undef
s1a-iw-grd-vh-20150926t155947-20150926t160015-007888-00b015-002_filter
s1a-iw-grd-vv-20150926t155947-20150926t160015-007888-00b015-001_filter
s1a-iw-grd-vv-20150926t155947-20150926t160015-007888-00b015-001_winddir
s1a-iw-grd-vh-20150926t155947-20150926t160015-007888-00b015-002_winddir