undef
s1a-iw-grd-vh-20170907t230121-20170907t230146-018276-01ebb6-002_filter
s1a-iw-grd-vv-20170907t230121-20170907t230146-018276-01ebb6-001_filter
s1a-iw-grd-vh-20170907t230121-20170907t230146-018276-01ebb6-002_winddir
s1a-iw-grd-vv-20170907t230121-20170907t230146-018276-01ebb6-001_winddir