The PathFinder Route Replanner was designed from the ground up to address the military’s need for an embedded, in-flight real-time route replanning capability that can determine near-optimal flight paths for changing battlefield conditions (e.g. weather, threats, mission updates). Its core algorithm is well-suited to solving a number of “open space” (i.e. air or sea) path optimization problems. Applications could include re-routing ships around severe weather, determining the optimal flight path to avoid detection by a pop-up threat, or determining the optimum flight path and accident scene approach route for an air ambulance.
The PathFinder Route Replanner adapts a platform’s planned route based on changing operational conditions to maximize the probability of mission success in real time with minimal user interaction. Examples of changing operational conditions include:
- Unplanned/moved/disabled threats to the platform
- Platform changes/damage (one engine out for example)
- In-flight mission updates/re-tasking
- Severe weather
When PathFinder determines a new route, the new route can be flown with the platform’s constraints. PathFinder incorporates the aircraft’s ability to maneuver, speed characteristics, and current fuel amount along with estimated fuel consumption. PathFinder honors airspace restrictions which can include political boundaries, restricted areas and no-fly zones, and, if desired, avoid populated areas. No-fly zones can be defined by altitude with arbitrary shapes and temporal constraints. PathFinder can also optimize the route with terrain occluding for low altitude routes.
PathFinder preserves a time on target or time at destination. For military application, PathFinder avoids or minimizes the amount of time that a platform is within a threat detection or lethal envelope (as selected by the user). PathFinder incorporates line-of-sight terrain masking and threat characteristics along with on-board defensive system’s ability to reduce a threat’s lethality. PathFinder can also minimize exposure to roads and other areas where threats are likely to be located.
The results of PathFinder are determined in a predictable and bounded period of time. With the maximum solution time bounded at two seconds, PathFinder running on modern single board computers typically provides replans in less than one second. Flexibility is provided to allow the user to specify the solution time constraint. If PathFinder has not completed calculations by the solution time constraint, then the best available solutions will be provided. Based on user needs, PathFinder software can be modified to apply a solution time constraint for events occurring within an area of regard surrounding the current aircraft position, with a longer time constraint for events occurring outside of the area of regard.