- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Improved Sparse Adaptive Algorithms for Accurate Non-contact Heartbeat Detection Using Time-Window-Variation Technique
摘要： Recently, a sparse adaptive algorithm termed zero-attracting sign least-mean-square (ZA-SLMS), has been clarified to be able to reconstruct robustly heartbeat spectrum by Doppler radar signal. However, since the strengths of noise evidently differ under different body motions, the sparse heartbeat spectra cannot be always acquired accurately by the constant regularization parameter (REPA) that balances the gradient correction and the sparse penalty, applying in the ZA-SLMS algorithm. In this paper, an improved ZA-SLMS algorithm is proposed by introducing adaptive REPA (AREPA), where the proportion of sparse penalty is adjusted based on the standard deviation of radar data. Moreover, to enhance the stability of heartbeat detection, a time-window-variation (TWV) technique is further introduced in the improved ZA-SLMS algorithm, considering the fact that the position of spectral peak associated with the heart rate (HR) is stable when the length of time window changes within a short period. Experimental results measured against five subjects validated that our proposal reliably improves the error of HR estimation than the standard ZA-SLMS algorithm.
关键词： heartbeat detection,time-window-variation,Doppler radar,regularization parameter,sparse adaptive algorithm
更新于2025-09-23 15:23:52
-
[IEEE 2018 International Conference on Radar (RADAR) - Brisbane, Australia (2018.8.27-2018.8.31)] 2018 International Conference on Radar (RADAR) - Predicting Phased Array Radar Performance Through Modelling
摘要： Modelling and simulation can reduce risk associated with complex radar system development because design choices can be validated before any hardware is developed. Models can also be used to accelerate algorithm development for existing radar systems. This paper describes the modelling results for two phased array radar designs: an MTI radar and a MIMO radar. These systems were modelled and then tested with radar data generated with commercially available radar hardware. The performance results for both models and the hardware-fed processing are analyzed and compared.
关键词： Radar Modelling,MTI Radar,MIMO Radar,Radar Simulation
更新于2025-09-23 15:22:29
-
Bistatic SAR: Forecasting Spatial Resolution
摘要： This paper derives closed form expressions for bistatic synthetic aperture radar spatial resolution of a generalized system from the k-space or the wavenumber domain. These spatial resolution equations have not previously appeared in the literature. From these equations, significant resolution is found in both range and cross-range forecasting a forward-scatter bistatic synthetic aperture radar image when the elevation angles of each bistatic platform are significantly different. Simulation and lab tests demonstrated the forward scatter resolution.
关键词： image resolution,synthetic aperture radar,radar remote sensing,spatial resolution,radar imaging,bistatic radar,microwave imaging
更新于2025-09-23 15:22:29
-
[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 - Recent Findings on the Sentinel-L Geolocation Accuracy Using the Australian Corner Reflector Array
摘要： Synthetic Aperture Radar (SAR) satellites observe range and azimuth geometric accuracies at the low centimeter level. The accuracy of geolocation is driven by several aspects, e.g. orbit determination, SAR image processing, or atmospheric error correction. Our paper concentrates on the Sentinel-1 mission and the compensation of the platform motion effects in the geolocation, which were found to limit the best possible geolocation capabilities of Sentinel-1. The key to advance the geolocation results is the rigorous compensation of the bistatic effect in azimuth, and the correction of the Doppler-induced shifts in range. First results for Sentinel-1 at the Australian reflector array consisting of 40 Corner Reflector (CR) show consistent improvement in the geolocation (1σ) to 6 cm in range and 28 cm in azimuth for both spacecrafts when using the Interferometric Wideswath (IW) product.
关键词： synthetic aperture radar,spaceborne radar,radar remote sensing,geodesy,geolocation
更新于2025-09-23 15:22:29
-
[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 in-Situ Demonstration of Passive Radio Sounding Using the Sun as a Source for Echo Detection
摘要： While radio echo sounders are powerful tools used to constrain subglacial conditions, current ice-penetrating radar systems are too resource intensive for multiyear deployment at a large scale. To address this, we present passive radio sounding as a low resource approach for observing the subsurface of ice sheets and glaciers. Although passive radar has been used for target tracking and military purposes, it has never been implemented for ice sounding. Nevertheless, recent work has proposed the passive radio sounding of Europa’s icy shell using Jupiter’s decametric radiation as a source for echo detection [1,2]. Expanding on this idea, we evaluate and discuss the challenges of developing a passive radio sounder that uses the Sun for echo detection. Our prototype measures the Sun’s direct and reflected path off the ocean to obtain the height of a cliff along the California coast. This serves as the first in-situ demonstration of an autocorrelation-based passive-sounder using a compact astronomical white noise source.
关键词： ice-penetrating radar,passive radar,radio echo sounding
更新于2025-09-23 15:22:29
-
[IEEE 2018 International Conference on Radar (RADAR) - Brisbane, Australia (2018.8.27-2018.8.31)] 2018 International Conference on Radar (RADAR) - Real Aperture Imaging Using Sparse Optimisation with Application to Low-Angle Tracking
摘要： Estimating the angle of arrival of a low-altitude target over the sea surface is made difficult due to the coherent multipath interference caused by the target image. A real aperture imaging technique for estimating azimuth and elevation of targets using a phased array multichannel radar, as described by Berry et al [1], is applied to this classical problem of suppressing low-angle multipath signals received by a naval radar from a low-flying target. The degree of spatial resolution which can be usefully attained is explored; this depends on many factors and the nonlinear problem formulation is not easily amenable to analysis. It is found that the technique is feasible for resolving the direct target signal, its specular reflection and multiple diffuse reflections even when the signals would be combined by a conventional beamformer to form a multipath null.
