PROCESS COMPENSATING FOR ARRAY ANTENNA RADIATING ELEMENT POSITIONING ERRORS

• US 20080030412A1
• Filed: 03/17/2007
• Published: 02/07/2008
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: ROUZEAU, Benjamin, LIENHART, Marc-Yves, CHEKROUN, Claude
• Granted Patent: US 7,453,398 B2
• Time in Patent Office: Days
• US Class Current: 343/703
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: G01S 7/4004 of parts of a radar system
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices

Abstract

The invention refers to array antennas consisting of a set of individual sources set out over the surface of the antenna and whose mechanical positioning is determined in such a way as to obtain the desired radiation pattern. The process according to the invention is designed to compensate for the positioning errors of radiating elements occurring when such an antenna is constructed. These positioning errors follow a law that is in theory random and whose result is known by determining the imperfection vector I whose components of real positioning errors measured for each feed of the antenna obtained comprising components forming values of an error function δ(n) where n represents the index attributed to the radiating element in question. The process according to the invention consists in first measuring the positioning errors. It then consists in determining the spatial spectral components making up error function δ(n). It finally consists in applying to each component an amplitude or phase modulation correction in order to compensate for the degradation of the error function δ(n) on the obtained antenna radiation pattern F(θ). The process according to the invention applies more particularly to antennas comprising radiating beams.

Claims

1. A process of compensating for the positioning errors of the radiating elements in an array antenna, comprising the following steps:

measuring the positioning error for each radiating element n and compiling an imperfection vector I, whose components are values of the positioning error function δ

(n),

modeling the error function δ

(n) as the sum of the spectral sinusoidal components E_n(i) calculated by the application of a Fourier transform to the imperfections vector I, followed by the application of an inverse Fourier transform to vector dd obtained in this way,

calculating correction functions Δ

_a(n), Δ

_φ

(n), by amplitude and/or phase modulation, applicable to each of the spectral sinusoidal components E_n(i) of function δ

(n), with the correction functions defined as the sums of the spectral sinusoidal components A_n(i) and Φ

_n(i),

determining the form of function Δ

(n) to be applied to each of the spectral sinusoidal components E_n(i) of function δ

(n) depending on the aiming angle θ

₀ of the antenna.

2. The process according to claim 1, wherein the function Δ

(n) is expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+\left(1-\mathrm{\gamma <br><br>}<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$

where γ

(i) represents a selection function equal to 1 or 0.

3. The process according to claim 2, wherein the value of γ

(i) is defined according to a threshold calculated from the aiming angle θ

₀.

4. The process according to claim 1, including a complementary spectral components weighting step for functions Δ

_a(n) and Δ

_φ

(n), while the overall correction function Δ

(n) is then expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>f<br><br>\left(i\right)·<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+f<br><br>\left(i\right)·<br><br>\left(1-\mathrm{\gamma <br><br>}<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$

5. The process according to claim 4 wherein weighting f(i) follows an increasing linear law according to i.

6. The process according to claim 4 wherein weighting f(i) follows an increasing logarithmic law according to i.

7. A process for the generation of a radiation pattern F(θ

) for a array antenna wherein it combines the correction process according to claim 1, with a step for determining the aiming phase law so as to construct the radiation pattern from the real positions of the radiating elements.

8. The process according to claim 2, including a complementary spectral components weighting step for functions Δ

_a(n) and Δ

_φ

(n), while the overall correction function Δ

(n) is then expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>f<br><br>\left(i\right)·<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+f<br><br>\left(i\right)·<br><br>\left(1-\mathrm{\gamma <br><br>}<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$

9. The process according to claim 3, including a complementary spectral components weighting step for functions Δ

_a(n) and Δ

_φ

(n), while the overall correction function Δ

(n) is then expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>f<br><br>\left(i\right)·<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+f<br><br>\left(i\right)·<br><br>\left(1-\mathrm{\gamma <br><br>}<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$

10. The process according to claim 8 wherein weighting f(i) follows an increasing linear law according to i.

11. The process according to claim 8 wherein weighting f(i) follows an increasing logarithmic law according to i.

12. The process according to claim 9 wherein weighting f(i) follows an increasing linear law according to i.

13. The process according to claim 10 wherein weighting f(i) follows an increasing logarithmic law according to i.

14. The process according to claim 7, wherein the function Δ

(n) is expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+\left(1-\mathrm{\gamma <br><br>}<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$

where γ

(i) represents a selection function equal to 1 or 0.

15. The process according to claim 7, wherein the value of γ

(i) is defined according to a threshold calculated from the aiming angle θ

₀.

16. The process according to claims 7, including a complementary spectral components weighting step for functions Δ

_a(n) and Δ

_φ

(n), while the overall correction function Δ

(n) is then expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>f<br><br>\left(i\right)·<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+f<br><br>\left(i\right)·<br><br>\left(1-\mathrm{\gamma <br><br>}<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$

17. The process according to claim 16 wherein weighting f(i) follows an increasing linear law according to i.

18. The process according to claim 16 wherein weighting f(i) follows an increasing logarithmic law according to i.

19. The process according to claim 14, including a complementary spectral components weighting step for functions Δ

_a(n) and Δ

_φ

(n), while the overall correction function Δ

(n) is then expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>f<br><br>\left(i\right)·<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+f<br><br>\left(i\right)·<br><br>\left(1-\mathrm{\gamma <br><br>}<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$

20. The process according to claim 15, including a complementary spectral components weighting step for functions Δ

_a(n) and Δ

_φ

(n), while the overall correction function Δ

(n) is then expressed as;

$\mathrm{\Delta <br><br>}<br><br>\left(n\right)=\underset{i}{\sum <br><br>}<br><br>f<br><br>\left(i\right)·<br><br>y<br><br>\left(i\right)·<br><br>A_n<br><br>\left(i\right)+f<br><br>\left(i\right)·<br><br>\left(1-y<br><br>\left(i\right)\right)·<br><br>{\mathrm{\Phi <br><br>}}_n<br><br>\left(i\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\gamma <br><br>}<br><br>\left(i\right)$