# An Obstacle-Tolerant Path Planning Algorithm for Mobile-Anchor-Node-Assisted Localization
## 6 Summary and Future Work  
Mobile-anchor-node-assisted localization (MANAL) has becomes more popular because it not only saves the power consumption of unknown nodes in sensor networks, but also adapts to various environments. The key problem of MANAL is the path planning of the MAN. Many path planning schemes have been proposed for MANAL; however, most of them only adapt to obstacle-free environments, which is not practical. In this paper, we propose an obstacle-tolerant path planning algorithm, called OTPP. Compared to the other path planning algorithms for MANAL, OTPP ensures that all unknown nodes are covered by at least three beacon points by using minimum beacon points in a unit square area. The experimental results show that OTPP performs better than the Z-curve as the total number of beacon points is reduced, localization errors lowered and coverage increased. This implies that OTPP is more adaptive to obstacle-present environments. In the future, we will consider more practical environments, such as obstacles with mobility or 3D spaces in path planning for application in unmanned aerial vehicles or detection of marine resources. [PERSON] and [PERSON] conceived and designed the experiments; [PERSON] performed the experiments; [PERSON] analyzed the data; and [PERSON] and [PERSON] wrote the paper. **Conflicts of Interest:** The authors declare no conflict of interest. Figure 15: OTPP compared with online path planning in terms of (**a**) localization error and (**b**) coverage ratio. The unit of communication range is meter (m). * (10) [PERSON] A study of sufficient conditions for Hamiltonian cycles. _Rose-Hulman Undergrad. Math. J._**2000**, \(1\), \(6\). * (11) [PERSON]; [PERSON]; [PERSON] Some simplified NP-complete problems. In Proceedings of the 6 th Annual ACM Symposium on Theory of Computing, Seattle, WA, USA, 30 April-2 May 1974; pp. 47-63. * (12) [PERSON]; [PERSON] Static path planning for mobile beacons to localize sensor networks. In Proceedings of the 5 th Annual IEEE International Conference on Pervasive Computing and Communications Workshops, White Plains, NY, USA, 19-23 March 2007; pp. 323-330. * (13) [PERSON]; [PERSON]; [PERSON]; [PERSON] Localization in wireless sensor networks using a mobile anchor node. In Proceedings of the IEEE/ ASME International Conference on Advanced Intelligent Mechatronics, Xi'an, China, 2-5 July 2008; pp. 602-607. * (14) [PERSON]; [PERSON]; [PERSON] Collaborative localization algorithm for wireless sensor networks using mobile anchors. In Proceedings of the 2 nd Asia-Pacific Conference on Computational Intelligence and Industrial Applications, Wuhan, China, 28-29 November 2009; pp. 309-312. * (15) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Path planning using a mobile anchor node based on trilateration in wireless sensor networks. _Wirel. Commun. Mob. Comput._**2011**, _14_, 1324-1336. [CrossRef]
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