A method and a device for separating echo signals of STWE SAR in elevation are provided. The method includes that: aliasing echo signals of multiple sub-swaths are received; for a target sub-swath of the multiple sub-swaths, multiple sub-beams associated with the target sub-swath are generated, the multiple sub-beams pointing to different directions of the target sub-swath respectively, and a null of each of the multiple sub-beams being used for deep nulling suppression on echo signals of sub-swaths except the target sub-swath; and the aliasing echo signals are processed based on the multiple sub-beams and multiple nulls corresponding to the multiple sub-beams to generate a target echo signal of the target sub-swath.

A synthetic aperture radar (SAR) system generates an image of a first swath. The SAR includes at least one SAR antenna, at least one SAR processor and at least one SAR transceiver. In operation the SAR defines a first beam to illuminate the first swath and one or more second beams to illuminate area(s) of ambiguity associated with the first beam. The SAR transmits a pulse via the first beam and receives backscatter energy. The SAR generates a first signal associated with the first beam and one or more second signals associated with the second beam(s). The second signal(s) are combined with determined complex vector(s), generating ambiguity signal(s) and the ambiguity signals are combined with the first signal to generate an image associated with the first swath.

A synthetic aperture radar (SAR) system may employ SAR imaging to advantageously estimate or monitor a transit characteristic (e.g., velocity, acceleration) of a vehicle, for example a ground based vehicle or water based vehicle. A dual-beam SAR antenna illuminate a moving target with a first radar beam and a second radar beam at an angular offset relative to the first radar beam. Pulses may be transmitted and backscattered energy received simultaneously by the SAR transceiver via the first and second radar beams. A SAR data processor may generate a first image from the first radar beam and a second image from the second radar beam, co-registering the first and second images, comparing the location of the moving target in the first and second images, and estimate a velocity of the moving target based at least in part on the angular offset.

A synthetic aperture radar (SAR) generates concurrent first radar pulses in first frequency channels. The SAR transmits, and receives returns of, the concurrent first radar pulses by first antenna feeds that form first beams in the first frequency channels and that are directed to respective first subswaths of a swath on the Earth separated by subswath gaps. The SAR generates concurrent second radar pulses in second frequency channels. The SAR transmits, and receives returns of, the concurrent second radar pulses by second antenna feeds configured to form second beams in the second frequency channels and that are directed to respective second subswaths of the swath on the Earth and that coincide with the subswath gaps. The SAR processes the returns of the first radar pulses from the first subswaths and the returns of the second radar pulses from the second subswaths to form a SAR image contiguous across the swath.

A signal processor 2 is configured so as to compensate for a peak shift of the distance between an SAR sensor 1 and a target, the peak shift occurring in the received signal subjected to range compression performed by an image reconstruction processing unit 14 due to a movement of the SAR sensor 1 during a time period until a reflected wave of a pulse signal is received by the SAR sensor 1 after the pulse signal is emitted from the SAR sensor 1. As a result, even when the SAR sensor 1 moves, an SAR image in which no azimuth ambiguity occurs can be reconstructed.

A synthetic aperture radar method for remote sensing of the surface of the Earth by means of a radar device on a flying object moving in an azimuth direction above the surface of the Earth, wherein the radar device includes an array of antenna elements for transmitting radar pulses in a transmitting operation and for receiving radar echoes of these radar pulses reflected at the surface of the Earth in a receiving operation. A calibration mode is carried out in which the transmission of the radar pulses in the transmitting operation is carried out with a pulse repetition rate such that only echo signals of a single radar echo are received by all antenna elements of the array at the same point in time in the receiving operation; in the receiving operation, the echo signals are recorded in a plurality of receiving channels, wherein a different antenna element is assigned to a respective receiving channel, and in the respective receiving channel the echo signals received by the assigned antenna element are digitized and directly stored, thereby obtaining digitized radar data; the digitized radar data are further processed to determine a set of calibrated parameters of the radar device for the SAR operating mode for obtaining SAR images.

A SAR imaging method for interferometric analyses is provided, including: receiving raw SAR data related to two or more SAR acquisitions of one and the same area of the earth's surface carried out by one or more synthetic aperture radars; and processing the raw SAR data to generate SAR images. For each SAR acquisition, the respective raw SAR data is processed based on two different sets of processing parameters: a first set that is the same for all the SAR acquisitions and which comprises focusing Doppler parameters computed based on physical Doppler parameters related to all the SAR acquisitions; and a second set which comprises respective radiometric equalization Doppler parameters related to the SAR acquisition and computed based on respective physical Doppler parameters related to the SAR acquisition. Processing includes: focusing the raw SAR data related to all SAR acquisitions based on the focusing Doppler parameters and, for each SAR acquisition, applying a respective radiometric equalization, based on the respective radiometric equalization Doppler parameters, to the respective SAR data to compensate for possible differences in pointing of the synthetic aperture radar(s), without degrading azimuth resolution and without introducing radiometric distortions.

A microwave and millimeter wave imaging system. In either a far-field or a near-field detection mode, a radially-polarized probe transmits an imaging signal along a predetermined scan path to detect a target in a sample. The imaging signal's orientation is independent of the target's orientation and changes at each target as the probe transmits the signal during scanning. A measurement system receives scattered waves reflected from the sample via a single channel and images the sample and the target based on the reflected waves independent of the orientation of the target.

A method according to the present invention comprises the steps of: dividing SAR raw data into one or more sub-aperture data by a predetermined number in an azimuth direction; performing a spectral length extension FFT on the sub-aperture data in the azimuth direction; multiplying the sub-aperture data by a chirp scaling function; performing a range FFT on the sub-aperture data; performing range compression, SRC, and a bulk RCMC on the sub-aperture data; performing an inverse chirp-z transform on the sub-aperture data in a range direction; multiplying the divided sub-aperture data by a predetermined first function; performing an IFFT on the sub-aperture data in the azimuth direction; recombining the sub-aperture data; multiplying the recombined data by a second function and deramping same; performing an azimuth FFT on the recombined data; performing an azimuth IFFT on the recombined data; multiplying the recombined data by a third function and deramping same; performing the azimuth FFT on the recombined data; performing azimuth compression by multiplying the recombined data by a fourth function; performing an azimuth inverse chirp-z transform on the recombined data; and multiplying the recombined data by a fifth function for phase preservation.

A method of determining feasible swaths of a synthetic aperture radar (SAR) includes determining a first plurality of swaths that are transmit-feasible and nadir-feasible, determining a second plurality of swaths of the first plurality of swaths that satisfy at least one hard constraint, the at least one hard constraint being an image quality constraint or a system constraint, and generating a graph of the second plurality of swaths. The method may include assigning each feasible swath of the second plurality of swaths to a node in a directed graph, and adding a directed edge in the directed graph when a pair of swaths of the second plurality of swaths satisfy one or more defined constraints. The method may include configuring the SAR to operate based at least in part on the generated graph of the second plurality of swaths. Operating the configured SAR may include obtaining SAR images.