RF Time of Flight Ranging for Wireless Sensor Network Localization
Steven Michael Lanzisera and Kristofer Pister
An enabling technology for large scale sensor networks is the ability to determine a sensor node's location after deployment. Some applications, such as inventory management, use sensors that move regularly, and this spatial information is crucial to the network's operation. A device to wirelessly measure the distance between two network nodes using an RF transceiver will be developed. The distance measurement is performed by calculating a cross correlation between a received and an expected signal. Methods for reducing the effects of noise, clock offset, and multipath propagation have been studied. Mitigation techniques for these three primary error sources have been implemented. We have demonstrated round trip time of flight (TOF) ranging using an FPGA, 2.4 GHz radio, and a custom PCB. Meter level accuracy has been achieved both indoors and outdoors . The end goal is to provide low power, accurate, self-contained, ad hoc localization to mobile sensor nodes. Currently, work is focused on developing a highly integrated version that can be used in more general mote deployments. This unit will include a low power 2.4 GHz transceiver along with a digital backend for TOF measurement.
- S. Lanzisera, D. Lin, and K. Pister, "RF Time of Flight Ranging for Wireless Sensor Network Localization," Workshop on Intelligent Solutions in Embedded Systems, June 2006.