I think you want the camera to maintain an angle of 0° to the vector angle of the X and Y axes. That should keep the camera pointed in the right direction.

The The G code command would look something like this: G1 X20 Y20 Z0 A45 F20

You could generate the path in a CAM program and just post compatible G code for whatever controller you are using. Or you could ''teach'' the path by jogging the movements and capturing the positions along the way, then just play it back, many industrial robots are programmed this way.

In a Galil motion controller there is a built in A axis tangent function to do exactly what you want.

Overall it should be pretty easy to do.