Generating one-meter terrain data for tactical simulations
In order to enhance a soldier’s effectiveness on the battlefield, simulation systems depicting operational scenarios require the accurate calculation of concealment, cover, and detection parameters. Measurement and analysis of tactical battlefield features requires the generation of metrically accurate terrain-elevation databases at higher resolution than the standard 90- and 30-meter data available from the National Imagery and Mapping Agency (NIMA). However, the generation and exploitation of higher-resolution terrain data can be slow and expensive and potentially a significant obstacle in conducting tactical terrain analysis. This article describes a low-cost system designed to address the generation and usage of 1-meter-resolution terrain in large-area tactical battlefield simulations.
The system, under development at the Naval Postgraduate School (NPS) in Monterrey, California, greatly enhances the cost effectiveness of highresolution terrain data by employing low-cost personal computer (PC)based software. The software, known as PVNT (or perspective view nascent technologies), can generate the terrain data and use it to create perspective views (Figures 1 and 2) and to perform line-of-sight (LOS) as well as weapons-effectiveness analysis.
Figure 1 shows a perspective view of two helicopters flying over Fort Hunter Ligget, California. Study of the terrain reveals trails and bushes. These features are on the order of one meter and their placing is accurate within approximately two meters. The images, generated under joy-stick control, are at better than 30 frames-per-second on a high-end PC.
PVNT operates on standard PCs running Windows[R] NT, 98, and 2000. NPS designed it to address the real-time generation of accurate battlefield views at any time of day and under all weather conditions. Its users include the Aviation and Missile Research, Development and Engineering Center (AMRDEC) in Huntsville, Alabama, which used the program to perform a weapons effectiveness comparison between a TOW (tube-launched, optically tracked, wire-guided missile system) 2B and a TOW FF (fire and forget).
Figure 2 shows a screen capture of PVNT windows used for LOS analysis. NPS generated two perspective views and displayed them in the upper windows. At the center bottom, a map view shows as light blue and medium blue the area under observation in each of the viewer windows. Both the perspective views and ground visibility cones move in real time under joy-stick control.
The user selected target routes of interest in a one-meter terrain dataset, and the system calculated hit probabilities for each route point from all possible attack positions within a four-kilometer radius. Figure 3 is a PVNT screen capture showing the result for a single route point. The light blue indicates those ground areas from which TOW 2B and TOW FF weapons can attack the single route point. The medium blue indicates those ground areas that only the TOW FF can attack. The additional successful attack area for the TOW FF provides a measure of greater weapon effectiveness. The basis of the software used LOS calculations is detailed knowledge of the terrain elevation. We can only achieve a meaningful result in this comparison using terrain data with one-meter or better resolution.
PVNT imports standard NIMA digital terrain evaluation data (DTED) and has local update tools that allow new information, gathered by local sensors and from data reports, to improve and enhance the information in the terrain database. It is unique in that most scene-visualization programs store the terrain surface as a polygon database, whereas PVNT uses raster formats (pixels), which are more appropriate for scientific scene visualization. Therefore, PVNT is more suitable for handling remotely sensed data and for integration with tactical battlefield sensor systems.
The software also has extensive feature-modeling and database editing capabilities. The left side of Figure 4 shows an image of trees and bushes in a sample terrain. The program measures the size and shape of identified features and executes a three-dimensional (3D) modeling program to fit the best tree outline to the measured feature. It categorizes the resulting objects by height as either trees (light blue) or lower vegetation (medium blue).
PVNT is a software package that addresses both the data-generation and data-exploitation issues. It allows the insertion of 3D models for a large variety of features that the user might encounter on the terrain. PVNT provides support for producing metrically accurate representations of the battlespace. It is therefore optimal for use in an operational environment where the live and virtual-reality worlds will come together. Development of faster and more automated PVNT terrain-creation code is an ongoing research effort at NPS, as are collaborative efforts that allow code sharing and the development of a user group.
Wolfgang Baer, Ph.D., currently holds an Associate Research Professor position at the Naval Postgraduate School (NPS) in Monterrey, California, where he teaches courses in networks and network programming. The author will provide sample copies of executables and sample one-meter terrain data. You can contact Dr. Baer via E-mail at email@example.com and telephonically at (831) 656-2209.
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