关键词： radar signal processing,low-angle tracking,sparse optimisation,multipath propagation,phased array multichannel radar
更新于2025-09-23 15:22:29
-
[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 - Validation of SAR Iceberg Detection with Ground-Based Radar and GPS Measurements
摘要： Calving of icebergs at the tidewater glacier fronts is a component of the mass loss in Polar regions. Studying the regional distribution of icebergs, their volume, motion, and interaction with the environment is of interest. Here, we present the results from a fieldwork campaign conducted in Kongsfjorden, Svalbard in April 2016, where both satellite and ground-based remote sensing instruments were used to observe dynamics of sea ice, icebergs, and growlers. We used a ground-based radar system, imaging the study area every second minute during five days. During the same observation period, we collected four RADARSAT-2 (RS-2) quad-pol images, that are used for automatic detection of icebergs. In addition, the fieldwork team collected GPS positions of some drifting and grounded icebergs in the fjord to be used as ground-truth data. The comparison and combination of satellite, ground-based radar, and in-situ data contribute to cross-validate the results.
关键词： synthetic aperture radar,ground-based radar,polarimetry,GPS mapping,Iceberg,detection,sea ice
更新于2025-09-23 15:22:29
-
[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 - Investigations on the Reconstruction of Multistatic Large Along-Track SAR Constellations for HRWS Imaging
摘要： This paper presents first the performance analysis of the state-of-the-art multi-channel SAR signal reconstruction algorithms that suffer from the geometrical approximations. Then, it proposes a two-step signal reconstruction method for spaceborne large along-track baseline multistatic SAR constellations operated with a pulse repetition frequency (PRF) under the Nyquist rate. The suggested algorithm first applies a bulk polychromatic reconstruction in wavenumber domain and then compensates the residual range variance in range-Doppler domain. This simple modification helps to reduce overall phase errors in the reconstruction process of the analysed case with respect to the state-of-the-art algorithms by about one order of magnitude. The performance of the algorithm is verified by showing the results in point target simulations for a multistatic X-band constellation with a resolution of about 15 times the carrier wavelength.
关键词： high-resolution wide-swath (HRWS) radar,multistatic radar signal processing,Digital beamforming
更新于2025-09-23 15:22:29
-
A Reflection Symmetry Approximation of Multilook Polarimetric SAR Data and its Application to Freeman-Durden Decomposition
摘要： Freeman–Durden decomposition is a frequently used technique to analyze the scattering characteristics of multilook Polarimetric Synthetic Aperture Radar (POLSAR) data. When it is applied to the real POLSAR data, two problems emerge, namely, the volume scattering overestimation and negative powers. Many researchers think these two problems are caused by the insufficient decomposition algorithm, and the improved decomposition algorithms become more and more complicated, and some new problems such as the decomposed component is not model based also emerge. In this paper, we try to solve the two problems through another way. We think they are caused not by the insufficient decomposition algorithm but by the dogmatic input. Freeman–Durden decomposition explicitly assumes reflection symmetry. Its input is a direct truncation of the measured coherency matrix. The truncation can be regarded as a reflection symmetry approximation (RSA) of the measured coherency matrix. We first show some reasons why we do not think the truncation is a good RSA. Then, a new RSA is proposed based on the sum of three reflection symmetry components derived from the measured coherency matrix. Experimental results with several real POLSAR images show that, if the new RSA is used as the input of Freeman–Durden decomposition, the above-mentioned two problems no longer exist.
关键词： Polarimetric Synthetic Aperture Radar (POLSAR),radar polarimetry,Polarimetric decomposition
更新于2025-09-23 15:22:29
-
A Sensitivity Analysis of the Standard Deviation of the Copolarized Phase Difference for Sea Oil Slick Observation
摘要： In this paper, a time series of 33 TerraSAR-X copolarized synthetic aperture radar (SAR) imagery collected in Stripmap mode over the Gulf of Mexico in a wide range of incidence angles and sea-state condition is exploited, together with a theoretical framework based on the X-Bragg scattering model, to analyze the effects of noise, angle of incidence, (AOI) and wind speed on the standard deviation of the copolarized phase difference (στc ) evaluated over sea surface with and without oil slicks. This large data set represents an unprecedented opportunity to analyze, for the ?rst time, the in?uence of both SAR acquisition and surface parameters on the broadening of the copolarized phase difference probability density function (pdf), (τc). Experimental results show that the X-Bragg scattering model, here adopted to predict the sea surface pτc (τc), gives an understanding of the increasing trend of στc with respect to AOI. It is shown that the noise signi?cantly contributes to broaden pτc (τc) over both slick-free and slick-covered sea surface, while the effects of low-to-moderate wind regimes are negligible. In addition, στc exhibits a larger sensitivity to the scene variability, if compared to single-polarization intensity channels, over both slick-free and oil-covered sea surface. This sensitivity is more pronounced at lower AOIs due to the higher noise equivalent sigma zero (NESZ) that affects larger AOIs.
关键词： Oceans,oil pollution,synthetic aperture radar,radar polarimetry
更新于2025-09-23 15:22:29