A5044296048- Synthetic Aperture Radar (SAR) Applications and Techniques
- Advanced SAR Imaging Techniques
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
- Ocean Waves and Remote Sensing
- Soil Moisture and Remote Sensing
- Arctic and Antarctic ice dynamics
- Astro and Planetary Science
- Oceanographic and Atmospheric Processes
- Cryospheric studies and observations
- Spacecraft and Cryogenic Technologies
- Underwater Acoustics Research
- Microwave Imaging and Scattering Analysis
- Geophysical Methods and Applications
- Radar Systems and Signal Processing
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Ultrasonics and Acoustic Wave Propagation
- Climate change and permafrost
- Spacecraft Design and Technology
- GNSS positioning and interference
- Seismic Imaging and Inversion Techniques
- Precipitation Measurement and Analysis
- Space Science and Extraterrestrial Life
- Sparse and Compressive Sensing Techniques
Maryland Department of Natural Resources
2016-2024
Johns Hopkins University Applied Physics Laboratory
2006-2016
Johns Hopkins University
1995-2012
Canadian Association of Learned Journals
2002-2005
Jet Propulsion Laboratory
1986
California Institute of Technology
1986
Environmental Research Institute of Michigan
1977
University of Michigan
1969-1971
A space-variant interpolation is required to compensate for the migration of signal energy through range resolution cells when processing synthetic aperture radar (SAR) data, using either classical range/Doppler (R/D) algorithm or related frequency domain techniques. In general, requires significant computation time, and leads loss image quality, especially in complex image. The new chirp scaling avoids interpolation, yet performs cell correction accurately. only multiplies Fourier...
This paper considers the effects of slowly moving targets as they appear in output an airborne coherent side-looking synthetic aperture imaging radar. The image a reflector is described, and two approaches to target indication (AMTI) are summarized. It shown that movement decreased radar scan rate increased, increased (Doppler processed) compression ratio increased.
A synthetic aperture radar (SAR) often is constrained to transmit only one polarization. Within this constraint, two aggressive measurement objectives are 1) full characterization and exploitation of the backscattered field, 2) invariance geometrical orientations features in scene. Full implies coherent dual-polarization support four Stokes parameters. These rotationally invariant with respect backscatterer orientation if transmission circularly polarized. Given that data products...
This paper reviews basic synthetic aperture radar (SAR) theory of ocean wave imaging mechanisms, using both known work and recent experimental theoretical results from the Marine Remote Sensing (MARSEN) Experiment. Several viewpoints that have contributed to field are drawn together in a general analysis backscatter statistics moving sea surface. A common focus for different scattering models is provided by mean image impulse response function, which shown be identical (spatially varying)...
The key innovation in the delay/Doppler radar altimeter is delay compensation, analogous to range curvature correction a burst-mode synthetic aperture (SAR). Following height estimates are sorted by Doppler frequency, and integrated parallel. More equivalent looks accumulated than conventional altimeter. relatively small along-track footprint size constant of system, typically on order 250 m for Ku-band flat-surface response an impulse rather more familiar step function produced satellite...
A synthetic aperture radar (SAR) with hybrid-polarity (CL-pol) architecture transmits circular polarization and receives two orthogonal, mutually coherent linear polarizations, which is one manifestation of compact polarimetry. The resulting relatively simple to implement has unique self-calibration features low susceptibility noise. It also enables maintenance a larger swath coverage than fully polarimetric SAR systems. research team composed various departments the Government Canada...
We introduce a new technique derived from the classical Stokes parameters for analysis of polarimetric radar astronomical data. This decomposition is based on m (the degree polarization) and chi Poincaré ellipticity parameter). Analysis crater Byrgius A demonstrates how m‐chi can more easily differentiate materials within ejecta deposits their relative thicknesses. use Goldschmidt to demonstrate coherent water ice. floor found be consistent with single bounce Bragg scattering suggesting...
The Mini‐RF radar instrument on the Lunar Reconnaissance Orbiter spacecraft mapped both lunar poles in two different RF wavelengths (complete mapping at 12.6 cm S‐band and partial 4.2 X‐band) look directions, removing much of ambiguity previous Earth‐ spacecraft‐based Moon's polar regions. are typical highland terrain, showing expected values cross section (albedo) circular polarization ratio (CPR). Most fresh craters display high CPR outside crater rim; pattern these distributions is...
We present new polarimetric radar data for the surface of north pole Moon acquired with Mini‐SAR experiment onboard India's Chandrayaan‐1 spacecraft. Between mid‐February and mid‐April, 2009, mapped more than 95% areas polewards 80° latitude at a resolution 150 meters. The polar region displays backscatter properties typical Moon, circular polarization ratio (CPR) values in range 0.1–0.3, increasing to over 1.0 young primary impact craters. These higher CPR likely reflect roughness...
