G01S13/9019

Method and apparatus for providing a passive transmitter based synthetic aperture radar

A method and apparatus for receiving signals from an unknown transmitting source and providing the location of the unknown transmitting source comprising a series of channels for receiving signals radiated by the unknown transmitting sources, generating preprocessed time domain data and generating a SAR image depicting a location of the unknown transmitting source, and a processor for processing the preprocessed time domain data to enhance a pixel value at each pixel location within the SAR image by summing signal data from each channel related to each pixel location to generate an enhanced SAR image.

Synthetic-aperture radar device
10948588 · 2021-03-16 · ·

A synthetic-aperture radar device of the present invention is the one having: a focal point information storing unit storing a plurality of pieces of focal point information determining positions of focal points; an image reproducing unit reproducing each radar image corresponding to the plurality of pieces of focal point information stored in the focal point information storing unit from a reception signal of a radio wave applied from a moving platform to an observation target and reflected by the observation target; an index calculating unit calculating an index representing an image forming state of the radar image reproduced by the image reproducing unit for each predetermined area; and a synthesizing unit synthesizing the plurality of radar images on the basis of the index calculated from each of the plurality of radar images, enabling obtaining a clear radar image without using positional information of the observation target.

System and Method for Radar Imaging for Antennas with Position Ambiguities

A radar system for generating a radar image of a scene. Receive radar measurements of reflectivity of each point in the scene measured by receivers. Solve a radar image recovery (RIR) problem using stored data to produce the radar image. By connecting the radar measurements to a shift of a reflection field with a receiver shift. The receiver shift defines an error between stored receiver positions and actual receivers positions, the reflection field is generated by reflecting the transmitted field from the scene in accordance with the reflectivity of each point in the scene. Connecting the reflection field to a shift of an incident field with a transmitter shift. The transmitter shift defines an error between stored transmitter positions and actual transmitters positions. Solve as a multilinear problem of joint estimation of the reflectivity of each point in the scene, the receiver shift, and the transmitter shift.

METHODS, COMPUTER PROGRAMS, RADAR SYSTEMS, ANTENNA SYSTEMS, AND FLYING PLATFORMS FOR DETECTING A HORIZONTALLY BURIED LINEAR OBJECT
20200408896 · 2020-12-31 · ·

A method for detecting a horizontally buried linear object is provided, the horizontally buried linear object having a longitudinal extension. The method comprises moving, with a flying platform comprising a radar for synthetic aperture radar, SAR, vertical imaging, along a trajectory corresponding to a synthetic aperture. The method further comprises transmitting and receiving radar signals while moving along the trajectory corresponding to the synthetic aperture. The method also comprises forming a SAR image based on collected data representing radar signal reflections received from the ground. The method additionally comprises detecting one or more features in the formed SAR image relating to the horizontally buried linear object. Said trajectory is oriented in a direction substantially perpendicular to an expected orientation of the longitudinal extension of the horizontally buried object and traversing the horizontally buried object.

System and method for robust sensor localization based on euclidean distance matrix

Systems and methods for radar systems to produce a radar image of a region of interest (ROI with targets. Sensors to transmit source signals to the ROI and to measure echoes reflected back from the targets corresponding to the transmitted source signals. A processor to calculate an estimate of a noisy and a partial Euclidean Distance Matrix (EDM) of the sensors and the targets. Decompose the noisy and the partial EDM into a low rank EDM that corresponds to locations to actual sensors and target locations, and a sparse matrix of distance errors, using a constrained optimization process. The low rank EDM is mapped into the sensors and the targets locations, to obtain estimated actual sensor locations. Implement an inverse imaging process using the estimated actual sensor locations and the received data, to produce the radar image to output to a communication channel.

Synthetic aperture radar
10712441 · 2020-07-14 · ·

Whether or not motion compensation is necessary is determined for each of received radio wave signals acquired through observation on the basis of information on a difference between an planned trajectory and an actual trajectory of a platform (103), and a motion compensation process is performed on the received radio wave signals for which the motion compensation is determined to be necessary. An image generation process is performed on the received radio wave signals on which the motion compensation process has been performed and the received radio wave signals on which the motion compensation process has not been performed depending on the results of determination, so that a SAR image of an observation object is generated.

System and method for fused radar imaging under position ambiguity of antennas

Systems and methods for a radar system to produce a radar image of a region of interest (ROI). A set of antennas to transmit radar pulses to the ROI and to measure a set of reflections from the ROI corresponding to the transmitted radar pulses. A processor acquires an estimate of the radar image, by matching the reflections of the ROI measurements for each antenna. Determine a set of shifts of the radar image. Wherein each shift corresponds to an antenna, and is caused by an uncertainty in a position of the antenna. Update the estimate of the radar image, based on the determined set of shifts of the radar image. Wherein for each antenna, the estimate of the radar image is shifted by the determined shift of the radar image corresponding to the antenna, that fits the reflections of the ROI measurements of the antenna.

System and Method for Determining a Change of Position and Orientation of an Object
20200096629 · 2020-03-26 ·

The disclosure concerns a method for determining a change in position and orientation of an object using data from a synthetic aperture radar (SAR) with the following steps: acquiring a radar image containing the object; dividing the radar image into at least two subimages; acquiring short radar information comprising a first reflected pulse, which has been recorded by the radar and/or a quantity derived therefrom, the first reflected pulse having information about image data of the radar image; for the short radar information, performing an autofocus method which determines a change in distance for each of the at least two subimages; and determining the change in position and orientation of the object given for each point of the object by the respective change in distance of the corresponding subimage.

METHOD AND APPARATUS FOR PROVIDING A PASSIVE TRANSMITTER BASED SYNTHETIC APERTURE RADAR

A method and apparatus for receiving signals from an unknown transmitting source and providing the location of the unknown transmitting source comprising a series of channels for receiving signals radiated by the unknown transmitting sources, generating preprocessed time domain data and generating a SAR image depicting a location of the unknown transmitting source, and a processor for processing the preprocessed time domain data to enhance a pixel value at each pixel location within the SAR image by summing signal data from each channel related to each pixel location to generate an enhanced SAR image.

System and method for robust sensor localization based on Euclidean distance matrix
20190391258 · 2019-12-26 ·

Systems and methods for radar systems to produce a radar image of a region of interest (ROI with targets. Sensors to transmit source signals to the ROI and to measure echoes reflected back from the targets corresponding to the transmitted source signals. A processor to calculate an estimate of a noisy and a partial Euclidean Distance Matrix (EDM) of the sensors and the targets. Decompose the noisy and the partial EDM into a low rank EDM that corresponds to locations to actual sensors and target locations, and a sparse matrix of distance errors, using a constrained optimization process. The low rank EDM is mapped into the sensors and the targets locations, to obtain estimated actual sensor locations. Implement an inverse imaging process using the estimated actual sensor locations and the received data, to produce the radar image to output to a communication channel.