GPR Early Results
What was the radar experiment like in Antarctica 1997 season like?
Well, since it was a component test, it was all mounted inside a small
There are three areas with early results:
The idea was to test the ability of the radar to detect rocks and buried
objects covered by snow. To do that, a set of seven common Antarctic rocks
and "meteowrongs" (rocks that look like meteorites, but are not) was covered
by snow at known positions in a row. The radar was dragged over and over
several times, with small displacements from the central line. The rocks
have different sizes and compositions. Also, two transversal metal pipes
at one side and one at the other marked the row position.
The figure shows raw radar data. The vertical axis corresponds to the
depth of the soundings. The upper line is equivalent to the surface, the
lower line corresponds to the deepest echoes recorded.. The horizontals
axis corresponds to the advancement of the sled on the snow. The perturbations
at both sides of the figure are the echoes of the marker pipes.
The seven objects lie between those markers. In this picture, there is
one rock that shows clearly without further processing. The magnification
shows a dark trace, echo of one of the rocks, and is indicated with a thick
white arrow. It is possible to detect the other smaller rocks with careful
examination of the data.
Of course the idea is to achieve automatic detection of buried objects,
for the meteorobot to indicate and mark position of potential meteorites.
Another goal was the demonstration of layer detection. The radar went over
patches of snow over the ice. And that is what we can see in the next raw
radar data. The arrows show when the sensor went over ice and snow. The
snow patch is about 20 cm. thick. The other bands are radar noise.
For a machine that explores the vast ice fields of Antarctica, an important
danger is to find crevasses, not always obvious given that they are covered
by snow. These are cracks in the ice field that are wide and deep enough
to swallow the rover. The detection of this features is one of the goals
of radar sensing. For that, test over small crevasses and voids were
performed. The following figure shows radar data taken over a void.
The radar sensed a cave under a meter of ice and compacted snow. The raw
data shows the change of the media (ice to air). At this point there is
no automatic interpretation or detection of the voids and cracks. It is
not even evident to the human eye. Crevasses appear in a similar way although
the marks are thinner and vertical.
Once again, the two vertical marks signals at the left and right sides
of the image are artificial markers that define the area of interest. The
arrows show the void perturbation.
Back to Radar
Robotic Search for Antarctic Meteorites 1998
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This document prepared by Michael