openspec: atmospheric-measurement-propagation — refraction + ionospheric delay biases with correction hooks (proposal + design + specs + tasks)

[montge]

Summary

OpenSpec change artifacts for atmospheric-measurement-propagation — the fifth and final change of the propagation tier.

Why

The microwave radar path models the atmosphere only as SNR loss (ITU-R P.676): range/elevation measurements carry zero refraction bending and zero ionospheric delay — synthetic truth is unphysically clean, and trackers never face the dominant real-world measurement-bias class.

What the change specifies

• tropospheric-refraction (new): Bean–Dutton exponential-profile ray integral (deterministic fixed quadrature) for elevation bending + excess range, 4/3-Earth cheap tier with a mandatory cross-check band, explicit low-elevation validity floor, and corrections whose residual after mismatched-parameter correction is measured and bounded (corrections are models; the tests say how good)
• ionospheric-group-delay (new): K·STEC/f² with fetched constant provenance, thin-shell obliquity mapping, configured VTEC only (no space-weather ingestion), exact 1/f² and L/S/X-band magnitude tests, and a unit-checked Chapman→VTEC bridge to the existing OTHR machinery (which stays untouched)
• biased-measurement-generation (new): opt-in bias-then-noise application in synthetic radar generation, default OFF with bitwise benchmark invariance, and the demonstration the tier was building toward: biased truth + uncorrected tracker degrades MOTP/ANEES measurably; corrections at the RAE→Cartesian seam recover near-honest statistics — the eval-consistency gates catching a physics-modeling gap end-to-end

Design notes

• Validation is deliberately component-level with fetched published values — no python fixture generator (closed forms + a fixed quadrature don't warrant one; recorded in the design so review doesn't mistake it for an omission)
• No committed scenario TOML gains knobs or bounds (the tracker_noise_sigma API/test-only precedent)
• Out of scope: MODTRAN/NRLMSISE, live TEC, OTHR changes, multipath, filter-side bias estimation (future §3.4 work)

openspec validate --all --strict: 46/46.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation
  • Added a structured proposal and design documentation for atmospheric effects on radar measurements.
  • Documented tropospheric refraction and ionospheric delay models, correction approaches, validity limits, and configuration expectations.
  • Defined opt-in measurement bias behavior while preserving existing benchmark results when disabled.
  • Added specifications for validation, deterministic demonstrations, benchmark comparisons, and migration tasks.
  • Added OpenSpec metadata and a phased implementation checklist.

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Review details

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: ea8cbae7-885c-4f1e-9cf2-fb24df48f8ef

📥 Commits

Reviewing files that changed from the base of the PR and between f182eb8 and 0a77fd0.

📒 Files selected for processing (1)

• openspec/changes/atmospheric-measurement-propagation/tasks.md

📝 Walkthrough

Walkthrough

This change adds an OpenSpec proposal for atmospheric measurement propagation, covering tropospheric refraction, ionospheric delay, opt-in biased measurement generation, inverse correction hooks, validation scenarios, benchmark invariance, and implementation tasks.

Changes

Atmospheric Measurement Propagation

Layer / File(s)	Summary
Design and scope .openspec.yaml, proposal.md, design.md	Defines the propagation scope, modeling decisions, generation and correction order, migration plan, exclusions, risks, and OpenSpec metadata.
Propagation and measurement requirements specs/tropospheric-refraction/spec.md, specs/ionospheric-group-delay/spec.md, specs/biased-measurement-generation/spec.md	Specifies refraction tiers, ionospheric delay and Chapman integration, opt-in biasing, inverse correction, deterministic behavior, and benchmark invariance scenarios.
Implementation and verification plan tasks.md	Lists planned propagation work, synthetic radar integration, benchmark demonstrations, invariance checks, and validation gates.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: copilot

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is clearly related to the PR and accurately summarizes the refraction, ionospheric delay, and correction-hook changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/atmospheric-measurement-propagation

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@openspec/changes/atmospheric-measurement-propagation/tasks.md`:
- Line 32: Update task 5.1’s documented OpenSpec validation command to include
the required --no-interactive flag, preserving the existing --all and --strict
options and all other gate commands unchanged.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 18ede1f3-7756-454c-a382-76f4cbcd010a

📥 Commits

Reviewing files that changed from the base of the PR and between befc7f7 and f182eb8.

📒 Files selected for processing (7)

• openspec/changes/atmospheric-measurement-propagation/.openspec.yaml
• openspec/changes/atmospheric-measurement-propagation/design.md
• openspec/changes/atmospheric-measurement-propagation/proposal.md
• openspec/changes/atmospheric-measurement-propagation/specs/biased-measurement-generation/spec.md
• openspec/changes/atmospheric-measurement-propagation/specs/ionospheric-group-delay/spec.md
• openspec/changes/atmospheric-measurement-propagation/specs/tropospheric-refraction/spec.md
• openspec/changes/atmospheric-measurement-propagation/tasks.md

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud