@Shadoko
I would suspect the identical lines to belong to one data block that was transmitted in sub-blocks which were logged with the time stamp of the time when the block was completed.
I agree on the time resolution being 20µs. Taking into account it's round trip time and 1µs corresponds to 300m at speed of light, the line of sight resolution is 3km. With an elevation angle of ~45° the lateral resolution on the surface would be ~4.5km.