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Applications of autonomous vehicles are found in various diversified fields including defense, agriculture, mining, and space exploration. For successful operation of an autonomous vehicle, the vehicle has to dynamically interact with the environment around it. This dissertation presents the development and implementation of a sensor component to represent the surrounding environment around an autonomous vehicle. The environment is modeled as a grid and each cell in the grid is assigned a traversability value. Each of the two algorithms, obstacle detection and terrain evaluation, have certain advantages and limitations. Also like any other sensor algorithm, these two algorithms have some uncertainties associated with their outputs. In my work these algorithms are fused together to complement the uncertainties and limitations of each of them, and outputs of the two algorithms are fused using the certainty factors approach.

Supported by NASA's Earth Surface and Interior (ESI) Program, we are producing a global set of Ground Control Points (GCPs) derived from the Ice, Cloud and land Elevation Satellite (ICESat) altimetry data. From February of 2003, to October of 2009, ICESat obtained nearly global measurements of land topography (+/- 86deg latitudes) with unprecedented accuracy, sampling the Earth's surface at discrete approx.50 m diameter laser footprints spaced 170 m along the altimetry profiles. We apply stringent editing to select the highest quality elevations, and use these GCPs to characterize and quantify spatially varying elevation biases in Digital Elevation Models (DEMs). In this paper, we present an evaluation of the soon to be released Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010). Elevation biases and error statistics have been analyzed as a function of land cover and relief. The GMTED2010 products are a large improvement over previous sources of elevation data at comparable resolutions. RMSEs for all products and terrain conditions are below 7 m and typically are about 4 m. The GMTED2010 products are biased upward with respect to the ICESat GCPs on average by approximately 3 m.

This study evaluates the data assimilation capabilities of Three Dimensional Multiquadric Interpolation (3DMQ) and the MM5 model when incorporating mesoscale observations from the United States Air Force Academy (USAFA) High Wind Alert system (HWAS). These mesoscale observations are incorporated into a triple nested (12, 4, and 1.33 km) high resolution model simulation and evaluated for their impact upon analyzed and forecasted wind values at USAFA during a severe down slope wind event that occurred on 6 March 2004. This evaluation is the first step in developing future forecasting and analysis tools for use by the military in various operations in complex terrain. The development of deployable automated tactical weather sensors in forward deployed locations requires an evaluation of the impact and usefulness these sensors would have on analysis forecast tools and mesoscale Numerical Weather Prediction (NWP) models. The juxtaposition of the HWAS network in complex terrain and the aviation training operations at USAFA provides an ideal set of data, mission and location for testing and evaluating a high resolution nested grid mesoscale NWP model. This study shows that incorporating HWAS observations into the 3DMQ data assimilation process has a significant impact upon verification of analyzed wind fields with the biggest impact occurring at the 1.33 km grid scale. Using these analyzed fields as initial conditions for MM5 model simulations, this study shows the ability of the 1.33 km model forecast wind fields to verify significantly better than either the 4 or 12 km through 18, 24, and 30 hour forecasts. Additionally, this study shows the limited, yet discernable impact HWAS observations have upon forecasted winds in the first several hours of MM5 model runs during a severe down slope wind event at USAFA.

The Workshop included attendance and discussions by about twenty-five YPG personnel including Test Officers (personnel responsible for conducting and coordinating test operations at YPG), YPG Test Branch Directors, and range technicians. Other personnel included five DRI staff (representing expertise in hydrology, modeling, geology, civil engineering, soil science), and representatives from the US Military Academy, and Strategic Planning, Test Resource Management Center. The workshop provided an environment for dynamic and interactive exchange regarding how best to link knowledge of science and engineering aspects of terrestrial terrain characterization with improving the efficiency of test operations. Issues of interest ranged from how to better characterize current test courses (e.g. terrain, soils, analogs for in theater military operations) to how to provide both test officers and products manufacturers (who are the primary YPG customers) with ready access to important environmental data and science to better conduct test operations.

Evaluation of Illumination and Terrain Geometry Effects on Spectral Response in Mountain Terrain - Final Report, Volume 2

The topographic complexity of various sections of the Ozark, Appalachian, and Interior Low Plateaus, as well as of the New England, Piedmont, Blue Ridge, Ouachita, and Valley and Ridge Provinces of the Eastern United States were characterized. The variability of autocorrelation within a small area (7 1/2-ft quadrangle) to the variability at widely separated and diverse areas within the same physiographic region was compared to measure the degree of uniformity of the processes which can be expected to be encountered within a given physiographic province. The variability of autocorrelation across the eight geomorphic regions was compared and contrasted. The total study area was partitioned into subareas homogeneous in terrain complexity. The relation between the complexity measured, the geomorphic process mix implied, and the way in which geobotanical information is modified into a more or less recognizable entity is demonstrated. Sampling strategy is described.

