Invariants

The most important bijux-gnss-core invariants are the ones downstream crates quietly depend on every day.

Invariant Map

flowchart LR
    public["public API"]
    artifacts["artifacts"]
    time["time and units"]
    boundary["dependency boundary"]
    trust["downstream trust"]

    public --> trust
    artifacts --> trust
    time --> trust
    boundary --> trust

Invariant Families

family	invariant	proof
public surface	stable core meaning is deliberately re-exported through src/api.rs	public API guardrail
private layout	callers do not need private module paths for stable contracts	public API guardrail
artifacts	payload validators enforce semantic coherence, not just parse shape	artifact validation tests
numeric evidence	non-finite or internally inconsistent persisted values are rejected rather than normalized silently	artifact validation tests
support inventory	support-matrix and navigation payloads remain versioned records	artifact and serialization tests
timekeeping	GPS, UTC, TAI, leap-second, and sample-trace conversions remain deterministic	property tests and regression corpus
dependency boundary	core stays free of higher-level workspace crate dependencies	integration guardrails
ownership boundary	core remains a foundation rather than runtime or repository policy	contract map and review-scope docs

Failure Signals

• A downstream crate imports a private core module for stable meaning.
• A serialized artifact accepts non-finite or contradictory values.
• A new core type duplicates a receiver, nav, signal, infra, or command concept.
• A time conversion passes examples but fails property-test edge cases.
• A core dependency points upward into a product or workflow crate.

First Proof Check

Start with the core invariants guide and contract map. Then confirm enforcement through the public API guardrail, navigation artifact validation, tracking artifact validation, timekeeping property tests, and integration guardrails.