Localization Using base Station Mobility By: Hersh Vardhan Shukla Guide: Jun Luo, Jacques Panchard By: Hersh Vardhan Shukla Guide: Jun Luo, Jacques Panchard

Definitions Localization : Finding the position of nodes w.r.t. a coordinate system. Synchronization : Bring two clocks into phase so that their difference is close to zero. Localization : Finding the position of nodes w.r.t. a coordinate system. Synchronization : Bring two clocks into phase so that their difference is close to zero.

Proposal To develop an efficient localization algorithm for Sensor Networks Provide synchronization for power efficiency To develop an efficient localization algorithm for Sensor Networks Provide synchronization for power efficiency

Related Work An Overview of Positioning by Diffusion-Michael Spratt Employ mobile nodes to gradually localize static nodes. Usually employ signal sensing (RSSI) techniques to ascertain position. An Overview of Positioning by Diffusion-Michael Spratt Employ mobile nodes to gradually localize static nodes. Usually employ signal sensing (RSSI) techniques to ascertain position.

Related Work Node Localization Using Mobile Robots in Delay-Tolerant Sensor Networks-Pubudu N Pathirana, Andrey V Savkin, Sanjay Jha, Nirupama Bulusu Uses RSSI Removes defficiencies of RSSI by using Robust Kilman Filter for Delay Tolerant Sensor Networks. Centralized approach Node Localization Using Mobile Robots in Delay-Tolerant Sensor Networks-Pubudu N Pathirana, Andrey V Savkin, Sanjay Jha, Nirupama Bulusu Uses RSSI Removes defficiencies of RSSI by using Robust Kilman Filter for Delay Tolerant Sensor Networks. Centralized approach

Related Work Localization of Wireless Sensor Networks with a Mobile Beacon- Mihail L. Sichitiu and Vaidyanathan Ramadurai The constraints imposed by the node being in the sensing distance of the mobile beacon. They then use Bayesian probability distribution to calculate how close the node can be wrt to the node with a given RSSI Localization of Wireless Sensor Networks with a Mobile Beacon- Mihail L. Sichitiu and Vaidyanathan Ramadurai The constraints imposed by the node being in the sensing distance of the mobile beacon. They then use Bayesian probability distribution to calculate how close the node can be wrt to the node with a given RSSI

Related Work MobiLoc: Mobility Enhanced Localization-Prabal Dutta, Sarah Bergbreiter Propose a scheme to find the inter node distances Distance measuring using TDOA and concept of Closest Point of Approach (CPA) The authors leave it to the user to apply existing localization algorithms to henceforth find the position of the nodes. MobiLoc: Mobility Enhanced Localization-Prabal Dutta, Sarah Bergbreiter Propose a scheme to find the inter node distances Distance measuring using TDOA and concept of Closest Point of Approach (CPA) The authors leave it to the user to apply existing localization algorithms to henceforth find the position of the nodes.

Scheme Semantics ASSUMPTIONS The Base Station has GPS installed on it. The ultrasonic transmitter at the base station is capable of transmitting at powers capable to reach distance of the order of Network radius; this assumption can be done away with if required. ASSUMPTIONS The Base Station has GPS installed on it. The ultrasonic transmitter at the base station is capable of transmitting at powers capable to reach distance of the order of Network radius; this assumption can be done away with if required.

Algorithm (Localization) The Base station moves in a circle circumscribing the network i.e. at the periphery of the network The Base station continuously broadcasts :- Its position wrt the centre of the Network circum-circle. It time stamps its broadcast message with its local clock. The time interval after which it is planning to broadcast again. The Base station moves in a circle circumscribing the network i.e. at the periphery of the network The Base station continuously broadcasts :- Its position wrt the centre of the Network circum-circle. It time stamps its broadcast message with its local clock. The time interval after which it is planning to broadcast again.

TDoA and CPA

Synchronization Now the nodes know its position wrt to the centre of the circle The position of the BS (from the beacon it sends) The time at which the beacon was sent. Hence the propagation delay Now the nodes know its position wrt to the centre of the circle The position of the BS (from the beacon it sends) The time at which the beacon was sent. Hence the propagation delay

Incremental Error Model The BS does a tiny phase shift after completion of each round. If the granulity be ∆DOT and the start position be R then after the completion of the round the BS starts at R+(∆DOT)/N A given node observes over N rounds and takes the (x,y) BS pair for min(∆δ) among these N rounds The BS does a tiny phase shift after completion of each round. If the granulity be ∆DOT and the start position be R then after the completion of the round the BS starts at R+(∆DOT)/N A given node observes over N rounds and takes the (x,y) BS pair for min(∆δ) among these N rounds