellites from another, they can in some cases use just one or two satellites from a system even when a lock requires 4 or more satellites.


All recent ones.


Considered that I follow hardware development fairly closely, I didn't even know this was not a thing on iPhone. And now Apple is making a big deal about it.

Could anyone shares any thoughts as to why Apple only include it now? And not earlier?


it's on iPhone now. before, if you wanted this, you'd have to make do with an android


"make do" ? Unless you were a cartologist, surveyor, or geo-cacher would you even care?


Including it on a spec sheet qualifies as making a big deal about it?


They actually mentioned it during the presentation.


But then you’re on android


Does anyone here have any insights or opinions on L5 only navigation? oneNav seems to think it's better than L1+L5, citing lower complexity and power usage, but with maintained accuracy. Sounds too good to be true, will devices skip the L1 band eventually?

https://onenav.ai/solution/


For those of us not deep into the technical details here: what's this mean?


GPS assumes* light travels in a straight line, which it doesn't due to atmospheric effects and reflections off buildings. L5 is a second frequency from the same satellites, which is affected by these problems differently, so the chip can compare the differences between the two signals and guess what's up with the atmosphere and buildings / throw out the dumber looking signal. It's also mostly independent so it's more data. L5 is also a bit less affected by atmosphere inherently.

The upshot is much better accuracy in urban canyons, and a small improvement where GPS was already good.

* Obviously people making chips and apps know this and try to mitigate it.


That was infinitely better than TFA, thanks.


the fucking article? edit: sorry


or, the fine article :)


I’ve anecdotally found that GPS is much worse in dense cities like New York than in sparse ones like Tucson. Hopefully my next phone will give me better location results.


This is so real. Last weekend I made it blocks down the road in downtown Atlanta before my phone got a lock worth using.


The single frequency situation isn't all that bad though since there are a dozen satellites in view and tracked even in urban outdoor environments.


It's certainly better than it used to be, since there are more satellites, and a lot of work goes into doing well in these environments (I used to do the GPS integration for Google Maps).

There are two big tricky parts about urban canyons. First, yeah, you still have quite a few satellites, but they're all in the same directions. Satellites directly above you don't really tell you anything. Satellites in front of and behind you can only tell you how far you are along that axis. You don't have any satellites to the sides, because you're in a canyon. So in an idealized version of a really bad urban canyon, the GPS can tell how far you are on the street, but not which street you're on, which is what the user actually wants to know. (I did a lot of work on knowing this from context, but it's still quite a mystery on a cold start.)

The second is that, unlike natural canyons, signals in urban canyons tend to bounce. So instead of seeing the satellite missing, you see it giving a signal that's consistent with if you were in the next street over. Which is the same problem we had in the first place. There's a lot of outlier detection done in the chips, but in a really noisy environment, sometimes that'll inevitably end up throwing out the good data and choosing the outlier.


Awesome explanation. Thank you.


I live in San Francisco. We don't exactly have the tallest buildings, but I can assure you from years of tracking runs in the downtown area here and nearby forested areas, GPS gets very screwed up unless it has a clear view of the sky. This is with a variety of Garmins, Apple iPhones and Apple Watch. I'm looking forward to the newer devices with L5.


It's known as the 'urban canyon' effect.

It can be significantly reduced if the GPS has access to a 3d model of the nearby buildings - then the GPS can guess which signals are probably reflections and which are direct.

Alas, I think this isn't done outside data centers/labs, because the data download to have a large 3d model to get a GPS fix isn't a service anyone wants to run for free.


Uber showed this in 2018, I don't know how widely used it is now. I doubt any phone app uses it offline at least.

https://www.uber.com/en-SE/blog/rethinking-gps/


Given how many Android phones already have this, maybe you could borrow one and compare? I want to know the answer.


Great, simple answer. Thank you!


