System and Related Circuits and Methods for Detecting and Locating Cellular Telephone Use Within a Geographical Area or Facility
First Claim
1. A system for locating a communication device, comprising:
- a plurality of receiver devices at respective locations within a region, wherein;
in a first operating mode, the receiver devices are configured to scan a frequency band to search for a signal of interest within the region, at least some of the receiver devices being configured to switch to a second operating mode in response to at least one of the receiver devices detecting the signal of interest at a frequency within the frequency band; and
in the second operating mode, the at least some of the receiver devices are configured to tune to the frequency of the signal of interest detected in the first operating mode to measure signal levels at the respective locations within the region; and
a processor in communication with the receiver devices and configured to determine a location of a communication device emitting the signal of interest from the signal levels measured by the at least some of the receiver devices in the second operating mode.
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Accused Products
Abstract
A system for detecting and locating illicit cellular telephone use within a facility includes an array of radio frequency (RF) receivers, each receiver being placed in a predetermined location in the facility, and a central server, the receivers being in electrical communication with the central server. The server commands a group or groups of receivers to tune to a frequency of interest and to perform detailed sample rate measurements of the RF signal level received at the receivers. The array of receivers is organized into a plurality of measurement areas covering widely separated areas of the facility or different buildings of the facility, and the plurality of receivers of a measurement area is organized into a plurality of measurement groups covering areas of approximately uniform RF propagation conditions. Each receiver scans a frequency band of interest non-synchronously and independently of the other receivers in the array. Also, each receiver is preferably a direct-conversion receiver.
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Citations
17 Claims
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1. A system for locating a communication device, comprising:
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a plurality of receiver devices at respective locations within a region, wherein; in a first operating mode, the receiver devices are configured to scan a frequency band to search for a signal of interest within the region, at least some of the receiver devices being configured to switch to a second operating mode in response to at least one of the receiver devices detecting the signal of interest at a frequency within the frequency band; and in the second operating mode, the at least some of the receiver devices are configured to tune to the frequency of the signal of interest detected in the first operating mode to measure signal levels at the respective locations within the region; and a processor in communication with the receiver devices and configured to determine a location of a communication device emitting the signal of interest from the signal levels measured by the at least some of the receiver devices in the second operating mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for locating a communication device, the method comprising:
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scanning a frequency band with a plurality of receivers located at respective locations in a region to search for a signal of interest emitted by a communication device within the region; identifying a frequency of a signal of interest detected by at least one of the receivers; tuning at least some of receivers to the frequency of the detected signal of interest; measuring signal levels at the at least some of the receivers tuned to the frequency of the detected signal of interest; and determining via a processor a location of the communication device emitting the signal of interest from the signal levels measured at the at least some of the receivers. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification