Path searching is challenging problem in many domains such as simulation war games, robotics, military mission planning, computer generated forces (CGF), etc. Effectiveness problems in military route planning are related both with terrain modelling and path planning algorithms. These problems may be considered from the point of view of many criterions. It seems that two criterions are the most important: quality of terrain reflection in the terrain model and computational complexity of the on(off)-line path planning algorithm. The paper deals with two above indicated problems of route planning effectiveness. Comparison of approaches used in route planning is presented. The hybrid, terrain merging-based and partial path planning, approach for route planning in dynamically changed environment during simulation is described. It significantly increase effectiveness of route planning process. The computational complexity of the method is given and some discussion for using the method in the battlefield simulation is conducted. In order to estimate how many times faster we can compute problem for finding shortest path in network with n big squares (b-nodes) with relation to problem for finding shortest path in the network withV small squares (s-nodes) acceleration function is defined and optimized.

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Military route planning in battlefield simulation: effectiveness problems and potential solutions

Distributed Interactive Simulation (DIS) is an architecture for building large-scale simulation models from a set of independent simulator nodes communicating via a common network protocol. DIS is most often used to create a simulated battlefield for military training. Computer Generated Forces (CGF) systems control large numbers of autonomous battlefield entities in a DIS simulation using computer equipment and software rather than humans in simulators. CGF entities serve as both enemy forces and supplemental friendly forces in a DIS exercise. Research into various aspects of CGF systems is ongoing. Several CGF systems have been implemented.

Computer-generated forces in distributed interactive simulation

features . Quadtree is contained within the erOB patch data structures. CGF system None (proposed IerOB) ICTOB quadtree contains individual and aggregate [Stanzione, 1995] features. Road and river networks are also stored as graphs within the quadtree. CGF system Intelligent Player Quadtree stores elevation only. [Pandari,1995] Table 3.5 (part 4 of 6) Summary of CGF and terrain reasoning terrain representations.

Terrain Representation And Reasoning In Computer Generated Forces : A Survey Of Computer Generated Forces Systems And How They Represent And Reason About Terrain

Unit Route Planning

This paper presents a new approach to the aircraft collision avoidance problem. This approach gives a recommended avoidance trajectory in both the horizontal and vertical planes of motion based on the geometric relationship between aircraft and threats. A new concept, the "threat map", is introduced to describe moving threats as static threats. Thus, motion planning for dynamic threats is reduced to path planning for stationary threat avoidance. At every time interval, the threat map is updated and the velocity direction of the aircraft is calculated to avoid the threats. The "risk space" is used to model a threat By avoiding the risk space, the aircraft avoids the threat while keeping a safe separation. Some simulation studies show the effectiveness of the proposed approach.

Aircraft collision avoidance trajectory generation

Techniques to allow simulated entities to avoid static terrain, such as trees, buildings, rivers, etc., have been in use in Distributed Interactive Simulation (DlS) environments for many years. Avoidance of objects in motion, “dynamic obstacles”, is much more complex. Although simple dynamic obstacle collision avoidance has been implemented in other systems, the resulting behavior is usually less than realistic. The Institute for Simulation and Training (1ST) has investigated techniques to allow simulated entities to make reasonably intelligent and realistic maneuvers intended to avoid dynamic (and static) objects. The goal has been to find new methods which will yield improved collision avoidance behavior without excessive computational cost. As a result of this work, 1ST has developed a novel approach to attack the DIS dynamic obstacle avoidance (DOA) problem by combining two disparate motion planning approaches: potential fields and grid based route planning.

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Jaime E. Cisneros

Papers

Dynamic obstacle avoidance