Patent ID: 7155239
Filing Date: 2006-12-26
Classification: G01S,Y10S

Abstract:
1. A method for determining a location estimation of a wireless device in a wireless location system having a plurality of reference devices, the method comprising: receiving signals from one or more of the plurality of reference devices at the wireless device; forming a first set comprising a plurality of elements, each element of the plurality of elements comprising a signal strength measurements of signals received at the wireless device from each of the plurality of reference devices from which the wireless device receives signals and an indicator of no signal strength measured for each of the plurality of reference devices from which the wireless device does not receive signals; forming a scan subset comprising each of the plurality of reference devices in the first set that has an associated signal strength measurement; forming a cluster set comprising calibration points selected from a plurality of calibration points based on the scan subset, wherein the plurality of calibration points comprise a set of received signal strength measurements from signals received at the calibration points from each of the plurality of reference devices; and calculating a calculated distance between the first set and each of the calibration points in the cluster set, when the cluster set has at least one element; calculating the calculated distance between the first set and each of the plurality of calibration points, when the cluster set has no elements; and selecting the calibration point having the smallest calculated distances as the location estimation.