On Android, you can open your Google account settings and disable their always-on location tracking "service". Of course, you have to take Google's word for it, and that doesn't stop GPS from working for apps like Maps when you request it.

I usually leave Location services off. I'll enable them for 5-10 seconds, get the directions from Maps, then disable the Location service again. Of course, they can still estimate my location with cell towers (or WiFi, but I usually have that disabled as well), so it's not a perfect solution. Saves a lot of battery life, though.