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Gamma IPTA LT1 SBAS Trial Runbook

Date: 2026-05-18

Goal

Validate whether the current local LT1 data pool and WSL Gamma installation can produce one usable SBAS/IPTA trial result with the official Gamma toolchain.

This is not yet a production integration design. The immediate goal is to run one conservative stack, inspect failures and product quality, then decide what should be productized in the system.

Actual trial root used in this repository:

D:\Code\Insar_management_system_v2\backend\runtime\gamma_ipta_trials\lt1b_r114_e1312_n438_20240516_20251002

Current Environment

  • WSL distro configured by the project: Ubuntu-24.04.
  • Gamma install found in WSL: /usr/local/GAMMA_SOFTWARE-20240627.
  • Installed package name present on disk: GAMMA_SOFTWARE-20240627_MSP_ISP_DIFF_IPTA.linux64_ubuntu2404.tar.gz.
  • Installed Gamma modules include MSP, ISP, DIFF, DISP, and IPTA.
  • GEO is not a separate directory in this install, but DIFF contains the relevant geocoding tools, including gc_map, geocode, and geocode_back.
  • Project Gamma environment script: deploy/wsl/profiles/gamma_env.sh.
  • Project WSL Python: /home/administrator/miniconda3/envs/insar_wsl_v1/bin/python.

Important command checks already performed:

  • IPTA/bin/ts_rate runs and prints usage. No license-denied error observed.
  • IPTA/bin/multi_def_pt runs and prints usage. No license-denied error observed.
  • ISP/bin/par_LT1_SLC exists and prints LT1 SLC conversion usage.
  • ISP/scripts/LT1_precision_orbit.py runs with the project conda Python and prints usage.

Data Pool Findings

Configured LT1 source pool:

  • D:\LuTan1_Image_Pool

Configured LT1 precise orbit pool:

  • D:\orbit_pools\envi\LT1A
  • D:\orbit_pools\envi\LT1B

High-level inventory:

  • LT1 scene directories found: 1500.
  • LT1A orbit TXT files found: 896, spanning 20230508 to 20251219.
  • LT1B orbit TXT files found: 858, spanning 20230510 to 20251219.

Metadata caveat:

  • *.meta.xml and *_Check.xml are not safe to parse as whole XML documents in PowerShell because many files contain malformed Chinese text near the tail, for example bad usePreciseOrbit closing text.
  • The needed productInfo block is structurally valid. For stack discovery, parse only <productInfo>...</productInfo>.
  • Gamma par_LT1_SLC should still use the original .meta.xml; do not rewrite source metadata unless a Gamma run proves the malformed tail is a blocker.

Candidate Stack

First trial should use a narrow single-center stack, not the broad system time-series grouping.

Recommended trial stack:

  • Satellite: LT1B
  • Relative orbit: 114
  • Direction: DESCENDING
  • Imaging mode: STRIP1
  • Polarization: HH
  • Approximate center: E131.2 / N43.8
  • Scene count at this center: 7
  • Scenes with precise orbit TXT currently present: 5

Use the 5 scenes with available precise orbit first:

Date Orbit TXT Scene
20240516 yes LT1B_MONO_SYC_STRIP1_012047_E131.2_N43.8_20240516_SLC_HH_S2A_0000399289
20240711 yes LT1B_MONO_SYC_STRIP1_012880_E131.2_N43.8_20240711_SLC_HH_S2A_0000450956
20240905 yes LT1B_MONO_SYC_STRIP1_013713_E131.2_N43.8_20240905_SLC_HH_S2A_0000501650
20250417 yes LT1B_MONO_SYC_STRIP1_017045_E131.2_N43.8_20250417_SLC_HH_S2A_0000713375
20251002 yes LT1B_MONO_SYC_STRIP1_019544_E131.2_N43.8_20251002_SLC_HH_S2A_0000891257

Do not include these two in the first run unless the missing orbits are added:

Date Orbit TXT Scene
20250612 no LT1B_MONO_SYC_STRIP1_017878_E131.2_N43.8_20250612_SLC_HH_S2A_0000772122
20250807 no LT1B_MONO_SYC_STRIP1_018711_E131.2_N43.8_20250807_SLC_HH_S2A_0000831367

Common bounding box across the broader 13-scene LT1B relOrbit 114 / E131-N44 candidate:

  • lon: 130.8615 .. 131.1638
  • lat: 43.7127 .. 44.0987

For the narrow E131.2/N43.8 trial stack, overlap is visually/metadata-wise much tighter:

  • Each scene center is around 131.20E, 43.79N.
  • Each scene bbox is roughly 130.81..131.62E, 43.48..44.10N.

