Patent ID: 8295955

Claim:
A location estimation system for estimating a location of a self-propelled object, the system comprising: a first guidance device comprising: a first modulator; a first light source coupled to the first modulator, wherein the first modulator is configured to modulate light of the first light source using a first modulation; wherein the first light source is configured to project modulated light, whereby a first spot is projected onto a first surface when the first light source is positioned for operation with the self-propelled object; a second guidance device comprising: a second modulator; a second light source coupled to the second modulator, wherein the second modulator is configured to modulate light of the second light source using a second modulation, the second modulation distinct from the first modulation; wherein the second light source is configured to project modulated light, whereby a second spot is projected onto a second surface when the second light source is positioned for operation with the self-propelled object; a first detector configured to: detect the first light spot based at least in part on the first modulation; detect the second light spot based at least in part on the second modulation; a data processing unit configured to: determine that the self-propelled object is in a first room at least partly in response to detecting the first light spot; determine a first location of the self-propelled object based at least in part on the first light spot; determine that the self-propelled object is in a second room at least partly in response to detecting the second light spot; and determine a second location of the self-propelled object based at least in part on the second light spot.