Differential GPS/inertial navigation approach/landing flight testresults

In November 1990, a differential GPS/inertial flight test was conducted to acquire a system performance database and demonstrate automatic landing using an integrated differential GPS/INS with barometric and radar altimeters. Flight test results obtained from postflight data analysis are presented. These results include characteristics of DGPS/inertial error, using a laser tracker as a reference. In addition, data are provided on the magnitude of the differential correlations and vertical channel performance with and without radar altimeter augmentation. Flight test results show one sigma DGPS/inertial horizontal errors of 9 ft and one sigma DGPS inertial vertical errors of 15 ft. Without selective availability effects, the differential corrections are less than 10 ft and are dominated by receiver unique errors over the time period of an approach. Therefore, the one sigma performance of the autonomous GPS (8-ft horizontal and 20-ft vertical) is very similar to the DGPS/inertial performance. Postprocessed results also demonstrate significant improvements in vertical channel performance when GPS/inertial is aided with radar altimeter along with a low-resolution terrain map     

High resolution miniature AMLCDs for projection and head-mountedsystems

The development of advanced active matrix liquid crystal displays is described. The displays are formed from single crystal silicon, and have integrated on-board scanner circuitry for row and column addressing. The display diagonal is 5 cm, and pixel pitch as low as 12 μm is under development. Operational 640 by 480 displays are described, and initial results with 1.250 by 1.024 displays are reported     

Digital Avionics?The Best is yet to Come!!!

This paper reviews some of the history and background of digital avionics and offers some tantalizing possibilities for the future. There are payoffs in many areas from digital avionics; however, the ultimate benefits are increased mission effectiveness and lower costs. Two major U. S. Air Force avionics programs designed to increase mission effectiveness are reviewed. Major barriers to the expanded use of digital avionics in civil transports as a means to lower operating costs are examined. The paper also examines lightning effects, architectures, optical components, displays, and voice interactive control which are current research areas that promise to yield significant advances for digital avionics systems. Finally, in a notice of optimism, it is concluded that the best is yet to come. As good as contemporary avionics are, we have only begun to visualize their ultimate potential.     

The development of materials processing in space

The assess the impact of the current crisis in the US space programme on the commercial aspects of space technology development, consultant Allan Spitzer has compiled a report based on interviews with senior representatives of government, industry and academe. The report concentrates on policies specifically related to materials processing in space (MPS) and covers areas such as access to space, the role of NASA, subsidies and pricing.     

The All-Electric Aircraft: A Systems View and Proposed NASA Research Programs

The previous papers have offered the distant vision of an all-electric aircraft?one which fully exploits the intrinsic features of electric power and electronic controls. This paper examines the path to that vision and the barriers along the way?some of which appear relatively easy to overcome while others are more formidable. It is interesting to conjecture what an all-electric aircraft will look like. The all-electric technologies may offer many design options and this paper suggests some tantalizing possibilities. The National Aeronautics and Space Administration (NASA) has sponsored or conducted a number of activities to foster the development of an all-electric airplane. The results of these activities are presented. Finally, in a look to the future, two NASA new initiatives are briefly discussed.