Secondary candidate if the first stack fails:

  • LT1B relOrbit 114 DESCENDING STRIP1 HH, center E130.8/N43.9.
  • 5 dates, 4 with orbit: 20250425, 20250620, 20250815, 20251010.
  • One scene is MONO_MH1 while the others are MONO_SYC; keep it as secondary, not first choice.

Current System Pairing Limitations

The current time-series stack selection is useful for broad discovery but is too coarse for Gamma IPTA production.

Observed code behavior:

  • LT1A/LT1B are normalized into the same satellite family LT1.
  • The compatibility key only uses direction, satellite family, imaging mode, and polarization.
  • Relative orbit, absolute track family, scene center/strip identity, receiving station, and detailed LT1 product variant are not hard grouping keys.
  • The stable-stack selector tries to recover by common AOI overlap and pairwise network connectivity.
  • The SBAS network selector uses time-baseline, center-distance and overlap thresholds, but does not use Gamma-derived perpendicular baseline at planning time.
  • Time-series processors currently accepted by the service are only isce2_stack_mintpy and sarscape_sbas; there is no gamma_ipta_sbas processor code yet.

For the Gamma IPTA trial, do not rely on the current automatic PS stack plan as the source of truth. Use a manually audited stack manifest first.

Trial Run Checklist

1. Create Isolated Work Directory

Actual root:

D:\Code\Insar_management_system_v2\backend\runtime\gamma_ipta_trials\lt1b_r114_e1312_n438_20240516_20251002

Keep these subdirectories:

input\scenes
input\orbits
gamma\slc
gamma\mli
gamma\diff
gamma\ipta
logs
publish

For the first trial, prefer symlinks or a manifest that points to source scenes. Avoid duplicating large TIFF files unless Gamma scripts require local flat layout.

2. Build Scene Manifest

For each selected scene, record:

  • scene directory
  • .tiff
  • .meta.xml
  • precise orbit TXT
  • date
  • relative orbit
  • direction
  • mode
  • polarization
  • center lon/lat
  • bbox

This manifest becomes the hand-audited truth for the trial.

3. Convert LT1 Products To Gamma SLC

For each selected scene:

source /mnt/d/Code/Insar_management_system_v2/deploy/wsl/profiles/gamma_env.sh
par_LT1_SLC <scene.tiff> <scene.meta.xml> <yyyymmdd>.slc.par <yyyymmdd>.slc

Then apply precise orbit:

/home/administrator/miniconda3/envs/insar_wsl_v1/bin/python \
  /usr/local/GAMMA_SOFTWARE-20240627/ISP/scripts/LT1_precision_orbit.py \
  <yyyymmdd>.slc.par <orbit_txt_or_orbit_folder>

4. Build SLC/MLI Tables

Create Gamma tables for the stack:

SLC_tab
RMLI_tab

Use multilook settings conservative enough for a first run. The goal is robustness and fast feedback, not final product resolution.

5. Baseline And Pair Network

Use Gamma baseline tools first, not the system's center-distance approximation:

  • base_init
  • base_perp
  • IPTA baseline tools such as base_orbit_pt, base_par_pt, base_ls_pt as needed by the official IPTA path.

For the first 5-scene stack, start with a simple connected small-baseline network:

  • adjacent pairs by time
  • add one or two skip pairs only if coherence and baseline look acceptable

Expected adjacent temporal intervals:

  • 20240516 -> 20240711: 56 days
  • 20240711 -> 20240905: 56 days
  • 20240905 -> 20250417: 224 days
  • 20250417 -> 20251002: 168 days

The large seasonal gaps are acceptable for a trial only if perpendicular baseline and coherence are reasonable. If they are poor, switch to a denser 2025-only or 2024-only local test, even with fewer dates.

