Technical Universityof Denmark

Radars and modifications

IIP KU Team

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Outline

• Background • Sample Results• Plans• Conclusions

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Background• Radars

– to measure ice thickness, image ice bed and map layers at depth

– to measure near-surface internal layers with 30-50 cm resolution

• Antennas– P-3 aircraft– Twin Otter

Antenna arrays

Equipment rack

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Background-- Specifications• VHF Radar• To measure thickness, map layers

and image ice-bed interface– Center freq = 150 or 450

MHz– Bandwidth = 20 or

50 MHz – Loop sensitivity > 210 dB– Depth resolution = 3-4.5 m in ice– Image

• Resolution – Cross-track = 40-

100 m– Along track = 100 m

• Swath width – Min = 1000

m– Maximum ~1500

m

• UHF radar• To map near-surface

internal layers– Center freq = 750 MHz– Bandwidth = 450 MHz– Resolution = 30-40 cm– Dynamic range >70 dB

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Sample results

Depth sounder mode SAR image mosaic (Paden, 2006)

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Results— Airborne UHF radar

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Existing antennas

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Antennas

• Dipoles length– 150 MHz

• Dipoles 1&4: 829 mm or 32.6 in• Dipoles 2&3: 0.817 mm or 32.2 in

– 450 MHz• Dipoles 1&4: 265 mm or 10.4 in• Dipoles 2&3: 262 mm or 10.3 in

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Simulations at 150 MHz

• Finite ground plane

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Simulations

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Experiments

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Experiments

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Modifications

• Dipole length– Adjustable

– Each arm consists of two pieces• Operate at 150 MHz with full length• Remove • 450 MHz

– Take out extra length

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Plans

• Duplicate radars• Integrate and test systems in Feb-

March 2007• Collect data over The Greenland ice

sheet in April-May 2007• We should perform a measurements

in November 2007 or March 2008