Navigation Models

NavModel is the abstract base for predicted-scene generators. Each subclass implements three methods:

• create_model() — populate the model’s internal state and metadata dict.

• to_features() — return a list of NavFeature instances for technique consumption.

• to_annotations() — return an Annotations collection for the summary PNG.

Concrete subclasses self-register via __init_subclass__; abstract bases set _abstract = True to opt out. The class method instances_for_obs() is the per-class hook that build_models_for_obs() iterates.

Registered concrete models, grouped by feature family:

• Stars (Stars) — NavModelStars (catalog-driven; one instance per observation). A simulated-image sibling NavModelStarsSimulated is reserved without an implementation.

• Bodies (Bodies) — NavModelBody (catalog-driven; one instance per body whose bounding box overlaps the extended FOV) and NavModelBodySimulated (simulated-image GUI variant).

• Rings (Rings) — NavModelRings (catalog-driven; one instance per planet whose ring system is configured and visible) and NavModelRingsSimulated (simulated-image GUI variant).

• Titan (Titan) — NavModelTitan (registered placeholder for atmospheric-body navigation; emits no features). A simulated-image sibling NavModelTitanSimulated is reserved without an implementation.

Shared annotation helpers live on NavModelBodyBase (body silhouette + label rendering) and NavModelRingsBase (per-edge polyline + label rendering).

The API surface is summarised under nav.nav_model.

• Stars
  • Star Navigation Model
    • Overview
    • Theory
      • Catalog reduction
      • Conflict marking
      • Magnitude detectability gate
      • Magnitude-margin effective SNR
      • Per-feature uncertainty
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
      • Module-level emission constants
      • Per-instrument overrides
    • Implementation
      • Annotation helpers
      • Per-image metadata
      • Call path
    • Examples
  • Simulated Star Navigation Model
    • Overview
    • Theory
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
    • Implementation
    • Examples
• Bodies
  • Body Navigation Model
    • Overview
    • Theory
      • Bounding-box construction
      • Anti-aliased silhouette extraction
      • Polyline sampling
      • Per-vertex position covariance
      • Visible-lit and overflow fractions
      • Lit-weighted predicted centroid
      • Sub-solar direction
      • Phase-and-irregularity coupling
      • Feature emission gates
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
      • bodies block
      • Body-shape catalogue
      • Module-level emission constants
      • Per-instrument overrides
    • Implementation
      • BodyShape dataclass
      • Annotation helpers
      • Per-image metadata
      • Call path
    • Examples
  • Simulated Body Navigation Model
    • Overview
    • Theory
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
      • Render geometry vs navigation geometry
    • Implementation
      • Call path
    • Examples
• Rings
  • Ring Navigation Model
    • Overview
    • Theory
      • Edge rendering
      • Per-edge feature filtering
      • Curvature classification
      • Per-vertex covariance
      • Annulus template
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
      • rings block
      • Per-planet ring catalogue
      • Module-level emission constants
      • Per-instrument overrides
    • Implementation
      • Annotation helpers
      • Per-image metadata
      • Call path
    • Examples
  • Simulated Ring Navigation Model
    • Overview
    • Theory
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
    • Implementation
      • Call path
    • Examples
• Titan
  • Titan Navigation Model
    • Overview
    • Theory
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
    • Implementation
    • Examples
  • Simulated Titan Navigation Model
    • Overview
    • Theory
      • Restrictions and assumptions
      • Sources of uncertainty
    • Configuration
    • Implementation
    • Examples