Patent ID: 8583400

Claim:
A method of determining a location of a portable handheld device in an indoor space: identifying a map of an indoor space, the map being based on a plurality of constraints; generating, by a processor, a first set of particles, each particle of the first set of particles representing a location on the map and being associated with a likelihood value; receiving data from an orientation device including a gyroscope; determining a direction and speed of movement based on the received data; applying the direction and speed of movement to each one of the first set of particles; adjusting, by the processor the likelihood value of each particular particle of the first set of particles, based on whether the particular particle violated one or more of the plurality of constraints; generating a second set of particles based on the likelihood values associated with the first set of particles; selecting, by the processor a particular particle of the second set of particles closest to an average representative location of the second set of particles when all of the particles of the second set of particles are within a threshold radius of one another; and identifying, by the processor an actual location of the portable handheld device in the indoor space based on a representative location of the selected particle.