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iPhone 14 Pro comes with dual-frequency GPS

apple.com

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Re: iPhone 14 Pro comes with dual-frequency GPS

#141

Post by londons_explore »

gsich wrote: post #122
londons_explore wrote: post #99

Earlier quoted context omitted.

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#142

Post by dhsysusbsjsi »

extrapickles wrote: post #136
Nappes wrote: post #120

Earlier quoted context omitted.

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#143

Post by dhsysusbsjsi »

MilaM wrote: post #52
shaky-carrousel wrote: post #21

Earlier quoted context omitted.

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.

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.

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#144

Post by tiernano »

LeoPanthera wrote: post #78
scarface74 wrote: post #19

Earlier quoted context omitted.

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.

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...

Re: iPhone 14 Pro comes with dual-frequency GPS

#145

Post by Der_Einzige »

londons_explore wrote: post #79
capableweb wrote: post #66

Earlier quoted context omitted.

> 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?

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#146

Post by tiernano »

willis936 wrote: post #70
tiernano wrote: post #16

Earlier quoted context omitted.

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...

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

Re: iPhone 14 Pro comes with dual-frequency GPS

#147

Post by snovv_crash »

lucb1e wrote: post #115
snovv_crash wrote: post #47

Earlier quoted context omitted.

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' pha…

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#148

Post by MilaM »

dhsysusbsjsi wrote: post #143
MilaM wrote: post #52

Earlier quoted context omitted.

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.

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#149

Post by mikotodomo »

tomcam wrote: post #56
jtolmar wrote: post #44

Earlier quoted context omitted.

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…

That was infinitely better than TFA, thanks.

the fucking article? edit: sorry
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