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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - End-to-End Simulator of Geosynchronous SAR Data for System Performance Assessment
摘要： The paper describes an end-to-end simulator for Geosynchronous SAR data. The tool is composed of two modules: a raw data time domain simulator and a processor for the generation of the L1 products. The simulated raw data include the effects of atmospheric and clutter decorrelation. The end-to-end simulator is a powerful and flexible tool to be used during the system design phase for the verification of the expected performance.
关键词： APS,clutter,decorrelation,Geosynchronous SAR,end-to-end simulator
更新于2025-09-23 15:23:52
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - High Resolution Measurements and Characterization of Urban, Suburban and Country Clutter at X-Band and Related Radar Calibration
摘要： At Tor Vergata University we are working on measurements and phenomenological characterization of urban, suburban and country radar clutter at X-band (3 cm wavelength, range resolution 8 to 10 m, azimuth resolution @ 1 km about 23.5 m) and on the related radar calibration problems. Measurements are 'high resolution' when compared to most surveillance radars, and the related applications are in the frame of clutter maps for cognitive radar, drones detection, radar ornithology, and more. After calibration, done using opportunity targets with known radar cross section and a clutter fence, we carry on an analysis and a comparison of land clutter, considering different weather conditions: dry and wet soil, as well as the rare event of snow. Using fixed opportunity targets, such as lamppost and/or a large cylindrical steel tanker, we describe the attenuation effects due to the natural clutter fence (in this case due to cane thicket near to the target position) and its mitigation when the natural fence is gradually removed. Finally, but importantly, we analyze the multipath phenomenon due to reflection/scattering on ground, and propose a procedure to estimate the multipath factor and to correct for it.
关键词： urban clutter,radar calibration,high resolution radar,multipath,X-band
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - First GMTI Results of the MIRANDA-35 Sensor
摘要： Frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) are nowadays frequently exploited for producing electro-magnetic images of the earth surface. In this paper, we present first ground moving target indication (GMTI) results of the 2016 campaign with the FMCW airborne system MIRANDA-35, and quantify the overall performances. More precisely, two specific operating modes, namely the along-track interferometry (ATI) and exo-clutter processing (EXO), are discussed in more detail. The system proved to be capable of providing GMTI products with reliable detection rates and acceptable false alarm rates.
关键词： FMCW,GMTI,SAR,Ground Moving Target Indication,Synthetic Aperture Radar,Exo-Clutter,Frequency-Modulated Continuous-Wave,Interferometry
更新于2025-09-23 15:23:52
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Adaptive Sidelobe Cancellation Technique for Atmospheric Radars Containing Arrays with Nonuniform Gain
摘要： The design and performance evaluation is presented of a partially adaptive array that suppresses clutter from low elevation angles in atmospheric radar observations. The norm-constrained and directionally constrained minimization of power (NC-DCMP) algorithm has been widely used to suppress clutter in atmospheric radars, because it can limit the signal-to-noise ratio (SNR) loss to a designated amount, which is the most important design factor for atmospheric radars. To suppress clutter from low elevation angles, adding supplemental antennas that have high response to the incoming directions of clutter has been considered to be more efficient than to divide uniformly the high-gain main array. However, the proper handling of the gain differences of main and sub-arrays has not been well studied. We performed numerical simulations to show that using the proper gain weighting, the sub-array configuration has better clutter suppression capability per unit SNR loss than the uniformly divided arrays of the same size. The method developed is also applied to an actual observation dataset from the MU radar at Shigaraki, Japan. The properly gain-weighted NC-DCMP algorithm suppresses the ground clutter sufficiently with an average SNR loss of about 1 dB less than that of the uniform-gain configuration.
关键词： robust adaptive beamforming,clutter suppression,atmospheric radars,partial adaptivity
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 14th International Conference on Intelligent Computer Communication and Processing (ICCP) - Cluj-Napoca (2018.9.6-2018.9.8)] 2018 IEEE 14th International Conference on Intelligent Computer Communication and Processing (ICCP) - Multimodal sparse LIDAR object tracking in clutter
摘要： one of the key components of the perception system in an autonomous vehicle or ADAS is the target tracking module. Using target tracking in the sea of clutter, self-driving cars are able to better understand the environment and make predictions about the surrounding objects. Cuboids obtained from a sparse LIDAR often exhibit a fluctuating behavior due to segmentation problems and errors accumulated from the motion correction module. Furthermore, targets in real life scenarios do not move in a predictable manner, so it is very difficult for a classical motion model to describe the complex behavior of any road objects in such cases. In this paper we propose a two-step data association scheme that efficiently and effectively finds correspondences between tracks and measurements. Then we aim to generate better position estimates for objects with an ambiguous dynamic behavior by associating and combining the results from two different motion models. The proposed solution runs in real time and it was validated using a high precision GPS, and also by projecting the corresponding image and assessing whether the prediction falls on the correct item.
