SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 43, ISSUE 13 - JULY 1, 2005

04 AIRCRAFT COMMUNICATIONS AND NAVIGATION
Includes all modes of communication with and between aircraft; air navigation systems (satellite and ground based); and air traffic control.

For related information see also 06 Avionics and Aircraft Instrumentation, 17 Space Communications, Spacecraft Communications, Command and Tracking, and 32 Communications and Radar.

20050180322 NASA Goddard Space Flight Center, Greenbelt, MD, USA

Nonlinear Attitude Filtering Methods

Markley, F. Landis; Crassidis, John L.; Cheng, Yang; January 4, 2005; 3 pp.; In English; AIAA Guidance, Navigation and Control Conference, 15-18 Aug. 2005, San Francisco, CA, USA; No Copyright; Avail: CASI; A01, Hardcopy

The extended Kalman filter (EKF) is the workhorse of real-time spacecraft attitude estimation. Since the group SO3 of rotation matrices has dimension three, most attitude determination EKFs use lower- dimensional attitude parameterizations than the nine-parameter attitude matrix itself. The fact that all three- parameter representations of SO3 are singular or discontinuous for certain attitudes has led to extended discussions of constraints and attitude representations in EKFs. The most successful EKF uses a nonsingular parameterization for the global attitude, which necessarily has more than three parameters, while employing a three-component representation for the attitude errors. This filter has become known as the Multiplicative Extended Kalman Filter. These issues are now well understood, however, and the EKF has performed admirably in the vast majority of attitude determination applications. Nevertheless, poor performance or even divergence arising from the linearization implicit in the EKF has led to the development of nonlinear filters, most recently sigma point or unscented filters and particle filters. Derived from text

Kalman Filters; Sulfur Oxides; Nonlinear Filters; Linearization

20050180618 ITT Industries, Inc., Reston, VA, USA

Technology Assessment for the Future Aeronautical Communications System

Budinger, James M., Technical Monitor; May 2005; 268 pp.; In English; Original contains color and black and white illustrations Contract(s)/Grant(s): NAS3-00174; WBS 22-184-10-05 Report No.(s): NASA/CR-2005-213587; TR04055; No Copyright; Avail: CASI; A12, Hardcopy

To address emerging saturation in the VHF aeronautical bands allocated internationally for air traffic management communications, the International Civil Aviation Organization (ICAO) has requested development of a common global solution through its Aeronautical Communications Panel (ACP). In response, the Federal Aviation Administration (FAA) and Eurocontrol initiated a joint study, with the support of NASA and U.S. and European contractors, to provide major findings on alternatives and recommendations to the ICAO ACP Working Group C (WG-C). Under an FAA/Eurocontrol cooperative research and development agreement, ACP WG-C Action Plan 17 (AP-17), commonly referred to as the Future Communications Study (FCS), NASA Glenn Research Center is responsible for the investigation of potential communications technologies that support the long-term mobile communication operational concepts of the FCS. This report documents the results of the first phase of the technology assessment and recommendations referred to in the Technology Pre-Screening Task 3.1 of AP-17. The prescreening identifies potential technologies that are under development in the industry and provides an initial assessment against a harmonized set of evaluation criteria that address high level capabilities, projected maturity for the time frame for usage in aviation, and potential applicability to aviation. A wide variety of candidate technologies were evaluated from several communications service categories including: cellular telephony; IEEE-802.xx standards; public safety radio; satellite and over-the-horizon communications; custom narrowband VHF; custom wideband; and military communications. Author

Satellite Communication; Air Traffýc Control; Civil Aviation; Very High Frequencies; Technology Assessment; Telecommunication

20050182067 Advanced Optical Systems, Inc., Huntsville, AL, USA

Laser Range and Bearing Finder for Autonomous Missions

Granade, Stephen R.; [2004]; 7 pp.; In English; SPIE Defense and Security Symposium, 28 Mar. 1 Apr. 2004, Orlando, FL, USA Contract(s)/Grant(s): NNM04AA23C; No Copyright; Avail: CASI; A02, Hardcopy

NASA has recently re-confirmed their interest in autonomous systems as an enabling technology for future missions. In order for autonomous missions to be possible, highly-capable relative sensor systems are needed to determine an object’s distance, direction, and orientation. This is true whether the mission is autonomous in-space assembly, rendezvous and docking, or rover surface navigation. Advanced Optical Systems, Inc. has developed a wide-angle laser range and bearing finder (RBF) for autonomous space missions. The laser RBF has a number of features that make it well-suited for autonomous missions. It has an operating range of 10 m to 5 km, with a 5 deg field of view. Its wide field of view removes the need for scanning systems such as gimbals, eliminating moving parts and making the sensor simpler and space qualification easier. Its range accuracy is 1% or better. It is designed to operate either as a stand-alone sensor or in tandem with a sensor that returns range, bearing, and orientation at close ranges, such as NASA’s Advanced Video Guidance Sensor. We have assembled the initial prototype and are currently testing it. We will discuss the laser RBF’s design and specifications. Keywords: laser range and bearing finder, autonomous rendezvous and docking, space sensors, on-orbit sensors, advanced video guidance sensor. Author

Laser Range Finders; Bearing (Direction); Autonomous Docking; Surface Navigation

Source: NASA.