Synthetic aperture radar (SAR) ground moving target indication (GMTI) has attracted a lot of interest from researchers for its ability simultaneously obtaining high-quality images stationary scenes and detection targets. In recent years, the research on tracking besides by using SAR-GMTI also raised interest. Compared with standard SAR, long observation time circular SAR (CSAR) makes it possible trajectory reconstruction. By prior knowledge road information, an effective method...

The polar format algorithm (PFA) is a frequency-domain with high computational efficiency especially for the resolution imaging applications in wide-angle staring synthetic aperture radar (WAS-SAR). Because of image distortion and defocus caused by plane wave assumption, effective scene limited to small region which defined as defocus-negligible region. In this article, novel sub-block first applied WAS-SAR proposed. This method combines spatially variant post-filtering (SVPF) can not only...

By introducing curvilinear structures extraction (CSE) instead of watershed algorithm (WA) or nonmaximum suppression (NMS) to edge strength map (ESM), an improved ratio exponentially weighted averages (ROEWA) detector with better capacity for weak edges detection is proposed extract smooth and direction synthetic aperture radar (SAR) images. Using the ROEWA, ESM calculated. Then CSE employed extracted edges, by acquiring eigenvectors eigenvalues Hessian matrix, (IESM) obtained, which ensures...

Road extraction is an important part of synthetic aperture radar (SAR) image interpretation. In recent years, circular SAR (CSAR) has attracted extensive attention from researchers owing to its ability 360° observation. Due the unique imaging geometry CSAR, CSAR images contain more complete road information. However, curvilinear-structured appearance roads in and complexity scene result difficulties extraction. The curvilinear structure detector (CSD) capable extracting structures with a...

Trajectory deviations in airborne synthetic aperture radar (SAR) will induce phase errors and degrade the quality of SAR images. For obtaining high resolution images, motion compensation (MOCO) is performed by using GPS or INS, furthermore, autofocusing algorithms should also be used for residual (RPE) correction. Map-Drift (MD), a commonly algorithm, has ability correcting quadric (QPE) improving imaging quality. In this paper, an improved MD algorithm proposed. proposed method, principal...

This paper designs a single rotatable dual-polarized antenna polarimetric active radar calibrator (PARC) and proposes corresponding dynamic calibration (DPC) method. The novel PARC simplifies the system equipment optimises antenna's pattern. By modulating time-delay of retransmitted signal PARC, is calibrated with DPC simulations verify that scheme possesses better accuracy than double-antenna scheme. (5 pages)

Low frequency ultra wideband (UWB) synthetic aperture radar (SAR) has shown a great potential when vehicle-size objects are obscured in foliage. The studies imply an angle of at least 180° to include the strongest (broadside) response target orientations unknown. However, linear SAR (LSAR) is limited. By using circular traces, data acquisition been increased, and detection capabilities could be improved. An airborne (CSAR) experiment was carried out Shaanxi by National University Defense...

This paper introduce an approach for detecting bridges when the difference in radar echo energy is not obvious. It consists of two steps: extracting targets with high anisotropy and bridge. Firstly, by image segmentation based on feature multi-aperture polarimetric entropy, we get certainty. And then utilize edge detection to extract straight line segmentations. Finally, parallel segmentations which meet bridges' geometric properties are selected as bridges. The proposed has been test CSAR...

Understanding human mobility patterns is essential for various applications, from urban planning to public safety. The individual trajectory such as mobile phone location data, while rich in spatio-temporal information, often lacks semantic detail, limiting its utility in-depth analysis. Existing methods can infer basic routine activity sequences this lacking depth understanding complex behaviors and users' characteristics. Additionally, they struggle with the dependency on hard-to-obtain...

Circular synthetic aperture radar (CSAR) enables 360-degree observation of the scene. Compared with coherent imaging, noncoherent imaging can suppress speckle and obtain a large number texture features. However, due to existence man-made anisotropic targets unique geometry CSAR, different subaperture images are quite different, which makes registration very difficult. Therefore, this manuscript proposed factorized strategy. First, full is divided into multiple subapertures; then adjacent...

With the continuous development of synthetic-aperture-radar (SAR) technology, SAR-image data are becoming increasingly abundant. For same scene, dual-frequency (high-frequency and low-frequency) SAR images can present different details feature information. Image fusion two frequencies combine advantages both, thus describing targets more comprehensively. registration is key step image determines quality fusion. Due to complex geometric distortion gray variance between with high resolution,...

By introducing improved curvilinear structure detector (ICSD), this paper proposed an approach for local road extraction from synthetic aperture radar (SAR) images. First, the ICSD is used to extract centerlines and direction of roads. Second, employed edges in SAR images, since image appear as structures its edge strength map (ESM). Then, roads are obtained by mutual verification between due large amount interference. Finally, missing pixels extracted. The experimental results shown...

Subject to the low pulse repetition frequency (PRF), or under sampling, grating-lobes will appear at azimuth in synthetic aperture radar (SAR) imagery. In this paper, presence of particular ring-shaped (RSGLs) circular SAR (CSAR) imagery is first reported as much authors know. Characteristics RSGLs are analysed detail, including radius, width and amplitude RSGLs. Benefiting from small RSGLs, a lower PRF adequate for acceptable image quality CSAR. Simulation results validate conclusions...

Non-cooperative ground moving targets appear smeared and dislocated in synthetic aperture radar (SAR) imagery as they are treated static the imaging procedure. In this paper, a non-searching method for Circular SAR (CSAR) target refocusing based on Inverse (ISAR) technique well sub-aperture segmentation is proposed. Firstly, range migration of directly extracted range-frequency domain fitted according to quadratic polynomial. Secondly, matched filter constructed by polynomial multiplied echo...

This paper introduces an extended factorized geometrical autofocus (FGA) algorithm for circular synthetic aperture radar (CSAR) which is based on the FGA in stripmap (SAR). The strategy that integrate with a fast back-projection (FFBP) processing chain and relies varying track parameters step by to obtain sharp image. focused quality of obtained image evaluated computing object function (intensity correlation). has been tried out wavelength-resolution CSAR data set erroneous parameters. To...

Long-term time series forecasting is a vital task and has wide range of real applications. Recent methods focus on capturing the underlying patterns from one single domain (e.g. or frequency domain), have not taken holistic view to process long-term time-frequency domains. In this paper, we propose Time-Frequency Enhanced Decomposed Network (TFDNet) capture both temporal periodicity domain. TFDNet, devise multi-scale enhanced encoder backbone develop two separate trend seasonal blocks...

Isotropy edge detection filters for synthetic aperture radar (SAR) images, such as crater-shaped window (CSW), cannot keep both high resolution and good speckle suppression ability at the same time. In this letter, an detector-combined CSW robust inhibition-augmented curvilinear operator (RUSTICO) has been proposed. First, preliminary strength map (ESM) is calculated by using CSW. Second, RUSTICO applied to suppress influence of obtain improved ESM (IESM). Moreover, nonmaximum hysteresis...

Circular synthetic aperture radar (CSAR) observes the scene by 360 degrees, characteristics of targets from different aspects can be obtained. The noncoherent imaging is more popular since textural features and lower speckle noise acquired. However, due to motion error platform topography observation scene, result full not derived simply superimposing subaperture images. In this paper, based on enhanced correlation coefficient (ECC), we proposed a registration strategy obtain CSAR,...