A critical component of SVS displays is the appropriate presentation of terrain to the pilot. At the time of this study, the relationship between the complexity of the terrain presentation and resulting enhancements of pilot SA and pilot performance had been largely undefined. The terrain portrayal for SVS head-down displays (TP-HDD) simulation examined the effects of two primary elements of terrain portrayal on the primary flight display (PFD): variations of digital elevation model (DEM) resolution and terrain texturing. Variations in DEM resolution ranged from sparsely spaced (30 arc-sec) to very closely spaced data (1 arc-sec). Variations in texture involved three primary methods: constant color, elevation-based generic, and photo-realistic, along with a secondary depth cue enhancer in the form of a fishnet grid overlay.

The National Aeronautics and Space Administration is currently funding research into the design of a Mars rover vehicle. This unmanned rover will be used to explore a number of scientific and geologic sites on the Martian surface. Since the rover can not be driven from Earth in real-time, due to lengthy communication time delays, a locomotion strategy that optimizes vehicle range and minimizes potential risk must be developed. In order to assess the degree of on-board artificial intelligence (AI) required for a rover to carry out its' mission, researchers conducted an experiment to define a no AI baseline. In the experiment 24 subjects, divided into stereo and monoscopic groups, were shown video snapshots of four terrain scenes. The subjects' task was to choose a suitable path for the vehicle through each of the four scenes. Paths were scored based on distance travelled and hazard avoidance. Study results are presented with respect to: (1) risk versus range; (2) stereo versus monocular video; (3) vehicle camera height; and (4) camera field-of-view.

This report presents the Navy's evaluation of the Defense Mapping Agency's prototype Digital Terrain Elevation Data (DTED) on Compact Disk-Read Only Memory (CD-ROM). The CD-ROM medium offers large savings in cost and in storage space, and is an appropriate on-line digital data base for mini-and micro-computers. A brief description of the CD-ROM technology is presented along with directions for reading the DTED data. Sample applications and results are described, and the evaluation team's recommendations are presented.

A method for classifying and mapping terrain features pertinent to off-road mobility in selected temperate, tropical, and desert areas was applied to subarctic terrain in this study. The area involved borders the Automotive Test Course of the U. S. Army Arctic Test Center at Fort Greely, Alaska, and is roughly 2000 ft wide and 15 miles long. Conditions mapped were those prevalent during the late summer. The classification and mapping method proved satisfactory with only minor modifications. Terrain factors unique to cold regions which require additional research before they can be properly classified and mapped for mobility test purposes include depth of thaw, snow depth, snow type, ice thickness, and stream turbidity.

A method for classifying and mapping terrain features pertinent to off-road mobility in selected temperate, tropical, and desert areas was applied to subarctic terrain in this study. The area involved borders the Automotive Test Course of the U. S. Army Arctic Test Center at Fort Greely, Alaska, and is roughly 2000 ft wide and 15 miles long. Conditions mapped were those prevalent during the late summer. The classification and mapping method proved satisfactory with only minor modifications. Terrain factors unique to cold regions which require additional research before they can be properly classified and mapped for mobility test purposes include depth of thaw, snow depth, snow type, ice thickness, and stream turbidity.

The objective of this research is to develop an objective evaluation method for determining the goodness of various data compression techniques applied to radar landmass simulation data, to validate the objective evaluation method by comparison with a subjective evaluation performed by experienced radar operators and to compare the objective evaluation with the currently used terrain RMS error criteria. This research consists of the computation of simulated radar shadow displays, the computation of various measures of goodness which are combined in a performance criteria, and the subjective evaluation of the simulated displays. The objective evaluation method which is developed measures the goodness of the data compression techniques in terms of the usefulness of the simulated radar displays. The results obtained demonstrates the inadequacy of the terrain RMS error criteria and the degrading smoothing effect introduced by polynomial data compression. It is recommended that, prior to the implementation of any terrain data compression technique in a radar landmass simulator, it be evaluated in the manner proposed.

A piloted simulation of three head-down display (HDD) concepts with flight-director guidance superimposed on forward-looking infrared (FLIR) imagery was performed to evaluate the task of low-level, terrain-following (TF), manual helicopter flight. The three display concepts were examined for the purpose of finding ways by which aircraft flight-attitude and command symbols and FLIR imagery could be integrated onto one instrument. In all cases, the FLIR imagery was centered on the flight-path vector of the aircraft. The three displays were then characterized by having: (1) pitch attitude conformal to the FLIR imagery; (2) pitch attitude conformal to the FLIR imagery, but with an increase in the scaling; and (3) pitch attitude nonconformal to the FLIR imagery with the same pitch scaling as in (2). The simulation was conducted on the Vertical Motion Simulator (VMS) at Ames Research Center, using NASA and Air Force test pilots. The pilots indicated that the nonconformal pitch attitude and FLIR display was the preferred way to display information because of the absence of pitch-attitude information on displays (1) and (2) during some portions of the operational flight envelope.

