A method for operating a synthetic aperture radar, SAR, mode, in an SAR instrument, wherein the method comprises the steps of: acquiring at least one subswath positioned in an across track direction of a movement of the SAR instrument, wherein the at least one subswath is acquired during at least one acquisition burst duration and/or at a predetermined radio frequency bandwidth; adjusting the at least one acquisition burst duration and/or the predetermined radio frequency bandwidth and/or a number of parallel simultaneous subswaths and/or an inserted burst duration for a further subswath based upon a predetermined parameter; constructing an SAR image based on the acquired at least one subswath.

A method of operating a Synthetic Aperture Radar SAR to acquire image data of a swath comprising one or more subswath(s) is provided, wherein the SAR is carried on a platform moving along a flight direction and a radiated beam is directed towards the swath, the method comprising: electronically steering the beam in azimuth direction along one subswath for each burst; and mechanically steering the beam in a direction opposite to the flight direction during each burst. The method allows to obtain an improved swath to resolution ratio.

A method of operating a synthetic aperture radar SAR to acquire image data, comprises steering the SAR beam in azimuth with respect to the direction of travel during a first time period to acquire image data for a first area on Earth to be imaged; steering the SAR beam in azimuth during one or more additional time periods to acquire image data for one or more additional areas on Earth to be imaged; and steering the SAR beam in azimuth in a rearward direction with respect to the direction of travel, during a time period including the first and one or more additional time periods, to reduce the speed of travel of the beam with respect to Earth.

There is a need to address the problem of compressed scanning in SAR acquisitions for microwave imaging. Embodiments of the present disclosure provide microwave imaging with multiple-input and multiple-output synthetic aperture radar using compressed multi-coset range migration technique. The present disclosure reduces the SAR acquisition time by compressed scanning, where a compressed scanning acquisition setup captures radar measurements to obtain a microwave image of a target scene by intermittently skipping blocks during SAR acquisition. Further, reconstruction of a microwave image of a target scene is performed using 2D Fourier Transform (FT) of the radar measurements based on a multi-coset range-migration framework. The multi-coset range migration framework makes use of intermittent scanning and formulates a compressed sensing-based architecture by leveraging block-sparsity constraints. Subsequently, a denoising convolutional neural network (DnCNN) is used to enhance and denoise the reconstructed microwave image to obtain a high-resolution image of the target scene.

A system and method for distinguishing targets of interest from main lobe clutter and sidelobe clutter includes an ESA or AESA divided into subarrays. A sum beam power profile is produced via one or more scans of the subarrays, and a difference beam power profile is produced via calculations involving the subarrays. A comparison of the sum beam power profile and the difference beam power profile accentuates signal power disparities between targets of interest and clutter. A threshold is then applied to isolate targets of interest. Different difference beam power profiles may be used for elevation comparisons and azimuth comparisons. Alternatively, subarrays may be selected such that the same difference beam power profile may be used for both elevation and azimuth. Scans may be time multiplexed such that data from different scans may be used to produce the sum beam power profile, the difference beam power profile, or both.

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.

Imaging systems and associated methods are described. According to one aspect, an imaging system includes processing circuitry configured to: access radar data for a plurality of sampling points at a plurality of different locations of an imaging aperture, and wherein the radar data results from the transmission and reception of electromagnetic energy via an antenna array with respect to a target imaging volume; access a plurality of different weightings that correspond to different ones of the sampling points of the imaging aperture; focus the radar data of the sampling points to generate an image of the target imaging volume; and wherein the processing circuitry is configured to use the different weightings of the sampling points to focus the radar data of respective ones of the sampling points.