Future Smart Dust systems present a novel set of challenges to a location system. We examined these challenges and found that location systems developed in the past for mobile computing systems and COTS sensor networks are not applicable to Smart Dust systems due to the novel characteristics of the latter.
We presented the Lighthouse location system for future Smart Dust systems. By extending the base station, this system allows Smart Dust to autonomously estimate their physical location with respect to the base station with high precision over distances of tens of meters without node calibration. Besides the single modified base station, the system does not require any additional infrastructure components. This is achieved by a new cylindrical lateration method. In contrast to traditional spherical methods, this approach does not have a wide baseline requirement. On the receiver side, only a simple optical receiver (amplified photo diode), moderate processing capabilities, and little memory are needed. That is, only marginal changes to the Smart Dust prototype developed at UC Berkeley are required.
We presented a prototype implementation of the system, a set of initial measurements, and a first analysis of several aspects of the system. Currently we are working on better support for node mobility and MMSE-based calibration. We are also currently analysing the system in more detail.
We plan to build a second revision of the base station prototype based on deflectable MEMS mirrors, which is expected to feature much improved accuracy, size, and power consumption.
Future work also includes an analysis of how a real Smart Dust implementation influences the quality of the location estimates. This includes factors like reduced clock resolution, increased clock skew, and the approximations mentioned in Section 4.5.3.