This study evaluates the data assimilation capabilities of Three Dimensional Multiquadric Interpolation (3DMQ) and the MM5 model when incorporating mesoscale observations from the United States Air Force Academy (USAFA) High Wind Alert system (HWAS). These mesoscale observations are incorporated into a triple nested (12, 4, and 1.33 km) high resolution model simulation and evaluated for their impact upon analyzed and forecasted wind values at USAFA during a severe downslope wind event that occurred on 6 March 2004. This evaluation is the first step in developing future forecasting and analysis tools for use by the military in various operations in complex terrain. The development of deployable automated tactical weather sensors in forward deployed locations requires an evaluation of the impact and usefulness these sensors would have on analysis forecast tools and mesoscale Numerical Weather Prediction (NWP) models. The juxtaposition of the HWAS network in complex terrain and the aviation training operations at USAFA provides an ideal set of data, mission and location for testing and evaluating a high resolution nested grid mesoscale NWP model. This study shows that incorporating HWAS observations into the 3DMQ data assimilation process has a significant impact upon verification of analyzed wind fields with the biggest impact occurring at the 1.33 km grid scale. Using these analyzed fields as initial conditions for MM5 model simulations, this study shows the ability of the 1.33 km model forecast wind fields to verify significantly better than either the 4 or 12 km through 18, 24, and 30 hour forecasts. Additionally, this study shows the limited, yet discernable impact HWAS observations have upon forecasted winds in the first several hours of MM5 model runs during a severe downslope wind event at USAFA.

Pilot performance using visual display for guiding high speed aircraft in close proximity to terrain

US Army and Joint constructive simulations require human operators to observe the exercise in progress, conduct analysis of the results, and provide a realistic reports and assessment of the action presented on their screens to the desired training audience. Current software tools provide excellent mathematical assessments (such as center of mass calculations, optimal routes, and sensor ranges) but poor human-like assessment of data (most likely route, probable enemy intention, etc.). This Thesis presents an artificial intelligence architecture specifically designed to reduce that manpower requirement by describing a concept for computer modeling that can produce realistic human-like assessment results. Specific concepts described are approaches for conducting a digital terrain assessment, development of avenues of approach, deployment of templated forces to a specific piece of terrain, and then a method of adjusting the templated force to react to actual sightings and known information. Also included are more detailed discussions and implementation details for use of gas diffusion as a method of analyzing avenues of approach through digital terrain. This approach seems quite promising as a method of modeling human movement tendencies and appears superior to classic path finding or optimal route selection methods.

Abstract?The Defense Applied Research Projects Agency (DARPA) Learning Applied to Ground Vehicles (LAGR) program aims to develop algorithms for autonomous vehicle navigation that learn how to operate in complex terrain. For the LAGR program, The National Institute of Standards and Technology (NIST) has embedded learning into a control system architecture called 4D/RCS to enable the small robot used in the program to learn to navigate through a range of terrain types. This paper describes performance evaluation experiments on one of the algorithms developed under the program to learn terrain traversability. The algorithm uses color and texture to build models describing regions of terrain seen by the vehicle?s stereo cameras. Range measurements from stereo are used to assign traversability measures to the regions. The assumption is made that regions that look alike have similar traversability. Thus, regions that match one of the models inherit the traversability stored in the model. This allows all areas of images seen by the vehicle to be classified, and enables a path planner to determine a traversable path to the goal. The algorithm is evaluated by comparison with ground truth generated by a human observer. A graphical user interface (GUI) was developed that displays an image and randomly generates a point to be classified. The human assigns a traversability label to the point, and the learning algorithm associates its own label with the point. When a large number of such points have been labeled across a sequence of images, the performance of the learning algorithm is determined in terms of error rates. The learning algorithm is outlined in the paper, and results of performance evaluation are described.

The Terrain Portrayal for Head-Down Displays (TP-HDD) simulation experiment addressed multiple objectives involving twelve display concepts (two baseline concepts without terrain and ten synthetic vision system (SVS) variations), four evaluation maneuvers (two en route and one approach maneuver, plus a rare-event scenario), and three pilot group classifications. The TP-HDD SVS simulation was conducted in the NASA Langley Research Center's (LaRC's) General Aviation WorkStation (GAWS) facility. The results from this simulation establish the relationship between terrain portrayal fidelity and pilot situation awareness, workload, stress, and performance and are published in the NASA TP entitled Terrain Portrayal for Synthetic Vision Systems Head-Down Displays Evaluation Results. This is a collection of pilot comments during each run of the TP-HDD simulation experiment. These comments are not the full transcripts, but a condensed version where only the salient remarks that applied to the scenario, the maneuver, or the actual research itself were compiled.

