USA as Represented by Secretary of the Navy

Aaron David Kahn

Michael W Schuette

Karen Swider Lyons

Richard O Stroman

Richard J Foch

Gregory S Page

Disclosed herein is a system comprising: a hydrogen fuel cell; a fuel storage tank; a regulator coupled to the storage tank and the fuel cell; an electronic auto pilot; a rechargeable battery; a power electronics module for delivering power from the fuel cell to the autopilot and the battery; and a heat exchanger coupled to the fuel cell. The fuel cell is characterized by: a minimum continuous power output of no more than 25 W; a maximum continuous power output of no less than 5000 W; a specific power of at least 200 W/kg based on the mass of the fuel cell and any control electronics, cooling components, air delivery components, and water management components; an ability to operate at least 2 psig of hydrogen at an inlet; and an ability to operate at temperatures up to 90&#xb0; C.

Hydrogen fuel cell propulsion system

A technique for finding and estimating the locations of atmospheric thermals for the purpose of exploiting the updraft energy to enable the aircraft to remain aloft while reducing or eliminating the need to expend fuel or energy and operational regardless of whether the aircraft is under powered flight or is gliding.

Atmospheric thermal location estimation

Embodiments include systems and methods of navigation. In on embodiment, a plurality of position and motion states of a vehicle are estimated. The states may be estimated based on information received from a satellite receiver and an inertial measurement sensor. Estimating the states comprises performing one or more of a plurality of update steps at the rate that information is received from the satellite receiver. The states are estimated at a rate greater than the rate at which the update steps are performed. In one embodiment, the states are estimated using a stepped extended Kalman filter.

System and method of navigation based on state estimation using a stepped filter

Embodiments include systems and methods of estimating at least one state of a modeled dynamic system. In particular, in one embodiment, an observer such as an extended Kalman filter is used to estimate the state of a modeled dynamic system. A covariance matrix associated with state variables of the observer is periodically checked for compliance with a specified condition, e.g., positive definiteness. If the matrix deviates from the specified condition, the matrix is set to a specified value.

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Alexandria, VA, United States of America

Aaron David Kahn