The Design and Test using Simulation techniques of an Automated UAV- VTOL Shipboard Recovery System

The design of an automated ship recovery system for a VTOL type unmanned air vehicle is described. The described system combines both hardware and software elements enabling the identification of the UAV (position/velocity) with respect to the moving platform. Guidance of the UAV is made from the calculation of the estimated position of the deck and of ship motion as a function of UAV operational limits. A system of guidance and control is described ensuring the safe recovery of the air vehicle. The system is modular in design. Each module is briefly described, viz: tracking filtering, “ship motion prediction”, landing period designator, guidance and control. Simulation is used to test the performance and robustness of the design. A Six degree-of-freedom air vehicle model is coupled with a ship motion simulation model in a closed loop. The environment imposed is derived from a test matrix covering various sea conditions from 1 to 6 meter significant wave heights; 12 relative wave headings from 0 to 180 degrees and various ship velocities on -board two different classes of ships (frigate and corvette). Each module is modified and tested in turn culminating with the evaluation of the combined system as a whole. Test results are displayed for each of the modules and the system as a whole. Results demonstrate that the proposed system is more robust than conventional techniques presently used ensuring consistent safe recovery of the vehicle even in severe sea conditions.