Simultaneous nulling in the sum and difference patterns of a monopulse radar antenna
First Claim
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1. In a monopulse radar system having:
- a phased array antenna, said phased array antenna comprising a multiplicity of equally spaced antenna elements, a sum channel means and a difference channel means connected to receive radar signals from said antenna and transmit sum and difference signals to radar receiver means, and computer means, said computer means generating interference source direction data θ
m from received radar signals;
the improvement residing in nulling means for effecting, simultaneous nulling in antenna sum and difference patterns, said nulling means comprisingan adaptive weight, wn, associated with each antenna element, each said adaptive weight being represented by wn =1+α
n +jβ
n, andmeans for setting each said adaptive weight, wn, in response to data developed by said computer, said computer developing weight settings in accordance with the functions
space="preserve" listing-type="equation">α
.sub.n =Re[A.sup.+ (AA.sup.+).sup.-1 B]
space="preserve" listing-type="equation">β
.sub.n =Im[A.sup.+ (AA.sup.+).sup.-1 B]wherein ##EQU39## N=number of elements n=elements number from 1 to Nan =sum amplitude weightbn =difference amplitude weightk=propagation constant=2π
/λ
λ
=wavelengthdn =n-(N+1)/2M=number of jammersm=jammer number from 1 to Mum =sin θ
m,θ
m =direction of mth jammer relative to boresight,us =sin θ
s, andθ
s =direction of desired signal relative to boresight.
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Abstract
A monopulse radar having a single set of adaptive weights shared by both sum and difference channels. The radar utilizes algorithm that effect simultaneous nulling in the sum and difference patterns of its phased array antenna. Algorithms are developed for both amplitude and phase nulling and for phase only nulling.
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Citations
2 Claims
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1. In a monopulse radar system having:
- a phased array antenna, said phased array antenna comprising a multiplicity of equally spaced antenna elements, a sum channel means and a difference channel means connected to receive radar signals from said antenna and transmit sum and difference signals to radar receiver means, and computer means, said computer means generating interference source direction data θ
m from received radar signals;
the improvement residing in nulling means for effecting, simultaneous nulling in antenna sum and difference patterns, said nulling means comprisingan adaptive weight, wn, associated with each antenna element, each said adaptive weight being represented by wn =1+α
n +jβ
n, andmeans for setting each said adaptive weight, wn, in response to data developed by said computer, said computer developing weight settings in accordance with the functions
space="preserve" listing-type="equation">α
.sub.n =Re[A.sup.+ (AA.sup.+).sup.-1 B]
space="preserve" listing-type="equation">β
.sub.n =Im[A.sup.+ (AA.sup.+).sup.-1 B]wherein ##EQU39## N=number of elements n=elements number from 1 to N an =sum amplitude weight bn =difference amplitude weight k=propagation constant=2π
/λλ
=wavelengthdn =n-(N+1)/2 M=number of jammers m=jammer number from 1 to M um =sin θ
m,θ
m =direction of mth jammer relative to boresight,us =sin θ
s, andθ
s =direction of desired signal relative to boresight.
- a phased array antenna, said phased array antenna comprising a multiplicity of equally spaced antenna elements, a sum channel means and a difference channel means connected to receive radar signals from said antenna and transmit sum and difference signals to radar receiver means, and computer means, said computer means generating interference source direction data θ
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2. In a monopulse radar system having:
- a phased array antenna, said phased array antenna comprising a multiplicity of equally spaced antenna elements, sum channel means and difference channel means connected to receive radar signals from said antenna and transmit sum and difference signals to radar receiver means, and computer means, said computer means generating interference source direction data θ
m from received radar signals;
the improvement residing in nulling means for effecting simultaneous nulling in antenna sum and difference patterns said nulling means comprising;an adaptive weight, wn having amplitude and phase components associated with each antenna element; and means for setting the phase component θ
n of said adaptive weight, wn in response to data developed by said computer, said computer developing weight settings in accordance with the function ##EQU40## wherein M=number of jammersm=Jammer number from 1 to M cm are elements of the matrix C matrix C=(AAT)-B an =sum amplitude weight dn =n-(N+1)/2 N=number of elements bn =difference amplitude weight, um =sin θ
mθ
m =direction of mth jammer relative to boresightus =sin θ
s, andθ
s =direction of desired signal relative to boresight.
- a phased array antenna, said phased array antenna comprising a multiplicity of equally spaced antenna elements, sum channel means and difference channel means connected to receive radar signals from said antenna and transmit sum and difference signals to radar receiver means, and computer means, said computer means generating interference source direction data θ
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Current AssigneeUnited States Of America As Represented By The Secretary Of The Air Force
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Original AssigneeUnited States Of America As Represented By The Secretary Of The Air Force
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InventorsHaupt, Randy L.
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Primary Examiner(s)Blum, Theodore M.
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Assistant Examiner(s)Barron, Jr., Gilberto
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Application NumberUS06/498,334Time in Patent Office915 DaysField of Search343/16 M, 343/18 E, 343/379, 343/380, 343/381, 343/382, 343/383, 343/384US Class Current342/81CPC Class CodesG01S 13/4409 HF sub-systems particularly...G01S 7/2813 Means providing a modificat...H01Q 25/02 providing sum and differenc...H01Q 3/2617 Array of identical elements
