N95 A-GPS the mystery solved

A while ago I speculated that the Nokia N95, might be using a A-GPS solution, now with the V12 firmware release available for unlocked phones from Nokia A-GPS really is supported and it does seem to make a difference.

There is a lot of confusion on the blogs and discussion groups as to what A-GPS, assisted GPS is, and how it works. This is a technology that is indepedent of network operators and does not use the location of Cell towers.

A-GPS works by supplementing the performance of the “not very good” GPS chipset on the N95 with an assistance server operated by Nokia. The assistance server knows the up to date ephemeris data of the GPS constellation and can help process whatever weak signal the phone is picking up and pass a possible location back to the phone.

This in theory and to some extent in practice means that the time to first location is reduced and you can expect to get a location in some areas where without A-GPS it would not be possible.

So how do you set it up and how can you tell it’s working… This is more informed speculation… some definitive information from Nokia would be good !!!

First you need to be brave and upgrade you firmware, after backing up everything on your N95, I still find this a little scary – a bit like a heart transplant operation for your phone..

With the V12 firmware you will find you have a new menu at – Tools>Settings>General>Positioning.

Here there are two sub-menus, Positioning Methods with the new option on Assisted GPS, which you need to enable and a sub menu called Positioning Server which contains the details for the assistance server. Here you will find the Nokia server already listed as supl.nokia.com , but you will need to manually enter an existing network access point to allow network access to the server, for me I used the Vodafone WAP APN on which I get vodafone’s new “unlimited” data tariff. You will need to enter your networks own APN here, I guess a Wifi access point should work just as well, but I have not tried.

Go to the Maps application or GPS Data tool and select the View Satellite Status menu, you should now more quickly than in the past see the familiar list of GPS satellite numbers and the open estimated signal strength bars – this is now coming from the assistance server and within a minute at least three of these will turn solid and you will have a location.

This has just worked for me on the window sill of a hotel room in the centre of Manchester giving a location in around 50 seconds !!!

I have been wrong about this in the past, but this seems to be progress !!

Written and submitted from the Novotel Manchester, using the Orange 802.11 network.

11 comments

  1. glenn

    Wow Ed, this is very cool and no doubt a breakthrough for many N-95 users.. thanks for sharing your brave experience… I too still cringe whenever I elect to update my firmware!!!

  2. Rob

    Ed,

    How did you update the firmware? I checked this yesterday using the Nokia software updater, but it picks up my vodafone product code and tells me i have the latest available version of firmware? Version 11…26. I called 191 but they didn’t seem to have a clue. Any ideas.

    Rob

  3. Peter

    Thank you Ed. I had updated my firmware (what a drama that was!) but hadn’t realised the availability of assisted GPS. What I haven’t been able to achieve since the very first time I used the phone’s positioning feature (ie before I downloaded maps) is positioning using cell locations when satellite signals are unavailable, such as indoors. Any suggestions?

  4. Peter

    Further to my last post, for the benefit of other Australian N95 owners, the latest firmware update (v.12) also gives access to the Telstra Next-G 3.5G network. Maybe only for Telstra subscribers (I’m using one of their 3G cards), but an unexpected bonus. I have yet try it in regional areas where other forms of coverage are not available but where Next-G is meant to be present.

  5. Ed

    Peter,

    Cell based location is controlled by your netowrk operator, who may or may not make this available to application developers. You will need to use a network based application (i.e. not on your phone) for this to work. This is a business rather than technical issue as the operators charge per location fix..

    This will give responsible accuracy in urban areas, say within a few hundred metres but will not work as well in rural areas.

  6. G

    Hey Ed, thanks for the clear review. I still find some things confusing with this AA-GPS. I thought with A-GPS the N95 would still need to locate itself via something like cell-based location, inorder to work out which of the sateliites it’s closest to from the assistence data (from the Nokia server). For example if you fired it up for the first time in a city, even with knowledge of satellite ephemeris data, it’d still need to have a rough idea where it was to choose the right/closest signals. right?

  7. brian stone

    I downloaded the new version of the N95 to V12. Ihe GPS works much faster now. However II have discovered a few problems:

    1. When I use the “Show route” option I get the turn by turn directions but the “Start tracking” is missing. I had been using this feature extensively with V11 and miss it. Can that option be put back. I would pay extra to be able to download it.

    2. The “Show on map” option gives me the directions on the map, but not my current position. I have to use the scroll key at each turn to display the next leg of the journey. This may be OK when walking, but is downright dangerous while driving.

    3. The distance, when the distance is less than one mile, are in yards. I would prefer 10ths of a mils as that is what my odometer reads and I have to do the conversion in my head while driving. Quick, how far is 485 yards in tenths of miles? (I set the System of measurements option to “Imperial.”)

    4. Whe i go the the “Find place” option, then select “Nearby” it does not display the landmarks English, but what appears to me as German. I don’t know how to change this to English (US).

    5. There seems to be a change to the Maps of Mexico, specifically Baja California. Previously the airports of Baja, including dire landing strips were indicated on the maps. Now these are gone completely — even major international airports like Tijuana and Los Cabos. Moreover, the roads are no longer trackable with the GPS and many of the minor roads that were visible before are gone. I would like the old Baja maps back. I would pay extra to be able to download the old maps.

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