关键词： Clutter,3D LIDAR objects,Vehicle Tracking,Data Association
更新于2025-09-23 15:22:29
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Sea Clutter Cancellation for Passive Radar Sensor Exploiting Multi-Channel Adaptive Filters
摘要： Sea clutter suppression in passive radar sensor is a challenging problem because the Doppler frequencies of low-velocity sea-surface targets are typically close to the spectrum of the sea clutter. Conventional approaches based on single-channel high-pass filters are effective for clutter suppression only when the clutter is concentrated in low Doppler region. For sea clutter that has a spread spectrum, however, these approaches have to compromise target signal reception. That is, they either form a narrow notch which does not effectively suppress clutter, or generate a broadened null that simultaneously mitigates low-velocity target signals. Therefore, it is desirable to design a filter that forms a notch broad enough to cover the entire clutter spectrum, with the frequency response rising sharply to a high gain outside the clutter band. Toward this end, in this paper, we develop a generalized multi-channel adaptive filter which, by forming multiple sharp notches over a set of discrete frequencies within the clutter spectrum, achieves effective clutter suppression and target signal preservation. We focus on the fast frequency-domain implementation, and the performance analysis in terms of the frequency response, signal energy loss, and computational complexities is also presented. The effectiveness of the proposed approaches is verified using real-data results.
关键词： interference cancellation,sea clutter,multi-channel adaptive filter,Passive radar sensor,normalized least mean square (NLMS)
更新于2025-09-23 15:22:29
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Noncoherent Detector Threshold Determination in Correlated Pareto Distributed Clutter
摘要： Setting thresholds for sliding window noncoherent detection processes is extremely difficult in the presence of a correlated clutter range profile. This is certainly the case when attempting to apply a trimmed sum of order statistics as the measurement of the clutter level. In order to facilitate this, a new expression for the threshold of such a detector is derived, which is a function of probabilities of two associated random variables. This then permits a Monte Carlo scheme to be applied to determine thresholds. In the case of real data, if a clutter map is assumed to be an accurate representation of the radar operating environment, then one can avoid estimating correlations in the process of determining thresholds. Examples of this will be provided to demonstrate the utility of the proposed scheme.
关键词： Correlated Clutter,trimmed sum OSs,order statistics (OSs),noncoherent detection
更新于2025-09-23 15:22:29
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Receive Beam-Steering and Clutter Reduction for Imaging the Speed-of-Sound Inside the Carotid Artery
摘要： Handheld imaging of the tissue’s speed-of-sound (SoS) is a promising multimodal addition to diagnostic ultrasonography for the examination of tissue composition. Computed ultrasound tomography in echo mode (CUTE) probes the spatial distribution of SoS, conventionally via scanning the tissue under a varying angle of ultrasound transmission, and quantifying—in a spatially resolved way—phase variations of the beamformed echoes. So far, this technique is not applicable to imaging the lumen of vessels, where blood ?ow and tissue clutter inhibit phase tracking of the blood echoes. With the goal to enable the assessment of atherosclerotic plaque composition inside the carotid artery, we propose two modi?cations to CUTE: (a) use receive (Rx) beam-steering as opposed to transmit (Tx) beam-steering to increase acquisition speed and to reduce ?ow-related phase decorrelation, and (b) conduct pairwise subtraction of data obtained from repetitions of the scan sequence, to highlight blood echoes relative to static echo clutter and thus enable the phase tracking of blood echoes. These modi?cations were tested in a phantom study, where the echogenicity of the vessel lumen was chosen to be similar to the one of the background medium, which allows a direct comparison of SoS images obtained with the different techniques. Our results demonstrate that the combination of Rx-steering with the subtraction technique results in an SoS image of the same quality as obtained with conventional Tx-steering. Together with the improved acquisition speed, this makes the proposed technique a key step towards successful imaging of the SoS inside the carotid artery.
关键词： atherosclerosis,clutter reduction,plaque characterisation,multimodal imaging,ultrasound tomography
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A Study of Cross-Polarized Sea Clutter Using the SSA2 High Frequency Approximation and the Two-Scale Model
摘要： Cross-polarized backscatter normalized radar cross section (NRCS) measurements have been of increasing interest due to their potential to improve wind speed retrievals at high wind speeds. The development of physics-based forward models for cross-polarized backscatter has been challenging due to the higher-order scattering mechanisms that contribute to this quantity. In this paper, predictions of the two-scale model (TSM) and the small slope approximation (SSA2) for cross polarized backscatter are examined to obtain insight into their relative merits. A recently introduced high frequency (HF) approximation for cross polarized backscatter under the SSA2 is also examined and compared to a similar approximation based on the TSM. The results provide guidance for the continued development of forward models for sea surface remote sensing using cross polarized backscatter.
关键词： Cross-polarized,high frequency approximation,Sea clutter,Two scale model
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Imaging of Moving Target for Cooperative Sar Between High-Orbit and Low-Orbit Satellites
摘要： When synthetic aperture radar (SAR) imaging is applied to observe ground scene containing a moving target, the imagery of moving target will be typically smeared due to range cell-migration and Doppler spectrum broadening caused by the target motions, especially for the accelerating targets within a long observation time. To eliminate these effects, a novel imaging algorithm using cooperative between SAR under high-orbit and low-orbit satellites is proposed. The range migration including range walk and range curvature within the coherent integration period has been corrected via the third-order keystone transform. Then, by estimating and compensating the phase errors and the fold factor terms, the target’s resolution is improved and the motion parameters are correctly estimated. The effectiveness of the proposed algorithm is demonstrated by simulations.
关键词： clutter suppression,Ground moving target detection (GMTI),space-borne SAR imaging,third-order keystone transform
更新于2025-09-23 15:21:21