Wireless geolocation system
First Claim
1. A wireless system for determining the location of a signal emitter which comprises:
- at least three mutually dispersed base station sites, each said base station site having at least one antenna for receiving said emitter signal, and each said base station site having an electronic extractor for separating a cyclostationary feature having a phase delay characteristic from said emitter signal; and
a central processing site, said central processing site being connected in electronic communication with each said base station site for receiving respective said cyclostationary features therefrom, and said central processing site having a processor for converting said phase delay characteristic of said cyclostationary feature into differential range estimates for determining the location of the signal emitter.
2 Assignments
0 Petitions
Accused Products
Abstract
A wireless system for locating a signal emitter includes at least three base stations for receiving the emitter signal, and a central processing site for converting information from the received signals into range estimates. Specifically, an antenna array at each base station for receives the emitter signal, and a beamformer isolates the direct path component of this received signal from interference and multi-path signals using cyclic phase minimizer techniques. In operation, an extractor is used to separate a cyclostationary feature from the direct path component of the emitter signal, and the cyclostationary feature is identified in an absolute time reference. The identified cyclostationary feature is then passed to the central processing site. At the central processing site, phase delay characteristics of the cyclostationary features from all participating base stations are compared with each other to obtain phase difference measurements. These phase difference measurements are then converted into differential range estimates for locating the emitter.
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Citations
20 Claims
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1. A wireless system for determining the location of a signal emitter which comprises:
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at least three mutually dispersed base station sites, each said base station site having at least one antenna for receiving said emitter signal, and each said base station site having an electronic extractor for separating a cyclostationary feature having a phase delay characteristic from said emitter signal; and a central processing site, said central processing site being connected in electronic communication with each said base station site for receiving respective said cyclostationary features therefrom, and said central processing site having a processor for converting said phase delay characteristic of said cyclostationary feature into differential range estimates for determining the location of the signal emitter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for locating a signal emitter which comprises the steps of:
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receiving said emitter signal at three mutually dispersed base stations; extracting a common cyclostationary feature having a phase delay characteristic from the emitter signal at each said base station; transmitting said extracted cyclostationary features and respective said phase delay characteristics from each of said base stations to a central processing site; and converting said phase delay characteristics of said cyclostationary features into differential range estimates at said central processing site for locating the signal emitter. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for identifying the direct path component of a radiated signal for use in determining the location of the signal source which comprises the steps of:
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identifying a phase delay characteristic of a cyclostationary feature of said signal; varying the power of said phase delay characteristic; monitoring said phase delay characteristic; determining a power range wherein relatively large changes in power of said phase delay characteristic result in relatively small changes in said phase delay characteristic; and using said phase delay characteristic in said range for determining the location of the signal source. - View Dependent Claims (17, 18, 19, 20)
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Specification