undef
s1a-iw-grd-vh-20171011t173159-20171011t173228-018768-01fad2-002_filter
s1a-iw-grd-vv-20171011t173159-20171011t173228-018768-01fad2-001_filter
s1a-iw-grd-vv-20171011t173159-20171011t173228-018768-01fad2-001_winddir
s1a-iw-grd-vh-20171011t173159-20171011t173228-018768-01fad2-002_winddir