Ten student pilots were given a 1 hour training session in the NASA Langley Research Center's General Aviation Simulator by a certified flight instructor and a follow-up flight evaluation was performed by the student's own flight instructor, who has also flown the simulator. The students and instructors generally felt that the simulator session had a positive effect on the students. They recommended that a simulator with a visual scene and a motion base would be useful in performing such maneuvers as: landing approaches, level flight, climbs, dives, turns, instrument work, and radio navigation, recommending that the simulator would be an efficient means of introducing the student to new maneuvers before doing them in flight. The students and instructors estimated that about 8 hours of simulator time could be profitably devoted to the private pilot training.

A complete and comprehensive description of the high resolution wind (HRW) model is presented. The HRW model has been in development at the U.S. Army Research Laboratory, formerly U.S. Army Atmospheric Sciences Laboratory, since 1978. This model is a two-dimensional, diagnostic atmospheric surface-layer wind model with a horizontal grid spacing of the order of 100 m over a domain of about 5 by 5 km. It uses Gauss? principle of least constraint and a direct variational relaxation method to adjust an initially uniform wind field to conform with topography, mass conservation, and buoyancy forces. A distinctive feature of the model is the use of a non-orthogonal, terrain following, warped coordinate system. A valuable observational dataset of surface wind has been provided from the field study of Meteorology and Diffusion Over Non-Uniform Areas (MADONA) at Porton Down, Salisbury, England during September and October 1992. Using the MADONA data, a critical evaluation for the HRW model for 39 cases has been carried out. The results of this study are presented, indicating both the range of validity and the limitations of the HRW model.

The problem of specification of required tire performance characteristics for operation in off-road situations can be a simple or complicated circumstance--depending on the sets of perspectives that are brought to bear in the evaluation of tire performance. The more detailed an individual is in specification or performance, the more complicated the issue becomes; primarily because the means for evaluation of performance cannot always be rigorously or exactly stated. Because a) proper first evaluation of tires requires actual on-terrain running interaction, b) test terrain variabilities cannot be readily described, and c) test measurement systems and techniques have yet to be fully delineated and rationalized, we are left with the situation of developing whole sets of procedures and standards that need to be continually upgraded or fine-tuned as more information becomes available.

Project TANK TRAP was conducted to determine the capability of selected tactical vehicles to traverse craters typical of those which could be produced with Atomic Demolition Munitions (ADM). The vehicles included in the test program were the M-60 Tank, M-113 Armored Personnel Carrier, and an articulated two-unit general purpose vehicle called the POLECAT. Trafficability testing of these vehicles was performed in the SCOOTER crater, the JANGLE U crater, and Pre-SCHOONER BRAVO crater.

This report describes the operational evaluation of an enroute system terrain-avoidance function in conjunction with the National Airspace System Enroute A3d2.1 system. Tests were conducted at the National Aviation Facilities Experimental Center, Atlantic City, New Jersey, in a low-altitude environment with simulated digital target data. Tests were designed to evaluate the performance of the terrain-avoidance function with respect to detection capability and adequacy of warning provided. Results indicate that although the terrain-avoidance function performed adequately for most enroute situations, false or late alerts could occur, due to the lag between the terrain-avoidance vector line and true aircraft heading. In most instances, the displayed information could be immediately and correctly interpreted by air traffic controllers and relayed to the pilots in adequate time for a safe response. Several functional changes made to the terrain-avoidance program to prevent problems encountered during testing were not subjected to detailed verification, thereby indicating a need for further testing of the function. Although these problems were encountered, the desirability of having a terrain-avoidance function as part of the enroute National Airspace System was not derogated.

Evaluation of lunar module guidance system performance over approach terrain of five proposed Apollo landing sites

In this report, we describe tools for the creation and modification of modular semi-autonomous forces (ModSAF) terrain databases to support the evaluation of a small autonomous robot in a tactical scenario. Our work is motivated by the modeling and simulation needs of the Demo 3 robotics program which is developing a small tactical robot called the experimental unmanned vehicle (XUV). The XUV is a small wheeled robot which must autonomously navigate through its environment. The primary mission of the XUV will be to augment the scout forces, so it must provide reconnaissance, surveillance, and target acquisition information (RSTA) to its operators. Modeling the XUV in a simulated environment is challenging since existing terrain databases do not have sufficient resolution to examine the mobility characteristics of small vehicles. Our tools increase the resolution and detail of existing terrain databases so that the databases have sufficient detail to challenge the mobility, chassis dynamics, and RSTA models of a small unmanned platform. To properly model a small vehicle such as the XUV, the terrain database in ModSAF needs to be modified. The modification is done in two phases. In the first phase, the resolution of the grid underlying the terrain is increased by placing additional elevation grid posts between the existing posts. Elevations are assigned to the new grid posts using mathematical terrain models such as the variable resolution terrain Model. The new, higher resolution terrain directly affects the vehicle dynamics and the line of sight algorithms. The new terrain does not directly affect the ModSAF route planning algorithms. In the second phase of our terrain database modifications, the slopes on the new terrain are examined. Regions that are steep or inaccessible to the XUV are marked as obstacles in the database.

