3-D mobile node localization using constrained volume optimization over ad-hoc sensor networks

This paper proposes a three dimensional mobile node localization and obstacle avoidance mechanism in ad-hoc sensor networks (AHSN). The localization task is performed through constrained volume optimization. Obstacle avoidance is achieved through weighted distribution method. Constrained volume optimization is performed by minimizing the squared location error and imposing the distance and boundary conditions. Obstacle avoidance is achieved by choosing the angular direction which minimizes the cost function. The solution to the constrained optimization problems ensures that the method is robust to change in environmental conditions and NLOS issues. Additionally, the algorithm is scalable and follows a distributed approach to localization. The performance of this method is assessed by deploying nodes in both indoor and outdoor environments. Improved localization accuracy is noted when compared to conventional methods in terms of statistical location estimates and Cramer-Rao lower bound localization error analysis.