Drone leading a vehicle using gps and following google maps


I am planning to make an autonomous drone that would be able to follow or lead a rover using GPS. The copter should be 10 meters ahead or behind the rover. I tried the follow me mode in mission planner but that only allows the copter to be behind or on top of the rover. I want the copter to be ahead of the rover and I dont know how to proceed with that. Kindly help!