This report is one of a series of three produced by a Rand study of the relationships between the tactical employment and the technological capabilities of advanced weapons for ground combat. The TIMER model was developed to determine the effects of terrain on target visibility during combat engagements. TIMER supplies data on the occurrence and duration of target visibility from defense positions, the maximum range at which target acquisition might occur, and the potential rate at which a defense force could fire on an attacking force. The model uses the digitalized data base developed by the Defense Mapping Agency. The report includes the TIMER inputs and program listings, and illustrates the results that TIMER can produce.

This report documents the training effectiveness of a map interpretation and terrain analysis course (MITAC) developed by the Army Research Institute to enhance nap-of-the-earth (NOE) navigation skills. A two- group transfer-of-training study showed that MITAC-trained student aviators could navigate along NOE routes at twice the speed and with one-third the errors of normally trained student aviators. Interviews with experienced NOE aviators exposed to the MITAC material indicated that their navigation skills and understanding of student problems were also increased. It has been recommended that all Army aviators with NOE flight requirements be given MITAC training.

The preliminary airworthiness evaluation of the UH-1H helicopter equipped with the receiver antenna of the Terrain Mapping Radar System was conducted in Lakehurst, New Jersey, between 21 November and 8 December 1986. The evaluation required 12 flights for a total of 14.8 hours, or which 12.0 hours were productive. Performance, handling qualities, and structural dynamic response tests were conducted. The modified UH-1H equipped with the receiver antenna demonstrated adequate handling qualities for the terrain mapping mission. However, the proposed mission profile requires extensive operation of the helicopter in an out-of-ground effect (OGE) hover. Although the handling qualities are acceptable, the degraded autorotational characteristics may preclude a safe autorotational landing in the event of a sudden engine failure at an OGE hover below 1000 feet above ground level. The minimum directional control margin and high pilot workload to maintain heading during low speed flight were a shortcoming. Three additional shortcomings were found during the evaluation.

US Army and Joint constructive simulations require human operators to observe the exercise in progress, conduct analysis of the results, and provide a realistic reports and assessment of the action presented on their screens to the desired training audience. Current software tools provide excellent mathematical assessments (such as center of mass calculations, optimal routes, and sensor ranges) but poor human-like assessment of data (most likely route, probable enemy intention, etc.). This Thesis presents an artificial intelligence architecture specifically designed to reduce that manpower requirement by describing a concept for computer modeling that can produce realistic human-like assessment results. Specific concepts described are approaches for conducting a digital terrain assessment, development of avenues of approach, deployment of templated forces to a specific piece of terrain, and then a method of adjusting the templated force to react to actual sightings and known information. Also included are more detailed discussions and implementation details for use of gas diffusion as a method of analyzing avenues of approach through digital terrain. This approach seems quite promising as a method of modeling human movement tendencies and appears superior to classic path finding or optimal route selection methods.

Fourteen Air Force pilots flew a simulated mission under various flight conditions to determine the adequacy of the C-5A Multimode Radar (MMR) terrain avoidance display symbology. A C-135B flight simulator converted to the C-5A cockpit configuration was employed as the test bed. The pilots were divided into two groups: One to fly a series of terrain avoidance mission profiles using the current MMR display; the other to fly the same missions using an alternate display configuration. Each pilot had to fly a 150 NM simulated mission under each of the following conditions: (1) VFR without the radar display; (2) VFR with the radar display; (3) marginal VFR with the radar display; and (4) IFR with the radar display. The two display configurations were evaluated by comparing pilot performance under the various flight conditions. No overall significant statistical differences in pilot performance were attributable to the display configurations, although the trend of the objective data favored the alternate display. A significant difference between the various flight conditions was obtained. Pilot ratings of both display configurations tended to favor the alternate scope.

