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Simulation and flight investigations were conducted by using a method of providing supple¬mentary information to the pilot in conjunction with a closed-circuit-television display during a VTOL instrument final approach including ...
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Simulation and flight investigations were conducted by using a method of providing supple¬mentary information to the pilot in conjunction with a closed-circuit-television display during a VTOL instrument final approach including deceleration and hover. The supplementary infor¬mation included range, cross range, ground speed, altitude, and rate-of-climb error and was displayed on an instrument called an approach profile indicator. The display was arranged to provide both quasi-command and situation information. Pilot comments indicated that the approach-profile-indicator display concept in conjunction with the closed-circuit television resulted in a decreased pilot workload and an increase in pilot confidence. Also, the results indicated that the approach profile repeatability was significantly improved because of the ground-speed and altitude information provided on the approach profile indicator.
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A flight investigation was conducted to determine the characteristic shapes of the altitude, ground-speed, and deceleration profiles of visual approaches for helicopters. Two hundred and thirty-six visual approaches were flown fro...
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A flight investigation was conducted to determine the characteristic shapes of the altitude, ground-speed, and deceleration profiles of visual approaches for helicopters. Two hundred and thirty-six visual approaches were flown from nine sets of initial conditions with four types of helicopters. Mathematical relationships were developed that describe the char¬acteristic visual deceleration profiles. These mathematical relationships were expanded to develop equations which define the corresponding nominal ground-speed, pitch-attitude, pitch-rate, and pitch-acceleration profiles. Results are applicable to improved helicopter handling qualities in terminal-area operations.
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GLONASS has been proposed as an augmentation to GPS/LAAS. We examine the incremental benefits of the additional signals from GLONASS to the availability of service for precision approaches. The methodology used for the modeling of...
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GLONASS has been proposed as an augmentation to GPS/LAAS. We examine the incremental benefits of the additional signals from GLONASS to the availability of service for precision approaches. The methodology used for the modeling of availability is the same as that adopted previously for the analysis of GPS/LAAS. The inclusion of GLONASS signals requires provision for adapting the models of measurement errors to account for the differences between GPS and GLONASS. The main difference of significance to LAAS is due to the frequency division multiple access scheme used by GLONASS, and the resultant inter-frequency biases in the measurements. The errors introduced by such biases at the reference and user receivers are uncorrelated, and have to be accounted for in the error models. As expected, the availability of service improves considerably with the additional ranging sources. The combined GPS and GLONASS signals provide consistent and robust performance with high levels of availability of service for the most demanding precision approaches.
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The effectiveness of single-epoch integer ambiguity resolution, which provides centimeter-level relative positioning in real-time, is a function of the number, quality and type of carrier phase measurements available. We apply the...
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The effectiveness of single-epoch integer ambiguity resolution, which provides centimeter-level relative positioning in real-time, is a function of the number, quality and type of carrier phase measurements available. We apply the Local-Minima Search (LMS) method epoch-by-epoch to GPS-GLONASS dual frequency carrier phase measurements taken over 2, 9 and 18 km baselines. While the application of LMS to GPS dual frequency measurements alone works quite well over these baselines, the addition of GLONASS improves the search success rate and greatly enhances the ability to validate the resulting solutions. At both 9 km and 18 km the LMS success rate was nearly 100%, when using the combined set of carrier phases. The addition of GLONASS reduced the average search ratio by more than 1/3 over the ratio obtained using only GPS phases. A fuller GLONASS constellation will certainly improve on these results.
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While direction is fundamental to geography, the implementation of directionalfunctions in Geographical Information Systems (GIS) is limited. The focus paper is the extension of direction-related concepts through the definition of...
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While direction is fundamental to geography, the implementation of directionalfunctions in Geographical Information Systems (GIS) is limited. The focus paper is the extension of direction-related concepts through the definition of directional regions, such as the area north of Washington DC. Directional regions are constructed from combinations of six elements: the feature, the reference, an orientation, a viewspan, a viewfield and a region of interest. This approach allows users to create new area features which can be incorporated in a GIS. These features are a valuable tool for geographical analysis, since they further constrain reasoning on a data set.... Geographical analysis, Geographic Information Systems (GIS).
