Cellular phone geolocation system
First Claim
1. A system for geolocating a cellular phone, said system comprising:
- a base station having a processor;
a plurality of dispersed transmitters for transmitting respective beacon signals from respective known locations, wherein each said beacon signal has an identifying characteristic for said respective transmitter;
a receive channel incorporated into said cellular phone, with said receive channel being activated to receive phase information from said beacon signals whenever said cellular phone dials a predetermined number; and
a means for passing said identifying characteristic and said phase information for each said beacon signal to said base station for use by said processor in determining the geolocation of said cellular phone.
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Accused Products
Abstract
A geolocation system for locating a cellular phone in a service area includes an auxiliary receive channel incorporated into the cellular phone. A plurality of transmitters are mutually dispersed at known locations to transmit low frequency beacon signals into the service area. Each beacon signal includes an identifying characteristic that can be used to identify the particular transmitter the signal emanated from. The low frequency of the signal prevents urban features within the service area from acting as signal waveguides and altering the path of the signal. When the user dials a predetermined number such as “911”, the auxiliary receive channel is activated to receive the transmission signals and extract phase related information and the identifying characteristic from each signal. The extracted information is then transmitted to a base station using the cellular phone'"'"'s normal communication link where the information is processed to determine the location of the cellular phone.
27 Citations
20 Claims
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1. A system for geolocating a cellular phone, said system comprising:
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a base station having a processor;
a plurality of dispersed transmitters for transmitting respective beacon signals from respective known locations, wherein each said beacon signal has an identifying characteristic for said respective transmitter;
a receive channel incorporated into said cellular phone, with said receive channel being activated to receive phase information from said beacon signals whenever said cellular phone dials a predetermined number; and
a means for passing said identifying characteristic and said phase information for each said beacon signal to said base station for use by said processor in determining the geolocation of said cellular phone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for geolocating a cellular phone in an urban area, said system comprising:
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a plurality of dispersed transmitters for transmitting respective beacon signals into the urban area from respective known locations, wherein each said beacon signal has an identifying characteristic for said respective transmitter and each said beacon signal has a wavelength longer than 150 meters to allow each said beacon signal to penetrate structures in the urban area;
a means coupled with the cellular phone for receiving said beacon signals and extracting phase information and said identifying characteristics from each said beacon signal; and
a means for using said phase information and said identifying characteristics to geolocate the cellular phone. - View Dependent Claims (13, 14, 15, 16)
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17. A method for geolocating a cellular phone within a service area, said method comprising the steps of:
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transmitting beacon signals into the service area from a plurality of dispersed predetermined locations, each beacon signal having a different identifying characteristic;
receiving said beacon signals at the cellular phone;
extracting phase information and said identifying characteristic from said beacon signals; and
using said phase information and said identifying characteristic to determine the position of said cellular phone. - View Dependent Claims (18, 19, 20)
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Specification