Patent US3590829A successfully refreshed from Google Patents.
Patent US5063529A successfully refreshed from Google Patents.
US5063529A
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Method for calibrating a phased array antenna
Assignee: Raytheon Co
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Filing: 1989-12-29
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Granted: 1991-11-05
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Expires: 2009-12-29
Abstract
Abstract A calibration method for a phased array antenna uses automated signal processing techniques to compute calibration coefficients, and can be performed while the antenna is on-line. The calibration method is based on a generalized model in which the array is characterized by a phase-state control function. The calibration coefficients for a phase shift element are computed using phase response measurements derived from an estimation of the residual aperture response attributable to the other elements. For each element of the array, a first set of I Q aperture response measurements is used to estimate (FIG. 1a, 10) the R I and R Q residual components of the total I Q aperture response attributable to the other elements. Using these residual components, a second set Y of I Q aperture response measurements is converted (FIG. 1b, 20) to measurements of the phase response attributable to the selected element. From these phase response measurements, the calibration coefficients φ i can be computed (FIG. 1c, 30) using the phase-state control function.
Inventors
- 👤 Charles W. Chapoton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:27
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/26; H01Q3/267
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
109 words
A method of calibrating a phased array antenna with N phase shift elements, each having a predetermined number of calibration coefficients and a phase response characterized by a phase-state control function Φ J =f(φ i=1 ,M,c), comprising the steps: inputting calibration signals to the antenna, causing an aperture response; for a selected phase shift element, estimating the residual aperture response attributable to the other elements; measuring the phase response of the selected element using said residual aperture response; computing calibration coefficients for the selected element from said phase response measurements using the phase state control function; and correcting phase response errors during phase steering operations using said calibration coefficients.
Claim 2
Independent Claim
109 words
A method of calibrating a phased array antenna with N phase shift elements, each having a predetermined number of calibration coefficients and a phase response characterized by a phase-state control function Φ J =f(φ i=1 ,M,c), comprising the steps: inputting calibration signals to the antenna, causing an aperture response; for a selected phase shift element, estimating the residual aperture response attributable to the other elements; measuring the phase response of the selected element using said residual aperture response; computing calibration coefficients for the selected element from said phase response measurements using the phase state control function; and correcting phase response errors during phase steering operations using said calibration coefficients.
Claim 3
Dependent Claim
16 words
The calibration method of claim 1, wherein the aperture response comprises in-phase I and quadrature Q.
Claim 4
Dependent Claim
69 words
The calibration method of claim 2, wherein the step of estimating residual aperture response comprises the steps: selecting a set X of phase state settings of the selected element; for each phase state setting, measuring the I and Q aperture responses to input calibration signals; calculating R I and R Q residual aperture response components from the I Q aperture responses using the identity (I.sub.x -R.sub.I).sup.2 +(Q.sub.x -R.sub.Q).sup.2 =S.sup.2.
Claim 5
Dependent Claim
44 words
The calibration method of claim 3, further comprising the step: selecting phase state settings for the non-selected elements such that the magnitude of said R I R Q residual components are on the order of the magnitude of the input calibration signal or less.
Claim 6
Dependent Claim
25 words
The calibration method of claim 4, wherein the phase state settings are selected such that said R I R Q residual components are near zero.
Claim 7
Dependent Claim
13 words
The calibration method of claim 4, wherein three phase state settings are selected.
Claim 8
Dependent Claim
36 words
The calibration method of claim 4, wherein each phase shift element comprises a predetermined number of phase bits, and each phase state setting is determined by a control word with a corresponding number of control bits.
Claim 9
Dependent Claim
106 words
The calibration method of claim 2, further comprising the step of estimating the signal output amplitude S for the selected element, and wherein the step of measuring the phase response of the selected element comprises the steps; selecting a set Y of phase state settings of the selected element; for each phase state setting, measuring the I and Q aperture responses for input calibration signals; measuring phase responses Φ J from the I Q aperture responses using said R I R Q residual components and the signal amplitude S, and using at least one of the inverse functions Φ.sub.J =cos.sup.-1 ((I.sub.y -R.sub.I)/S) Φ.sub.J =sin.sup.-1 ((Q.sub.y -R.sub.Q)/S)
Claim 10
Dependent Claim
32 words
The calibration method of claim 8, further comprising the step of orthogonalizing the residual vector R I /R Q and the phase response vector such that the two vectors are substantially orthogonal.
Claim 11
Dependent Claim
26 words
The calibration method of claim 9, wherein the step of computing the calibration coefficients is accomplished by using the inverse function with the smaller residual component.
