In addition to the few screenshots I've posted, at least a couple of tutorial videos are found in the web. These show you how to connect ExtGPS and Nokia N770/N800/N810 devices:

Nokia Users: ExtGPS - Internal GPS Sharing for S60v3

The Mobile Gadgeteer: Use your Nokia N95 as a Bluetooth GPS receiver and modem for your N800

Guys, thanks for posting! I've always thought that the software is famous enough when it gets into Youtube...

I just realized that I have not uploaded any screenshots at all. Here's some basic screens of ExtGPS, taken on E90.

Firstly, the Bluetooth permission screen. If Bluetooth is not enabled, this is skipped and you will only get the Bluetooth error screen.


Positioning permission, allows accessing the GPS


The main screen, before connecting


The main screen, device connected and GPS fix obtained using E90's bigger screen


About dialog. Running yet unreleased version ;)


And finally, the other device. In this case, it's E65 connected to E90. Not much point really, just to show that it is possible to connect two S60 devices:

If you are more into GPS navigation, you might also know that there's varying levels of navigation statements outputted by different GPS devices. In case you are pondering if ExtGPS on S60 device is suitable for your application, here's a sample NMEA data as outputted by Nokia E90.

$GPGGA,184403.000,6630.11553,N,02544.24599,E,1,04,1.9,64.3,M,22.2,M,,*6D
$GPGLL,6630.11553,N,02544.24599,E,184403.000,A,A*57
$GPGSA,A,3,03,18,21,29,,,,,,,,,3.4,1.9,2.9*34
$GPGST,184403.000,53.0,108.2,21.5,52.6,79.5,62.2,205.0*5D
$GPGSV,3,1,11,03,55,207,22,08,15,321,,32,32,192,,18,53,087,23*7A
$GPGSV,3,2,11,19,55,270,,21,16,095,31,22,55,161,22,26,21,024,*78
$GPGSV,3,3,11,28,10,346,,29,15,015,20,14,01,151,*4B
$GPRMC,184403.000,A,6630.11553,N,02544.24599,E,1.4,305.1,161007,9.1,W,A*12
$GPVTG,305.1,T,314.3,M,1.4,N,2.7,K,A*21

Basically, the data contains location, accuracy, satellite positions on the sky, speed and heading - you rarely get more than this in NMEA 0183 format. Binary formats are of course a different matter...

PS. Extra points for those who can guess what's the most famous hotel next to this parking lot :)

Recently, Forum Nokia released a new developer tool for measuring S60 application's power consumption (Nokia Energy Profiler) Here are some results and conclusions about power usage while using ExtGPS on Nokia E90 communicator.

The biggest power hog is the screen backlight. Alone, it consumes about 650 milliwatts of power. When the screen is dimmed and screen saver is activated, the power usage is about 70mW - this is when the only running application is energy profiler itself - I guess the profiler itself uses some power as the official standby times suggest around 20mW power usage in idle.

When GPS has obtained a fix and laptop is connected via Bluetooth port, the long time power usage is about 530 mW (dimmed screen). E90 has BP-4L battery which is rated for 3.7V 1500mAh. This totals about 5.5 watthours, meaning that the battery should be good for 10 hours of GPSing!

N95 has 950mAh battery, which could last for 6 hours 30 minutes, if you don't use any other phone features. This about the same usetime as those "normal" external BTGPS units.

To make our series complete, here are the instructions how to setup ExtGPS for Linux applications, using Bluetooth serial port.

Unlike the other howtos, this one is command line based. Probably suits better for Linux enthusiasts :-)

Make sure ExtGPS is up and running and your phone is discoverable. In the following dumps, aa:bb:cc:dd:ee:ff should be your phone's Bluetooth MAC address.

Perform a scan for "Serial Port" services:

ubuntu@ubuntu:~$ sdptool search SP
Inquiring ...

Searching for SP on aa:bb:cc:dd:ee:ff ...
Service Name: Symarctic ExtGPS
Service Description: Share phone's built-in GPS ...
Service Provider: Symarctic Solutions
Service RecHandle: 0x10016
Service Class ID List:
  "Serial Port" (0x1101)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 5
Language Base Attr List:
  code_ISO639: 0x656e
  encoding:    0x6a
  base_offset: 0x100

(... continues with other services...)

Create /dev/rfcommX device for ExtGPS, by "rfcomm bind" command. Note the parameters, "1" is the id for /dev/ entry, mac address and the last one is RFCOMM channel ID from service, in my case it's channel 5 (chanel no. 5 ?):

ubuntu@ubuntu:~$ sudo rfcomm bind 1 aa:bb:cc:dd:ee:ff 5

When application connects to /dev/rfcomm1, it's opened to ExtGPS. You can test the connection, e.g.:

ubuntu@ubuntu:~$ cat /dev/rfcomm1

After this, the connection icon on ExtGPS should be green and device name shown next to it. If the satellite icon is also green (meaning a fix), you should now see raw GPS NMEA data on your terminal. Issuing Ctrl-C should break the connection, turning the connection icon back to red.