Inverted-Landing Aircraft
An aircraft defining an upright orientation and an inverted orientation, a ground station; and a control system for remotely controlling the flight of the aircraft. The ground station has an auto-land function that causes the aircraft to invert, stall, and controllably land in the inverted orientation to protect a payload and a rudder extending down from the aircraft. In the upright orientation, the ground station depicts the view from a first aircraft camera. When switching to the inverted orientation: (1) the ground station depicts the view from a second aircraft camera, (2) the aircraft switches the colors of red and green wing lights, extends the ailerons to act as inverted flaps, and (3) the control system adapts a ground station controller for the inverted orientation. The aircraft landing gear is an expanded polypropylene pad located above the wing when the aircraft is in the upright orientation.
1 . A method of calculating the absolute altitude of an aircraft that is changing altitudes, comprising:
using a ground-camera to repeatedly image a feature of a fixed size on the ground;
calculating an imaged size of the feature;
calculating a rate of change in the imaged size over time;
calculating a rate of descent; and
calculating an estimated absolute altitude using the rate of change of the monitored ground image and the estimated rate of descent.
2 . The method of calculating the absolute altitude of an aircraft that is changing altitudes of claim 1 , wherein the rate of decent is established by monitoring the change in the true altitude.
3 . The method of calculating the absolute altitude of an aircraft that is changing altitudes of claim 2 , wherein the change in true altitude is measured by monitoring a change in air pressure.
4 . The method of claim 1 , wherein the aircraft includes a first camera oriented to view downward and forward while the aircraft is in an upright orientation, and a second camera oriented to view downward and forward while the aircraft is in an inverted orientation, and further comprising the step of using the first camera as the ground-camera while the aircraft is in the upright orientation, and using the second camera as the ground-camera while the aircraft is in the inverted orientation.