Patent ID: 9709663
Date: 2017-07-18
CPC Classifications: G01S,H04W

Claim:
1. A method for determining the location of a tag object in an unknown location using radio signals comprising the steps of: transmitting a first RF data packet from said tag object (T) and recording the time (t receiving said first RF data packet at a primary stationary anchor (Am) at a first known location (Xm, Ym, Zm) and recording the time (m receiving said first RF data packet at a secondary stationary anchor (As) at a second known location (Xs, Ys, Zs), a first known distance (dms) between said first known location and said second known location being known, and recording the time (s transmitting a second RF data packet from said primary stationary anchor (Am) and recording the time (m receiving said second RF data packet at said tag object (T) and recording the time (t receiving said second RF data packet at said secondary stationary anchor (As) and recording the time (s transmitting a third RF data packet from said tag object (T) and recording the time (t receiving said third RF data packet at said primary stationary anchor (Am) and recording the time (m receiving said third RF data packet at said secondary stationary anchor (As) and recording the time (s communicating the collected timing data between the primary stationary anchor (Am) and the secondary stationary anchor (As); computing a first unknown distance (dmt) between the tag object (T) and the primary stationary anchor (Am) based on the collected timing data; computing a second unknown distance (dst) between the tag object (T) and the secondary stationary anchor (As) based on the timing data, the first known distance (dms) and the first unknown distance (dmt); and computing the location (xt, yt) of the tag object (T) based on the first known distance (dms), first unknown distance (dmt) and second unknown distance (dst).