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Synthetic aperture radar system capable of detecting moving targets

Assignee: Swedish Defence Research Agency

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Filing: 2000-11-02

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Granted: 2003-02-11

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Expires: 2020-11-02

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Abstract

Abstract A Synthetic Aperture Radar (SAR) system and method capable of detecting moving targets which includes a platform that moves over a number of objects, such as a ground surface, and supports radar equipment which reproduces the objects by means of a fast backprojection synthetic aperture technique via at least two antennas without requirement as to directivity or fractional bandwidth. The imaging process is divided into three steps which are carried out in a determined order, the steps and the order being formation of sub-aperture beams at one speed, performing clutter suppression, and detection of moving targets.

Inventors

👤 Mats Peterson
👤 Hans Hellsten
👤 Lars Ulander

Bibliographic Details

Application Number —

Jurisdiction US

Data Source google_patents

Last Synchronized 2026-11-08 09:49

CPC Classifications

G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/52; G01S13/522; G01S13/524; G01S13/5244; G01S13/88; G01S13/89; G01S13/90; G01S13/9004; G01S13/9017; G01S13/9021; G01S13/9029

Claims Analysis

Total Claims: 15

Claim 1

Independent Claim 77 words

A method of detecting moving targets using a synthetic aperture radar (SAR) system having a platform which moves over a number of objects and supports radar equipment which reproduces the objects using a fast backprojection synthetic aperture technique via at least two antennas, said method comprising steps in the following order: forming sub-aperture beams over said two antennas at a speed; performing clutter suppression on said sub-aperture beams; and detecting moving targets using said clutter-suppressed sub-aperture beams.

Claim 2

Independent Claim 77 words

Claim 3

Dependent Claim 22 words

The method as set forth in claim 1 , wherein the speed is ground speed of said platform moving over said objects.

Claim 4

Dependent Claim 19 words

The method as set forth in claim 1 , wherein said step of performing clutter suppression includes GMTI filtering.

Claim 5

Dependent Claim 25 words

The method as set forth in claim 1 , wherein the step of detecting moving targets includes combining the clutter-suppressed sub-aperture beams by relative speed.

Claim 6

Dependent Claim 25 words

The method as set forth in claim 1 , wherein the step of performing clutter suppression includes estimating the clutter statistics of the sub-aperture beams.

Claim 7

Dependent Claim 68 words

The method as set forth in claim 4 , wherein said clutter statistics are estimated by means of a covariance matrix ({tilde over (C)}), the matrix being inverted ({tilde over (C)} −1 ) and used, together with a steering vector (Ã), in the test  A ~ H  C ~ - 1  Y ~  2  > H 1 < H 0  λ .

Claim 8

Dependent Claim 28 words

The method as set forth in claim 4 , wherein the clutter statistics of a sub-image beam are estimated from surrounding sub-aperture beams connected to surrounding sub images.

Claim 9

Dependent Claim 30 words

The method as set forth in claim 4 , wherein the sub-aperture beams are divided into range bins and the estimation of the clutter statistics is performed for said bins.

Claim 10

Independent Claim 90 words

A method of detecting moving targets using a synthetic aperture radar (SAR) system, comprising the steps of; moving radar equipment over a number of objects and reproducing the objects with a fast backprojection synthetic aperture technique, without requirement as to directivity or fractional bandwidth, using at least two antennas; forming, using said two antennas, sub-aperture beams at a speed; performing clutter suppression with GMTI filtering on said sub-aperture beams, said clutter suppression including estimation of clutter statistics of said sub-aperture beams; and detecting moving targets using said clutter-suppressed sub-aperture beams.

Claim 11

Independent Claim 90 words

Claim 12

Dependent Claim 25 words

The method as set forth in claim 9 , wherein the step of detecting moving targets includes combining the clutter-suppressed sub-aperture beams by relative speed.

Claim 13

Dependent Claim 68 words

The method as set forth in claim 9 , wherein said clutter statistics are estimated by means of a covariance matrix ({tilde over (C)}), the matrix being inverted ({tilde over (C)} −1 ) and used, together with a steering vector (Ã), in the test  A ~ H  C ~ - 1  Y ~  2  > H 1 < H 0  λ .

Claim 14

Dependent Claim 28 words

The method as set forth in claim 9 , wherein the clutter statistics of a sub-image beam are estimated from surrounding sub-aperture beams connected to surrounding sub images.

Claim 15

Dependent Claim 30 words

The method as set forth in claim 9 , wherein the sub-aperture beams are divided into range bins and the estimation of the clutter statistics is performed for said bins.

References Cited (Backward Citations)

US4965582A Cited

SE456117B Cited

US4866446A Cited

US5442364A Cited

US5969662A Cited

US5898399A Cited

US5805098A Cited

US6384766B1 Cited

US6388605B1 Cited

US6300914B1 Cited

US6388606B1 Cited

USPTO Annuity & Maintenance Windows

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2006-02-10	2006-08-12	2007-02-11	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2010-02-10	2010-08-12	2011-02-11	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2014-02-10	2014-08-12	2015-02-11	$7700.00	Window Closed / Lapsed

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