Technical University of Denmark Radars and modifications IIP KU Team

2 of 15 Outline Background Sample Results Plans Conclusions

3 of 15 Background Radars –to measure ice thickness, image ice bed and map layers at depth –to measure near-surface internal layers with cm resolution Antennas –P-3 aircraft –Twin Otter Antenna arrays Equipment rack

4 of 15 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 = m in ice –Image Resolution –Cross-track= 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 = cm –Dynamic range >70 dB

5 of 15 Sample results Depth sounder mode SAR image mosaic (Paden, 2006)

6 of 15 Results— Airborne UHF radar

7 of 15 Existing antennas

8 of 15 Antennas Dipoles length –150 MHz Dipoles 1&4: 829 mm or 32.6 in Dipoles 2&3: 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

9 of 15 Simulations at 150 MHz Finite ground plane

10 of 15 Simulations

11 of 15 Experiments

12 of 15 Experiments

13 of 15 Modifications Dipole length –Adjustable –Each arm consists of two pieces Operate at 150 MHz with full length Remove 450 MHz –Take out extra length

14 of 15 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