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iPhone 14 Pro comes with dual-frequency GPS

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Re: iPhone 14 Pro comes with dual-frequency GPS

#81

Post by microtonal »

GekkePrutser wrote: post #20
coder543 wrote: post #11

Earlier quoted context omitted.

> 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 enviro…

> 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-...

Re: iPhone 14 Pro comes with dual-frequency GPS

#82

Post by capableweb »

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?

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#83

Post by [deleted] »

shaky-carrousel wrote: post #21
NelsonMinar wrote: post #3

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.

[deleted]

Re: iPhone 14 Pro comes with dual-frequency GPS

#84

Post by joecool1029 »

orev wrote: post #61
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.

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

Re: iPhone 14 Pro comes with dual-frequency GPS

#85

Post by FPGAhacker »

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?

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

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

Re: iPhone 14 Pro comes with dual-frequency GPS

#86

Post by londons_explore »

s1mon wrote: post #75
willis936 wrote: post #69

Earlier quoted context omitted.

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.

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#87

Post by joecool1029 »

matt_attack wrote: post #51
pxeboot wrote: post #41

Earlier quoted context omitted.

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.

Re: iPhone 14 Pro comes with dual-frequency GPS

#88

Post by sorenjan »

joecool1029 wrote: post #76
causality0 wrote: post #65

Earlier quoted context omitted.

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 sa…

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_...

Re: iPhone 14 Pro comes with dual-frequency GPS

#89

Post by GekkePrutser »

microtonal wrote: post #81
GekkePrutser wrote: post #20

Earlier quoted context omitted.

> 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.

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