Visual pose estimation for shipboard landing of autonomous parafoils
This paper outlines an investigation into the use of a simple, focal-plane imaging sensor for guidance of an autonomous parafoil system for approach and landing on a moving platform such as a ship underway. The perspective-projective transformation between an object in a three-dimensional world and an image on a two-dimensional plane is analyzed and then formulated using a homogeneous coordinate system. The estimation problem is addressed; specifically, the challenge of dealing with the out-of-frame condition due to parafoil oscillation as it approaches the target. A dual-mode Kalman estimation-scheme is proposed that suspends measurement when the target is out-of-frame, and incorporates a two-view measurement when the target reenters the frame.
Development and Testing of the Miniature Aerial Delivery System Snowflake
Proceedings of the 20th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, Seattle, WA, May 4-7, 2009.
Precision Aerial Delivery Systems in a Tactical Environment
A systems level analysis of precision aerial delivery systems provides a basis for comparing the characteristics of different types of systems and the implications that component and control approach selection have on system performance. High-glide and low-glide systems types are described. The effects of glide ratio, control response and sensor selection on terminal accuracy are analyzed. Wind data is necessary for all system types. The paper discusses the use of wind data, the need for an accuracy estimate as part of the wind data and the trade between wind data accuracy and attainable offset. In tactical situations, the concept of operations and the selection of system type and desired offset performance is affected by the threat scenario, and the operator's knowledge of threats and their distribution. Several novel operational concepts are discussed, along with the implications for system performance requirements. As part of the analysis, this paper suggests new nomenclature needed to analyze systems, introduces key operational concepts, and areas for future study.