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Pervasive Systems Centre School of Electronics and Computer Science WiSE: Wireless Sensing in ECS

Seminar: Two-Way Time of Flight Ranging in WSNs

Evangelos Mazomenos
Evangelos Mazomenos

Title: "Two-Way Time of Flight Ranging in WSNs"
Speaker: Evangelos Mazomenos, Electronic Systems and Devices Research Group, Electronics and Computer Science, University of Southampton
Date: Tuesday 03rd May 2011
Time: 12.00
Location: Mountbatten Seminar Room [Level 4] (53/4025A)

Relative ranging between Wireless Sensor Network (WSN) nodes is considered to be an important requirement for a number of distributed applications. This paper focuses on a two-way, time-of-flight (ToF) technique which achieves good accuracy in estimating the point-to-point distance between two wireless nodes. The underlying idea is to utilize a two-way time transfer approach in order to avoid the need for clock synchronization between the participating wireless nodes. Moreover, by employing multiple ToF measurements, sub-clock resolution is achieved. A calibration stage is used to estimate the various delays that occur during a message exchange and require subtraction from the initial timed value. The calculation of the range between the nodes takes place on-node making the proposed scheme suitable for distributed systems. Care has been taken to exclude the erroneous readings from the set of measurements that are used in the estimation of the desired range. The two-way ToF technique has been implemented on commercial of-the-self (COTS) devices without the need for additional hardware. The system has been deployed in various experimental locations both indoors and outdoors and the obtained results reveal that accuracy between 1m RMS and 2.5 m RMS in line-of-sight conditions over a 42 m range can be achieved.

Evangelos Mazomenos was born in Athens, Greece in 1982. In 2000 he enrolled at the Engineering School of Electrical and Computer Engineering, University of Patras. He graduated with a Diploma in Electrical and Computer Engineering in 2006. Since October 2007 he pursues a Ph.D degree at the School of Electronics and Computer Science (ECS) at the University of Southampton. His research interests are basically within the area of wireless sensor networks and include, target detection and tracking, bayesian estimation theory, real-time systems, signal processing, healthcare monitoring and network architecture. In 2009 he was awarded the prestigious Leslie H. Paddle Scholarship for postgraduate studies from the Institute of Engineering and Technology (IET). He has co-authored a number of publications in international conferences and journals.

More Information.
Posted by Dr Geoff Merrett on 12 Apr 2011.
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