undef

s1a-iw-grd-vh-20170918t221849-20170918t221914-018436-01f0a9-002_filter

s1a-iw-grd-vv-20170918t221849-20170918t221914-018436-01f0a9-001_filter

s1a-iw-grd-vv-20170918t221849-20170918t221914-018436-01f0a9-001_winddir

s1a-iw-grd-vh-20170918t221849-20170918t221914-018436-01f0a9-002_winddir