The short of it is that for the past two decade or so the us govt has been rolling out a new signal that the latest series of GPS satellites transmit that uses 1. more bandwidth, 2. more transmit power, 3. in a protected region of spectrum, 4. using modern encodings and error correction. This makes it a lot easier to pick up the signal from noisy environments.


Are there any specific use cases where this will see outside benefit (urban areas)? Or is it just faster fix and higher precision without PPS/RTK?


inside of the mall when your weather widget pulls your location every 5 minutes they will better know what stores you went in to in what order


Wouldn't the WiFi and Bluetooth beacons provide more accurate and more granular points of data than polling GPS for this purpose?


That would require calibration (this is the layout of the store, the receiver is here, reflections can occur here and so on) while a GPS system would allow owners to just connect to a centralized app and bam, here is where all your visitors walked for the last 3 months.


wow, that's your retort/sales pitch for GPS only tracking? it truly needs some work.


Nope, it's simply information, free for everyone to read :) I'm neither selling or arguing for/against anything.


Made me chuckle because it's so true...


> Are there any specific use cases where this will see outside benefit (urban areas)?

When you only way have one radio signal from a satellite, it is impossible to tell how the ionosphere has effected the signal.

When you have two, and each a slightly different frequency, you can model signal path changes and apply some corrections for better general accuracy.


Dual-band GPS allows detecting (and correcting for) multipath interference, i.e. signals bouncing off building and being received multiple times. This should improve accuracy in cities a fair bit.


based on the keynote, they say it will be better in "urban jungles". It was part of the Apple Watch Ultra and said it worked better for the Boston (IIRC) Maraton. I would hope for the phone it works better for navagation in Car Play... I dont know how many times my phone things, when driving forward, that im turning down a side road...


Chicago Marathon. The Boston marathon is mostly a very open path.

Source: I watched the keynote and I’ve run both.


Return to the route.

Return to the route.

Return to the…

FUCK YOU SHORESY, I’M ON THE ROUTE.


That last bit is a software issue. Apple maps is constantly trying to route me to a parallel street for 1 block in a city and it actually thinks I listen to it. Google maps doesn't have either of these behaviors on the same hardware/APIs.

No, a more accurate GPS will not fix Apple's bugs.


I'm using waze, not Apple Maps


Dual frequency mitigates the ionospheric delay error of GPS signals, yielding more accurate measurements.


This. Adding a second channel means that without RTK/PPK you can get ~30cm precision. The rest is just technical details.


For others who are not into that lingo, RTK/PPK are Real-Time and Post-Processed Kinematics. I had an idea of what the word kinematics means (Wikipedia says "describes the motion of [(groups of)] points") so this sounds like you use the accelerometer and gyroscope in addition to GNSS to get better accuracy, but actually no this has nothing to do with measuring your motion. Instead, RTK is something about signals' phase and requires an additional ground station (sounds similar to differential GPS, but by looking at phase data rather than position offset?), and PPK is never mentioned on Wikipedia and I don't understand descriptions from other sources. Post-processing is mentioned in differential GPS, however, to make the difference between the two topics (DGPS, RTK/PPK) even more confusing.

If you could elaborate, I'd be interested. It seems very specialistic (though you drop it as if it should be obvious) so I doubt most people here know the terms.


PPK uses exactly the same processing method as RTK, except rather than process in real-time it just logs the information and the merges with afterwards with the data logged from a base station. This is used primarily for remote sensing applications where centimeter accuracy of data is only needed in postprocessing and not at capture time - eg. drones with cameras for 3D reconstruction.

The reason to use PPK is weight and cost - it just uses a normal GPS receiver and doesn't need an RTK sideband antenna, since the base station information can be downloaded over the internet at postprocessing time.

RTK/PPK gives ~3cm precision, while standard GPS gives 6m precision. This new dual-band giving 30cm precision means it is good enough to not use RTK/PPK except in the most demanding applications.


Honest concern: how do we know that Apple isn't going to secretly share this data anyone who asks for it politely? I know they've been very good at maintaining privacy-first appearance, but where is too much good stuff a bad combo?

