Best-practice Miaplpy phase linking for small bridge AOIs and asc/desc decomposition

[emanueliwanow]

Hi,

I'm using Miaplpy as a phase-linking engine inside a larger workflow for bridge monitoring with Sentinel-1. My processing chain is:

• ISCE: Sentinel-1 TOPS stack generation (SLCs + interferograms)
• Miaplpy: stack loading + phase linking only
• SARvey: LOS time-series and velocity estimation based on the phase-linked stack
• Custom scripts: combine ascending and descending LOS into vertical and horizontal displacements, and then compute Hotelling T² statistics from those time-series.

So Miaplpy is not used for time-series or velocity estimation in my case; its role is to produce a high-quality, phase-linked interferometric stack that SARvey then ingests.

Context

• AOIs are very small (individual bridges, ~500 m)
• Both ascending and descending tracks are processed
• Goal: stable LOS time-series and velocities over the bridge deck that can be reliably combined into vertical and horizontal components

Questions

1. Phase linking parameter recommendations for small AOIs

   For small AOIs (hundreds to a few thousand points), what are sensible starting values or ranges for key phase linking parameters, such as:

   • Number of siblings / neighbors used in the phase linking step
   • Any coherence or amplitude-based masks that should be applied before PL
   • Handling of PS vs distributed scatterers in this context

   I’m especially interested in settings that are known to work well in urban/infrastructure monitoring.

2. Using Miaplpy only up to phase linking

   Since I only use Miaplpy up to the phase-linking step:

   • Is there any specific “best practice” for exporting / structuring the phase-linked stack so that it plays nicely with external tools (in my case SARvey)?
   • Are there particular metadata or auxiliary outputs from the PL step that you recommend preserving and checking (e.g. quality measures, masks)?

3. Diagnostics to check PL quality before handing off to SARvey

   Before I send the data into SARvey, I’d like to verify that PL worked well, especially because small AOIs are more fragile statistically.

   • Are there recommended diagnostic plots or statistics in Miaplpy to assess PL quality (e.g. residual phase distributions, coherence before/after PL)?
   • Any additional checks you’d suggest when the final goal is asc/desc decomposition into vertical and horizontal displacements?

4. Consistency between ascending and descending PL

   Since I use both geometries together:

   • Are there any recommendations to keep PL settings consistent across asc/desc stacks?
   • Any pitfalls to avoid that might make it harder to combine asc/desc time-series later?

5. Examples / references

   If there are examples or publications where:

   • Miaplpy is used mainly for phase linking that is then passed to another package, and/or
   • The AOI is a small infrastructure element (bridge, dam, etc.),

   I’d be grateful for links or pointers.

I can share:

• My current Miaplpy PL configuration,
• A description of the ISCE interferogram stack I'm feeding in,
• And some small sample datasets or summary plots if helpful.

Thanks a lot for any advice on tuning phase linking for this kind of application.