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Estimation Contracts

Estimation contracts are the most sensitive public surface in bijux-gnss-nav. They describe what a position, integrity, PPP, RTK, or filter claim means, not just the Rust shape of solver structs.

Estimation Flow

flowchart LR
    obs["observations"]
    states["satellite states and corrections"]
    solver["solver or filter"]
    quality["integrity and quality evidence"]
    claim["solution claim or refusal"]

    obs --> solver
    states --> solver
    solver --> quality --> claim

Contract Families

family owns first proof
position PVT, DOP, weighting, smoothing, refusal, and runtime-neutral navigation engine behavior position-estimation source
integrity RAIM detection, exclusion, solution separation, and downgrade evidence RAIM source
EKF reusable state, models, statistics, traits, and filter mechanics EKF source
PPP precise point positioning config, measurements, state, lifecycle, models, quality, and filter behavior PPP source
RTK differencing, ambiguity, baseline, antenna, execution, and quality evidence RTK source
solution claims public support, downgrade, refusal, and advanced-claim reporting solution-claim source

Review Rules

  • A public estimation type is a scientific promise when downstream crates use it to decide quality, support, refusal, or operator reporting.
  • Solver-local helpers should stay private unless another owner needs the same scientific meaning.
  • A successful solution and an honest refusal are both public outcomes; docs must describe both.
  • PPP and RTK changes need quality and downgrade evidence, not only numeric convergence output.

Reader Checks

  • Did the change alter a solution claim or only an implementation detail?
  • Which tests prove position, integrity, PPP, RTK, or filter behavior?
  • Can receiver and command layers render the result without reinterpreting nav science?
  • Does core still own the shared observation and navigation-epoch record meaning?

First Proof Check

Inspect the estimation guide, public API, estimation source, and focused integration tests for position, public PPP convergence, and RTK ambiguity fixing.