Convergence is really nice, in theory

January 11, 2008

I’ve been trying to test the GPS on my newly-arrived N810. So far I have not succeeded in getting a fix from my window. Time-To-First-Fix while walking outside (with very good view of the sky) has been 5-10 minutes.

This is not what I had been hoping for. It seems I’ll still be carrying an external GPS with me, at least sometimes — just like like I have to carry a camera with me if I want to take half decent photos, even though my phone has two cameras in it. Good gadgets seem to be difficult to make. Good convergence gadgets are still, in my opinion, mostly an unproven theory.

Otherwise I’m very satisfied with the device: it feels really solid, and I’m still amazed how they fit the keyboard into a device smaller than the N800.

Not SiRF III? 

Anyway, about the GPS: There were rumours around the internet that the chipset is SiRF III, but this does not seem to be the case. Internettablettalk forum member ag2 found this string in /usr/sbin/gpsdriver:

GPS5300GPS5300GPS5300GPS5300GPS5300GPS5300GPS5300GPS5300GPS5300GPS5300GPS5300GP

GPS5300 is a gps-on-a-chip for OMAP based phones from Texas Instruments. From their product brochure (emphasis mine):

The GPS5300 NaviLink 4.0 solution enables a rapid time to first fix (TTFF) from weak satellite signals… .

Questions:

  • Can someone confirm the chipset details?
  • Assuming we do have a GPS5300 on the tablets, does “rapid” have an alternate meaning in Dallas? Maybe it’s just that everything is bigger there, even time-to-first-fix.
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15 Responses to “Convergence is really nice, in theory”

  1. Luarvique L. Luarvique Says:

    It is just a shitty GPS chip from Texas Instruments, also used in N95 and E90. It has most likely been chosen for its size (one of the smallest on the market, AFAIK) and its goo integration with the rest of the OMAP2 chipset.

    As far as satellite acquisition, this chip sucks. Not much has been done about it, although I have heard that the latest Symbian/S60 firmwares for N95 and E90 have assisted GPS where cell tower locations are used to reduce TTFF. Alas, GSM-less N810 can’t do the same trick.

  2. symbianguru Says:

    With AGPS on the N95s, I get a lock in under 30 seconds consistently.

    That being said, I wonder if there’s a way to use the Tablet’s data connection in the same way. Obviously it wouldn’t work all the time, but it would be nice to have when you ARE near your phone.

  3. rossburton Says:

    I’ve noticed that orientation of the N810 really matters, when I first got mine I left it on the window (where my BT GPS sits) screen-up and after four hours, still no fix. Once I’d aligned it so the screen was pointing forwards, it got a fix in a minute.

  4. Luarvique L. Luarvique Says:

    As far as I know, BT data connection can’t be used to get active cell tower data, at least not without some extra software running on the phone and relaying this data to the tablet.

  5. jku Says:

    Thanks for the tip Ross, will have to try aiming more carefully.

    symbianguru: I assume the AGPS action happens at chip-level (phone chips talking to the gps chip) so there is probably nothing we can do about it in the driver (assuming driver code was available) or application code — Not that I know anything about how these things are implemented. I’d love to be wrong.

  6. Brian Says:

    Yes, unfortunate that the n810 doesn’t provide any “kitchen window” gratification. It makes the first-try experience a frustration. I find that it’s fine outside, though. Not stunning, but fine for a convergence device IMHO. I was pleased to discover that, where I really need it to work, it does: in the car. I can prop it in the ashtray forward of the shift, and it locks in a minute or two. I like it down low – not in my face all the time, esp. at night. I happily purchased the nav upgrade – I think it was worth it. Strange how both Nokia and Wayfinder think they can ship these products w/o any manuals!

  7. Tom Says:

    also dissapointed in the gps, and the charge for the wayfinder, but am otherwise very satisfied, the wifi connection is flaky, but i should try a few other spots to have a final verdict. the gps was the reason i got it though, the form makes this a worthwhile product though

  8. Ze Stuart Says:

    I read the PDF you linked to: there was very heavy mention of AGPS in there, and it leads me to think this chip is not designed to be deployed without APGS support.

    Both my n95 and e90 were *useless* for GPS before the AGPS was bundled into their firmware, but now I get 20-25s lock-ons that are very reliable (even on a train moving at 130mph).

    I think that GPS on the n810 will only become truly great when it can use the tablet’s data connection to pull AGPS info from the internet. Maybe some kind of 3-day cache, like some HTC devices use? (Sorry for swearing, didn’t mean to hint at Windows Mobile! :p)


  9. I got my n810 yesterday, and took it on the road. In my car, it consistently found my location in about 30-45 seconds.


  10. That’s driving from Atlanta, GA to Orlando, msotly FL on I75, by the way…

  11. Soknet Says:

    I’ve read somewhere that the first time the GPS is used, it takes longer than the rest of the times.

    Jku, Can you it again and post the results here?

    Thanks

  12. jku Says:

    Soknet, I’m not seeing any change, although I may have rebooted in between. Looking at the header files, the driver seems to save last known position and may use that to get next fix — but I have no idea if the “last known position” is saved on gpsdriver shutdown.

  13. macintrash Says:

    Hi Jussi,

    Do not be pissed off so much.
    Even with SiRF III, it takes time to find the cordinates from the cold boot.
    The cold boot happens when
    - you use the device first time,
    - you use the device after long long absence
    - you carry device somewhere unknown far from the last place where you used it

    The trick in N95 and E90; supposed it has a cellular and the rough poistion is provided as the pre-indication to GPS device, then the GPS device can “guess” where the satelites positions are. It will help GPS device from the cold boot.

    In fact, when I used my Garmin Nuvi 360 (yes, SiRF III inside!) in Helsinki, it took > 20min to get the postion. I almost arrived at the destination, just 500m before, when it started to navigate me :-P

  14. jku Says:

    macintrash,

    I just removed the battery from my external SiRF III (Nokia LD-3W) for a few minutes and then started it. Got a fix in 30 seconds from my window. Maybe it’s saving previous coordinates or something, I don’t care: the point is that it works for me and the N810 GPS doesn’t (and neither device uses cell-based A-GPS, so that’s a moot point).

    I am actually trying to develop location-aware software for the N810 and it is quite difficult: Getting a fix requires a lot of leg work. Twice I’ve been standing in the middle of a park for 10 minutes before giving up (my QA enthusiasm has its limits, at least in Helsinki weather conditions).

    It is of course possible that I just have a lemon — maybe I should visit the flagship store and try one of their devices…

  15. jku Says:

    I just realized I had forgotten Ross’s advice. Tried it, and what do you know: it seems to work. The N810 will not get a fix when it’s standing on its stand, but will if the screen points upwards.

    I’ll test some more and post again.


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