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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1993

Parallel runway requirement analysis study. Volume 1: The analysis

The correlation of increased flight delays with the level of aviation activity is well recognized. A main contributor to these flight delays has been the capacity of airports. Though new airport and runway construction would significantly increase airport capacity, few programs of this type are currently underway, let alone planned, because of the high cost associated with such endeavors. Therefore, it is necessary to achieve the most efficient and cost effective use of existing fixed airport resources through better planning and control of traffic flows. In fact, during the past few years the FAA has initiated such an airport capacity program designed to provide additional capacity at existing airports. Some of the improvements that that program has generated thus far have been based on new Air Traffic Control procedures, terminal automation, additional Instrument Landing Systems, improved controller display aids, and improved utilization of multiple runways/Instrument Meteorological Conditions (IMC) approach procedures. A useful element to understanding potential operational capacity enhancements at high demand airports has been the development and use of an analysis tool called The PLAND_BLUNDER (PLB) Simulation Model. The objective for building this simulation was to develop a parametric model that could be used for analysis in determining the minimum safety level of parallel runway operations for various parameters representing the airplane, navigation, surveillance, and ATC system performance. This simulation is useful as: a quick and economical evaluation of existing environments that are experiencing IMC delays, an efficient way to study and validate proposed procedure modifications, an aid in evaluating requirements for new airports or new runways in old airports, a simple, parametric investigation of a wide range of issues and approaches, an ability to tradeoff air and ground technology and procedures contributions, and a way of considering probable blunder mechanisms and range of blunder scenarios. This study describes the steps of building the simulation and considers the input parameters, assumptions and limitations, and available outputs. Validation results and sensitivity analysis are addressed as well as outlining some IMC and Visual Meteorological Conditions (VMC) approaches to parallel runways. Also, present and future applicable technologies (e.g., Digital Autoland Systems, Traffic Collision and Avoidance System II, Enhanced Situational Awareness System, Global Positioning Systems for Landing, etc.) are assessed and recommendations made.

Ebrahimi, Yaghoob S.↗
NASA NTRS1993

Microphysical properties of the November 26 cirrus cloud retrieved by Doppler radar/IR radiometer technique

Gaining information about cirrus cloud microphysics requires development of remote sensing techniques. In an earlier paper. Matrosov et al. (1992) proposed a method to estimate ice water path (IWP) (i.e., vertically integrated ice mass content IMC) and characteristic particle size averaged through the cloud from combined groundbased measurements of radar reflectivities and IR brightness temperatures of the downwelling thermal radiation in the transparency region of 10-12 mu m. For some applications, the vertically averaged characteristic particle sizes and IWP could be the appropriate information to use. However, vertical profiles of cloud microphysical parameters can provide a better understanding of cloud structure and development. Here we describe a further development of the previous method by Matrosov et al. (1992) for retrieving vertical profiles of cirrus particle sizes and IMC rather than their vertically averaged values. In addition to measurements of radar reflectivities, the measurements of Doppler velocities are used in the new method. This provides us with two vertical profiles of measurements to infer two vertical profiles of unknowns, i.e., particle characteristic sizes and IMC. Simultaneous measurements of the IR brightness temperatures are still needed to resolve an ambiguity in particle size-fall velocity relationships.

Matrosov, Sergey Y.↗
NASA NTRS1999

A Simulation Study of Instrument Meteorological Condition Approaches to Dual Parallel Runways Spaced 3400 and 2500 Feet Apart Using Flight-Deck-Centered Technology

A number of our nations airports depend on closely spaced parallel runway operations to handle their normal traffic throughput when weather conditions are favorable. For safety these operations are curtailed in Instrument Meteorological Conditions (IMC) when the ceiling or visibility deteriorates and operations in many cases are limited to the equivalent of a single runway. Where parallel runway spacing is less than 2500 feet, capacity loss in IMC is on the order of 50 percent for these runways. Clearly, these capacity losses result in landing delays, inconveniences to the public, increased operational cost to the airlines, and general interruption of commerce. This document presents a description and the results of a fixed-base simulation study to evaluate an initial concept that includes a set of procedures for conducting safe flight in closely spaced parallel runway operations in IMC. Consideration of flight-deck information technology and displays to support the procedures is also included in the discussions. The procedures and supporting technology rely heavily on airborne capabilities operating in conjunction with the air traffic control system.