Seriously though, I love iPhones as the next guy, and find them very convenient, but are we trading convenience for carrying an unbound GPS tracker in every pocket, and if so, how do we change course? Is it even possible these days to unsubscribe from Apple/Google without feeling like one's living back in the stone age?


Use android AOSP, and only specifically control what application controls you give, you can turn GPS access off on android and it is truely off.


afaiu this also means that every non-Ultra Apple watch will benefit from dual-frequency GPS when paired with an iPhone 14


I though the Apple Watch had its own GPS and used that for signal?


It does have it’s own GPS. But if it tethered with your phone, it uses that instead to save battery life. The same is true for cellular Apple Watches.


Similarly, if you are using CarPlay, it will use your car's GPS instead of the built-in one. I figured this out when my car's GPS developed a fault which often gave a lock hundreds of meters away from my actual position, and my phone did the same thing when connected via CarPlay.


Cars also do dead reckoning with wheel and steering data so you get pretty decent data in tunnels where basic GPS fails.


Could you expand more on this? Very curious what this means/how it works


Most headunits with Carplay require you to have the vehicle speed sensor connected to them. They also have a compass. So, if you lose GPS, you have the 3 components you need for dead reckoning: A starting location, a heading, and a speed. It works pretty good even in complex areas like parking garages.


Does not seem to be the case for bmw g30/31 (5 series). The onboard satnav works in tunnels and does not think I'm driving down a side road, but CarPlay does...


Hmm, there must be a lot of cars without their own GPS then, or maybe apps can choose to use it or not? When I use Waze with rental cars I often see Waze responding to my phones orientation when CarPlay is active. Unless Waze is using orientation just for visual and the GPS is used for the position


Orientation uses the accelerometer, not GPS.


I did not know this. handy to know!


Even iPads using an iPhone as a tether will use the iPhone GPS for location =)


Huh that sounds odd. Doesn't a tablet have a bigger battery than a phone?


Yes, but iPads without the cellular option also lack a GPS receiver.


Wifi-only iPads do not have a GPS receiver in them. At least not the last time I bought one. So this could still be handy in some cases.



I’d honestly be more excited about it using a USB-C connector.


Support for Galileo and Glonass was touted maybe a decade ago, but there was never any massive improvement in accuracy. Same story?

Even worse, Apple Maps still freezes after I leave a tunnel - I’ve been through at least 3 different models in the meantime.


I for one absolutely recall "classic" GNSS based purely on GPS. The combination of only having GPS, early slow hardware with only cold starts, young software implementations, made for quite a ropey experience.

I think my first proper experience was a PCMCIA GPS card in an HP IPaq running TomTom 2, or possibly some Garmin version. Revolutionary at the time, and brilliant on long journeys, but compared to today it was awful.


I still have an old Garmin for sea kayaking that I sometimes use. With a completely clear view of the sky it can easily take quite a few minutes to get a fix.


This is actually how all gps devices still work, including the latest smartphones and watches. It's just that now, devices can pre-download the almanac over your data connection, mostly eliminating that delay.


Well most offline devices don't take minutes now except for the first fix in a long time. It's generally around 30 seconds to a minute.

Usually the almanac is stored in non-volatile memory so additional startup fixes are much faster.


It's more than that too, old receivers couldn't track and download from as many satellites at once. All modern receivers can pull almanac/ephemeris data from pretty much everything they see at once now.


I've got an eMap - last time I tried it (after it was off for N years), it took upwards of 20 minutes to get a fix with a clear sky because it could only track (AFAIK) 6 satellites and without the hints from recent use, it struggled badly.


But there was another big important to positioning: Incorporating other signals (cell & WiFi). There's a huge difference on the same Android device with and without Google services (which do the aforementioned job).


> Support for Galileo and Glonass was touted maybe a decade ago, but there was never any massive improvement in accuracy. Same story?

