A Strategic Framework for Searching Mobile Targets Using Mobile Sensors

This paper presents a cooperative, combinatorial search model for a multi-mobile sensor, multi-mobile target scenario in a two dimensional grid space. In the proposed model, sensors and targets act as searchers and hiders of a search game. A search game is a game between searcher and hider, modeled on a graph. In this paper, the identified problem states that multiple targets enter into a grid from the same or different sides and try to exit on the opposite directions of their respective entry sides. Alternatively, multiple mobile sensors are randomly deployed in the grid and try to maximize the number of target searched and to minimize search time before the targets leave the grid. This problem fits into several real life scenarios such as international border security, terrorist searching in a specified area, finding spies etc. The novelty of the proposed model is interpreting the problem as a search game and formulating strategies for the mobile sensors to optimize their moves to maximize the number of target searched and minimize search time. In this paper, shortest path and random walk strategies for the targets are analyzed by applying suitable mathematical models and on the other hand, advantages of cooperative over non-cooperative strategies for the mobile sensors are also shown with the help of analytical methods and simulation results. The significant mathematical concepts applied in the proposed model are as follows-computing shortest path, random walk, Markov chain, probability graph, overlapping of multiple probability graphs, cooperative and non-cooperative strategies etc.