Hello All,
I was wondering if it possible to build 'Locate Me' service in cell phone.
For instance, you are at a particular location and you want your friend to be there. If somehow he can locate you, then he can use GPS device to get driving directions to that place.

Here's how I think it can work.
1. Friend AB meets Friend DC for the first time.
2. Each of them have a digital certificate in their cell phone. (Digi Cert can be issued by the service provider)
3. AB and DC decide to exchange their contact details (name, phone number, person photo and Digi. Cert.)
4. AB go to contact details of his phone menu, searches for DC and choose 'automatic' option to allow DC to automatically locate him (AB).
5. DC on the other hand, go to his contact details of his phone menu, searches for AB and chooses 'prompt' option. This way, every time AB wants to know where DC is, DC will get a prompt, whether he should allow AB to know where he is.

When AB and DC decide to meet.
1. DC searches for AB in his phone book and clicks on 'locate AB' option.
2. DC's phone sends its Digi Cert to AB.
3. AB's phone validates the Digi Cert against its local storage once authenticated replies back to DC's phone with its location.
4. Once DC sees AB's location, he clicks on 'navigate me' / 'driving directions' option. DC's phone then uses its built in GPS feature to display the driving directions to AB's location.

I think we have all the pieces to build this kind of functionality, I wonder if anyone is working on it.