6. Differential Interferograms

Use official Gamma DIFF commands/scripts for:

  • coregistration
  • interferogram generation
  • simulated topographic phase
  • differential phase
  • filtering
  • coherence
  • unwrapping if needed by the chosen IPTA path

Do not implement custom SBAS inversion in the management system.

7. IPTA Processing

Use Gamma IPTA commands for point/stack time-series processing. Confirm exact command sequence against the installed:

/usr/local/GAMMA_SOFTWARE-20240627/IPTA/html/IPTA_users_guide.pdf

Commands observed in the local IPTA module include:

  • multi_def_pt
  • ts_rate
  • ts_rate_pt
  • base_ls_pt
  • base_par_pt
  • ph_base_pt
  • atm_mod_pt
  • pt2geo
  • dis_ipta

8. Review Outputs

Minimum acceptance checks for the first run:

  • every selected scene converts to SLC
  • precise orbit update succeeds for every SLC
  • all intended pairs generate interferograms
  • coherence is not uniformly poor
  • unwrapping or IPTA point solution is not globally unstable
  • one geocoded velocity or displacement-rate raster/vector product can be inspected
  • logs and command manifests are complete enough to reproduce the run

Trial Progress On 2026-05-18

Files Created For This Trial

  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/input/scene_manifest.json
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/01_prepare_slc.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/02_mli_and_baseline.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/03_coreg_one_pair.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/04_cc_stats.py
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/05_coreg_adjacent_pairs.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/06_prepare_rdc_dem.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/07_coreg_common_ref_stack.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/08_diff_unwrap_common_ref.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/09_mb_ts_rate.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/10_float_stats.py
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/11_make_timeseries_previews.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/12_geocode_export_timeseries.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/13_phase_to_los.py
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/14_build_trial_summary.py
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/15_make_los_velocity_maps.sh
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/16_plot_monitor_point_timeseries.py
  • backend/runtime/gamma_ipta_trials/lt1b_r114_e1312_n438_20240516_20251002/scripts/17_make_geocoded_web_previews.sh

Completed

  • Created a hand-audited 5-scene LT1B manifest for relOrbit 114 / DESCENDING / STRIP1 / HH / E131.2 N43.8.
  • Converted all 5 LT1 TIFF products with Gamma par_LT1_SLC.
  • Applied precise orbit updates with Gamma LT1_precision_orbit.py.
  • Built gamma/slc/SLC_tab.
  • Built 8x8 multilooked MLI products with Gamma multi_look.
  • Built gamma/mli/RMLI_tab.
  • Generated all-pair and adjacent-pair baseline tables with Gamma base_calc.
  • Ran adjacent-pair coregistration for all 4 selected adjacent pairs using Gamma SLC_coreg.py.
  • Generated 4 interferograms and coherence products using Gamma create_offset, SLC_intf, and cc_wave.
  • Generated browse previews using Gamma rasmph and raspwr.
  • Computed coherence statistics for each adjacent pair.
  • Reused the existing Copernicus30 DEM cache covering E131.2/N43.8.
  • Generated a reference-geometry RDC DEM for 20240905 using Gamma gc_map1, geocode, and gc_map_fine.
  • Built a common-reference RSLC/RMLI stack in 20240905 geometry.
  • Generated common-reference differential interferograms with Gamma phase_sim_orb and SLC_diff_intf.
  • Filtered common-reference differential interferograms with Gamma adf.
  • Unwrapped common-reference differential interferograms with Gamma mcf.
  • Ran Gamma IPTA mb to solve the image-based phase time-series.
  • Ran Gamma IPTA ts_rate to estimate a linear phase-rate map.
  • Generated Gamma preview rasters for ts_rate, sigma_rate, and hgt_correction.
  • Exported phase-rate, sigma, height-correction, and LOS-rate rasters to EPSG:4326 GeoTIFF.
  • Generated explicit LOS velocity maps in mm/year for both away-from-radar-positive and toward-radar-positive conventions.
  • Generated one example monitoring-point LOS displacement curve as PNG, CSV, and metadata JSON.
  • Generated north-up WGS84 web preview PNGs from the geocoded LOS GeoTIFF products.

