Patent ID: 7289466

Claim:
A method of determining the location of a wireless device, the method comprising: generating a first beacon from a first anchor node having a known location, the first beacon including a series of data packets, at least a first packet of the first beacon including an indication of the source and the direction of the first beacon at the time the first data packet is generated; generating a second beacon from a second anchor node having a known location, the second beacon including a series of data packets, at least a second packet of the second beacon including an indication of the source and the direction of the second beacon at the time the second data packet is generated; capturing the first data packet and the second data packet with the wireless device; and estimating the position of the wireless device with respect to the first and second anchor nodes; wherein the first and second beacons are spatially narrow beacons; and wherein the step of capturing the first data packet and the second data packet includes the following: capturing a third data packet also generated by the first anchor node and including an indication of the source and direction of first beacon at the time the third data packet is generated; observing the signal strength of the first beacon at the time of receipt of the first data packet and the third data packet; and selecting the first data packet or the third data packet for use in the estimating step.