As mentioned in Section 2, communication between a node and the base station requires an uninterrupted line-of-sight (LOS) even for ``plain'' Smart Dust (i.e., without using the Lighthouse Location System). Hence, the presented location system does not introduce additional restriction with respect to LOS.
Temporary LOS obstructions can cause wrong position estimates if a dust node misses one of the laser beams. However, the probability of such errors can be reduced by comparing two or more consecutive positions estimates and rejecting them if they differ by more than a small threshold. Reflected laser beams are typically not detected by the receiver hardware, since diffuse reflection reduces the laser light intensity drastically.
Note that other localization systems based on ultrasound and radio waves provide location estimates even in the case of an obstructed line-of-sight. However, the resulting location estimates are typically wrong due to relying on signals reflected around the obstruction. Often it is difficult to detect such situations [14], which may result in using wrong location estimates unnoticed.