Claim 12
Dependent Claim
50 words
The calibration method of claim 9, wherein the step of orthogonalizing is accomplished by selecting phase state settings for the non-selected elements such that a selected phase increment is added to the residual vector R I /R Q to rotate it to be substantially orthogonal to the phase response vector.
Claim 13
Dependent Claim
37 words
The calibration method of claim 9, further comprising the step of rotating the residual vector R I /R Q and the phase response vector such that the vector outputs appear primarily in respective I and Q channels.
Claim 14
Dependent Claim
22 words
The calibration method of claim 12, wherein the step of rotating is accomplished by adjusting the phase of the input calibration signal.
Claim 15
Dependent Claim
36 words
The calibration method of claim 13, wherein each phase shift element comprises a predetermined number of phase bits, and each phase state setting is determined by a control word with a corresponsding number of control bits.
Claim 16
Dependent Claim
48 words
The calibration method of claim 1, wherein the step of computing calibration coefficients comprises the steps of: estimating a reference calibration coefficient corresponding to a reference phase shift increment; computing the calibration coefficients from said phase response measurements and the reference calibration coefficient using the phase-state control function.
Claim 17
Dependent Claim
35 words
The calibration method of claim 15, wherein the number of phase response measurements is greater than the number of calibration coefficients, and the step of computing the calibration coefficients is performed by least squares processing.
Claim 18
Dependent Claim
24 words
The calibration method of claim 16, wherin the step of estimating a reference calibration coefficient is accomplished by setting all phase states to zero.
Claim 19
Independent Claim
237 words
A method of calibrating a phased array antenna with N phase shift elements, each having a predetermined number of calibration coefficients and a phase response characterized by a phase-state control function Φ J =f(φ i-1 ,M,c), comprising the steps: inputting calibration signals to the antenna, causing I and Q aperture response; for a selected phase shift element, selecting a set X of control words; for each control word X, measuring the resultant I and Q aperture responses to an input calibration signal; estimating R I and R Q residual components of the aperture response attributable to the non-selected elements, and the signal output amplitude for the selected element, from the I and Q aperture responses using the identity (I x -R I ) 2 +(Q x -R Q ) 2 =S 2 ; for the selected element, selecting a set Y of control words; for each control word Y, measuring the resultant I and Q aperture responses to an input calibration signal; measuring the phase responses Φ J from the I and Q aperture responses using the R I and R Q residual components and the S signal amplitude, and using at least one of the inverse functions Φ.sub.J =cos.sup.-1 ((I.sub.y -R.sub.I)/S) Φ.sub.J =sin.sup.-1 ((Q.sub.y -R.sub.Q)/S) computing calibration coefficients for the selected element from said phase response measurements using the phase state control function; and correcting phase response errors during phase steering operations using said calibration coefficients.
Claim 20
Independent Claim
237 words
A method of calibrating a phased array antenna with N phase shift elements, each having a predetermined number of calibration coefficients and a phase response characterized by a phase-state control function Φ J =f(φ i-1 ,M,c), comprising the steps: inputting calibration signals to the antenna, causing I and Q aperture response; for a selected phase shift element, selecting a set X of control words; for each control word X, measuring the resultant I and Q aperture responses to an input calibration signal; estimating R I and R Q residual components of the aperture response attributable to the non-selected elements, and the signal output amplitude for the selected element, from the I and Q aperture responses using the identity (I x -R I ) 2 +(Q x -R Q ) 2 =S 2 ; for the selected element, selecting a set Y of control words; for each control word Y, measuring the resultant I and Q aperture responses to an input calibration signal; measuring the phase responses Φ J from the I and Q aperture responses using the R I and R Q residual components and the S signal amplitude, and using at least one of the inverse functions Φ.sub.J =cos.sup.-1 ((I.sub.y -R.sub.I)/S) Φ.sub.J =sin.sup.-1 ((Q.sub.y -R.sub.Q)/S) computing calibration coefficients for the selected element from said phase response measurements using the phase state control function; and correcting phase response errors during phase steering operations using said calibration coefficients.
Claim 21
Dependent Claim
32 words
The calibration method of claim 18, further comprising the step of orthogonalizing the residual vector R I /R Q and the phase response vector such that the two vectors are substantially orthogonal.
Claim 22
Dependent Claim
25 words
The calibration method of claim 19, wherein the step of measuring phase responses is accomplished by using the inverse function with the smaller residual component.
Claim 23
Dependent Claim
49 words
The calibration method of claim 19, wherein the step of orthogonalizing is accomplished by selecting control words for the non-selected elements such that a selected phase increment is added to the residual vector R I /R Q to rotate it to be substantially orthogonal to the phase response vector.
