You may need to create an application on your phone that will save your position data to a local db (on your phone) for later syncing when you get back to network or just plain writes to a text file on the local filesystem that you can transfer onto your main database
An android phone should be able to do this even when there is no network (a quirk I'ved experienced is that GPRS must be ON for the thing to work)
I would recommend a phone with Good battery life and some good internal storage (depending on where you save the data)
Android version >= 2.3.4
Regards