undef

s1b-iw-grd-vv-20171208t175750-20171208t175815-008631-00f53c-001_filter

s1b-iw-grd-vh-20171208t175750-20171208t175815-008631-00f53c-002_filter

s1b-iw-grd-vh-20171208t175750-20171208t175815-008631-00f53c-002_winddir

s1b-iw-grd-vv-20171208t175750-20171208t175815-008631-00f53c-001_winddir