Waller, Marvin C.↗
NASA NTRS2003

IFR Operations at Non-Towered, Non-Radar Airports: Can we do Better Than One-at-a-Time?

This paper describes a new concept for operations in non-radar terminal airspace around small, nontowered airports. Currently, air traffic operations in instrument meteorological conditions (IMC) at airfields without control towers and radar service are severely constrained by what is known as the one-in/one-out paradigm. Under these conditions only one operation (either arrival or departure) is allowed to occur at a time. Since these operations can take over 15 minutes to complete, capacity at these airports is severely restricted in IMC. The proposed concept is an attempt to break this current paradigm by applying emerging airborne and ground-based technologies to enable simultaneous operations by multiple aircraft in nonradar terminal airspace around small non-towered airports in IMC. The general philosophy underlying this concept of operations is the establishment of a newly defined area surrounding these airports called a Self-Controlled Area (SCA). Aircraft operating within the SCA are required to have a specified minimum level of equipage. Within the SCA, pilots are responsible for separating themselves from other similarly equipped aircraft through the use of new onboard systems and procedures. This concept also takes advantage of newly developed automation at the airport, which provides appropriate sequencing information to the pilots for safe and improved operations. Such operations would enhance the opportunity for point-to-point air taxi or charter operations into smaller airfields that are closer to a traveler s origin and destination. A description of this concept of operations and a simulation environment used for evaluation is provided in this paper.

Jones, K.↗
NASA NTRS2005

Probabilistic Analysis of Impact of Wake Vortices on Closely-Spaced Parallel Approaches

One of the primary constraints on the capacity of the nation's air transportation system is the landing capacity of its largest airports. Many airports with closely spaced parallel runways suffer a severe runway acceptance rate when the weather conditions do not allow full utilization of these parallel runways. The present requirement for simultaneous independent landings in Instrument Meteorological Conditions, IMC, is at least 4300 feet of lateral runway spacing (as close as 3000 feet for runways with a Precision Runway Monitor). Operations in Visual Meteorological Conditions, VMC, to Closely Spaced Parallel Approaches only require a lateral runway spacing greater than 750 feet. A study by Hardy and Lewis integrated and extended earlier studies and concepts in lateral traffic separation, longitudinal station keeping, wake prediction, wake display, and the concepts of R N P into a preliminary system concept for Closely Spaced Parallel Approaches in IMC. This system allows IMC airport acceptance rates to approach those for VMC. The system concept that was developed, presented traffic and wake information on the NAVigation Display, NAV, and developed operational procedures for a mix of conventional and Runway Independent Aircraft with different approach speeds to Closely Spaced Parallel Runways. This paper first describes some improvements made on the technology needed to better predict and formulate a probabilistic representation for the time-dependent motion and spreading of the hazardous region associated with the lift-generated vortex wakes of preceding aircraft. In this way, the time at which the vortex wakes of leading aircraft intrude into the airspace of adjacent flight-corridor/runway combinations can be more reliably predicted. Such a prediction is needed because it determines restraints to be placed on in-trail separation distances; or, the allowable time intervals between aircraft executing nearly simultaneous landings or takeoffs on very closely-spaced runways. Improved estimates of wake spreading are achieved by inclusion of representations in the equations for wake spreading due to ambient turbulence and due to the long-wave instability of a vortex pair. Wake motion and spreading due to the time-averaged wind and its variations with time, are retained. The more detailed representation of wake spreading presented here permits the development of probabilistically-based uncertainty estimates for wake spreading. Measurements needed within actual aircraft wake vortices to validate and support this analysis are also described. The second part of the paper uses the improvements in the accuracy of the location of wake vortices to extend the preliminary system concept for Closely Spaced Parallel Approaches described earlier with more robust operational procedures. Additionally, improvements in longitudinal station keeping, wake display, and risk assessment methodologies are incorporated and described.

