I use Cyclemeter on my iphone mounted on a QuadLock. I has been flawlessly reliable for the last five years. It does all the things you require, automatically sends your location at regular intervals to any email addresses you Iist. It also does all the things an iphone does--I've even had brief Facetime chats while riding out in the country. The one thing it can't do is be compact and light, but you carry a smartphone anyway.