  We present a dynamic path planning algorithm to navigate an amphibious rotor
craft through a concave time-invariant obstacle field while attempting to
minimize energy usage. We create a nonlinear quaternion state model that
represents the rotor craft dynamics above and below the water. The 6 degree of
freedom dynamics used within a layered architecture to generate motion paths
for the vehicle to follow and the required control inputs. The rotor craft has
a 3 dimensional map of its surroundings that is updated via limited range
onboard sensor readings within the current medium (air or water). Path planning
is done via PRM and D* Lite.