Hardy, Gordon H.↗
NASA NTRS2005

Influence of Graphical METARS on Pilots' Weather Judgment

VFR flight into IMC conditions accounts for over 10% of general aviation fatalities each year. Recent research suggests that pilots may not properly assess weather conditions. New graphical weather information systems (GWISs) may positively or negatively influence pilot weather-related judgments. Since GWIS information is not always current it may not be veritical. In the current investigation twenty-four GA pilots made visibility and ceiling estimates of simulated weather conditions either with or without a GWIS display. Pilots generally overestimated weather conditions and their judgments were influenced by the GWIS. The results revealed an interaction between ceiling and visibility that suggests a new model for understanding VFR flight into IMC. The current results suggest an important area for future research into understanding pilots decisions to continue into deteriorating weather conditions. Results are discussed in terms of advancing aviation decision making models for understanding VFR into IMC flight, and the design of GWIS symbology to foster accurate assessments.

Coyne, Joseph T.↗
NASA NTRS2014

General Aviation Flight Test of Advanced Operations Enabled by Synthetic Vision

A flight test was performed to compare the use of three advanced primary flight and navigation display concepts to a baseline, round-dial concept to assess the potential for advanced operations. The displays were evaluated during visual and instrument approach procedures including an advanced instrument approach resembling a visual airport traffic pattern. Nineteen pilots from three pilot groups, reflecting the diverse piloting skills of the General Aviation pilot population, served as evaluation subjects. The experiment had two thrusts: 1) an examination of the capabilities of low-time (i.e., <400 hours), non-instrument-rated pilots to perform nominal instrument approaches, and 2) an exploration of potential advanced Visual Meteorological Conditions (VMC)-like approaches in Instrument Meteorological Conditions (IMC). Within this context, advanced display concepts are considered to include integrated navigation and primary flight displays with either aircraft attitude flight directors or Highway In The Sky (HITS) guidance with and without a synthetic depiction of the external visuals (i.e., synthetic vision). Relative to the first thrust, the results indicate that using an advanced display concept, as tested herein, low-time, non-instrument-rated pilots can exhibit flight-technical performance, subjective workload and situation awareness ratings as good as or better than high-time Instrument Flight Rules (IFR)-rated pilots using Baseline Round Dials for a nominal IMC approach. For the second thrust, the results indicate advanced VMC-like approaches are feasible in IMC, for all pilot groups tested for only the Synthetic Vision System (SVS) advanced display concept.

Glaab, Louis J.↗
NASA NTRS2010

An Operations Concept for Integrated Model-Centric Engineering at JPL

As JPL's missions grow more complex, the need for improved systems engineering processes is becoming clear. Of significant promise in this regard is the move toward a more integrated and model-centric approach to mission conception, design, implementation and operations. The Integrated Model-Centric Engineering (IMCE) Initiative, now underway at JPL, seeks to lay the groundwork for these improvements. This paper will report progress on three fronts: articulating JPL's need for IMCE; characterizing the enterprise into which IMCE capabilities will be deployed; and constructing an operations concept for a flight project development in an integrated model-centric environment.

