Reduced-power GPS-based system for tracking multiple objects from a central location
August 25, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesDigital circuit for correcting phase shift of digital signal Digital global positioning system receiver Method and apparatus for determining the position of a vehicle Method and system for locating an unknown transmitter Vehicle location system Method and apparatus for position detection Positioning method utilizing artificial satellites in geosynchronous altitude orbits Vehicle tracking system employing global positioning system (GPS) satellites Differential data signal transmission technique GPS tracking system InventorsApplicationNo. 924478 filed on 08/25/1997US Classes:701/207, Employing position determining equipment342/357.07, Tracking or monitoring (i.e., lost or stolen vehicles)342/457, Land vehicle location (e.g., bus, police car701/213, Using Global Positioning System (GPS)701/215, Having multiple GPS antennas or receivers (e.g., differential GPS)701/300RELATIVE LOCATIONExaminersPrimary: Nguyen, Tan T.Attorney, Agent or FirmForeign Patent References
International ClassesH04B 007/185G01S 005/02 AbstractLocation of an object to be tracked is determined by measuring, at a receiver situated at the object, the propagation time differences between the signals from a plurality of GPS satellites, each of which is received by the receiver situated at the object. The measured propagation time difference values are transmitted to a central station where the location of the object to be tracked is calculated based upon the propagation time differences of the signals transmitted from the satellites and data derived from a receiver apart from the object but also receiving signals from the satellites.Field of SearchEmploying position determining equipmentUsing Global Positioning System (GPS) Means to improve accuracy of position or location Having multiple GPS antennas or receivers (e.g., differential GPS) Having an self-contained position computing means (e.g., dead reckoning) With radar or optical ground scanner RELATIVE LOCATION Synchronous satellite With satellite signal correction Position indicating (e.g., triangulation) Land vehicle location (e.g., bus, police car | |
