Patent US4617570A successfully refreshed from Google Patents.
US4617570A
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US
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Interference cancelling receiver having high angular resolution intercept of transmitted radiators
Assignee: United States Department of the Army
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Filing: 1983-08-26
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Granted: 1986-10-14
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Expires: 2003-08-26
Abstract
Abstract A swept interference canceller including a multiplexed interference cancelling receiver coupled to a scanned notch antenna and an omni-directional antenna as well as an estimator type of angular beam splitting system for accurately measuring angular bearing of a plurality of sequentially received radiating sources in a dense communication environment. A difference signal between the signals received by the two antennas is developed which is then split into a plurality of equal time samples which are then simultaneously fed into two synchronous multi-stage shift registers. The output stages of one of the shift registers operate so that they all have the same output states. The output stages of the other shift register, however, operate so that the first half have the same output state as the first shift register while the second half are of the opposite output state. The outputs from the two shift registers are summed and fed to a logic gate which operates to generate an output signal following the occurrence of the middle time sample which is a time corresponding to the position of the boresight axis of the signal received from a radiating source.
Inventors
- 👤 Frank S. Gutleber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:20
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01S3/58; G01S3/66
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
275 words
Receiver apparatus in a multiple access signal communications system including one or more transmitters, comprising in combination: first antenna means having an omnidirectional antenna beam pattern; second antenna means having a generally omnidirectional antenna pattern with a single notched portion; means for scanning said second antenna means to position said notched portion in the direction of said one or more transmitters; means, responsive to RF signals received by said first and second antenna means, for determining the center of a transmitted radiation pattern from said one or more transmitters for providing an indication of the bearing of said transmitters relative to said receiver apparatus including means for generating a difference RF signal between said RF signals received by said first and second antenna means, means responsive to said difference RF signal for providing a video signal therefrom, means for splitting said video signal into a plurality of pulse signal samples of substantially equal pulse width; and means for determining the pulse signal sample substantially at the mid-point of said plurality of signal samples which thereby indicates the direction of the said transmitted radiation including first means for storing said plurality of pulse signal samples in a predetermined signal state, second means for storing said plurality of pulse signal samples and inverting the signal state of one half of said signal samples to a state opposite from said predetermined signal state, and means for determining the occurrence of the inverted one half signal samples stored in said second means relative to the plurality of pulse signal samples stored in said first means, said occurrence providing an indication of the boresight axis of said transmitted radiation pattern.
Claim 2
Dependent Claim
275 words
Receiver apparatus in a multiple access signal communications system including one or more transmitters, comprising in combination: first antenna means having an omnidirectional antenna beam pattern; second antenna means having a generally omnidirectional antenna pattern with a single notched portion; means for scanning said second antenna means to position said notched portion in the direction of said one or more transmitters; means, responsive to RF signals received by said first and second antenna means, for determining the center of a transmitted radiation pattern from said one or more transmitters for providing an indication of the bearing of said transmitters relative to said receiver apparatus including means for generating a difference RF signal between said RF signals received by said first and second antenna means, means responsive to said difference RF signal for providing a video signal therefrom, means for splitting said video signal into a plurality of pulse signal samples of substantially equal pulse width; and means for determining the pulse signal sample substantially at the mid-point of said plurality of signal samples which thereby indicates the direction of the said transmitted radiation including first means for storing said plurality of pulse signal samples in a predetermined signal state, second means for storing said plurality of pulse signal samples and inverting the signal state of one half of said signal samples to a state opposite from said predetermined signal state, and means for determining the occurrence of the inverted one half signal samples stored in said second means relative to the plurality of pulse signal samples stored in said first means, said occurrence providing an indication of the boresight axis of said transmitted radiation pattern.
Claim 3
Dependent Claim
17 words
The combination of claim 1 wherein said notched portion comprises a relatively steep slope beam pattern null.
Claim 4
Dependent Claim
116 words
The combination of claim 1 wherein said first means for storing said plurality of pulse signal samples comprises a shift register having a plurality of stages at least equal in number to said plurality of pulse signal samples and having a respective number of output stages of the same operative state, and wherein said second means for storing said plurality of pulse samples comprises a shift register having a plurality of output stages also at least equal to the number of said pulse signal samples and having a respective number of output stages the second half of which have an operative output state opposite to the operative output stage of the first half of output stages.
