Formation flight control

An apparatus for controlling a formation flight of a trailing aircraft relative to a vortex generated by a leading aircraft, comprising:

• a position module configured to determine a position of the vortex relative to the trailing aircraft based on an estimator state vector comprising a relative position between the vortex and trailing aircraft, wherein the position module determines the position of the vortex relative to the trailing aircraft by recursively updating the estimator state vector based on a plurality of sensed measurements, wherein the position module updates the estimator state vector based on a selectable subset of the plurality of sensed measurements each time step;
• a desired position module configured to determine a desired position of the trailing aircraft relative to the vortex for providing desired vortex-induced aerodynamic benefits based on the position of the vortex;
• and
• a control module configured to control flight of the trailing aircraft based on the desired position of the trailing aircraft.

An apparatus for controlling a formation flight of a trailing aircraft relative to a vortex generated by a leading aircraft, comprising:

• a position module configured to determine a position of the vortex relative to the trailing aircraft based on an estimate of wind conditions at the leading aircraft and an estimator state vector comprising a relative position between the vortex and the trailing aircraft, the estimator state vector being based on a first set of measurements, wherein the position module updates the estimator state vector based on a comparison between at least one actual measurement obtained by the trailing aircraft and the position of the vortex relative to the trailing aircraft determined by the position module, the at least one actual measurement differing from the first set of measurements;
• a peak-seeking module configured to determine a desired position of the trailing aircraft for providing desired vortex-induced aerodynamic benefits based on the position of the vortex relative to the trailing aircraft and a mapping function of an individual performance metric;
• a limiter module configured to monitor the desired position of the trailing aircraft and modify the desired position of the trailing aircraft into a modified desired position of the trailing aircraft to avoid unintended crossings of the trailing aircraft into the vortex;
• and
• a control module configured to control flight of the trailing aircraft based on one of the desired position of the trailing aircraft and modified desired position of the trailing aircraft.