Security system including a method and system for acquiring GPS satellite position
First Claim
1. A method for acquiring GPS satellite position comprising:
- maintaining a GPS receiver in a stand-by mode;
selecting a time at which a compressed GPS data payload is to be transmitted;
setting the GPS receiver to an active state at the pre-determined time; and
returning the OPS receiver to a stand-by state after an interval having a length selected to download the compressed GPS data payload.
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Abstract
A security system and a method and apparatus utilize a transmitter and a receiver with a GPS sub-system in a GPS appliance. Ephemeris and almanac data are updated at preprogrammed times within coordinated windows of opportunity. Each GPS receiver is preferably kept in an inactive state to reduce power consumption except at the preprogrammed times and uses time-compressed formats of GPS ephemeris data. An additional receiver makes possible the use of a coordinated window of opportunity whereby the receiver is set to an active state to receive complete ephemeris data sets when transmitted. The security system monitors conditions. Security sensors may respond to a condition to “awaken” a transmitter that may then transmit a report providing the location of the appliance. The report may include manifest information such as the identity of a container to which the GPS system is affixed, the sensor reporting the breach and its location.
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Citations
15 Claims
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1. A method for acquiring GPS satellite position comprising:
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maintaining a GPS receiver in a stand-by mode; selecting a time at which a compressed GPS data payload is to be transmitted; setting the GPS receiver to an active state at the pre-determined time; and returning the OPS receiver to a stand-by state after an interval having a length selected to download the compressed GPS data payload. - View Dependent Claims (2)
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3. A GPS appliance comprising a GPS receiver having a control to set said receiver to an active state or a stand-by state;
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a timer coupled to said control; said control normally providing a signal to set said GPS receiver to the stand-by state, said timer being set to activate said control to set said GPS to an active state at a time corresponding to time transmission of compressed GPS data payload by a selected satellite constellation. - View Dependent Claims (4, 5)
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- 6. A GPS Appliance comprising a GPS receiver, a transmitter, at least one condition-responsive sensor, a register for providing information to be transmitted in response to sensing of a condition by said condition responsive sensor, a timer to set said GPS receiver to an active state at a time to receive a GPS receiver in response to receipt of a GPS data payload, the threshold circuit to activate said transmitter in response to occurrence of a condition sensed by a sensor, said transmitter including means for transmitting position information and information from said information register.
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14. A GPS appliance comprising a GPS receiver having a control to set said receiver to an active state or a stand-by state;
- and a timer coupled to said control;
said control normally providing a signal to set said GPS receiver to the stand-by state, said timer being set to activate said control to set said GPS to an active state at a time corresponding to time transmission of compressed GPS data payload by a selected satellite constellation; and further comprising access control via user authentication, said access control comprising a storage location to store programmed authorization identification and a processor to determine entry of an authorized code. - View Dependent Claims (15)
- and a timer coupled to said control;
Specification