Date/Time Difference in Sentinel 1

Hello all,

So I am working with Google Earth Engine and I have retrieved all of the viable Sentinel 1 returns over my region of interest. By viable, I mean that I have filtered all sentinel 1 returns spatially over my area, temporally to all available data, filtered to GRD products only, filtered to IW instrument mode only, and the filtered to ascending pass only. Finally, I filtered the returns from that selection and split the returns into sentinel 1a and sentinel 1b. I then take the mean over my region of interest and plot the results. However, I am noticing that the time stamps of the returned data is odd. Here is what I am receiving…
Below is a 10 file sample of my exported file names. They are saved as YYYY-MM-dd T hh:mm:ss My question is this: why are the minute time stamp observations going back and forth between 05 and 21? Should they not all be the same? When plotted, the data is distinctly different. I originally thought it was maybe ascending/descending difference but I filtered for that and the time difference is too small. Then I thought that it was the difference between sentinel 1a and 1b but I filtered for that as well too. Now I’m assuming this is related to the incidence angle or look angle of the acquisition but how do I know what angle corresponds to which set of data? I’m calling the sets the “5” minute return set and the “21” minute return set. Please advise.


Looks like your site is covered by two ascending orbits tracks and the the corresponding incidence-angles are different.

Hi, I would also suggest that your products are from two tracks - check the relative orbit given in the manifest file (parameter relativeOrbitNumber). Also you may wish to examine the planning over your site - Google Earth kml files are available at:

The red tracks are for IW.