Why don't you supply a source to go along with your bold claim? Instead, here is the first set of test results I found on google: https://rxnetworks.com/press-releases/test-confirms-that-gal...

It shows that using more than just GPS substantially improved accuracy in challenging environments. Dual frequency GPS should show strong improvements too.


> Dual frequency GPS should show strong improvements too.

It does. Reviews of Garmin's GPSMap 66sr which was the first one with dual band, are really good. Especially in tough tracking situations.

Time to First Fix is also better.


Yeah. I used various Garmin GPS devices before, GPS (eTrex 30, gpsmap 62s) and GPS+GLONASS+Galileo. But my multi-band gpsmap 66sr gets a fix insanely quick compared to these other devices and the tracks are very accurate/steady. Here is a nice review that compares the gpsmap 66sr, gps 66i, iPhone 12 Pro and Fenix 6x Pro Solar:

https://hikingguy.com/hiking-gear/garmin-gpsmap-66sr-review-...


I've been thinking about getting one of those, I would really want to buy a GPSMap 66sr but I also use InReach a lot. Which the 66i has, but it lacks the dual-band GPS... So neither option is really perfect. And it's a big expense for me so I don't want to buy something that gets superseded a month later (again)

In the end I decided I'd wait until Garmin comes up with a GPSMap which has both dualband and InReach. But it's turning out a long wait.. They did come up with a replacement for the InReach Mini I'm using so its resale value has also dropped in the meantime :(

So for now I'm still using the InReach Mini 1 + my crappy phone GPS.


Luckily I don't need InReach, so it was an easy decision for me. Last year I made the mistake to cheap out and get a 64sx. It's a fine GPS, but it's was not really a big improvement over my 62s. Having GLONASS and Galileo as well was nice, but the 64sx is not multi-band, only has a few extra connectivity options, and still has the same old interface as the 62s.

However, I love the 66sr. Not only is it fast and accurate, the screen is so much nicer than the 62/64 series. The UI has the same base interface, but looks much refreshed compared to the 62/64. And I love the support for Live Geocaching. No need to plan ahead and do pocket queries, but I can just download caches on-device.

I was first a bit hesitant about the built-in lithium battery (no more replaceable AA batteries), but then the 66sr has more than double the battery life of the 66s (36 hours vs. 16 hours), so it's not an issue in practice for my uses.


Would the iPhone 14's built-in Satellite SOS (and satellite location sharing with friends) feature replace your need for an InReach device? It depends on how you use the InReach, I guess.


I don't know.. I don't use iPhones anymore (for software compatibility and price reasons - on a Spanish salary they are simply too expensive) but if Samsung would get a similar feature then perhaps...

It depends how well it works though. And how much fussing around is actually required with that targeting stuff. Of course in an emergency I may not always be able to fuss with it a lot. It depends on real-world usability. I'm sure the various hiking sites will put it to the test when it comes out.


> Support for Galileo and Glonass was touted maybe a decade ago

I bought a new phone in 2021 and it newly touted Galileo support but when actually opening up GPSTest, there were no satellites. On the forums, it turns out nobody could receive any Galileo. This isn't something that has been around for very long as of today, and when it's advertised, it might not even work.

Also, "As of 2012, [Galileo] was scheduled to have 15 satellites operational in 2015 and reach full operation in 2020" (Wikipedia). The first satellite had been launched only a year prior, 2011. This really wasn't a thing yet, a decade ago.

GLONASS is something my previous phone (Huawei, Feb 2017, €240) could reliably receive along with BeiDou, so that has been around a bit longer.

The difference between my GPS-only 2012 phone and the Huawei was night and day. Multiple minutes to find a fix versus mere seconds, both under reasonable conditions next to a window (both lying on the windowsill, started searching for a fix at the same time). Whether that's due to GLONASS and BeiDou or if the GPS chip itself also made a leap, I don't know, but yes this has gotten a lot better and it's definitely noticeable as a regular user, if you use GNSS specifically.

