Issues in latitude and longitude to send to server when screen off, force stop, uninstall

Hi All
I am responsible to do vehicle tracking through android mobile, my responsibilities are fetching latitude and longitude and send it to server every 1 minute. I did that using android service and my problems are
1. when screen goes off data could not send to server (if the screen is on no issue to send data)
2. if force stop happens it should restart automatically
3. cannot allow to uninstall, if they like to uninstall they should provide password.
Finally I'am struggle with these 3 steps, so I unable to release my app
Can anyone share (rajesh006r@gmail.com) ideas to fulfill these issues.
Thanks in advance