Hunter-Liggett Military Reservation was visited to conduct a soil/terrain evaluation of selected areas and to compare the soil strength data collected at the time of visit with the other 155mm XM718/741 Remote Anti-Armor Mine System (RAAMS) test areas previously characterized. Soil/terrain data were collected at eight sites located in the valley used in TEMAWS experiments. The sites sampled included a range of soil types in undulating to rolling terrain. Most sites were covered with short grasses and broad-leaf plants. All sites sampled were very firm at time of testing. The surface cone index ranged from 137 to 563+, and at 2 in. the cone index exceeded the capacity of the instrument (750+). The number of blows necessary to drive the dynamic cone penetrometer 0 to 3 in. ranged from 7 to 30, and for the surface foot ranged from 67 to 120. For the range of soil strength measured, the mines will not penetrate the target and will bounce after impacting the ground. It is estimated from previous penetration analysis for RAAMS that the magnitude of the rigid body g forces that the RAAM can experience upon impacting such firm soils at 200 ft/sec would range from 5000 to 9000 g's. (Author)

The Winds on Critical Steamline Surfaces (WOCSS) complex terrain wind flow model is designed to simulate lateral, mechanical forcing effects on air flows along elevated, solid boundaries, these effects exert significant influence on observed flow field properties, such as transport and diffusion. The degree to which WOCSS model outputs are more reliable than a basic mass consistency model (that does not address lateral forcing dynamics in complex terrain) is discussed in terms of statistical and spatial results, and conclusions regarding this comparison are presented. Results indicate that the WOCSS model does not predict directional changes resulting from lateral forcing, which is a serious limiting factor in its potential application. The WOCSS model was also found to have an oversimplified mass consistency algorithm, averaging speed-up effects over the entire lateral free-flow surface, which restricts prediction of localized lateral speed-up effects in the vicinity of mechanical flow obstacles. Finally, the WOCSS model tends to over-predict the quantity of flow restricted space under both stable and unstable conditions in the transition from moderate to rugged complex terrain when wind speeds are generally less than or equal to 4.0 m/s. However, despite the observed WOCSS model limitations, the WOCSS model did demonstrate the potential to selectivity predict reasonable and significant dynamic lateral forcing spaces over a variety of terrain and stability conditions.

This report presents the results of a flight test and evaluation program of a prototype terrain following/terrain avoidance (TF/TA) AN/APQ-141 radar system for search and rescue applications installed on an HH-53B helicopter. The report also presents an evaluation of the addition of symbology to the low light level television (LLLTV) display installed as part of the limited night recovery system (LNRS) in the same aircraft.

NASA's Synthetic Vision Systems (SVS) Project is striving to eliminate poor visibility as a causal factor in aircraft accidents as well as enhance operational capabilities of all aircraft through the display of computer generated imagery derived from an onboard database of terrain, obstacle, and airport information. To achieve these objectives, NASA 757 flight test research was conducted at the Eagle-Vail, Colorado airport to evaluate three SVS display types (Head-up Display, Head-Down Size A, Head-Down Size X) and two terrain texture methods (photo-realistic, generic) in comparison to the simulated Baseline Boeing-757 Electronic Attitude Direction Indicator and Navigation/Terrain Awareness and Warning System displays. The results of the experiment showed significantly improved situation awareness, performance, and workload for SVS concepts compared to the Baseline displays and confirmed the retrofit capability of the Head-Up Display and Size A SVS concepts. The research also demonstrated that the tunnel guidance display concept used within the SVS concepts achieved required navigation performance (RNP) criteria.

NASA's Synthetic Vision Systems (SVS) Project is striving to eliminate poor visibility as a causal factor in aircraft accidents as well as enhance operational capabilities of all aircraft through the display of computer generated imagery derived from an onboard database of terrain, obstacle, and airport information. To achieve these objectives, NASA 757 flight test research was conducted at the Eagle-Vail, Colorado airport to evaluate three SVS display types (Head-up Display, Head-Down Size A, Head-Down Size X) and two terrain texture methods (photo-realistic, generic) in comparison to the simulated Baseline Boeing-757 Electronic Attitude Direction Indicator and Navigation/Terrain Awareness and Warning System displays. The results of the experiment showed significantly improved situation awareness, performance, and workload for SVS concepts compared to the Baseline displays and confirmed the retrofit capability of the Head-Up Display and Size A SVS concepts. The research also demonstrated that the tunnel guidance display concept used within the SVS concepts achieved required navigation performance (RNP) criteria.

This report documents the training effectiveness of a map interpretation and terrain analysis course (MITAC) developed to enhance the ability of helicopter pilots to navigate accurately during low altitude terrain following flight. A study comparing student aviators taught by the MITAC technique with a control group of students taught by conventional techniques showed MITAC to be significantly superior in enhancing the aviator's ability to navigate rapidly and accurately during low-level flight. (Author/RE)

The purpose of the work reported herein was to establish a standard traverse terrain description for the German theater of operation to serve as a traverse terrain data base for relevant mobility tests and computer model evaluation, too. Steps performed were: 1) the selection of a suitable traverse in cooperation with U.S. Army representatives and in succession; and 2) the establishment of a traverse terrain data base prior to the first vehicle tests. The mobility test program addressed above was aimed at generating wheeled vs. tracked vehicles mobility data as part of the NBC Surrogate Reconnaissance System performance evaluation program. Here, the U.S. Army Waterways Experiment Station (WES) had the key coordination role to design and specify a suitable vehicle test program. Keywords: Maps; Photographs.

