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.

Cellular Connectivity: LTE with MDM9615 WiFi: 2.4 and 5 GHz with BCM4334
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  • doobydoo - Friday, October 19, 2012 - link

    'Right, so if you have good vision, like I do, then at a foot away, you can see those pixels.'

    If you can see that then you would also be capable of observing that the SG3 doesn't have full pixels, it uses a PenTile display which overall has fewer sub pixels over a greater area than the iPhone 5 screen, making it both absolutely lower quality and relatively lower quality per area.
    Reply
  • KoolAidMan1 - Friday, October 19, 2012 - link

    You can discern individual pixels on an iPhone 5 display?

    Lies.
    Reply
  • dsumanik - Wednesday, October 17, 2012 - link

    Im sure this guy said the same thing when the 4 came out...3.5 was "big enough"

    Just watch when apple adds an even bigger screen he will be saying it is "perfect"

    The problem with iSheeps is that they need to get out there and actually use a different phone from a different ecosystem for a month, then switch back.

    Apple's devices are well built and tightly integrated, but there are serious shortcomings, drawbacks, and flaws that you will notice once you return to the platform.

    That said,

    Personally i purchase apple products due to the insanely high resale value, which allows me to keep up with new gear on a yearly basis for a reasonable price.

    Sent from my iphone 5
    Reply
  • khurtwilliams - Thursday, October 18, 2012 - link

    "iSheeps"? Must you resort to name calling to make your point? Reply
  • rarson - Thursday, October 18, 2012 - link

    "Personally i purchase apple products due to the insanely high resale value, which allows me to keep up with new gear on a yearly basis for a reasonable price."

    I don't see it. Maybe if you buy the newest thing as soon as it comes out and sell your old last-gen device that most people are still happy with, then you're selling it for a decent amount, but you're still spending way more money than any reasonable person would. There's absolutely no monetary argument to buy Apple products, because if money is your concern, then you shouldn't be buying them in the first place.

    Apple's phone prices are much closer in line with their hardware; for laptops and desktops, the resale value argument goes WAY out of whack.
    Reply
  • darwiniandude - Friday, October 19, 2012 - link

    I bought an early 2011 MBP last year for $2650 AUD. got a high res screen option etc. I heard rumours of the retina model and sold it just before the 12 months was up so the new purchaser still had a little warranty me could buy AppleCare if they wished. I sold it for $2300 AUD. This means I lost $350 over the year, it cost me $350 to have that machine for a year. I didn't buy AppleCare ($429 AUD) either.
    The retina model came out, and retailed for $2499 AUD

    I've been doing this since my first Mac, in 2006. I can't believe the crazy used prices on Macs especially if they are still current model and about a year old. I pay about $300-$400 a year to have the latest and greatest and a machine that is always in warranty. If I bought a cheap PC notebook for $400 I'd be suffering with an underpowered plastic machine with little ram, no SSD, and it might last more than a year but I wouldn't be happy with it anyway. Each to their own. I could never stay current with PCs because a year later the system was next to worthless, even if I'd put a $1000 video card in it at the time. (I now, reluctantly, game on consoles or a little in bootcamp)
    Reply
  • david22 - Thursday, October 18, 2012 - link

    "there are serious shortcomings, drawbacks, and flaws"

    So what are they?

    The problem with trolls is that they just spout bull.
    Reply
  • MobiusStrip - Friday, October 19, 2012 - link

    Apple refuses to pull its head out of its ass or LEARN. One profound impediment to making iOS devices useful is Apple's ridiculous fear, which you can see in its crippled SDK. One example: the lack of developer access to the dock port.

    But then there is just plain stupidity. There's no excuse for bullshit like this: http://goldmanosi.blogspot.com/2012/06/will-apple-...
    Reply
  • darwiniandude - Friday, October 19, 2012 - link

    Um, when someone calls me and I miss the call, iPhone shows a missed call. Then my carrier (Telstra) sends me a text message "You have a missed call from 0412xxxxxx" then "Please call 101 you have 1 new voicemail(s)"
    I get multiple alerts for both those SMS messages.
    Reply
  • rex251 - Sunday, October 21, 2012 - link

    Why going all the way in calling people that like apple products as sheeps?
    I think you should accept the fact that some people like small phones, and maybe like small smartphones, which neither iphone5 or sgs3 are.
    From my perspective iphone 4/4s screen was maximum I would go with something called phone into my pocket, but I do not, instead finding xperia mini great sized, although too thick.
    My point, why would we have to considere as progress only bigger screen phones as such, we do have plenty of tablets to pick from for that usage?
    Reply

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