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Iceberg Detection Using RADARSAT-1
Synthetic Aperture Radar
Kelley Lane
Research Engineer, C-CORE
Ice Management and RADARSAT
Effective ice management is important in ship navigation and offshore resource exploration in Newfoundland
Regions such as the Grand Banks which are characterized by considerable fog, cloud, and precipitation, rely on radar-based systems as the primary sensing tool
Four primary radar tools for iceberg surveillance Ship/rig based marine radar Airborne radar Coastal HF radar RADARSAT-1
Target Detection Software
C-CORE has been involved in a multi-year program investigating the target detection capabilities of RADARSAT-1
To aid in this research an automated Target Detection Software (TDS) has been developed for the detection and discrimination of icebergs
TDS has been used in several Near-Real Time demonstrations and is currently being used operationally
Target Detection in imagery
Mean level of sea clutter varies depending on the wind speed and the range of incidence angles
Detection of targets in the presence of sea clutter relies on adaptively determining an appropriate threshold level
Constant Fault Alarm Rate (CFAR) - determines a threshold in a localized area.
The sea clutter distribution along with a specified CFAR is used to derive an appropriate threshold for the detection of possible targets
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Rada
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SurfaceSurfaceScatteringScattering
VolumeVolumeScatteringScattering
Volume scattering (most dominant)due to the low absorption of the non-saline glacial ice allowing considerable penetration of the radar energy into the iceberg volume
Surface scatteringdependent on the specific surface structure of individual icebergs, including variations due to any snow or water on the surface of the iceberg
Ships Versus Icebergs
Generally, pixel statistics can be used to discriminate between icebergs and vessels
Generally, vessel targets have stronger echoes resulting in higher pixel mean and variance
hard to discriminate in lower resolution data due to lower numbers of pixels available for statistics
shape characteristics may also be used (icebergs are generally more irregularly shaped while vessels tend to be elongated)
Work is being conducted on the discrimination of ships and icebergs
Ships Versus Icebergs
Generally, pixel statistics can be used to discriminate between icebergs and vessels
Generally, vessel targets have stronger echoes resulting in higher pixel mean and variance
hard to discriminate in lower resolution data due to lower numbers of pixels available for statistics
shape characteristics may also be used (icebergs are generally more irregularly shaped while vessels tend to be elongated)
Work is being conducted on the discrimination of ships and icebergs
Supply Boat
Hibernia
RADARSAT ScanSAR Narrow ImageRADARSAT ScanSAR Narrow Image50 metre pixels50 metre pixels
islands
RADARSAT ScanSAR Narrow ImageRADARSAT ScanSAR Narrow Image50 metre pixels50 metre pixels
90 m
70 m
130 m
200 m
170 m
60 m
100 mRADARSAT Wide3 ImageRADARSAT Wide3 Image30 metre pixels30 metre pixels
RADARSAT Fine ImageRADARSAT Fine Image~8 metre pixels~8 metre pixels