Definitions and short explanations of key concepts in the field of instructional evaluation are presented. Evaluation is defined as the process of determining the value of programs, projects, materials, and personnel. It is distinguished from research in that the aims of research are less time- and situation-specific, attempting to uncover principles that apply universally. In evaluation, less attention is paid to generalizing findings to a larger population. Astute evaluators argue that thorough evaluation begins as the program is conceptualized and planned. Also important is the distinction between formative evaluation conducted during the development or improvement of a program or product, and summative evaluation conducted after completion of an effort. Considerable attention is being given to the balance between quantitative and qualitative measures as part of an evaluation. The two most important criteria for judging evaluation seem to be isomorphism (similar or identical structure so as to fit with reality-based information) and credibility (believability). The two most important criteria for judging the adequacy of research are internal validity and external validity. Evaluation is the disciplined inquiry that yields information about the performance of educational programs, products, and processes. One figure pictures the inquiry domain. (Contains 7 references.) (SLD)

An elevation model of Great Sand Dunes, Colorado, USA Landform features: active dune field, sand sheet, sabkha Resolution: 3.3 meter, 5,300 x 5,300 height samples File format: GeoTIFF This is one model of a set of elevation models: https://doi.org/10.5281/zenodo.3938020 . Please cite the entire set of models. When using this elevation model in an academic publication, please cite the following article, which describes the process and rationale for compiling elevation models: Kennelly, P. J., Patterson, T., Jenny, B., Huffman, D. P., Marston, B. E., Bell, S. and Tait, A. M. (2021). Elevation models for reproducible evaluation of terrain representation. Cartography and Geographic Information Science, 48:1, 63–77. DOI:  10.1080/15230406.2020.1830856

An elevation model of Great Sand Dunes, Colorado, USA Landform features: active dune field, sand sheet, sabkha Resolution: 3.3 meter, 5,300 x 5,300 height samples File format: GeoTIFF This is one model of a set of elevation models: https://doi.org/10.5281/zenodo.3938020 . Please cite the entire set of models. When using this elevation model in an academic publication, please cite the following article, which describes the process and rationale for compiling elevation models: Kennelly, P. J., Patterson, T., Jenny, B., Huffman, D. P., Marston, B. E., Bell, S. and Tait, A. M. (2021). Elevation models for reproducible evaluation of terrain representation. Cartography and Geographic Information Science, 48:1, 63–77. DOI:  10.1080/15230406.2020.1830856

This report describes the development and evaluation of the Night Readiness, LLC Virtual Terrain Board (VTB) (V2.0c) and its instructional modules for NVG ground training. The evaluation consisted of a training effectiveness assessment of the VTB, using feedback from qualified NVG Training Course terrain board instructors and students undergoing refresher training and students attending initial NVG ground training at six military VTB installations. The primary objectives of the training effectiveness evaluation were to determine if the established terrain board learning objectives could be accomplished with the VTB, to identify additional learning objectives that could be accomplished using the VTB, and to identify areas of improvement required to increase the training value of the VTB system. The results indicated that the VTB is an effective training device that can accomplish most aspects of the established terrain board learning objectives. Specific limitations identified by some instructors and students included demonstrations of the effects of different color/wavelengths of light, illumination levels on halos, and effects related to NVG gain. VTB development currently in progress along with the improvements recommended in this evaluation will provide a balanced, practical approach to improving the usability, versatility and training effectiveness of the VTB.

Local topographic effects and spatial land-surface variability present unique challenges for weather forecasting in areas of complex terrain. The primary goal of this research is to improve the accuracy of weather forecasts over the fine-scale topography of the Intermountain West using statistical and numerical modeling techniques. Specifically, we seek to determine where, when and why decreasing the horizontal grid spacing of numerical models improves forecast accuracy and to evaluate the added benefits of using statistical techniques to correct for systematic numerical model deficiencies.