Bayer, Todd J.↗
NASA NTRS2018

Is MBSE Helping? Measuring Value on Europa Clipper

JPL’s Integrated Model Centric Engineering Initiative (IMCE) has led the infusion of MBSE at JPL. In 2009 I authored for IMCE a set of challenges that confronted systems engineering at JPL, based on examination of issues and lessons from several recent projects (the “Five System Engineering Challenges”). In 2012 I augmented this work to describe specific areas where it appeared MBSE could help address these challenges. Around the same time, the Europa Clipper Mission became the first project at JPL to attempt, in close collaboration with IMCE, a widespread adoption of MBSE. This adoption has been highly successful so far. Europa Clipper completed Phase A (Formulation) with a successful System Requirements Review / Mission Definition Review, and is nearing the end of Phase B, with a successful Flight System Preliminary Design Review in October 2017. This is an opportune time to take stock of the progress and the work yet to go. This paper proposes a practical method for measuring value added through use of MBSE, applies this method to the Europa Clipper Project, and suggests how it might be applied to other projects and organizations.

Bayer, Todd↗
NASA NTRS1978

Traveling wave tube circuit

A traveling wave tube (TWT) has a slow wave structure (SWS) which is severed into two or more sections. A signal path, connects the end of an SWS section to the beginning of the following SWS section. The signal path comprises an impedance matching coupler (IMC), followed by an isolator, a variable phase shifter, and a second IMC. The aggregate band pass characteristic of the components in the signal path is chosen to reject, or strongly attenuate, all frequencies outside the desired operating frequency range of the TWT and yet pass, with minimal attenuation in the forward direction, all frequencies within the desired operating frequency range. The isolator is chosen to reject, or strongly attenuate, waves, of all frequencies, which propagate in the backward direction. The aggregate phase shift characteristic of the components in the signal path is chosen to apply signal power to the beginning of the following SWS section with the phase angle yielding maximum efficiency.

Connolly, D. J.↗
NASA NTRS1983

Image motion compensation for the OSS-3/7 telescopes

The three telescope for the NASA Office of Space Science (OSS) Missions 3/7 will be clustered on the Instrument Point System (IPS). The IPS is to be mounted on a Spacelab pallet in the space shuttle orbiter. The three telescopes include the Ultraviolet Imaging Telescope (UIT), the Hopkins Ultraviolet Telescope (HUT), and the Wisconsin Ultraviolet Photopolarimetry Experiment (WUPPE). All three instruments have the ability to view from earth orbit stellar objects which are fainter than those which can be seen with ground-based telescopes. An Image Motion Compensation (IMC) system will be required for the appropriate conduct of the observations. The OSS-3/7 pointing problem is discussed, and a cost effective IMC system is proposed.

Shelton, H.L.↗
NASA NTRS1984

PDSS/IMC qualification test software acceptance procedures

Tests to be performed for qualifying the payload development support system image motion compensator (IMC) are identified. The performance of these tests will verify the IMC interfaces and thereby verify the qualification test software.

Source record↗
NASA NTRS1984

Reflight certification software design specifications

The PDSS/IMC Software Design Specification for the Payload Development Support System (PDSS)/Image Motion Compensator (IMC) is contained. The PDSS/IMC is to be used for checkout and verification of the IMC flight hardware and software by NASA/MSFC.

Source record↗
NASA NTRS1984

PDSS/IMC CIS user's guide

The Spacelab Payload Development Support System PDSS Image Motion Compensator (IMC) computer interface simulation (CIS) user's manual is given. The software provides a real time interface simulation for the following IMC subsystems: the Dry Rotor Reference Unit, the Advanced Star/Target Reference Optical sensor, the Ultra Violet imaging telescope, the Wisconson Ultraviolet Photopolarimetry Experiment, the Cruciform Power distributor, and the Spacelab Experiment Computer Operating System.

Source record↗
NASA NTRS1989

GOES I/M image navigation and registration

Image Navigation and Registration (INR) is the system that will be used on future Geostationary Operational Environmental Satellite (GOES) missions to locate and register radiometric imagery data. It consists of a semiclosed loop system with a ground-based segment that generates coefficients to perform image motion compensation (IMC). The IMC coefficients are uplinked to the satellite-based segment, where they are used to adjust the displacement of the imagery data due to movement of the imaging instrument line-of-sight. The flight dynamics aspects of the INR system is discussed in terms of the attitude and orbit determination, attitude pointing, and attitude and orbit control needed to perform INR. The modeling used in the determination of orbit and attitude is discussed, along with the method of on-orbit control used in the INR system, and various factors that affect stability. Also discussed are potential error sources inherent in the INR system and the operational methods of compensating for these errors.

