Backpacking family trackable app, IPhone Android?

I know there are a good amount of GPS Apps out there. Tough to choose which one to get so I thought I'd ask the Guru's. I'm looking for a phone app that I can track my outings with in the San Gabriel mountains on my IPhone, yet have the same app on my Girlfriends Android so she can track where I am along with distress signal if ever needed. I do a lot of solo outings so a didtress signal would be comforting if needed. Any insight would be greatly appreciated.