Giving out GPS coordinates to server (URL)

The requirements are: 1) Working on all Android bases 2) The design is a background image and a button in the vertical/horizontal center — Hide 3) When application is hidden, it runs in background 4) Preferably the application runs itself on phone start — again in the background 5) In interval X (can be 5 seconds) it sends the GPS coordinates to an URL (for example [login to view URL]) with POST data containing current GPS coordinates 6) It has to contain some kind of security variable in the POST data (for example dynamic md5 of something that could be verified on the server side) - Preferably the GPS coordinates should be such as Google Maps do use.