The present application presents various techniques for improving the performance of range tracking motion compensation method for high resolution radar imaging. Three improved techniques are described herein: improved cross-correlation alignment through updates to the reference range profile to follow the target's changing illumination angle; improved cross-correlation alignment through local peak boosting; and, improved polynomial smoothing through subdivision into multiple windows.

Systems and methods are provided for interrogating a moving acoustic source using radar and processing data using a selection of motion compensation techniques adapted from synthetic aperture radar (SAR) to remove the effects of linear and nonlinear target motion so that the range-Doppler map retains only vibration information in the Doppler dimension. Vibration and sound waveforms can thus be selectively reproduced at specific ranges directly from the radar baseband waveform, without the need for additional complex analysis or audio processing.

A synthetic-aperture-radar-signal processing device includes a range bin selection unit which selects, from an observed image, range bins including a signal from an isolated reflection point, a phase evaluation unit which evaluates phases in an azimuth direction in the range bins, a window function multiplication unit which designs a window function on the basis of results of the evaluation by the phase evaluation unit and multiply the range bins by the window function, and a phase error correction unit which corrects the observed image by estimating a phase error from the range bins multiplied by the window function.

The various technologies presented herein relate to utilizing direction of arrival (DOA) data to determine various flight parameters for an aircraft A plurality of radar images (e.g., SAR images) can be analyzed to identify a plurality of pixels in the radar images relating to one or more ground targets. In an embodiment, the plurality of pixels can be selected based upon the pixels exceeding a SNR threshold. The DOA data in conjunction with a measurable Doppler frequency for each pixel can be obtained. Multi-aperture technology enables derivation of an independent measure of DOA to each pixel based on interferometric analysis. This independent measure of DOA enables decoupling of the aircraft velocity from the DOA in a range-Doppler map, thereby enabling determination of a radar velocity. The determined aircraft velocity can be utilized to update an onboard INS, and to keep it aligned, without the need for additional velocity-measuring instrumentation.

There are provided: a high-accuracy factor calculator for calculating, by a high-accuracy computation method, a distance R from a moving platform to a pixel position (a, b) within an observation target corresponding to an predicted position (x.sub.t, y.sub.t) and a phase factor A when a determination processor determines that an error is out of an allowable range; and a low-accuracy factor calculator for calculating, by a computation method with lower accuracy than that of the high-accuracy factor calculator (e.g., a computation method using an approximation algorithm), a distance R′ from the moving platform to the pixel position (a, b) corresponding to the predicted position (x.sub.t, y.sub.t) within the observation target and a phase factor A′ when the determination processor determines that the error is within the allowable range.

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.

A radar image processing device is provided for generating a radar image from a region of interest (ROI). The radar image processing device receives transmitted radar pulses and radar echoes reflected from the ROI at different positions along a path of a moving radar platform and stores computer-executable programs including a range compressor, a graph modeling generator, a signal aligner, a radar imaging generator and a focused image generator. The radar image processing device performs range compression on the radar echoes by deconvolving the transmitted radar pulses and a radar measurement to obtain frequency-domain signals, generate a graph model represented by sequential positions of the moving radar platform and a graph shift matrix computed using the frequency-domain signals, iteratively denoise and align the frequency-domain signals to obtained denoised data and time shifts by solving a graph-based optimization problem represented by the graph model, wherein the approximated time shifts compensate phase misalignments caused by perturbed positions of the moving radar platform, and perform radar imaging based on the denoised data and the estimated time shifts to generate focused radar images.

Devices, systems, and methods for removing non-linearities in an inverse synthetic aperture radar (ISAR) image are provided. A method includes estimating pitch and roll about range and doppler axes of a time series of ISAR images including the ISAR image, interpolating ISAR image data based on the estimated pitch and roll resulting in interpolated ISAR image data, and resampling based on the interpolated ISAR image data and the time series of TSAR images resulting in an enhanced image.

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.

A synthetic-aperture-radar-signal processing device includes a range bin selection unit which selects, from an observed image, range bins including a signal from an isolated reflection point, a phase evaluation unit which evaluates phases in an azimuth direction in the range bins, a window function multiplication unit which designs a window function on the basis of results of the evaluation by the phase evaluation unit and multiply the range bins by the window function, and a phase error correction unit which corrects the observed image by estimating a phase error from the range bins multiplied by the window function.