SENTINEL1 imaging time

I have a question about sentinel1 imaging time,when I read the file "S1A_IW_GRDH_1SDV_20150225T044319_20150225T044344_004775_005ED1_EC04.SAFE\annotation\s1a-iw-grd-vh-20150225t044319-20150225t044344-004775-005ed1-002.xml”,there is a 2015-02-25T04:43:19.764551
but I don’t know whether is the local time or UTC time?
can you tell me ?
thank you

It is UTC, see:

thanks for your answer. I have read the Sentinel-1 Product Specification, unluckly I didn’t found the description about the sentinel1 imaging time. maybe I should read it carefully.

Search for “start time” in the PDF and you will find it.

thanks for your advice, I hava found the main words in the pdf file.
thank you!