Article tracking system
AssigneeRF Technologies, Inc.
InventorJay Werb
Life of this patent
Estimating the term…
Abstract
System for tracking mobile tags. Cell controllers with multiple antenna modules generate a carrier signal which is received by the tags. Tags shift the frequency of the carrier signal, modulate an identification code onto it, and transmit the resulting tag signal at randomized intervals. The antennas receive and process the response, and determine the presence of the tags by proximity and triangulation. Distance of a tag from an antenna is calculated by measuring the round trip signal time. The cell controllers send data from the antenna to a host computer. The host computer collects the data and resolves them into positional estimates. Data are archived in a data warehouse, such as an SQL Server.
Claims71
A tag comprising:
- a receiver for receiving a first signal in a first frequency range;
- a discriminator that operates on the first signal to provide a second signal that can be discriminated from the first signal;
- a digital logic device that generates tag-specific data;
- a modulator that modulates the tag-specific data onto the second signal to generate a tag signal;
- a transmitter that transmits the tag signal;
- and
- an enabling device that periodically enables the tag to receive the first signal and transmit the second signal at times that are independent of the first signal.
A method for providing a tag signal, comprising acts of:
- receiving at a tag a first signal;
- operating with the tag on the first signal to provide a second signal that can be discriminated from the first signal;
- generating with the tag, tag-specific data;
- modulating with the tag, the tag-specific data onto the second signal to generate a tag signal;
- transmitting with the tag, the tag signal;
- and
- periodically enabling the tag to receive and transmit at times independent of any received first signal.
A method for detecting a tag, comprising acts of:
- receiving at a tag a first signal;
- operating with the tag on the first signal to provide a second signal that can be discriminated from the first signal;
- generating with the tag, tag-specific data;
- modulating with the tag, the tag-specific data onto the second signal to generate a tag signal;
- transmitting with the tag, the tag signal;
- receiving the tag signal with a tag reader;
- detecting a presence of the tag based on receipt of the tag signal at the tag reader;
- and
- wherein the tag is periodically enabled to receive and transmit at times independent of any received first signal.
Dependencies are inferred from the claim text.