Date: August 2010 Creator: Pasupathy, Karthikeyan Description:
Wireless sensor networks are composed of sensor nodes, which can
monitor an environment and observe events of interest. These
networks are applied in various fields including but not limited
to environmental, industrial and habitat monitoring. In many
applications, the exact location of the sensor nodes is unknown
after deployment. Localization is a process used to find sensor
node's positional coordinates, which is vital information. The
localization is generally assisted by anchor nodes that are also
sensor nodes but with known locations. Anchor nodes generally
are expensive and need to be optimally placed for effective
localization. Passive localization is one of the localization
techniques where the sensor nodes silently listen to the global
events like thunder sounds, seismic waves, lighting, etc.
According to previous studies, the ideal location to place
anchor nodes was on the perimeter of the sensor network. This
may not be the case in pas