US 12,259,466 B2
System for extraction of a region of interest (ROI) from a composite synthetic aperture radar (SAR) system phase history
Adour Vahe Kabakian, Monterey Park, CA (US); David Wayne Payton, Malibu, CA (US); Brian N. Limketkai, Santa Monica, CA (US); Soheil Kolouri, Agoura Hills, CA (US); and Qin Jiang, Malibu, CA (US)
Assigned to The Boeing Company, Arlington, VA (US)
Filed by The Boeing Company, Chicago, IL (US)
Filed on Dec. 7, 2021, as Appl. No. 17/643,156.
Claims priority of provisional application 63/135,550, filed on Jan. 8, 2021.
Prior Publication US 2022/0221578 A1, Jul. 14, 2022
Int. Cl. G01S 13/90 (2006.01)
CPC G01S 13/9027 (2019.05) [G01S 13/9052 (2019.05); G01S 13/9054 (2019.05); G01S 13/9088 (2019.05)] 20 Claims
OG exemplary drawing
 
1. A method that extracts a region of interest (ROI) from composite synthetic aperture radar (SAR) phase history data, the method comprising:
receiving, by a SAR system, the composite SAR phase history data of a plurality of backscattered return signals produced as a result of the SAR system illuminating a scene with a SAR beam;
obtaining a location of a ROI within the scene; and
extracting from the composite SAR phase history data a component SAR phase history data corresponding to the ROI, wherein the component SAR phase history data is to be utilized for object detection;
wherein the extracting the composite SAR phase history data comprises: sectorizing the SAR beam into a plurality of sectors, wherein each sector is defined
between a first sectoral angle and a second sectoral angle and each sector corresponds to a Doppler frequency interval having a first frequency value and a second frequency value; and
decomposing the composite SAR phase history data into a plurality of sectoral SAR phase history data via Doppler processing of an induced azimuth signal,
wherein each sectoral SAR phase history data corresponds to a unique sector of the plurality of sectors, the component SAR phase history data corresponds to a first sectoral SAR phase history data corresponding to a first sector of the plurality of the sectors, and the first sector corresponds to a first Doppler frequency interval;
wherein the Doppler processing of the induced azimuth signal includes:
determining a first Doppler frequency in the induced azimuth signal from the backscattered return signals received at a first directional angle (θ1) from the normal direction to the travel path, wherein the first Doppler frequency (f1) is defined by the first directional angle, a velocity of the SAR system along the travel path and a wavelength of a carrier frequency of the SAR system, and
bandpass filtering the induced azimuth signal, with a bandpass filter having a passband, to produce a new induced azimuth signal that includes frequency components of the induced azimuth signal that fall within the passband.