Abstract: The apparatus includes: a radar circuit including a set of antennas for transmission and reception, a transmitter, a receiver, and a medium access control (MAC) controller. The apparatus further includes a controller operably connected to the radar circuit, the controller configured to identify a discrete Fourier transform (DFT) of a long constant amplitude zero autocorrelation (CAZAC) sequence including multiple segments, identify, via the MAC controller, time-frequency resources for the multiple segments, identify a set of time-frequency sub-channels in the time-frequency resources, and sequentially map each of the multiple segments to each of the set of time-frequency sub-channels. The radar circuit is configured to transmit, via the transmitter, a first signal based on the set of time-frequency sub-channels.

Abstract: The present application describes an apparatus that includes a radar antenna device to acquire synthetic aperture radar data, radar receiver and transmitter equipment coupled to the radar antenna device, and a synthetic aperture radar processing device in communication with the radar receiver and transmitter equipment. This processing device includes a processor structured to process the synthetic aperture radar data, which is representative of a defocused image. The processor is further structured to define an image processing constraint corresponding to an image region expected to have a low radar return and generate one or more output signals as a function of the image processing constraint and the data. The one or more output signals are representative of a more focused form of the defocused image.

Abstract: A fast method for divergent-beam backprojection is proposed for generating an electronic image from a preprocessed divergent-beam sonogram, the sinogram being a collection of divergent beam projections. The method consists of the following steps: subdividing the sinogram into multiple sub-sinograms; performing a weighted backprojection of said sub-sinograms, to produce multiple corresponding sub-images; and aggregating said sub-images to create the electronic image. The subdivision of the sinogram into sub-sinograms can be performed in a recursive manner. A dual of the proposed method provides a fast means for reprojecting an electronic image, i.e., generating a divergent-beam sinogram from the image. These methods are applicable to fan-beam and cone-beam tomography utilizing a variety of scanning trajectories, including spiral. These methods do not require rebinning, and offer speedups similar to the FFT when compared to conventional backprojection and reprojection algorithms.