(Internal, Bluetooth) GPS and power consumption

[gpsmad]

Hi!

I'm a proud owner of a N82, but I'm a bit confused about the GPS settings on the phone.

Internal GPS and Assisted GPS are no problem, they just work (and I know how).

Network based positioning is a bit blurry, though. It depends on my provider to give the phone additional information to triangulate my position? It seems to work quite good (tried it with all other methods disabled, but that was no "real" test).

Next, I've an external GPS mouse. If I enable all methods on my phone (most notably Internal and Bluetooth GPS) will the phone use both methods and drain the battery very fast? Or has it some "fallback" (use Bluetooth if available, if not try it with the internal GPS receiver)?

I've read the article on power consumption over here. How did he measure the power consumption? Do I need extra equipment or is there some hidden (or obvious) way directly on the phone?

Finally, what do you think is less power-intensive (for the phone), internal GPS or GPS via bluetooth? Would you advise to disable the internal GPS if the bluetooth variant uses less power or doesn't it matter?

Cheers!

[dez_borders]

Originally Posted by gpsmad

Next, I've an external GPS mouse. If I enable all methods on my phone (most notably Internal and Bluetooth GPS) will the phone use both methods and drain the battery very fast? Or has it some "fallback" (use Bluetooth if available, if not try it with the internal GPS receiver)?

I believe that once you select (from your GPS app) the Internal GPS device, bluetooth will not connect to the external GPS device.

If you select the Bluetooth GPS device, the Internal GPS chip will be powered off.

In both cases above, if you use Assisted GPS or Network GPS, then a short burst of GPRS/3G data will be sent/received immediately after starting the GPS app, and only once. No data is sent or received during Nagivation. You can therefore discount the battery drain of A-GPS and Network GPS modes.

[gpsmad]

Thanks for the reply!

The "fallback" was easy to test - if I power-off my GPS mouse, the phone will use the internal GPS chip. But if the bluetooth GPS device can't get a lock it will *not* fallback and try it with the internal GPS chip.

Interesting observation: I'm using the Nokia LD-3W and it seems that the phone uses A-GPS to get a faster lock with it *unless* I'm moving (walking), then it takes aeons to get a lock (whereas the internal GPS chip locks very quickly).

You provided the power-consumption stats of the N95, is there a simple way to do the same with the N82? As written earlier, I'd like to know whether it's "cheaper" to use an external GPS device via bluetooth or to use the internal GPS chip (in terms of power-consumption).

Cheers!

[N/A]

Nokia Energy Profiler:

http://www.forum.nokia.com/info/sw.n..._Profiler.html

[gpsmad]

Thanks! Exactly what I was searching for!

Here are the numbers I got from my N82 (given that I read the numbers correctly):

Display: 0.21W
Display off: 0.16W
Stby: 0.04-0.06W

Sports Tracker (with network access)
* With bluetooth GPS (LD-3W): 0.40W
This is an average of 1600 readings.
It started a bit higher ~0.8W but came down between 0.15W and 0.30W shortly.

* With internal GPS: 0.52W
This is an average of 1550 readings, the series was pretty much constant.

After disabling the network connection of Sports Tracker I got these readings (average of 1400 readings):
* Bluetooth GPS: 0.28W (this time the graph was very constant too)
* Internal GPS: 0.52W

For the measurements I discarded the first and last few (100-200) readings.

Cheers!