Fiorello, J. L., Jr.↗
NASA NTRS1992

Simulation and flight test evaluation of head-up-display guidance for Harrier approach transitions

Position and speed guidance displays for STOVL aircraft curved, decelerating approaches to hover and vertical landing have been evaluated for their effectiveness in reducing pilot workload and improving performance. The NASA V/STOL Systems Research Aircraft, a modified YAV-8B Harrier prototype, was used to evaluate the displays in flight, while the NASA Ames Vertical Motion Simulator was used to extend the flight test results to instrument meteorological conditions (IMC) and to examine performance in various conditions of wind and turbulence. The simulation data showed close correlation with the flight test data, and both demonstrated the feasibility of the displays. With the exception of the hover task in zero visibility, which was Level-3, averaged Cooper-Harper handling qualities ratings given during simulation were Level-2 for both the approach task and the hover task in all conditions. During flight tests in calm and clear conditions, the displays also gave rise to Level-2 handling qualities ratings. Pilot opinion showed that the guidance displays would be useful in visual flight, especially at night, as well as in IMC.

Dorr, D. W.↗
NASA NTRS1993

Normalized vertical ice mass flux profiles from vertically pointing 8-mm-wavelength Doppler radar

During the FIRE 2 (First International Satellite Cloud Climatology Project Regional Experiment) project, NOAA's Wave Propagation Laboratory (WPL) operated its 8-mm wavelength Doppler radar extensively in the vertically pointing mode. This allowed for the calculation of a number of important cirrus cloud parameters, including cloud boundary statistics, cloud particle characteristic sizes and concentrations, and ice mass content (imc). The flux of imc, or, alternatively, ice mass flux (imf), is also an important parameter of a cirrus cloud system. Ice mass flux is important in the vertical redistribution of water substance and thus, in part, determines the cloud evolution. It is important for the development of cloud parameterizations to be able to define the essential physical characteristics of large populations of clouds in the simplest possible way. One method would be to normalize profiles of observed cloud properties, such as those mentioned above, in ways similar to those used in the convective boundary layer. The height then scales from 0.0 at cloud base to 1.0 at cloud top, and the measured cloud parameter scales by its maximum value so that all normalized profiles have 1.0 as their maximum value. The goal is that there will be a 'universal' shape to profiles of the normalized data. This idea was applied to estimates of imf calculated from data obtained by the WPL cloud radar during FIRE II. Other quantities such as median particle diameter, concentration, and ice mass content can also be estimated with this radar, and we expect to also examine normalized profiles of these quantities in time for the 1993 FIRE II meeting.

Orr, Brad W.↗
NASA NTRS1994

Simulation and flight test evaluation of head-up-display guidance for harrier approach transitions

Position and speed guidance displays for STOVL aircraft curved, decelerating approaches to hover and vertical landing have been evaluated for their effectiveness in reducing pilot workload and improving performance. The NASA V/STOL Systems Research Aircraft, a modified YAV-8B Harrier prototype, was used to evaluate the displays in flight, whereas the NASA Ames Vertical Motion Simulator was used to extend the flight test results to instrument meteorological conditions (IMC) and to examine performance in various conditions of wind and turbulence. The simulation data showed close correlation with the flight test data, and both demonstrated the feasibility of the displays. With the exception of the hover task in zero visibility, which was level-3, averaged Copper-Harper handling qualities ratings given during simulation were level-2 for both the approach task and the hover task in all conditions. During flight tests in calm and clear conditions, the displays also gave rise to level-2 handling qualities ratings. Pilot opinion showed that the guidance displays would be useful in visual flight, especially at night, as well as in IMC.

HARRIER APPROACH↗