Observation and Tracking Contracts

Observation and tracking records are shared language at the boundary between signal facts, receiver runtime, navigation interpretation, and persisted artifacts. Core owns the record meaning; higher crates own the behavior that creates or consumes those records.

Record Flow

flowchart LR
    signal["signal facts"]
    receiver["receiver stages"]
    core["core observation<br/>and tracking records"]
    nav["navigation consumers"]
    infra["artifact persistence"]
    command["operator reports"]

    signal --> receiver --> core
    core --> nav
    core --> infra
    core --> command

Record Families

family	record meaning	behavior owner
acquisition	requests, results, hypotheses, evidence, refinement, uncertainty	receiver acquisition
tracking	epochs, transitions, lifecycle state, assumptions, uncertainty	receiver tracking
observations	epoch measurements, manifests, decisions, support classes, uncertainty classes	receiver observation construction and nav consumption
quality	measurement quality, covariance status, rejection reasons	receiver and nav interpretation
differencing	single- and double-difference records	nav and RTK consumers
signal timing	travel time, transmit time, and delay alignment evidence	receiver production, nav use

Boundary Decisions

• Core records must stay solver-neutral and runtime-neutral.
• Receiver owns how acquisition, tracking, and observations are produced.
• Signal owns reusable code and DSP facts used by receiver.
• Nav owns estimator, correction, PPP, RTK, and differencing behavior.
• Infra owns persistence of these records after they become artifacts.

First Proof Check

Inspect crates/bijux-gnss-core/src/observation/, crates/bijux-gnss-core/src/observation_quality.rs, crates/bijux-gnss-core/docs/CONTRACTS.md, crates/bijux-gnss-core/docs/SERIALIZATION.md, crates/bijux-gnss-core/tests/tracking_artifact_validation.rs, and receiver or nav tests that serialize or consume observation records.