US 12,596,191 B2Granted

Synthetic aperture radar using alternating beams and associated methods

AssigneeEagle Technology, LLC

InventorsDonald A. Lieb, Robert Riley, Robert M. Taylor, Kerry T. Speed, Timothy E. Durham

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Abstract

A synthetic aperture radar (SAR) for a flight vehicle may include an elongate phased array antenna oriented with a long axis in an elevation direction. The elevation direction is normal to a direction of flight of the flight vehicle. A transmitter is coupled to the elongate phased array antenna, and a receiver is coupled to the elongate phased array antenna. A controller is coupled to the transmitter and receiver and is configured to generate temporally alternating sets of receive beams for respective swaths to be used to form a SAR image across a surface below the flight vehicle. The same center frequency is used to create consistent SARs for all swaths, allowing for coherent combination between subsequent passes over the same swath.

Claims21

Dependent claims

A synthetic aperture radar (SAR) for a flight vehicle, the SAR comprising:

an elongate phased array antenna oriented with a long axis in an elevation direction, the elevation direction being normal to a direction of flight of the flight vehicle, the elongate phased array antenna comprising a plurality of steerable elements forming a one-dimensional array along the long axis;
a transmitter coupled to the elongate phased array antenna;
a receiver coupled to the elongate phased array antenna;
and a controller configured to cooperate with the transmitter and receiver to generate temporally alternating sets of receive beams for respective first and second swaths to be used to form a SAR image across a surface below the flight vehicle, the alternating sets of receive beams comprising a first set of receive beams for the first swath and comprising a plurality of first subswaths, with adjacent first subswaths being separated by a respective first gap, and a second set of receive beams for the second swath and comprising a plurality of second subswaths, with adjacent second subswaths being separated by a respective second gap, wherein the plurality of second subswaths overlap with the respective first gaps in the plurality of first subswaths.

1 more element

A synthetic aperture radar (SAR) for a flight vehicle, the SAR comprising:

an elongate phased array antenna oriented with a long axis in an elevation direction, the elevation direction being normal to a direction of flight of the flight vehicle, the elongate phased array antenna comprising a plurality of steerable elements forming a one-dimensional array along the long axis;
a transmitter coupled to the elongate phased array antenna;
a receiver coupled to the elongate phased array antenna;
and a controller coupled to the transmitter and receiver and configured to generate a first set of receive beams for a first swath and comprising a plurality of first subswaths, with adjacent first subswaths being separated by a respective first gap;
generate a second set of receive beams for a second swath and comprising a plurality of second subswaths, with adjacent second subswaths being separated by a respective second gap, and with the plurality of second subswaths overlapping with the respective first gaps in the plurality of first subswaths;
the first and second set of receive beams to be used to form a SAR image across a surface below the flight vehicle;
and operate the transmitter to transmit during the respective first and second gaps in the first and second sets of receive beams.

4 more elements

A method for operating a synthetic aperture radar (SAR) for a flight vehicle, the SAR comprising an elongate phased array antenna oriented with a long axis in an elevation direction, the elevation direction being normal to a direction of flight of the flight vehicle, the elongate phased array antenna comprising a plurality of steerable elements forming a one-dimensional array along the long axis, a transmitter coupled to the elongate phased array antenna, and a receiver coupled to the elongate phased array antenna, the method comprising:

operating a controller coupled to the transmitter and receiver to generate temporally alternating sets of receive beams for respective first and second swaths to be used to form a SAR image across a surface below the flight vehicle, the alternating sets of receive beams comprising a first set of receive beams for the first swath and comprising a plurality of first subswaths, with adjacent first subswaths being separated by a respective first gap, and a second set of receive beams for the second swath and comprising a plurality of second subswaths, with adjacent second subswaths being separated by a respective second gap, wherein the plurality of second subswaths overlap with the respective first gaps in the plurality of first subswaths.

Dependencies are inferred from the claim text.