System and method for distributed signal compression for cooperative geolocation
First Claim
1. A method for geolocating a signal source, comprising:
- using a first receiver to receive a signal being emitted by said signal source, and to time stamp said signal as a first signal;
using a second receiver to receive said signal and to time stamp said signal as a second signal;
modifying said second signal using frequency companding to form a reduced bandwidth second signal;
supplying said first signal and said reduced bandwidth second signal to a processing subsystem remote from said first and second receivers;
using said processing subsystem to analyze said time stamp for said reduced bandwidth second signal and said time stamp for said first signal, and correlating said reduced bandwidth second signal and said first signal, to determine a time difference of arrival of said reduced bandwidth second signal relative to said first signal; and
using said time difference of arrival to geolocate said signal source.
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Accused Products
Abstract
A cooperative geolocation system and method. The system and method involves time stamping a plurality of received signals and modifying, such as compressing, one or more of the received signals, either with the same or with different rates of compression. A processing subsystem including a geolocation processor is used to correlate various pairs of received signals and to extract time difference of arrival (TDOA) or frequency difference of arrival (FDOA) information and to use this information in cooperatively geolocating the signal source emitting the signals being analyzed. The system enables greater rates of data compression, and thus frees up bandwidth in a network in which it is employed, as compared with previously existing cooperative geolocation systems. The present system further can perform the cooperative geolocation determination without first decompressing the compressed signals, but rather performing a correlation process directly on designated pairs of signals to extract the needed TDOA/FDOA information.
10 Citations
21 Claims
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1. A method for geolocating a signal source, comprising:
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using a first receiver to receive a signal being emitted by said signal source, and to time stamp said signal as a first signal; using a second receiver to receive said signal and to time stamp said signal as a second signal; modifying said second signal using frequency companding to form a reduced bandwidth second signal; supplying said first signal and said reduced bandwidth second signal to a processing subsystem remote from said first and second receivers; using said processing subsystem to analyze said time stamp for said reduced bandwidth second signal and said time stamp for said first signal, and correlating said reduced bandwidth second signal and said first signal, to determine a time difference of arrival of said reduced bandwidth second signal relative to said first signal; and using said time difference of arrival to geolocate said signal source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for determining a time difference of arrival (TDOA) of a signal being emitted by a signal source, and being received by a plurality of receivers, the method comprising:
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using a first receiver to receive said signal being emitted by said signal source, and to time stamp said signal as a first signal; using a second receiver to receive said signal and to time stamp said signal as a second signal; modifying said second signal using frequency companding to form a reduced bandwidth second signal; using said time stamp for said second signal and said time stamp for said first signal, and correlating said second signal and said first signal, to determine a time difference of arrival of said second signal relative to said first signal, without the need to further modify said second signal; using a third receiver to receive said signal and to time stamp said signal as a third signal; modifying said third signal to produce a modified third signal having a reduced bandwidth; using said time stamp for said modified third signal and said time stamp for said first signal to determine a time difference of arrival for said modified third signal relative to said first signal; and where the second reduced bandwidth signal and said modified third signal include different levels of bandwidth reduction from one another and that also differ from said first signal in bandwidth. - View Dependent Claims (11, 12, 13, 15, 16)
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14. (canceled)
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17. A geolocation system for geolocating a signal source that is emitting a signal, the system comprising:
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a first subsystem for receiving said signal being emitted by said signal source, and time stamping said signal as a first signal, and transmitting said first signal with said time stamp; a second subsystem that receives said signal, time stamps said signal as a second signal, modifies said second signal using frequency companding to produce a reduced bandwidth second signal, and transmits said reduced bandwidth second signal; a processing system for receiving said first signal and said compressed second signal, correlating said second signal and said first signal, and using said time stamps associated with said first and second signals to geolocate said signal without requiring further modification to said second signal. - View Dependent Claims (18, 19, 20, 21)
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Specification