If your sat phone happens to be of the Globalstar variety, it can also act as a very basic GPS with an accuracy of about 1/4 mile. Its a little known menu function under options that is only available during a call. I know it works on the GSP-1600, I don't know about the new GSP-1700. Essentially, it displays the current longitude and latitude of the phone in degrees and minutes.

Certainly, a separate (and much more accurate) GPS would be ideal, but if the GSP-1600 is all you have, that could be enough.

Craig.