Case Studies
Measuring the Thickness of Polar Ice
The customer is an academic researcher in climate change. He wants to record the depth of the permafrost ice sheets in the arctic regions of Canada, Greenland and elsewhere. The change in world climate is directly related to the changes in the thickness of polar ice. Abrupt changes can be a predictor of climatic changes in the world.
The measuring apparatus is an ice-penetrating radar mounted on an aircraft flying at 500-600 meters. The radar pulses at 20 kHz Pulse Repeat Frequency (PRF), captures the reflections of groups of 32-64 pulses. Each pulse is 2.5 microseconds and there is a dead time of 50 m s between the groups. The groups of pulses give information about the thickness and constitution of the ice. It was found that the echo delay of 1 m s corresponds to about 100 meters of thickness, and that the thickness of the ice can reach 3 km in some regions.
The customer was already using MATLAB offline in his calculations and he needed a means for quickly capturing and analyzing the data on the same aircraft.
GAGE'S SOLUTION
We suggested a capture card to record the echoes of the ice thickness radar for run and to save on hard drive for analysis. The capture depth requirement was calculated as 1 GigaSample at the capture speed of 100 MS/s. This figure was reached by multiplying the capture depth for a single record by the maximum expected number of records for each group, and then by the expected total number of groups in a run. The customer required 14 bit resolution in order to distinguish the different layers of ice.
Gage's solution enables the customer to capture and process the data with existing MATLAB software. The results can be obtained at almost instantaneous speed, thus saving time and effort in allowing the quick return to ice cap areas worthy of further study.
PRODUCT RECOMMENDED
CompuScope 14100 - 1G
CompuScope SDK for MATLAB for Windows
This application note is provided "as is" without any warranties of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability or fitness for a particular purpose. Gage Applied Technologies further does not warrant the accuracy and completeness of the material contained herein. Gage Applied Technologies may make changes to this material, or to the products described in it, at any time without notice.
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