Orbit Contracts

Orbit contracts define the typed satellite-state and ephemeris meaning consumed by correction families, position solvers, PPP, RTK, and validation reports. The contract begins after navigation-product bytes are decoded into domain records and ends before receiver scheduling or repository persistence.

Orbit State Flow

flowchart LR
    product["navigation product<br/>broadcast or precise"]
    decode["format decoder"]
    orbit["orbit state<br/>ephemeris satellite position clock"]
    uncertainty["satellite uncertainty"]
    estimator["estimator or correction consumer"]

    product --> decode --> orbit
    orbit --> uncertainty
    orbit --> estimator
    uncertainty --> estimator

Owned Surfaces

surface	owner	reader promise
GPS broadcast orbit	GPS orbit source	GPS ephemeris becomes typed satellite state
Galileo broadcast orbit	Galileo orbit source	Galileo ephemeris follows navigation-domain rules
BeiDou broadcast orbit	BeiDou orbit source	BeiDou ephemeris uses its own constellation law
GLONASS orbit state	GLONASS orbit source	FDMA and GLONASS-specific state stay explicit
shared broadcast helpers	broadcast-orbit helper source	common broadcast-orbit behavior is reused deliberately
uncertainty	satellite-uncertainty source	orbit quality reaches downstream estimators as typed evidence

Boundary Decisions

• File discovery and dataset placement belong to infra before decoded product bytes reach nav.
• Receiver acquisition, tracking, and observation scheduling belong to receiver after nav returns typed state or refusal evidence.
• Coordinate, unit, and time record semantics come from core, but constellation-specific orbit interpretation belongs here.
• A precise-product provider seam is part of nav when it supplies satellite state; repository storage for that product remains infra.

First Proof Check

Inspect orbit source, the orbit guide, and focused orbit tests for broadcast reference behavior, broadcast accuracy, GLONASS broadcast reference behavior, and SP3 reference accuracy.