Smart Dust sensor networks - consisting of cubic millimeter scale sensor 
nodes capable of limited computation, sensing, and passive optical 
communication with a base station - are envisioned to fulfill complex large 
scale monitoring tasks in a wide variety of application areas. In many 
potential Smart Dust applications such as object detection and tracking, 
fine-grained node localization plays a key role. However, due to the unique 
characteristics of Smart Dust, traditional localization systems cannot be 
used. In this paper we present and analyse the Lighthouse location systems, a 
novel laser-based location system for Smart Dust, which allows tiny dust nodes 
to autonomously estimate their location with high accuracy without additional 
infrastructure components besides a modified base station device. Using an 
early 2D prototype of the system, node locations could be estimated with an 
average accuracy of about 2% and an average standard deviation of about 0.7% 
of the node's distance to the base station.