| 摘要 |
Determination of the location and bearing of an asset having an RF-tag imbedded therein is accomplished through extended radio frequency triangulation. A beacon arrangement determines the direction of an RF tag from a specially designed beacon node. RF-tag localization is further improved by repeating this measurement from multiple spatially displaced beacon nodes. The beacon nodes are equipped with multiple strategically located antennas and transmit frames with each symbol cyclically switched to a different antenna. The symbols traveling different distances result in phase shifts within the frame received by the RF-tag. From the phase shifts and the known arrangements of the antennas the angle at which the RF-tag is RF visible from the specific beacon node can be estimated. Determination of the signal phase shifts are part of the baseband processing hardware, the rest of the location determination procedure may be realized in software.
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