Key Outputs

  • SLC stack: gamma/slc/SLC_tab
  • MLI stack: gamma/mli/RMLI_tab
  • All-pair baseline table: gamma/diff/bperp_all_pairs.txt
  • Adjacent-pair table: gamma/diff/itab_adjacent
  • Pair-specific RSLC products: gamma/rslc/*_to_*.rslc
  • Pair-specific quality reports: gamma/rslc/*_to_*.rslc.coreg_quality
  • Adjacent interferograms: gamma/int/*.int
  • Adjacent coherence rasters: gamma/int/*.cc
  • Adjacent interferogram previews: gamma/int/*.int.bmp
  • Adjacent coherence previews: gamma/int/*.cc.bmp
  • Coherence statistics: logs/*_cc_stats.txt
  • Reference RDC DEM: gamma/dem/20240905_8rlks.rdc.dem
  • Common-reference stack tables: gamma/common_20240905/SLC_tab, gamma/common_20240905/RMLI_tab
  • Common-reference differential stack: gamma/common_20240905/diff/*/*_8rlks.diff_filt.unw
  • Gamma mb time-series list: gamma/common_20240905/timeseries/diff_ts.tab
  • Gamma mb phase time-series: gamma/common_20240905/timeseries/diff_ts_*.diff
  • Gamma mb residual sigma: gamma/common_20240905/timeseries/sigma_ts
  • Gamma mb height correction: gamma/common_20240905/timeseries/hgt_correction
  • Gamma ts_rate output: gamma/common_20240905/timeseries/ts_rate
  • Gamma ts_rate sigma output: gamma/common_20240905/timeseries/sigma_rate
  • Preview rasters: gamma/common_20240905/timeseries/*.bmp
  • Geocoded GeoTIFF exports: publish/geotiff/*.tif
  • Explicit LOS velocity previews: publish/geotiff/los_rate_toward_mm_per_year.bmp, publish/geotiff/los_rate_away_mm_per_year.bmp
  • Geocoded web previews: publish/geotiff/los_rate_toward_mm_per_year.geo_preview.png, publish/geotiff/los_sigma_mm_per_year.geo_preview.png
  • Monitoring-point curve: publish/monitor_points/auto_low_sigma_high_rate_timeseries.png
  • Monitoring-point values: publish/monitor_points/auto_low_sigma_high_rate_timeseries.csv
  • Trial summary: publish/trial_summary.json

Baseline Notes

base_calc generated 10 all-pair entries. The adjacent temporal network is:

Pair Delta days Bperp from base_calc
20240516 -> 20240711 56 646.09670
20240711 -> 20240905 56 -236.76960
20240905 -> 20250417 224 249.35880
20250417 -> 20251002 168 59.18150

The first validated pair was 20240711 -> 20240905 because it has a 56-day interval and moderate perpendicular baseline in this stack.

Adjacent-Pair Quality

Final SLC_coreg.py quality-test summaries:

Pair Accepted offsets Final std range Final std azimuth
20240516 -> 20240711 2476 / 2688 0.0861 0.1120
20240711 -> 20240905 2483 / 2656 0.0370 0.1245
20240905 -> 20250417 2322 / 2688 0.0487 0.0617
20250417 -> 20251002 2274 / 2688 0.0304 0.0533

Coherence statistics from Gamma big-endian float files:

Pair valid [0,1] p25 median p75 p99 Comment
20240516 -> 20240711 100% 0.127489 0.212285 0.323520 0.649398 Weakest pair; high Bperp and low coherence
20240711 -> 20240905 100% 0.629307 0.733220 0.802884 0.909973 Strong pair
20240905 -> 20250417 100% 0.339094 0.485239 0.612798 0.833928 Usable trial pair
20250417 -> 20251002 100% 0.394165 0.582921 0.734878 0.932300 Usable trial pair

All adjacent pairs generated expected Gamma products. The full 5-scene chain can continue, but the first pair is a quality risk for unwrapping/IPTA. A more conservative follow-up is to run the 4-scene sub-stack from 20240711 to 20251002, or keep the 5-scene stack but down-weight or exclude 20240516 -> 20240711 if later unwrapping/IPTA residuals are poor.

