The Generic Mapping Tools 5 Synthetic Aperture Radar (GMT5SAR)

GMT5SAR is one of the most relevant contribution of the open source community for Interferometric SAR (InSAR) processing, and all the information related with this project can be found in the next website http://gmt.soest.hawaii.edu/projects/gmt5sar.

Tool to Automate the Interferometry Generation process using Sentinel 1 A/B data

In this section, I will provide a short script written in C-shell (csh) aimed to automatize the initial step of the interferometry process in GMT5SAR. This contribution was inspired considering the innecesaries steps that you have to do to start the interferometry process once you have uploaded the interferometric pairs into the orig folder. For general purposes, a brief explanation of this process is given in the next.

The natural way to perform interferometry with Sentinel 1 data by using GMT5SAR the first time is with the test data available in https://topex.ucsd.edu/gmtsar/downloads/. By downloading this compressed file, you also will have access to the configuration file, a readme file where the process steps are ilustrated, and you will be able to see the folders esctructures you need in order to run properly the p2p_S1A_SLC.csh script.

Summarizing, the interferometry generation of Sentinel 1 in GMT5SAR require the creation of 5 folders:

  • orig: where should be located the two Sentinel 1 images to be used as interferometric pair. Both images must be uncompressed.
  • topo: a folder to locate the DEM of reference
  • raw: in this folder will be saved the Sentinel 1 data after the exection of the step make_s1a_slc
  • SLC: in this folder are saved some temporal files generated during the interferometry process
  • intf: in this folder are saved all the products generated in the interferometry

    • Assuming that the reader is related to the process explained in the readme.txt file included in the test data, in order to execute the p2p_S1A_SLC_Launcher.csh script, you only have to create the two first folders, I mean orig and topo. In orig you should put the two images uncompressed, and in topo you will have the DEM of reference.

    Image of reference to show the way how the Sentinel 1 images should be located in the orig folder

    Image of reference to show the way how the Sentinel 1 images should be found in the orig folder

    In folder topo a dem.grd file must be present in order to start the interferometry. This DEM file can be generated and downloaded from GMTSAR downloads website

    Image of reference to show the way how the Sentinel 1 images should be found in the orig folder

    The script must be executed in the main folder (the folder that contains the two folders, the readme.txt, and the config_s1a.txt file). To execute the script you have to write in the terminal

  • Burst 001: ./p2p_S1A_SLC_Launcher.csh 001
  • Burst 002: ./p2p_S1A_SLC_Launcher.csh 002
  • Burst 003: ./p2p_S1A_SLC_Launcher.csh 003
    • Note: In each case, advoid writing the fragment Burst 001, Burst 002, and Burst 003 You won't need to do anything else to make the 3 interferometries, all the steps are automatized in the script.

    The Script:

    p2p_S1A_SLC_Launcher.csh

    Script for running the interferometry for the three burts (It has to be used together with the Launcher):

    p2p_S1A_SLC_Executer.csh