Editing Dead reckoning (section)

==Localization of mobile sensor nodes==
[[Location estimation in sensor networks|Localizing]] a static [[sensor node]] is not a difficult task because attaching a [[Global Positioning System]] (GPS) device suffices the need of localization. But a [[mobile wireless sensor network|mobile sensor node]], which continuously changes its geographical location with time is difficult to localize. Mostly mobile sensor nodes within some particular domain for data collection can be used, ''i.e'', sensor node attached to an animal within a grazing field or attached to a soldier on a battlefield. Within these scenarios a GPS device for each sensor node cannot be afforded. Some of the reasons for this include cost, size and battery drainage of constrained sensor nodes.
To overcome this problem a limited number of reference nodes (with GPS) within a field is employed. These nodes continuously broadcast their locations and other nodes in proximity receive these locations and calculate their position using some mathematical technique like [[trilateration]]. For localization, at least three known reference locations are necessary to localize. Several localization algorithms based on [[Sequential Monte Carlo]] (SMC) method have been proposed in literature.<ref>{{Cite book|publisher = ACM|date = 1 January 2004|location = New York, NY, USA|isbn = 978-1-58113-868-9|pages = 45–57|series = MobiCom '04|doi = 10.1145/1023720.1023726|first1 = Lingxuan|last1 = Hu|first2 = David|last2 = Evans| title=Proceedings of the 10th annual international conference on Mobile computing and networking | chapter=Localization for mobile sensor networks |citeseerx = 10.1.1.645.3886|s2cid = 705968}}</ref><ref>{{Cite book|title = Monte Carlo Localization of Mobile Sensor Networks Using the Position Information of Neighbor Nodes|publisher = Springer Berlin Heidelberg|date = 22 September 2009|isbn = 978-3-642-04382-6|pages = 270–283|series = Lecture Notes in Computer Science|doi = 10.1007/978-3-642-04383-3_20|first1 = Hamid|last1 = Mirebrahim|first2 = Mehdi|last2 = Dehghan|editor-first = Pedro M.|editor-last = Ruiz|editor-first2 = Jose Joaquin|editor-last2 = Garcia-Luna-Aceves}}</ref> Sometimes a node at some places receives only two known locations and hence it becomes impossible to localize. To overcome this problem, dead reckoning technique is used. With this technique a sensor node uses its previous calculated location for localization at later time intervals.<ref>Haroon Rashid, Ashok Kumar Turuk, 'Dead reckoning localisation technique for mobile wireless sensor networks', IET Wireless Sensor Systems, 2015, 5, (2), p. 87-96, DOI: 10.1049/iet-wss.2014.0043
IET Digital Library, http://digital-library.theiet.org/content/journals/10.1049/iet-wss.2014.0043</ref> For example, at time instant 1 if node A calculates its  position as ''loca_1'' with the help of three known reference locations; then at time instant 2 it uses ''loca_1'' along with two other reference locations received from other two reference nodes.  This not only localizes a node in less time but also localizes in positions where it is difficult to get three reference locations.<ref>{{Cite journal|title = IET Digital Library: Dead reckoning localisation technique for mobile wireless sensor networks|journal = IET Wireless Sensor Systems|volume = 5|issue = 2|pages = 87–96|first = Haroon|last = Turuk|doi = 10.1049/iet-wss.2014.0043|year = 2015|arxiv = 1504.06797|s2cid = 14909590}}</ref>