For a given transmission polarization, the four-element Stokes vector captures all of information inherent to dual-polarized backscattered signals. parameters are linear combinations like-polarized power, cross-polarized and cross product between complex image amplitudes in two receive channels. Most so-called synthetic aperture radar (SAR) systems provide only like- cross-product images, ignoring product. In so doing, potentially valuable is thrown away. most SARs, data sufficient generate...
The Magellan Venus orbiter carries only one scientific instrument: a 12.6-centimeter wavelength radar system shared among three data-taking modes. synthetic-aperture mode images echoes from the surface at resolution of between 120 and 300 meters, depending on spacecraft altitude. In altimetric mode, relative height measurement accuracies may approach 5 terrain's roughness, although orbital uncertainties place floor about 50 meters absolute uncertainty. areas extremely rough topography,...
RADARSAT, the first Canadian remote-sensing spacecraft, is designed to provide Earth observation information for five years. The satellite scheduled launch in 1994. only payload instrument a 5.6-cm-wavelength (C-band) synthetic aperture imaging radar (SAR). RADARSAT will gather data on command up 28 min during each cycle of its 800-km (nominal) near-polar orbit. Image resolutions from 10 100 m at swath widths 45 500 km be available. mission reviewed, and design, characteristics,...
The two mini-radio-frequency (mini-RF) radars flown in near-polar lunar orbits (on Chandrayaan-1 and the Lunar Reconnaissance Orbiter) were first of their kind, hybrid-polarimetric. This new paradigm transmits circular polarization, receives coherently on orthogonal linear polarizations. resulting data support calculation 2 × covariance matrix backscattered field, from which follow four Stokes parameters. These are basis science products observations, include images that traditional radar...
Abstract Expressions are presented for Doppler frequency shift, bandwidth, zero offset angle in spacecraft yaw and, the SAR mode, rate of modulation, azimuth time-bandwidth product, resolution, available integration time and location principal ambiguities. The equations simply expressed with virtually no approximations based on angles referenced to satellite. Earth rotation is included, as geosynchronous case. (These results differ from expressions be found elsewhere literature, most which...
The general problem is considered of a partially coherent synthetic aperture radar (SAR) imaging scene that subjected to random fade. impulse response, frequency and response extended fields are formally derived, the addressed estimating SAR from measures spectra Corresponding distributed scenes. Explicit results obtained using Gaussian functions describe SAR, its coherence, coherence.
Airborne radar sounding is an established tool for observing the bed conditions and subglacial hydrology of ice sheets glaciers. The specularity content echoes has also been used to detect hydrologic transition a water system from network distributed canals concentrated channels beneath Thwaites Glacier. However, physical dimensions bodies in these networks have not constrained by observations. In this letter, we use variety simple scattering, attenuation, cross-sectional models provide...
Although diverse measurements have indicated H + , OH − or 2 O species in the lunar polar regions, pinpointing its location, form, and abundance specific reservoirs has proven elusive. Here we report on first orbital radar of Shackleton crater near south pole. Mini‐RF observations indicate a patchy, heterogeneous enhancement CPR (circular polarization ratio) walls whose strength decreases with depth toward floor, result that is most consistent roughness effect due to less mature regolith...
The symmetric scattering characterization method (SSCM) has been recently introduced for high-resolution of certain targets under coherent conditions. SSCM is based on the Poincare/spl acute/ sphere representation, which supports a decomposition target scattering, as well assessment and validation backscatter coherence. In this paper, investigated ship using Convair-580 polarimetric synthetic aperture radar (SAR) data. It shown that parameters permit identification dominant scatterers with...
The Mini‐RF radar on the Lunar Reconnaissance Orbiter spacecraft has revealed a great variety of crater ejecta flow and impact melt deposits, some which were not observed in prior imaging. craters Tycho Glushko have long flows that exhibit variations backscatter circular polarization ratio along flow. Comparison with optical imaging reveals these changes are caused by features commonly seen terrestrial lava flows, such as rafted plates, pressure ridges, ponding. Small (<20 km) sized also...
The respective classification accuracy levels of compact and quadrature polarimetric synthetic aperture radars (SARs) are compared through results reported in the literature. Classification methodologies critiqued. A faulty methodology compromises many those studies. An appropriate leads to trustworthy results. When correctly implemented, classifications from hybrid dual-polarimetric data achieve comparable a quadrature-polarized SAR, within few percent.
There has been a controversial issue of many years standing in airborne Synthetic Aperture Radar (SAR) ocean imaging which this paper addresses and resolves. Investigators have strongly divided on the reasons for apparent improvement wave contrast response to processor focus adjustment. The dispute centered two parameters dynamics: orbital velocity phase velocity. This shows that both are fundamental importance SAR problem. first affects received signal, leads bunching, is scaled by ratio...