Implementation note:

  • SLC_coreg.py writes the refined offset parameter file to a secondary-date path such as gamma/slc/20240711.slc.off.
  • Trial scripts copy that file to pair-specific paths such as gamma/rslc/20240711_to_20240905.rslc.off.
  • Future skip-pair or non-adjacent networks must use pair-specific offset files to avoid accidental reuse after the same secondary scene is coregistered to another reference.

Common-Reference Time-Series Trial

The image-based Gamma IPTA path was also run using a common 20240905 reference geometry. This is closer to the official mb -> ts_rate time-series chain than the first adjacent-pair wrapped interferogram check.

Common-reference inputs and products:

  • reference geometry: 20240905
  • DEM source: existing Copernicus30 cache under backend/runtime/pyint_dem_cache
  • RDC DEM: gamma/dem/20240905_8rlks.rdc.dem
  • common-reference SLC table: gamma/common_20240905/SLC_tab
  • common-reference MLI table: gamma/common_20240905/RMLI_tab
  • common-reference differential ITAB:
1 3 1 1
2 3 2 1
3 4 3 1
3 5 4 1

Filtered differential coherence statistics:

Pair valid [0,1] p25 median p75 p99
20240516 -> 20240905 100% 0.497369 0.884586 0.945308 0.980583
20240711 -> 20240905 100% 0.919149 0.968188 0.979449 0.990185
20240905 -> 20250417 100% 0.366279 0.790519 0.909991 0.978094
20240905 -> 20251002 100% 0.193104 0.815562 0.917209 0.972355

Gamma mb outputs:

  • gamma/common_20240905/timeseries/diff_ts_001.diff through diff_ts_005.diff
  • gamma/common_20240905/timeseries/diff_ts.tab
  • gamma/common_20240905/timeseries/itab_ts
  • gamma/common_20240905/timeseries/sigma_ts
  • gamma/common_20240905/timeseries/hgt_correction

Gamma ts_rate outputs:

  • gamma/common_20240905/timeseries/ts_rate
  • gamma/common_20240905/timeseries/ts_const
  • gamma/common_20240905/timeseries/sigma_rate
  • gamma/common_20240905/timeseries/ts_rate.bmp
  • gamma/common_20240905/timeseries/sigma_rate.bmp
  • gamma/common_20240905/timeseries/hgt_correction.bmp

GeoTIFF exports:

  • publish/geotiff/ts_rate_rad_per_year.tif
  • publish/geotiff/sigma_rate_rad_per_year.tif
  • publish/geotiff/sigma_ts_rad.tif
  • publish/geotiff/hgt_correction_m.tif
  • publish/geotiff/los_rate_m_per_year.tif
  • publish/geotiff/los_sigma_m_per_year.tif
  • publish/geotiff/los_rate_away_mm_per_year.tif
  • publish/geotiff/los_rate_toward_mm_per_year.tif
  • publish/geotiff/los_sigma_mm_per_year.tif
  • publish/geotiff/los_rate_toward_mm_per_year.geo_preview.png
  • publish/geotiff/los_sigma_mm_per_year.geo_preview.png
  • publish/trial_summary.json

Float output statistics using Gamma big-endian float:

File Non-zero pixels p25 median p75 p99
ts_rate 8,868,956 -1.663257 -0.271621 0.869116 2.787572
sigma_rate 8,868,956 0.396037 0.677578 1.010539 2.298520
sigma_ts 8,892,237 0.000704 0.001557 0.002535 0.518188
hgt_correction 8,892,250 -16.989384 7.596325 36.411520 98.636933

Explicit LOS velocity output statistics in mm/year:

File Non-zero pixels p01 p25 median p75 p99
los_rate_toward_mm_per_year.rdc 8,868,956 -52.779640 -16.455760 5.142855 31.491957 84.590944
los_sigma_mm_per_year.rdc 8,868,956 0.530715 7.498536 12.829198 19.133450 43.519972

This is a successful first local Gamma official-chain time-series trial. It is still a technical validation run, not a production-grade SBAS product: the stack has only 5 dates, the network is minimal, and reference region and unwrapping masks were conservative defaults.

The exported GeoTIFFs are EPSG:4326, 2222 x 2237, Float32, LZW-compressed Cloud Optimized GeoTIFFs with NoData=0.

