1,181 research outputs found

    Advanced supersonic transport fixed-base simulator evaluations at landing approach

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    Equations of motion simulating the landing approach case for the supersonic cruise vehicle were programmed and exercised using a fixed base simulation facility. Unaugmented and augmented system comparisons using this facility are provided. Refinements necessary for system performance improvement are made. The unaugmented longitudinal responses to elevator commands are slow and sluggish, requiring augmentation to increase the speed of the response. In the lateral directional case, the Dutch roll is highly underdamped and requires an augmentation system to increase this damping and provide satisfactory flying qualities. The status of this fixed base study is that the longitudinal equations, updated with recent wind tunnel data, were evaluated on the simulator and the system found to be satisfactory. The lateral axis equations are linearized and are not yet updated to large excursion capability; consequently, only limited, preliminary findings on this system are available. The basic results so far indicate augmentation systems are required to provide a satisfactory longitudinal system, and that additional study and evaluation of the lateral directional case are necessary before a more complete assessment can be made

    Simulated final approach path captures using the microwave landing system

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    Computer simulation results are presented for intercepting final approach paths using various Microwave Landing System (MLS) path capture concepts. This study, conducted under the Advanced Transport Operating System (ATOPS) program, simulated these captures using the MD-80 aircraft as the study model. Several different capture concepts were investigated. Systems that could be retrofitted into existing aircraft with minimum hardware and software changes were considered. An enhanced ILS look-alike capture provided improved tracking performance over conventional ILS without using a full-up path computer. The other concepts used waypoint databases and path computers to provide smart captures. These captures included lateral path intercepts as well as vertical path control. Winds, turbulence, and MLS noise were included in the simulation. In all cases, acceptable tracking errors were obtained during transition to the final approach path

    Evaluation of microwave landing system approaches in a wide-body transport simulator

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    The objective of this study was to determine the suitability of flying complex curved approaches using the microwave landing system (MLS) with a wide-body transport aircraft. Fifty pilots in crews of two participated in the evaluation using a fixed-base simulator that emulated an MD-11 aircraft. Five approaches, consisting of one straight-in approach and four curved approaches, were flown by the pilots using a flight director. The test variables include the following: (1) manual and autothrottles; (2) wind direction; and (3) type of navigation display. The navigation display was either a map or a horizontal situation indicator (HSI). A complex wind that changed direction and speed with altitude, and included moderate turbulence, was used. Visibility conditions were Cat 1 or better. Subjective test data included pilot responses to questionnaires and pilot comments. Objective performance data included tracking accuracy, position error at decision height, and control activity. Results of the evaluation indicate that flying curved MLS approaches with a wide-body transport aircraft is operationally acceptable, depending upon the length of the final straight segment and the complexity of the approach

    Simulation of automatic precision departures and missed approaches using the microwave landing system

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    Results of simulated precision departures and missed approaches using MLS guidance concepts are presented. The study was conducted under the Terminal Configured Vehicle (TCV) Program, and is an extension of previous work by DAC under the Advanced Transport Operating System (ATOPS) Technology Studies Program. The study model included simulation of an MD-80 aircraft, an autopilot, and a MLS guidance computer that provided lateral and vertical steering commands. Precision departures were evaluated using a noise abatement procedure. Several curved path departures were simulated with MLS noise and under various environmental conditions. Missed approaches were considered for the same runway, where lateral MLS guidance maintained the aircraft along the extended runway centerline. In both the departures and the missed approach cases, pitch autopilot takeoff and go-around modes of operation were used in conjunction with MLS lateral guidance

    Guidance studies for curved, descending approaches using the Microwave Landing System (MLS)

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    Results for the Microwave Landing System (MLS) guidance algorithm development conducted under the Advance Transport Operating System (ATOPS) Technology Studies (NAS1-16202) are documented. The study consisted of evaluating guidance law for vertical and lateral path control, as well as speed control, for approaches not possible with the present Instrument Landing System (ILS) equipment. Several specific approaches were simulated using the MD-80 aircraft simulation program, including curved, descending (segmented glide slope), and decelerating paths. Emphasis was placed on development of guidance algorithms specifically for approaches at Burbank, where proposed flight demonstrations are planned. Results of this simulation phase are suitable for use in future fixed base simulator evaluations employing actual hardware (autopilot and a performance management system)

    Guidance law simulation studies for complex approaches using the Microwave Landing System (MLS)

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    This report documents results for MLS guidance algorithm development conducted by DAC for NASA under the Advance Transport Operating Systems (ATOPS) Technology Studies program (NAS1-18028). The study consisted of evaluating guidance laws for vertical and lateral path control, as well as speed control, by simulating an MLS approach for the Washington National Airport. This work is an extension and generalization of a previous ATOPS contract (NAS1-16202) completed by DAC in 1985. The Washington river approach was simulated by six waypoints and one glideslope change and consisted of an eleven nautical mile approach path. Tracking performance was generated for 10 cases representing several different conditions, which included MLS noise, steady wind, turbulence, and windshear. Results of this simulation phase are suitable for use in future fixed-base simulator evaluations employing actual hardware (autopilot and a performance management system), as well as crew procedures and information requirements for MLS

    Embedding value: perspectives on a foundation level course in arts and humanities

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    The number of learners opting to study on a foundation level programme at universities in England has risen sharply over the last few years.  Foundation level courses at university represent a vital opportunity for learners to progress to undergraduate courses, especially those learners from areas where participation in higher education has been traditionally very low.  This paper offers a reflection on the foundation level course delivered at LJMU’s School of Humanities and Social Science, which has featured on the institutional prospectus since 2017.  The tutors reflect on the adjustments that have been made to both the organisation and delivery of teaching, underlined by the development of an inclusive and open learning community.  Based on the authors’ experiences, it is argued that foundation level courses at university are well calibrated to support the UK government’s levelling up agenda and, ahead of the 2021 Spending Review, the paper is therefore a counterpoint to recommendations made on the foundation level programme in the Augar Review of post-18 education funding

    Fusing Quantitative Requirements Analysis with Model-based Systems Engineering

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    A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. “Requirements engineering” provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. “Design by shopping” emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. “Model-based engineering” emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined
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