I use a find my phone app that if you text a code word will return your gps coordinates and the street address for the police. I use it to send my last known address when I'm playing in the woods. If you have a signal to make a call you can text yourself first or during the call to get more detailed info of where you are.
I use an iphone app called "Basic GPS". It will give you a readout of your location in Lat Lon (several options), UTM and MGRS. It has both a text and email option. Sometimes when I do a spur of the moment hike by myself I will text my location to my wife from the trailhead (if I have cell reception). That way if I don't show up at home that night she at least knows what trail I started up. If SAR doesn't find me, she can at least recover the car!