Claim 24
Dependent Claim
37 words
The calibration method of claim 19, further comprising the step of rotating the residual vector R I /R Q and the phase response vector such that the vector outputs appear primarily in respective I and Q channels.
Claim 25
Dependent Claim
22 words
The calibration method of claim 22, wherein the step of rotating is accomplished by adjusting the phase of the input calibration signal.
Claim 26
Dependent Claim
48 words
The calibration method of claim 18, wherein the step of computing calibration coefficients comprises the steps of: estimating a reference calibration coefficient corresponding to a reference phase shift increment; computing the calibration coefficients from said phase response measurements and said reference calibration coefficient using the phase-state control function.
Claim 27
Dependent Claim
35 words
The calibration method of claim 24, wherein the number of phase response measurements is greater than the number of calibration coefficients, and the step of computing the calibration coefficients is performed by least squares processing.
Claim 28
Dependent Claim
24 words
The calibration method of claim 25, wherin the step of estimating a reference calibration coefficient is accomplished by setting the control word to zero.
Claim 29
Independent Claim
324 words
A method of calibrating a phased array antenna with N phase shift elements, each having a predetermined number of calibration coefficients and a phase response characterized by a phase-state control function Φ J =f(φ i=1 ,M,c), comprising the steps: inputting calibration signals to the antenna, causing I and Q aperture response; for a selected phase shift element, selecting a set X of control words so as to minimize the R I and R Q residual components of the aperture response attributable to the non-selected elements; for each control word X, measuring the resultant I and Q aperture responses to an input calibration signal; estimating said R I and R Q residual components of the aperture response, and the signal output amplitude for the selected element, from the I and Q aperture responses using the identity (I x -R I ) 2 +(Q x -R Q ) 2 =S 2 ; for the selected element, selecting a set Y of control words; selecting control words for the non-selected elements such that a selected phase increment is added to the residual vector R I /R Q to rotate it to be substantially orthogonal to the phase response vector; for each control word Y, measuring the resultant I and Q aperture responses to an input calibration signal; adjusting the phase of the input calibration signals to rotate the residual vector R I /R Q and the phase response vector such that the vector outputs appear primarily in respective I and Q channels; measuring the phase responses Φ J from the I and Q aperture responses using the R I and R Q residual components and the S signal amplitude, and using at least one of the inverse functions Φ.sub.J =cos.sup.-1 ((I.sub.y -R.sub.I)/S) Φ.sub.J =sin.sup.-1 ((Q.sub.y -R.sub.Q)/S) computing calibration coefficients for the selected element from said phase response measurements using the phase state control function; and correcting phase response errors during phase steering operations using said calibration coefficients.
Claim 30
Independent Claim
324 words
A method of calibrating a phased array antenna with N phase shift elements, each having a predetermined number of calibration coefficients and a phase response characterized by a phase-state control function Φ J =f(φ i=1 ,M,c), comprising the steps: inputting calibration signals to the antenna, causing I and Q aperture response; for a selected phase shift element, selecting a set X of control words so as to minimize the R I and R Q residual components of the aperture response attributable to the non-selected elements; for each control word X, measuring the resultant I and Q aperture responses to an input calibration signal; estimating said R I and R Q residual components of the aperture response, and the signal output amplitude for the selected element, from the I and Q aperture responses using the identity (I x -R I ) 2 +(Q x -R Q ) 2 =S 2 ; for the selected element, selecting a set Y of control words; selecting control words for the non-selected elements such that a selected phase increment is added to the residual vector R I /R Q to rotate it to be substantially orthogonal to the phase response vector; for each control word Y, measuring the resultant I and Q aperture responses to an input calibration signal; adjusting the phase of the input calibration signals to rotate the residual vector R I /R Q and the phase response vector such that the vector outputs appear primarily in respective I and Q channels; measuring the phase responses Φ J from the I and Q aperture responses using the R I and R Q residual components and the S signal amplitude, and using at least one of the inverse functions Φ.sub.J =cos.sup.-1 ((I.sub.y -R.sub.I)/S) Φ.sub.J =sin.sup.-1 ((Q.sub.y -R.sub.Q)/S) computing calibration coefficients for the selected element from said phase response measurements using the phase state control function; and correcting phase response errors during phase steering operations using said calibration coefficients.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1994-11-04 | 1995-05-06 | 1995-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-04 | 1999-05-06 | 1999-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-04 | 2003-05-06 | 2003-11-05 | $7700.00 | Window Closed / Lapsed |