Probably you haven't noticed because phones, by default at least, upload WiFi identifiers around them to Google/Apple which then return a location, so in both cases you get a fairly good position within whatever your ping time to goopple is, and goopple gets a nice map of users' locations in return. (Or to Mozilla, if you modified your phone to use MLS instead. I tried it once, was nice, but a hassle to set up so my current phone doesn't have it anymore.)


Is there a noticeable difference? The gps on my iphone12 hasnt let me down yet.


Its an interesting choice, yes, l5 works better inside (supposedly) but its not good enough for AR. For that you need visual positioning/SLAM (just with pre-calculated maps, so not simultaneous, or mapping)


Only dual frequency? Triple frequency for L-band corrections is all the rage these days. If you have that you can get close to RTK accuracy anywhere (with good sky view).


iPhones don't have dual-band GNSS already?! You can get tri-band Android phones for far less than the cheapest iPhone 13.


Such as? I'd be interested but don't know I would find any. Dual-frequency is already hard to come by and only mentioned somewhere far down their spec sheets.


I have a Pixel 6 Pro, which shows me connecting to GPS on L1 & L5, GLOSNASS on L1, Galileo on E1 and E5a, and BeiDou on B1 and B2a. Unfortunately for the GP's point, that's quad-system but still only dual-band, as L1, E1, and B1 are 1575.42 MHz and L5, E5a, and B2a are 1176.45 MHz.

Quite fun, but not surprising: all the satellites I'm picking up on L5 frequencies I'm also picking up on L1 frequencies, between 24 and 27 signals, sitting in my front room. British houses are not very good at blocking GPS, it seems.

The various signal plan pages on the ESA Navipedia were useful for validating those values: https://gssc.esa.int/navipedia/index.php/Category:GNSS_Signa...


> You can get tri-band Android phones for far less than the cheapest iPhone 13

you get what you pay for


I wonder when it will include the L3 band GPS receiver ;)


I wonder if it's doing L1/L2, or L1/L5...


L1/L5.


Neat, if so! Where do you see that, though?


Apologies for lack of a better source. A slide during the live presentation mentioned this. I’d estimate a 10% chance I’m misremembering.


Pretty big slide at 0:29:28 into the event:

https://imgur.com/a/mSZ17Fv

That said, this was talking about the Apple Watch Ultra. I'd assume it's the same for the phone, but I don't have proof of that.


Thanks! Indeed, it seems logical that they’re shipping the same tech inside these same gen devices. I think Apple has been very consistent with that (except for when they intentionally ship older tech like in the SE)


All the better to track you with, my dear.


My team and I are watching you as we speak. Spoiler alert: Your tinfoil hat doesn't help.


Weird, I thought we stopped doing tinfoil hat jokes post-Snowden.


Ah, I was just joking around my username!


I'm glad that this will massively increase safety of the general public. No more cut out signals confusing police responders. What are you afraid of? It can only be used by authorized apps.


GPS is passive.


I don’t share parent’s pessimism, but I think that comment was probably referring to tracking inside apps and having better tracking accuracy.

Basically Pokemon Go would know you went to the burger shop and not the Hawaian pancake shop 50m before.


Tracking apps and phones in general don't rely purely on GPS/GNSS. WiFi and Bluetooth-based positioning systems have been used in tandem with satellite positioning for years now. This won't change much, except for having better positioning in the middle of nowhere.


pokemon go[1] has maps based on visual maps, so are much more accurate and gives you where the phone is pointing, not just lat lon height. My old company had 20cm accuracy, we can assume that its reasonably close to that now. even with shitty crowd sourced photos.

[1] well niantic: https://nianticlabs.com/news/lightshipsummit/?hl=en


Dual band (30cm accuracy) would mean that they know that you weren't walking on the sidewalk during pokemon go and could report you for jwalking.


On iOS, the only way to read GPS location also sends GPS location to Apple, so GP has a point. This has been supported on Android for years without such tracking.


but the android running it is active, whats your point?




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