In commercial aviation, over 30-percent of all fatal accidents worldwide are categorized as Controlled Flight Into Terrain (CFIT) accidents, where a fully functioning airplane is inadvertently flown into the ground. The major hypothesis for a simulation experiment conducted at NASA Langley Research Center was that a Primary Flight Display (PFD) with synthetic terrain will improve pilots ability to detect and avoid potential CFITs compared to conventional instrumentation. All display conditions, including the baseline, contained a Terrain Awareness and Warning System (TAWS) and Vertical Situation Display (VSD) enhanced Navigation Display (ND). Each pilot flew twenty-two approach departure maneuvers in Instrument Meteorological Conditions (IMC) to the terrain challenged Eagle County Regional Airport (EGE) in Colorado. For the final run, flight guidance cues were altered such that the departure path went into terrain. All pilots with a synthetic vision system (SVS) PFD (twelve of sixteen pilots) noticed and avoided the potential CFIT situation. The four pilots who flew the anomaly with the conventional baseline PFD configuration (which included a TAWS and VSD enhanced ND) had a CFIT event. Additionally, all the SVS display concepts enhanced the pilot s situational awareness, decreased workload and improved flight technical error (FTE) compared to the baseline configuration.

Three models used to predict the wind field and pollutant dispersion in complex terrain are compared with smoke dispersion data acquired as part of the AMADEUS field experiments in 1987 near Red Bluff, California. The models evaluated were WADOCT, HOTMAC/RAPTAD, and RAMS. The data base for model testing encompassed 7 fog-oil smoke releases from ground level under stable meteorological conditions. Smoke concentrations were measured out to 4 km downwind. Time-dependent meteorological and source data were available from these tests to be used as model input. The results showed that the WADOCT model predicted quite well for the first 300 m downwind but then underpredicted the plume concentration by an order of magnitude at distances of 4 km downwind. The HOTMAC/RAPTAD model revealed a similar behavior. The inability of those two models to predict the trajectory of the plume and the observed limited vertical growth of the plume, in the downwind valley, are the likely causes of the underprediction. The RAMS model revealed very poor wind field and dispersion predictions based on the large grid spacing that was required (for this application) in order to make the computer run times manageable.... Smoke, Complex terrain, Dispersion modeling, Computer modeling, RA 3.

This report describes the formulation of a digital data base and the equipment utilized to display computer generated images of the resultant terrain scenes. Real time and nonreal time equipment is described. Necessary input data for formulation of digital data bases is delineated. Resulting scene data is to be utilized as stimulus material for evaluation of CGI systems to determine their effectiveness as a medium for training navigators and pilots.

NASA and the U.S. Army have designed, developed, and flight evaluated a Computer Aiding for Low Altitude Helicopter Flight (CALAHF) guidance system. This system provides guidance to the pilot for near terrain covert helicopter operations. It automates the processing of precision navigation information, helicopter mission requirements, and terrain flight guidance. The automation is presented to the pilot through symbology on a helmet-mounted display. The symbology is a 'pilot-centered' design which preserves pilot flexibility and authority over the CALAHF system's automation. An extensive flight evaluation of the system has been conducted using the U.S. Army's NUH-60 STAR (Systems Testbed for Avionics Research) research helicopter. The evaluations were flown over a multiwaypoint helicopter mission in rugged mountainous terrain, at terrain clearance altitudes from 300 to 125 ft and airspeeds from 40 to 110 knots. The results of these evaluations showed that the pilots could precisely follow the automation symbology while maintaining a high degree of situational awareness.

The feasibility of acoustical scale modeling techniques for modeling wind effects on long range, low frequency outdoor sound propagation was evaluated. Upwind and downwind propagation was studied in 1/100 scale for flat ground and simple hills with both rigid and finite ground impedance over a full scale frequency range from 20 to 500 Hz. Results are presented as 1/3-octave frequency spectra of differences in propagation loss between the case studied and a free-field condition. Selected sets of these results were compared with validated analytical models for propagation loss, when such models were available. When they were not, results were compared with predictions from approximate models developed. Comparisons were encouraging in many cases considering the approximations involved in both the physical modeling and analysis methods. Of particular importance was the favorable comparison between theory and experiment for propagation over soft ground.

Side looking airborne radar (SLAR) imagery acquired in diverse terrains and environments, was studied to demonstrate its value in military tactical terrain analysis. Capabilities unique to SLAR, such as all-weather and day or night image acquisition, are highlighted. In addition, other capabilities and limitations are also stressed to permit the utilization of SLAR with other sensors for maximum data retrieval. Imagery studied was selected on the basis of geographic location and data content, not system characteristic, and estimates are made of the improved data content that could be realized by modification of system parameters. By using a broader range of the electro-magnetic spectrum than most sensors and by operating under many controllable parameters, the appropriate radar system and system configuration can be selected for any mission by the user to realize maximum target information. (Author)

This report presents the results of an evaluation of the capabilities of an airborne laser profile system to obtain ground truth data for the evaluation of the range tracking capability of high resolution radar altimeters. Quantitative evaluations were made of man-made objects such as seats/steps at a football stadium and various buildings. Qualitative evaluations were made with natural terain such as trees, lakes, land elevations, and power lines along a trackline over Florida.