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When an airport experiences low ceiling or visibility conditions the arrivalcapacity is significantly reduced. This is particularly true at airports that use both their main runway and their crosswind runway in Visual Meteorologic...
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When an airport experiences low ceiling or visibility conditions the arrivalcapacity is significantly reduced. This is particularly true at airports that use both their main runway and their crosswind runway in Visual Meteorological Conditions (VMC). The consequence of this is an increase in delays. A concept for continuing to conduct approaches in Instrument Meteorological Conditions (IMC) to converging runways has been proposed which calls for coordinating the approaches to the two runways such that a stagger between the aircraft is maintained. This procedure is known as Dependent Converging Instrument Approaches (DCIA). This paper develops a DCIA procedure applicable to any runway geometry. The procedure is defined and modeled to capture its safety critical aspects. From this analysis recommendations are made concerning the stagger values and other factors relevant to applying this procedure safely.
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The Loran-C monitor developed by Ohio University will collect Loran signal data for storage on magnetic tape. Stationed at the Ohio University Airport, Athens, Ohio, the monitor will provide valuable information concerning the dai...
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The Loran-C monitor developed by Ohio University will collect Loran signal data for storage on magnetic tape. Stationed at the Ohio University Airport, Athens, Ohio, the monitor will provide valuable information concerning the daily and seasonal variation of the Loran-C signals for use in non-precision approach studies. With the aid of a second monitor, located in Gallion, Ohio, it can be determined if the errors found at a particular geographic location correlate with those found at another location. This will give some indication as to how far apart monitors can be positioned to obtain accurate non-precision approach data for various airports.
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During recent years the problems of congestion, noise pollution, and safety in the vicinity of airports have indicated that changes must be made in the operational aspects of aircraft land¬ing approaches. Suggested changes includ...
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During recent years the problems of congestion, noise pollution, and safety in the vicinity of airports have indicated that changes must be made in the operational aspects of aircraft land¬ing approaches. Suggested changes include curved approaches, steep approaches, decelerating approaches, and combinations of these. This paper describes a system which is capable of con¬trolling an aircraft automatically along a curved, descending, decelerating approach. A simu¬lation study was conducted to determine the necessary modifications to the basic flight-proven control system. This basic system is presently being used to accomplish straight-in automatic landing approaches on a short-haul transport aircraft (B-737 terminal configured vehicle). This study shows that both 3° (normal) and 5° (steep) approaches could be accomplished with only minor modifications to the basic control system.
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The introduction of independent helicopter IFR routes at hub airports was investigated in a real time air traffic control system simulation involving a piloted helicopter simulator, computer generated air traffic, and air traffic ...
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The introduction of independent helicopter IFR routes at hub airports was investigated in a real time air traffic control system simulation involving a piloted helicopter simulator, computer generated air traffic, and air traffic controllers. The helicopter simulator was equipped to fly area navigation (RNAV) routes and microwave landing system approaches. Problems studied included: (1) pilot acceptance of the approach procedure and tracking accuracy; (2) ATC procedures for handling a mix of helicopter and fixed wing traffic; and (3) utility of the cockpit display of traffic information (CDTI) for the helicopter in the hub airport environment. Results indicate that the helicopter routes were acceptable to the subject pilots and were noninterfering with fixed wing traffic. Merging and spacing maneuvers using CDTI were successfully carried out by the pilots, but controllers had some reservations concerning the acceptability of the CDTI procedures.
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The Precision Approach Path Indicator (PAPI) is a simple visual aid that has been developed to assist pilots during their approach to landing. The development of the system by the RAE was reported in Ref 1 and the operational tria...
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The Precision Approach Path Indicator (PAPI) is a simple visual aid that has been developed to assist pilots during their approach to landing. The development of the system by the RAE was reported in Ref 1 and the operational trials and technical evaluation by ICAO were reported in Ref 2. The PAPI system uses a set of four two-colour high intensity light projectors. Each beam consists of a white upper half and red lower half. The transition from one colour to the other occurs over a very small angle. This sharp transition is an essential feature of the PAPI system and it is therefore important that all units should exhibit this characteristic. Similarly, operational considerations dictate the minimum beam-spread and intensity requirements for the light projectors. It is essential that the correct isocandela specification is adhered to in all PAPI units. (Author)
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