NASA Scientific and Technical Aerospace Reports

20040071101 Texas Univ., Austin, TX, USA
Parameterized Consideration Set Model for Airport Choice: An Application to the San Francisco Bay Area
Basar, G.; Bhat, C.; Oct. 2003; 58 pp.; In English
Report No.(s): PB2004-105725; SWUTC/03/167520-1; No Copyright; Avail: CASI; A04, Hardcopy
Airport choice is an important air travel-related decision in multiple airport regions. This report proposes the use of a
probabilistic choice set multinomial logit (PCMNL) model for airport choice that generalizes the multinomial logit model used
in all earlier airport choice studies. This study discusses the properties of the PCMNL model, and applies it to examine airport
choice of business travelers residing in the San Francisco Bay Area. Substantive policy implications of the results are
discussed. Overall, the results indicate that it is important to analyze the choice (consideration) set formation of travelers.
Failure to recognize consideration effects of air travelers can lead to biased model parameters, misleading evaluation of the
effects of policy action, and a diminished data fit.
NTIS
Airports; Cities; Decisions
20040073485 Sikorsky Aircraft, USA
The Development of a New Lateral-Control Arrangement
Baker, Paul S.; October 1941; 39 pp.; In English; No Copyright; Avail: CASI; A03, Hardcopy
Development work on an arrangement using ailerons and spoilers for lateral control was carried out by the
Vought-Sikorsky Aircraft Division of the United Aircraft Corporation on a small commercial airplane in flight and on an airfoil
in a wind tunnel. Spoiler hinge moments were reduced by aerodynamic balance. The arrangement was then built into an
experimental airplane and further improvements were adopted as the result of flight and tunnel tests. The use of ailerons for
lateral control with flaps up, spoilers with flaps full down, and gradual transition as the flaps are lowered was found to provide
lateral control under the flight conditions for which they were best suited. The ailerons were of short span, permitting the use
of long-span flaps, and were drooped to a relatively large angle when the flaps were deflected. A high maximum lift coefficient
was thus attained. With large control deflections in the intermediate flap-angle range and spoiler effectiveness near neutral
improved by "ventilating" the spoiler, the lateral control was satisfactory for the experimental airplane and was
a definite improvement over that of a conventional control arrangement.
Author
Lateral Control; Sikorsky Aircraft; Wind Tunnel Tests; Commercial Aircraft; Flight Tests; Aircraft Design
20040073561 Naval Postgraduate School, Monterey, CA
Autonomous Landing System for a UAV
Lizarraga, Mariano I.; Mar. 2004; 147 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422364; No Copyright; Avail: CASI; A07, Hardcopy
This thesis is part of an ongoing research conducted at the Naval Post-graduate School to achieve the autonomous
shipboard landing of Unmanned Aerial Vehicles (UAV). Two main problems are addressed in this thesis. The first is to
establish communication between the UAV’s ground station and the Autonomous Landing Flight Control Computer
effectively. The second addresses the design and implementation of an autonomous landing controller using classical control
techniques. Device drivers for the sensors and the communications protocol were developed in ANSI C. The overall system
was implemented in a PC1O4 computer running a real-time operating system developed by The Math- works, Inc. Computer
and hardware in the loop (HIL) simulation, as well as ground test results show the feasibility of the algorithm proposed here.
Flight tests are scheduled to be performed in the near future.
DTIC
Autonomous Navigation; Autonomy; Drone Vehicles; Landing Aids
20040073580 Naval Postgraduate School, Monterey, CA
Crossbow Executive Summary
Muldoon, Richard; Mar. 2002; 18 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422417; SEI12-001-ES; No Copyright; Avail: CASI; A03, Hardcopy
Distributing naval combat power into many small ships and unmanned air vehicles that capitalize on emerging technology
offers a transformational way to think about naval combat in the littorals in the 2020 timeframe. Project CROSSBOW is an
engineered system of systems that proposes to use such distributed forces to provide forward presence, to gain and maintain
access, to provide sea control, and to project combat power in the littoral regions of the world. Project CROSSBOW is the
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