Claim 5
Dependent Claim
77 words
The combination of claim 3 wherein said determining means additionally includes first signal summing means coupled to said plurality of output stages of said first means for storing, second signal summing means coupled to said output stages of said second means for storing, and logic gate coupled to said first and second summing means and being operative to output a pulse at the occurrence of the inverted one half signal samples stored in said second shift register.
Claim 6
Dependent Claim
19 words
The combination of claim 4 wherein said first and second summing means comprises first and second linear adder means.
Claim 7
Dependent Claim
27 words
The combination of claim 5 and additionally including first and second signal sampling means respectively coupled between said first and second adder means and said logic gate.
Claim 8
Dependent Claim
14 words
The combination of claim 6 wherein said logic gate comprises an inhibitor logic gate.
Claim 9
Dependent Claim
28 words
The combination of claim 7 and additionally including first and second threshold detector means respectively coupled between said first and second adder means and said inhibitor logic gate.
Claim 10
Independent Claim
238 words
A method of intercepting and determining the location of one or more radiating sources in a dense communications environment comprising the steps of: receiving signals from said radiating sources by first antenna means having an omnidirectional antenna beam pattern; receiving signals from said radiating sources by second antenna means having a generally omnidirectional antenna pattern with a single notched portion; scanning said second antenna means to position said notched portion in the direction of said one or more transmitters; and generating a difference signal between said signals received by said first and second antenna means, generating a video signal from said difference signal, splitting said video signal into a plurality of pulse signal samples of substantially equal pulse width, and determining the pulse signal sample substantially at the mid-point of said plurality of signal samples which thereby indicates the direction of the said transmitted radiation including storing said plurality of pulse signal samples in a predetermined signal state in first storage means, storing said plurality of pulse signal samples in second storage means and inverting the signal state of one half of said signal samples therein to a state opposite from said predetermined signal state and determining the occurrence of the inverted one half signal samples stored in said second means relative to the plurality of pulse signal samples stored in said first means, said occurrence providing an indication of the boresight axis of said transmitted radiation pattern.
Claim 11
Independent Claim
238 words
A method of intercepting and determining the location of one or more radiating sources in a dense communications environment comprising the steps of: receiving signals from said radiating sources by first antenna means having an omnidirectional antenna beam pattern; receiving signals from said radiating sources by second antenna means having a generally omnidirectional antenna pattern with a single notched portion; scanning said second antenna means to position said notched portion in the direction of said one or more transmitters; and generating a difference signal between said signals received by said first and second antenna means, generating a video signal from said difference signal, splitting said video signal into a plurality of pulse signal samples of substantially equal pulse width, and determining the pulse signal sample substantially at the mid-point of said plurality of signal samples which thereby indicates the direction of the said transmitted radiation including storing said plurality of pulse signal samples in a predetermined signal state in first storage means, storing said plurality of pulse signal samples in second storage means and inverting the signal state of one half of said signal samples therein to a state opposite from said predetermined signal state and determining the occurrence of the inverted one half signal samples stored in said second means relative to the plurality of pulse signal samples stored in said first means, said occurrence providing an indication of the boresight axis of said transmitted radiation pattern.
Claim 12
Dependent Claim
35 words
The method of claim 9 wherein said first and second storage means comprise first and second shift registers having a plurality of stages at least equal in number to said plurality of pulse signal samples.
Claim 13
Dependent Claim
50 words
The method of claim 9 and wherein said determining step comprises sampling and summing the pulse signal samples stored in said first and second storage means, and generating an output pulse at the occurrence of the first of said inverted one half signal samples stored in said second storage means.
Claim 14
Dependent Claim
26 words
The method of claim 11 wherein said determining step additionally includes the step of threshold detecting the summed signal samples prior to generating said output pulse.
Claim 15
Dependent Claim
31 words
The method of claim 12 wherein said output pulse generating step comprises generating said output pulse with an inhibitor logic gate which is responsive to the threshold detected summed signal samples.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-13 | 1990-04-14 | 1990-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-13 | 1994-04-14 | 1994-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-13 | 1998-04-14 | 1998-10-14 | $7700.00 | Window Closed / Lapsed |