[Bug]: Azimuth FM rate mismatch fails for historical S1A data

[vbrancat]

Checked for duplicates

Yes - I've already checked

Describe the bug

The azimuth FM-rate mismatch correction fails for some historical S1A data (2015-2017). The failure seems to be happening during the computation of the DC coefficients with the following error:

Traceback (most recent call last):
  File "/mnt/aurora-r0/vbrancat/codes/COMPASS/src/compass/s1_cslc.py", line 56, in <module>
    main()
  File "/mnt/aurora-r0/vbrancat/codes/COMPASS/src/compass/s1_cslc.py", line 51, in main
    run(parser.run_config_path, parser.args.grid_type)
  File "/mnt/aurora-r0/vbrancat/codes/COMPASS/src/compass/s1_cslc.py", line 43, in run
    s1_geocode_slc.run(cfg)
  File "/mnt/aurora-r0/vbrancat/codes/miniconda3/envs/compass/lib/python3.11/site-packages/compass/s1_geocode_slc.py", line 77, in run
    cumulative_correction_luts(burst, dem_path=cfg.dem,
  File "/mnt/aurora-r0/vbrancat/codes/miniconda3/envs/compass/lib/python3.11/site-packages/compass/utils/lut.py", line 65, in cumulative_correction_luts
    compute_geocoding_correction_luts(burst,
  File "/mnt/aurora-r0/vbrancat/codes/miniconda3/envs/compass/lib/python3.11/site-packages/compass/utils/lut.py", line 214, in compute_geocoding_correction_luts
    az_fm_mismatch = burst.az_fm_rate_mismatch_from_llh(lat, lon, height,
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/aurora-r0/vbrancat/codes/miniconda3/envs/compass/lib/python3.11/site-packages/s1reader/s1_burst_slc.py", line 936, in az_fm_rate_mismatch_from_llh
    dc_coeffs = interp_coeffs(fm_rate_aztime_sec_vec,
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/aurora-r0/vbrancat/codes/miniconda3/envs/compass/lib/python3.11/site-packages/s1reader/s1_burst_slc.py", line 929, in interp_coeffs
    coeff_interpolator = InterpolatedUnivariateSpline(
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/aurora-r0/vbrancat/codes/miniconda3/envs/compass/lib/python3.11/site-packages/scipy/interpolate/_fitpack2.py", line 716, in __init__
    x, y, w, bbox, self.ext = self.validate_input(x, y, w, bbox, k, None,
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/mnt/aurora-r0/vbrancat/codes/miniconda3/envs/compass/lib/python3.11/site-packages/scipy/interpolate/_fitpack2.py", line 247, in validate_input
    raise ValueError("x and y should have a same length")
ValueError: x and y should have a same length

For some bursts, the variable fm_rate_aztime_sec_vec has a length of 4 while the variable self.extended_coeffs.dc_coeff_arr has a length of 3. I suspect that there is an inconsistency in the burst metadata for historical data. Strangely enough, the error seems to occur for all the bursts in subswath 1 and 3 while I am able to process all the bursts in subswath 2.

What did you expect?

I expected [...]

Reproducible steps

This bug can be replicated by running the following bash file on aurora

/mnt/aurora-r0/vbrancat/data/S1/stack_processor/Rosamond/Ascending/no_iono/2015/run_files/run_20150207_t064_135520_iw1.sh

Environment

No response

[seongsujeong]

@vbrancat Thanks for reporting the issue. I have seen some format changes for azimuth FM rate in annotation file, which was take care of #59, but I might also need to take a look if DC polynomials has some changes as well.

Would it easy for you to pinpoint the SAFE file that the azimuth FM rate mismatch mitigation did not work?

[seongsujeong]

Closing this issue as it was addressed in #113