android navigation for autonomous RC motorboat help needed. TIA

We need some help on creating an autonomous RC motorboat using Arduino and a magnetometer and probably GPS for navigation.

The requirement is to have the autonomous RC motorboat navigate from the shore out to a buoy that is approximately 1/2 mile out.

We are thinking that we could take an Arduino and at least a magnetometer to accomplish. I am not sure if a GPS will also be required. We would stand on the shore and point the boat towards the buoy and then push a button that would establish the heading. What is not clear to me is how we adjust for correction when the boat starts drifting off course. We are open to using any other sensors.

The thought was if we added GPS then we could point the boat towards the buoy and then push a button that would take the X/Y heading returned from the magnetometer (basically a compass heading) and the current GPS coordinates. Using this information we could then make the adjustments needed to get back on course.

Does this sound reasonable?

The goal is to come as close to the buoy as possible. We will not know the coordinates of the buoy, distance to the buoy or any additional information.

We really appreciate any help.

The Ardupilot project will give you a lot of the hardware and software you need for an autopilot, but it sounds as if the hardest part will be locating the buoy. Is there some way for the boat to sense it when it gets near enough? Are you allowed to survey it from the shore and calculate its exact position so that you can use a GPS-based dead-reckoning system?