I am very new to the use of SAR data, but I’m working hard to learn what I can. I want to apply the L - band data from ALOS to my research so that I might detect land subsidence in a forested region. I am trying to accomplish this in the Sentinel 1 toolbox, but I am having issues co-registering my images. They are both 1.5 CEOS ALOS images with similar orbit values and are both ascending. They have a small baseline and should be a fine pair for InSAR. However, when I try to co-register the pair using “InSAR optimized Co-registration” and then check the quality using the RGB view, they are offset and do not line up at all. Ive tried adjusting the settings in the tool, including the number of GCPs and the parameters under the re-sampling tab. Ive also tried using a smaller spatial subset. There are no errors being produced. I then attempted to calibrate the image (SAR processing -> radiometric -> calibrate) followed by a terrain correction, as the terrain of my study area is pretty rough. When I do that, I get an error stating: “Terrain Flattening: Detected ALOS PALSAR products are not currently supported.”

I realize a lot of my troubles may be related to my newness to all this, but if there is any advice anyone could give me that could point me in the right direction, it would be very much appreciated!


First, please check if that is a L1.5 product. It should be a L1.1 to be
able to do any InSAR.
For ALOS 1 L1.1, run ALOS deskew first before coregistration. In the
Coarse-Fine-Registration tab select a large coarse registration window.

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Its definitely 1.5 and not 1.1! Thank you! Hopefully I can get it to work now.

Quick question: Can I orthorectify the level 1.1 ALOS imagery (including the multilooking process to remove the stretching) before I do InSAR, or should I do it after?

InSAR is always the 1st step - if you “disturb” the intensity&phase-information beforehand InSAR will no longer be possible (coherence will be lost).

Ok, got it! thank you!

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