Precise Product and Fixture Care

bijux-gnss-nav relies on public-data, golden, and precise-product fixtures that carry scientific meaning, not only test convenience.

Fixture Evidence Flow

flowchart LR
    fixture["public data<br/>golden fixture"]
    parser["format parser"]
    model["orbit clock bias<br/>or antenna model"]
    solver["estimator or<br/>validation check"]
    proof["test evidence"]

    fixture --> parser --> model --> solver --> proof

Care Rules

fixture family	care requirement	first proof
SP3	preserve orbit reference meaning and epoch alignment	SP3 reference accuracy tests
CLK	preserve clock product timing and interpolation assumptions	CLK reference accuracy tests
ANTEX	preserve antenna calibration meaning and frequency mapping	ANTEX parser and model tests
bias SINEX	preserve signal-bias source, units, and time window	bias parser and correction tests
broadcast decoder fixtures	preserve constellation-specific bit and field meaning	GPS, Galileo, BeiDou, and GLONASS decoder tests
public station truth	preserve coordinate frame, reference epoch, and accepted tolerance rationale	public-data and station-truth tests

Change Discipline

• Explain whether changed behavior means the code was wrong, the expectation was wrong, or the external product assumption changed.
• Do not broaden tolerances only to make a reference test green.
• Keep parser fixtures with parser proof and solver fixtures with estimator proof.
• Preserve provenance for public-data and precise-product files.
• Update tests and docs together when a fixture changes the scientific claim.

First Proof Check

Inspect crates/bijux-gnss-nav/docs/FORMATS.md, crates/bijux-gnss-nav/docs/ORBITS.md, crates/bijux-gnss-nav/docs/TESTS.md, crates/bijux-gnss-nav/tests/integration_sp3_reference_accuracy.rs, crates/bijux-gnss-nav/tests/integration_clk_reference_accuracy.rs, and the fixture-backed parser tests for the changed product family.