Scenario kind pagesEdit on GitHubSource: docs/kinds/by-kind/eo-coverage.md

eo-coverage (scenario kind)

Scenario kind of the engine v0.38.0, family Mission analysis, links and space operations. Advisory: analysis output from a research and engineering tool, not type-approved navigation equipment and not a safety-of-life service. Every label here is the engine's or the verification matrix's; a kind is MODELLED unless the matrix says otherwise (how a label is earned: the README's Evidence section).

What it does#

Earth-observation payload footprint & coverage geometry (SMAD space triangle): Earth angular radius, swath width, nadir ground sample distance, maximum off-nadir access, circular period, J2 nodal period and equatorial ground-track spacing with a contiguous-coverage flag, for an orbit altitude, inclination (sun-synchronous by default) and sensor FOV/IFOV. MODELLED spherical-Earth geometry (no radiometry/MTF/atmosphere/jitter/glint); node spacing R_e·(ω − Ω̇)·T_nodal with first-order J2 secular rates.

One run of scenarios/eo-coverage.toml summarises as: eo-coverage: 700 km, ±7.5° FOV -> 184 km swath, 9.8 m nadir GSD, access to 745 km off-nadir; node spacing 2752 km (gapped) (MODELLED)

Inputs#

From the schema (kshana kinds --json):

  • Required fields: none
  • Optional fields: altitude_km, half_fov_deg, ifov_microrad, max_off_nadir_deg, inclination_deg

The example scenarios/eo-coverage.toml sets, among others:

Field Value Unit
altitude_km 700 km
half_fov_deg 7.5 deg
ifov_microrad 14 not stated
kind eo-coverage text
max_off_nadir_deg 45 deg

Run it#

kshana scenarios/eo-coverage.toml

What it gives#

The scalar results of that run, with the units the engine states:

Result Value Unit
altitude_km 700 km
contiguous_equatorial_coverage false flag
earth_angular_radius_deg 64.303554 deg
equatorial_ground_track_spacing_km 2752.173944 km
half_fov_deg 7.5 deg
inclination_deg 98.187982 deg
max_access_ground_range_km 745.175016 km
max_off_nadir_deg 45 deg
nadir_gsd_m 9.8 m
nodal_period_min 98.892806 min

Result label (the engine's): MODELLED — spherical-Earth space-triangle geometry; swath/GSD/access are geometric (no radiometry/MTF/atmosphere/jitter/glint), ground-track spacing is R_e·(ω − Ω̇)·T_nodal with first-order J2 secular rates

The chart the engine writes for scenarios/eo-coverage.toml, kind eo-coverage

Evidence#

VALIDATED: the verification matrix rows that name this kind.

  • VALIDATED SMAD space-triangle geometry: Earth angular radius, swath width, nadir GSD, maximum off-nadir access and circular period, plus the first-order J2 nodal period (eo_payload::j2_nodal_period) and the equatorial ground-track spacing R_e (omega_ Tests: eo_payload_coverage_reference.rs.

The rows the run itself exercised, with the oracle the matrix gives each (the public sources are named there):

  • MODELLED Deterministic, scenario-hashed, SBOM + cross-platform golden gates. Oracle (ExternalDataset): SBOM conformance to the official CycloneDX 1.5 JSON Schema (+ valid SPDX identifiers) — an external published standard, zero validation errors over the full dependency graph; the FoM-determinism / byte-reproducibility part remains a pinned self-consistency check, so the row stays MODELLED
  • VALIDATED SMAD space-triangle geometry: Earth angular radius, swath width, nadir GSD, maximum off-nadir access and circular period, plus the first-order J2 nodal period (. Oracle (ExternalDataset): Orekit 12.2 (Apache-2.0) and GeographicLib 2.1 (MIT), both run as separate programs, pre-registered (766823f3) before the engine change and any oracle run: sphere quantities within 1e-9 relative (worst: angular radius 5.4e-16, swath 7.0e-13, access 1.9e-14), period 1e-12 (1.6e-16), nadir GSD 1e-7 (2.9e-10), the J2 nodal period and node spacing within 0.1 % of an Orekit numerical J2 propagation with a node detector (1

Limitations#

What the run's own report says is not modelled or not validated:

  • MODELLED — spherical-Earth space-triangle geometry; swath/GSD/access are geometric (no radiometry/MTF/atmosphere/jitter/glint), ground-track spacing is R_e·(ω − Ω̇)·T_nodal with first-order J2 secular rates (result label)
  • MODELLED spherical-Earth geometry (no radiometry/MTF/atmosphere/jitter/glint); node spacing R_e·(ω − Ω̇)·T_nodal with first-order J2 secular rates. (kind catalogue (kshana kinds --json))
  • HONEST SCOPE: MODELLED spherical-Earth geometry only -- no radiometry / MTF / atmosphere / pointing-jitter / sun-glint model. Ground-track spacing is R_e*(omega - dOmega/dt)*T_nodal with first-order J2 secular rates; the inclination defaults to the sun-synchronous one for the altitude. Run: kshana scenarios/eo-coverage.toml (scenario file comment, lines 7 to 11)
  • Reproducibility & software assurance is MODELLED, not validated: a sub-claim is externally checked, but the whole capability composes modelled pieces, so the capability stays Modelled. (verification matrix (docs/MODELLED-RATIONALE.md))

See also#