title: Real time location broadcast
body: <p>I'm developping an android cab booking app , My goal is that all registered users on the passenger app can see the location of all near by cabs in a realtime map ,when they click the cab marker they can see information about the cab , driver ,distance...then send a request to driver</p>
  
  <p>the geolocalisation of the cabs must be done through the driver smartphones , the drivers have also their own app and they must be registered .
  for I made a registration system with PHP/MySQL, It't supposed after login into the app to show a map with current location in it (passenger's location) and all near by cabs.
  My question is how can I broadcast and show the registered drivers' locations to all registered passengers maps ?? </p>