Item tracking system that switches between short-range and long-range location services
An item tracking system that uses smart tracking labels to track an item's position, and that switches between short-range tracking within a local area using short-range interfaces like Bluetooth and long-range tracking within a global or regional area using long-range interfaces like GPS. Long-range communication interfaces may be disabled when the tracking label comes within range of a short-range network such as a Bluetooth network within a warehouse. Switching to short-range services when they are available may significantly reduce the total power requirement for a tracking label. In an illustrative embodiment a tracking label may periodically broadcast an advertising message over Bluetooth; when a Bluetooth gateway in a warehouse or other local area responds to this message, the label disables long-range interfaces and switches position tracking to use short-range services. When the label loses communication with a short-range network, it re-enables the long-range interfaces.
1. An item tracking system that switches between a short-range communication interface and a long-range communication interface, comprising:
a multiplicity of tracking labels, each tracking label of said multiplicity of tracking labels comprising
a unique identifier;
a long-range wireless communication interface configured to receive navigation signals from a plurality of long-range transmitters;
a short-range wireless communication interface configured to receive localization signals from one or more short-range communication devices located in a local area;
a controller coupled to said short-range wireless communication interface and to said long-range wireless communication interface;
wherein said controller is configured to
when said short-range wireless communication interface establishes communication with said one or more short-range communication devices, disable said long-range wireless communication interface;
when said short-range wireless communication interface loses communication with said one or more short-range communication devices, enable said long-range wireless communication interface;
calculate a location of said each tracking label from either or both of said navigation signals and said localization signals at a sequence of times; and,
transmit tracking label update messages over either or both of said short-range wireless communication interface and said long-range wireless communication interface, wherein each tracking label update message of said tracking label update messages comprises said unique identifier of said each tracking label;
a time; and,
said location of said each tracking label at said time;
a database comprising a tracking history associated with each tracking label of said multiplicity of tracking labels;
a server coupled to said database, wherein said server is configured to
receive one or more tracking label update messages associated with said each tracking label; and, add contents of said each tracking label update message to said tracking history associated with said each tracking label.
2. The item tracking system of claim 1 , wherein said long-range wireless communication interface comprises one or more of a GPS receiver, a cellular communication interface, and a Wi-Fi communication interface.
3. The item tracking system of claim 1 , wherein said short-range wireless communication interface comprises one or more of a Bluetooth interface and a LoRaWAN interface.
4. The item tracking system t of claim 1 , wherein said controller is further configured to calculate said location of said each tracking label from one or more of a received signal strength indictor, an angle of arrival, and a time of flight of said localization signals or said navigation signals.
5. The item tracking system of claim 1 , wherein said one or more short-range communication devices comprise a Bluetooth gateway.
6. The item tracking system of claim 1 , wherein said one or more short-range communication devices comprise a Bluetooth beacon.
7. The item tracking system of claim 1 , wherein
said controller is further configured to repeatedly broadcast an advertising message on said short-range wireless communication interface;
when a device of said one or more short-range communication devices receives said advertising message, said device transmits a message to said controller to turn off said long-range wireless communication interface.
8. The item tracking system of claim 7 , wherein
said device of said one or more short-range communication devices is configured to repeatedly transmit a heartbeat message to said controller after said controller receives said advertising message; and,
said controller is further configured to enable said long-range wireless communication interface when said controller stops receiving said heartbeat message.
9. The item tracking system of claim 1 , wherein said each tracking label further comprises one or more sensors;
said each tracking label update message further comprises one or more sensor values captured by at least one of said one or more sensors of said each tracking label.
10. The item tracking system of claim 9 , wherein
when said short-range wireless communication interface establishes communication with said one or more short-range communication devices, said controller is further configured to modify a frequency at which said one or more sensor values are captured.
11. The item tracking system of claim 9 , wherein
when said short-range wireless communication interface establishes communication with said one or more short-range communication devices, said controller is further configured to modify a frequency at which said tracking label update messages are transmitted.
12. The item tracking system of claim 9 , wherein said one or more sensors comprise one or more of a temperature sensor;
a humidity sensor;
a light sensor;
a motion sensor;
a pressure sensor;
a shock sensor;
a sensor that measures peeling or bending;
a sensor that detects opening of a container or breaking of a seal.