The iPhone 5 Review
by Anand Lal Shimpi, Brian Klug & Vivek Gowri on October 16, 2012 11:33 AM EST- Posted in
- Smartphones
- Apple
- Mobile
- iPhone 5
GNSS: Subtle Improvements
Section by Brian Klug
Like the iPhone 4S and the iPhone 4 CDMA before it, Apple has gone with the GNSS (Global Navigation Satellite System) leveraging both GPS and Russian GLONASS which lives entirely on the Qualcomm baseband. In the case of the iPhone 4S and 4 CDMA, that was onboard MDM6610 and MDM6600 respectively, both of which implemented Qualcomm’s gpsOneGen 8 with GLONASS tier. Going to on-baseband GNSS is really the way of the future, and partially the reason why so many of the WLAN, BT, and FM combos don’t include any GNSS themselves (those partners know it as well). In this scheme GNSS simply uses a dedicated port on the transceiver for downconversion, additional filtering (on RTR8600), and then processing on the baseband. The advantage of doing it all here is that often it eliminates the need for another dedicated antenna for GNSS, and also all of the assist and seed information traditionally needed to speed up getting a GPS fix already exists basically for free on the baseband. We’re talking about both a basic location seed, precision clock data, in addition to ephemeris. In effect with all this already existing on the baseband, every GPS start is like a hot start.
There was a considerable bump in both tracking accuracy and time to an assisted GPS fix from the iPhone 4 which used a monolithic GPS receiver to the 4 CDMA and 4S MDM66x0 solution. I made a video last time showing just how dramatic that difference is even in filtered applications like Maps.app. GLONASS isn’t used all the time, but rather when GPS SNR is either low or the accuracy of the resulting fix is poor, or during initial lock.
With MDM9615 now being the baseband inside iPhone 5, not a whole lot changes when it comes to GNSS. MDM9615 implements gpsOneGen 8A instead of just 8, and I dug around to figure out what all has changed in this version. In version 8A Qualcomm has lowered power consumption and increased LTE coexistence with GPS and GLONASS, but otherwise functionality remains the same. MDM9x25 will bring about gpsOneGen 8B with GLONASS, but there aren’t any details about what changes in that particular bump.
I spent a lot of time playing with the iPhone 5 GNSS to make sure there aren’t any issues, and although iOS doesn’t expose direct NMEA data, things look to be implemented perfectly. Getting good location data is now even more important given Apple’s first party turn by turn maps solution. Thankfully fix times are fast, and getting a good fix even indoors with just a roof between you and clear sky is still totally possible.
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ArmedandDangerous - Tuesday, October 16, 2012 - link
What ever happened to the One X International review that was promised when you were reviewing the US version? Lots of promised articles and reviews that were never ever done...MrCake - Wednesday, October 17, 2012 - link
Yeah, already posted this comment for podcast 8, but it bears repeating. I'm less angry now, but still facepalming.It's not my expertise but I have designed a few hundred aluminum parts, so here's how it probably
works. The call-out is most likely equivalent to mil-std-171 7.2.2; this is a ~.0005" thickness coat,
decorative and scratch resistant. The coating itself is super hard, and can only be scratched by harder materials. The problem is the base metal yield strength is still fairly low. Chamfers (yes, we do pronounce the "h") have sharp edges, which make point contacts and therefore have theoretically infinite contact stresses till they're rounded off. To summarize; small contact areas, equal high pressures even at low forces; pressures over material yield cause deformations, and deformations over .0005" make you see silver. The chamfer finish is probably not a post anodization process,it's diamond ground and has a much finer surface finish. The rest of the phone is cnc milled, and is matte from either a sandblasting, or vibratory media process to remove machining marks. Anodize surfaces are as glossy/matte as their surface finish. And as to the "structural integrity" concern repeated, and repeated, and repeated; The iphone is thin, but the anodize coating is a couple orders of magnitude thinner and has negligible affect on structural integrity.
A possible fix would be mil-std-171 7.5.2 Anodize Type III which is an anodized hardcoat. It's a
similar process but coats to .002" thick, packs it's molecules much denser, and can pass a hardness test to rockwell C60. It's a reasonable response to the scratching issue, however it may not be appropriate for other reasons(prone to cracking instead of scratching, tolerance issues, more costly, less pretty.)
syxbit - Wednesday, October 17, 2012 - link
Great job guys. I'd appreciate it if you went into as much detail on the upcoming Nexus device(s).KPOM - Wednesday, October 17, 2012 - link
They will.WooDaddy - Wednesday, October 17, 2012 - link
I didn't RTFA (as if I need to question Anand consistently excellent analysis as it has been Anandtech's inception), but as soon as I saw the phrase 'murdered out' regarding the black/slate color, I was done. It was like Anand was at a poetry slam and he dropped the mic signifying that there is no one better.VivekGowri - Wednesday, October 17, 2012 - link
Hey, hey, I wrote that part :Pjuhatus - Wednesday, October 17, 2012 - link
iPhone review.. what about..Does it work as a phone??
SJD - Wednesday, October 17, 2012 - link
Don't know if I'm the first one to say this, but the HTC One S battery isn't removable. (At least it isn't over here in the UK - don't know if your version in the US is any different).Table - Physical Comparison - Page 1
Origin64 - Wednesday, October 17, 2012 - link
I do really want to point out that the iPhone 5 being 20% lighter than the 4 isn't really substantial, seeing as how a Galaxy S 1 weighs about half of that.Apple has excellent construction quality, but they build their phones from glass and aluminium and they are heavier than the competition. There's no advantage here, no breakthrough, the iPhone 5 is just a different design that has a thinner battery and less glass. It's not as interesting as you make it seem.
thunng8 - Wednesday, October 17, 2012 - link
What are you on about? The Galaxy S weighs 119g and the iphone 5 weighs 112g.