Whenever a sensor resolves its own position, it can
work as a beacon and help other nodes on location computation. Simulation
results indicate that TPSS is an e?®ective self-positioning scheme for sensor
networks with short range beacons.
This chapter is organized as follows. Section 2 summarizes the current
research on location discovery. The network model to be studied is described
in Section 3. The new positioning scheme, TPSS, is proposed in Section 4.
Simulation results are reported in Section 5. And we conclude our chapter in
Section 6.
2 An Overview on Current Location Discovery Schemes
for Sensor Networks
The popular Global Positioning System(GPS) [39] localization system may not
be a practical solution for outdoor sensor networks. It is infeasible to install
GPS on each sensor due to cost, form factors, power consumption and antenna
requirements. Further, GPS requires direct Light-Of-Sight (LoS) communication,
which renders it unfeasible for many outdoor application environments.
Therefore in the past several years, extensive research has been directed to
designing GPS-less location discovery schemes [1??“5, 8,13??“15,17, 18,20??“22,26??“
35, 37]. These positioning algorithms di?®er in their assumptions on network
deployment, device capabilities, node mobility, signal propagation, error requirement,
etc. Thus, they can be classified di?®erently. For example, some
methods are designed for static sensor networks, where sensors remain stationary
after deployment, while others are for dynamic sensor networks where
sensors and beacons are mobile [2,18].
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