System and method for directionally classifying radio signals
First Claim
1. A system for directionally classifying of a radio signal originating from an emitter, said system comprising:
- a receiving station including;
a switch, including at least two input ports and at least one output port, said switch alternately coupling each of said at least two input ports with said output port;
an antenna, coupled with a respective one of said at least two input ports, receiving at least a radio signal originating from said emitter and producing a first electric received signal;
at least a second antenna, coupled with a respective another one of said at least two input ports, receiving at least said radio signal originating from said emitter and producing a second electric received signal; and
a single channel receiver, coupled with said output port of said switch, performing reception operations on said first electric received signal and on said second electric received signal and producing a first and a second received signals respectively;
at least one other receiving station including;
at least a first other antenna, receiving respective said radio signal originating from said emitter and producing another electric received signal; and
another receiver, coupled with said at least first other antenna, performing reception operations on said another electric signal produced by said first other antenna and producing another received signal, said another receiver being asynchronous with said single channel receiver; and
a directional classifier, including a phase difference detector, coupled with said single channel receiver and with said another receiver, said phase difference detector measuring a plurality of first phase differences between said first received signal and said another received signal when said switch couples said antenna with said single channel receiver, producing a first phase difference measurement curve, said phase difference detector further measuring a plurality of second phase differences between said second received signal and said another received signal when said switch couples said second antenna with said single channel receiver, producing a second phase difference measurement curve, said directional classifier subtracting said second phase difference measurement curve from said first phase difference measurement curve producing a phase difference estimate between said first electric received signal and said second electric received signal, thereby alleviating errors in the phase difference measurements, said errors being caused by error factors, said error factors including at least one of clock drift, phase ambiguity, and Doppler shift.
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Accused Products
Abstract
A system for directionally classifying of a radio signal originating from an emitter. The system includes a receiving-station, which includes at least two antennas, a single-channel-receiver producing a first and a second received signals and a switch alternately coupling each of the antennas with the single-channel-receiver. The system further includes another receiving-station which includes another receiver, producing another received signal, coupled with a first other antenna. The system further includes directional-classifier which includes a phase-difference-detector, coupled with the single-channel-receiver and with said another receiver. The phase-difference-detector produces a first phase difference measurement when the switch couples one antenna with the single-channel-receiver. The phase-difference-detector further produces a second phase-difference-measurement when the switch couples the other antenna with the single-channel-receiver. The directional classifier subtracts the second phase-difference-measurement from the first-phase-difference measurement producing a phase-difference-estimate. The receiving station and the other receiving station are in relative motion one with respect to the other.
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Citations
12 Claims
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1. A system for directionally classifying of a radio signal originating from an emitter, said system comprising:
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a receiving station including; a switch, including at least two input ports and at least one output port, said switch alternately coupling each of said at least two input ports with said output port; an antenna, coupled with a respective one of said at least two input ports, receiving at least a radio signal originating from said emitter and producing a first electric received signal; at least a second antenna, coupled with a respective another one of said at least two input ports, receiving at least said radio signal originating from said emitter and producing a second electric received signal; and a single channel receiver, coupled with said output port of said switch, performing reception operations on said first electric received signal and on said second electric received signal and producing a first and a second received signals respectively; at least one other receiving station including; at least a first other antenna, receiving respective said radio signal originating from said emitter and producing another electric received signal; and another receiver, coupled with said at least first other antenna, performing reception operations on said another electric signal produced by said first other antenna and producing another received signal, said another receiver being asynchronous with said single channel receiver; and a directional classifier, including a phase difference detector, coupled with said single channel receiver and with said another receiver, said phase difference detector measuring a plurality of first phase differences between said first received signal and said another received signal when said switch couples said antenna with said single channel receiver, producing a first phase difference measurement curve, said phase difference detector further measuring a plurality of second phase differences between said second received signal and said another received signal when said switch couples said second antenna with said single channel receiver, producing a second phase difference measurement curve, said directional classifier subtracting said second phase difference measurement curve from said first phase difference measurement curve producing a phase difference estimate between said first electric received signal and said second electric received signal, thereby alleviating errors in the phase difference measurements, said errors being caused by error factors, said error factors including at least one of clock drift, phase ambiguity, and Doppler shift. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for directionally classifying of a radio signal originating from an emitter, said method comprising the procedures of:
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coupling a first antenna with a single channel receiver; measuring a plurality of first phase differences between a received signal from said first antenna and a received signal from a reference antenna and producing a first phase difference measurement curve; coupling a second antenna with said single channel receiver; measuring a plurality of second phase differences between a received signal from said second antenna and a received signal from said reference antenna and producing a second phase difference measurement curve; subtracting said second phase difference measurement curve from said first phase difference measurement curve to produce a phase difference estimate between said received signal from said first antenna and said received signal from said second antenna thereby alleviating errors in the phase difference measurements, said errors being caused by error factors, said error factors including at least one of clock drift, phase ambiguity, and Doppler shifts; and directionally classifying said emitter according to said phase difference estimate.
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Specification