Location Tracking And Positioning In DTNs

as the vast research in the eld of technology increases, location dependent applications becomes highly important as positioning and tracking of mobile devices plays an important role in context aware and pervasive services. While physical localization and logical localization for satellite has been highly and extensively researched, networks with xed reference points like GSM and WiFi are densely deployed and tracking and positioning techniques in Sparse Disruption Tolerant Networks (DTN) have not been well researched. In this paper, we propose a cooperative and localized method called Pulse Counting for DTN localization and a probability based tracking method called ProbTracking to solve the problem. To evaluate user walking steps and movement orientation, we use Pulse Counting by using cellphones accelerometer and electronic compass. By exploiting the encounters of mobile nodes, it improves the accuracy and estimates user’s location by accumulating walking segments. There are several methods for renement of location estimation which are also discussed, such as, mutual renement of location estimation for encountering nodes based on maximum likelihood and adjustment of trajectory based on reference points. We use ProbTracking method to track user movement which uses Markov chain to describe movement patterns and predicts the most possible user walking trajectory without full record of users location.