The *.bmp files generated by Gamma rasdt_pwr are RDC processing-geometry browse images. They are useful for quick processing QA but are not map products and should not be used as the default UI map preview. The UI/default web preview should use the *.geo_preview.png files generated from the EPSG:4326 GeoTIFF products.

LOS Sign Convention

Gamma ts_rate is a phase-rate raster in rad/year. Converting phase rate to LOS displacement rate requires a sign convention:

  • los_rate_away_mm_per_year = phase_rate * wavelength / (4*pi) * 1000
  • los_rate_toward_mm_per_year = -phase_rate * wavelength / (4*pi) * 1000

Gamma dispmap documents two conventions:

  • sflg=0, the default: motion away from radar is negative, so motion toward radar is positive; deformation and unwrapped phase have opposite signs.
  • sflg=1: motion away from radar is positive; deformation and unwrapped phase have the same sign.

For system productization, use explicit names and prefer los_rate_toward_mm_per_year as the default display product because it matches Gamma dispmap default sflg=0. Keep the away-positive version available when another downstream convention requires direct phase-sign products.

Monitoring Point Curve

An example monitoring point was selected automatically from low-sigma, high-rate, non-edge pixels:

  • radar pixel: range 336, azimuth 2290
  • approximate lon/lat: 131.4340324903, 43.8008322757
  • reference date in the plotted time series: 20240711
  • LOS convention: toward radar positive, away from radar negative
  • fitted LOS velocity: 50.1085 mm/year
  • fitted LOS velocity sigma: 0.0063 mm/year

Generated outputs:

  • publish/monitor_points/auto_low_sigma_high_rate_timeseries.png
  • publish/monitor_points/auto_low_sigma_high_rate_timeseries.csv
  • publish/monitor_points/auto_low_sigma_high_rate_metadata.json

The plotted values are:

Date LOS displacement, toward-positive mm
20240516 -7.673957
20240711 0.000000
20240905 7.673922
20250417 38.412669
20251002 61.464305

This is a single example point only. It is not a validated monitoring-point network and should not be interpreted as a representative area-wide deformation curve. The automatic selection favors a non-edge pixel with relatively high absolute velocity and low fitted sigma so the curve is visually inspectable. Production monitoring points need one of these inputs:

  • user-clicked map lon/lat
  • imported engineering monitoring-point layer
  • a configured regular grid or point-of-interest set
  • a quality-filtered automatic point sampler with spacing, coherence/sigma thresholds, and manual review

Until that is implemented, the single curve is a capability demonstration and should be labeled as such in the UI.

Current Open Items

  • Review the ts_rate.bmp, sigma_rate.bmp, hgt_correction.bmp, LOS velocity BMPs, monitoring-point PNG, and exported GeoTIFFs visually in GIS.
  • Tune reference region, coherence thresholds, and pair network before treating the result as production.
  • Decide whether to keep the weak/long 2025 pair, add skip-pairs, or use a denser data sequence when more LT1 precise orbits are available.
  • Keep system integration as orchestration around Gamma commands; do not implement custom SBAS inversion in application code.

Productization Decisions After Trial

If the 5-scene trial succeeds, add a new managed processor instead of bending existing ISCE/SARscape flows:

processor_code = gamma_ipta_sbas
engine_code = gamma
workflow = gamma_ipta_sbas

Required system changes:

  • Add a Gamma IPTA stack manifest builder.
  • Add LT1-specific hard grouping keys:
    • satellite platform, not only family, unless cross-satellite LT1A/LT1B is explicitly validated
    • relative orbit
    • orbit direction
    • imaging mode
    • polarization
    • scene strip/center bucket
    • product variant or station/submode where it affects compatibility
  • Add a Gamma baseline audit step before final pair network selection.
  • Persist selected Gamma pair network separately from the coarse planning graph.
  • Keep system code as orchestration only; Gamma remains the processing authority.

Current Recommendation

Use the manual audited LT1B relOrbit 114 DESCENDING STRIP1 HH / E131.2 N43.8 stack and the trial scripts as the reference path for productization.

Do not start Gamma IPTA production from the current automatic time-series plan. It can be used for discovery, but production stack selection needs the hard grouping keys and Gamma baseline audit described above.

For the next engineering step, add a managed gamma_ipta_sbas processor that orchestrates the Gamma commands rather than reimplementing SBAS inversion in application code.