Asset tracking with error adaptive boundary
First Claim
1. A method of tracking assets from central stations using tracking devices enabled to receive site identities broadcast from transmitters at fixed locations within a wireless network, and enabled to wirelessly communicate position reports to the central stations, the method comprising the steps of:
- attaching a tracking device to an asset, and placing said asset into service within the wireless network;
tracking the location of said asset by periodically communicating position reports containing current site identities from said tracking device to a central station;
upon receipt at said central station of a first position report containing a first site identity, comparing said first site identity with a default list of site identities corresponding to said tracking device;
disregarding said first position report and continuing said tracking step if said first site identity is found within said default list;
storing said first site identity if said first site identity is not found within said default list;
upon receipt at said central station of a subsequent position report containing a second site identity, comparing said second site identity with said default list;
adding said first site identity to said default list and continuing said tracking step if said second site identity is found on said default list, and producing an alert signal if said second site identity is not found on said default list.
4 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods for tracking assets from central stations using tracking devices enabled to receive GPS coordinates or site identities broadcast from transmitters at fixed locations within a wireless network. Plural position fixes are taken over time and forwarded to the central station. The position fixes are compared to establish a likelihood that apparent excursions from a predetermined boundary area are valid or not, prior to generating an alert signal that the asset has moved from the boundary area.
73 Citations
35 Claims
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1. A method of tracking assets from central stations using tracking devices enabled to receive site identities broadcast from transmitters at fixed locations within a wireless network, and enabled to wirelessly communicate position reports to the central stations, the method comprising the steps of:
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attaching a tracking device to an asset, and placing said asset into service within the wireless network; tracking the location of said asset by periodically communicating position reports containing current site identities from said tracking device to a central station; upon receipt at said central station of a first position report containing a first site identity, comparing said first site identity with a default list of site identities corresponding to said tracking device; disregarding said first position report and continuing said tracking step if said first site identity is found within said default list; storing said first site identity if said first site identity is not found within said default list; upon receipt at said central station of a subsequent position report containing a second site identity, comparing said second site identity with said default list; adding said first site identity to said default list and continuing said tracking step if said second site identity is found on said default list, and producing an alert signal if said second site identity is not found on said default list. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for tracking assets by utilizing site identities broadcast from transmitters at fixed locations within a wireless network, comprising:
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a central station coupled to a communications network; a tracking device, for attaching to an asset, operable to receive the site identities broadcast from transmitters at fixed locations within the wireless network, and operable to wirelessly communicate position reports to said central station through said communications network, and wherein said central station is operable to track the location of said tracking device by periodically receiving position reports containing current site identities from said tracking device, and wherein said central station is operable to, upon receipt of a first position report containing a first site identity, compare said first site identity with a default list of site identities corresponding to said tracking device, and wherein said central station is operable to disregard said first position report and continue tracking said tracking device if said first site identity is found within said default list, and wherein said central station is operable to store said first site identity if said first site identity is not found within said default list, and wherein said central station is operable to, upon receipt of a subsequent position report containing a second site identity, compare said second site identity with said default list, and wherein said central station is operable to add said first site identity to said default list and continue tracking said tracking device if said second site identity is found on said default list, and wherein said central station is operable to produce an alert signal if said second site identity is not found on said default list. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of tracking assets to detect valid geofence boundary excursions from central stations using tracking devices enabled to produce present location geographic fixes, and enabled to wirelessly communicate position reports to the central stations, the method comprising the steps of:
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attaching a tracking device to an asset, and placing said asset into service within the boundary of the geofence; tracking the location of said asset by periodically communicating position reports containing present geographic fixes from said tracking device to a central station, and repeatedly updating a buffer for storing a previous position fix and a penultimate position fix; receiving a present position report having a present position fix, and updating said buffer; determining if said present position fix is an excursion from the geofence boundary; continuing said tracking step if said present position fix is not an excursion; if said present position fix is an excursion, then calculating a first vector angle between said penultimate fix and said previous fix, and calculating a second vector angle between said previous position fix and said present position fix, and calculating a differential angle between said first vector angle and said second vector angle; comparing said differential angle with a threshold angle; continuing said tracking step if said differential angle is greater than said threshold angle, and producing an alert signal if said differential angle is less than said threshold angle. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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27. A system for tracking assets located within a geofence boundary to detect valid geofence boundary excursions, comprising:
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a central station coupled to a communications network; a tracking device, for attaching to an asset, operable to produce present location geographic fixes, and operable to wirelessly communicate position reports to said central station, and wherein said central station is operable to track the location of said asset by periodically receiving position reports containing present geographic fixes from said tracking device, and operable to repeatedly update a buffer having a previous position fix and a penultimate position fix stored therein, and wherein said central station is operable to receive a present position report having a present position fix, and operable to update said buffer upon receipt of said present position report, and wherein said central station is operable to determine if said present position fix is an excursion from the geofence boundary, and wherein said central station is operable to continue to track said tracking device if said present position fix is not an excursion, and wherein said central station is operable, if said present position fix is an excursion, to calculate a first vector angle between said penultimate fix and said previous fix, and operable to calculate a second vector angle between said previous position fix and said present position fix, and operable to calculate a differential angle between said first vector angle and said second vector angle, and wherein said central station is operable to compare said differential angle with a threshold angle, and wherein said central station is operable to continue to track said tracking device if said differential angle is greater than said threshold angle, and wherein said central station is operable to produce an alert signal if said differential angle is less than said threshold angle. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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28. The system of 27, and wherein said central station is an Internet server.
Specification