Fixed orientation in incremental alignment ?

[hkyon]

Hi,
I'm testing the incremental alignment. I have bi-temporal drone images of the same flight path.
I set the preference of "keep point". First, we aligned 10 images of Time 1. After adding 10 images of Time 2, incremental alignment was performed to align the Time 2 images while keeping the orientation of Time1 image fixed. The images seem to be well aligned, but the orientation information of the Time 1 images has changed slightly.
Can I fix the orientation parameters of Time 1 images?
Or is there an approach other than incremental alignment ?