A method and a system for detection and synthetic aperture (SA) imaging of a target are disclosed. The method may include illuminating a scene with a search signal transmitted from a moving platform, receiving a search return signal from a target present in the scene, and estimating, from the search return signal, the range and the angular location of the target. The method may also include generating an SA transmission signal and a local oscillator (LO) signal with a time delay therebetween based on the estimated range, and illuminating the scene with the SA transmission signal pointed along an imaging direction based on the estimated angular location of the target. The method may further include receiving an SA return signal from the target, mixing the SA return signal with the LO signal to generate SA signal data, and generating an SA image of the target from the SA signal data.

A method of remote sensing of a body of water comprising: using a radar apparatus installed on a vessel to obtain a plurality of radar intensity images of the surface of the body of water; registering a geographic location of each of the plurality of radar intensity images, wherein registering the geographic location of each of the plurality of radar intensity images comprises: applying one or more of the following calibration offsets to increase image sharpness: an azimuthal alignment error () corresponding to an angular offset between a heading recorded by a navigation unit installed on the vessel and a true heading of the vessel; a start range error () corresponding to an error in a distance from an antenna to a data processing unit of the radar apparatus for a first range bin in the plurality of radar intensity images; and/or a system time error () corresponding to a total time delay resulting from a time delay due to communication of data between the radar apparatus and the data processing unit and/or a computer-induced time stamp delay between a true image recording time and an image time-stamp; and generating one or more time-integrated images of the surface of the body of water.

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.

Systems, methods, tangible non-transitory computer-readable media, and devices associated with sensor output segmentation are provided. For example, sensor data can be accessed. The sensor data can include sensor data returns representative of an environment detected by a sensor across the sensor's field of view. Each sensor data return can be associated with a respective bin of a plurality of bins corresponding to the field of view of the sensor. Each bin can correspond to a different portion of the sensor's field of view. Channels can be generated for each of the plurality of bins and can include data indicative of a range and an azimuth associated with a sensor data return associated with each bin. Furthermore, a semantic segment of a portion of the sensor data can be generated by inputting the channels for each bin into a machine-learned segmentation model trained to generate an output including the semantic segment.

Disclosed is a calibration method of performing dual radiometric compensation by using an antenna gain pattern of a synthetic aperture radar (SAR) both in a time domain and in a frequency domain. The method may include performing frequency-domain radiometric compensation in relation to an elevation angle and performing time-domain radiometric compensation in relation to a frequency to calibrate the antenna gain pattern.

A direction finding system and method to utilize synthetic apertures within a single short pulse transmission to extrapolate additional data relating to the signal to thereby increase the accuracy of the direction finding results given by a single short pulse is provided. The direction finding system may further exploit the movement of a platform to create the synthetic apertures within the signal data.

Range-compressed data are determined by range-compressing echo data, and are set as first data to be decomposed by first decomposition. Starting from n=1, iteration is performed as follows. nth data to be decomposed are up-sampled. nth decomposition is performed on the up-sampled data. Dependency on slant ranges between a reference point and sub-apertures before and after synthesis is determined. nth azimuth-synthesized data are acquired by performing, according to the dependency on the slant ranges, nth azimuth synthesis on data acquired by the nth decomposition. The nth azimuth-synthesized data are set as (n+1)th data to be decomposed by (n+1)th decomposition. The n is increased by 1. A next iteration is performed until the n reaches a positive integer N greater than 1. A focused image is acquired by performing azimuth focusing on the Nth azimuth-synthesized data by BP.

During a location technique, a sensor module in a vehicle, which has non-retractable wheels in contact with a driving surface, determines a location of the vehicle. In particular, the sensor module is positioned on or in a direction of a side-facing surface of the vehicle. Moreover, during operation, the sensor module may transmit radar signals approximately perpendicular to a direction of motion of the vehicle. Then, the sensor module may receive reflected radar signals. Furthermore, the sensor module may analyze a time sequence of the reflected radar signals. Next, the sensor module may determine the location of the vehicle based at least in part on the analyzed time sequence of reflected radar signals.

A system and method for forming synthetic aperture radar images. Radar return pulses are grouped into sub-dwells, and their frequency content is separated into frequency sub-bands. A coarse image is formed for each sub-band/sub-dwell combination. The coarse images are iteratively interpolated to higher resolution and combined, to form a single high-resolution synthetic aperture radar image.

A radar assembly for receiving signals at spaced frequencies from an unknown transmitting source comprising a receiver operative to receive signals; the receiver comprising a series of channels, each channel comprising a low pass filter configured to allow passage of a signal from an unknown transmitting source, an analog to digital converter configured to transform the signal from the unknown transmitting source to a digital signal, a Hilbert transform configured to transform the digital signal from the unknown transmitting source into a single sideband signal, a Fourier transform configured to transform the single sideband signal into a plurality of regularly spaced frequency samples, and an inverse Fourier transform for extracting regularly spaced frequency samples; whereby extracted pulses form a train of pulses that are inputted into an imager which utilizes synthetic aperture radar to form an image of the area of interest containing the unknown transmitting device and method thereof.