Execution Model

The receiver execution model is a staged evidence pipeline. Each stage consumes typed state from the previous stage and emits enough diagnostics for the next stage, reports, and validation tests to explain what happened.

Stage Flow

sequenceDiagram
    participant Source as Sample source
    participant Runtime as Receiver runtime
    participant Acq as Acquisition
    participant Track as Tracking
    participant Obs as Observations
    participant Nav as Navigation handoff
    participant Art as Artifacts

    Source->>Runtime: sample frames and capture timing
    Runtime->>Acq: acquisition requests and signal profile
    Acq->>Track: accepted or degraded candidates with reasons
    Track->>Obs: channel states, code phase, carrier, CN0
    Obs->>Nav: observation epochs when navigation is enabled
    Nav->>Art: navigation epochs and filter evidence
    Obs->>Art: observations, residuals, quality reports
    Track->>Art: tracking reports and channel diagnostics
    Acq->>Art: candidate lists and explainability

Execution Ownership

stage	receiver-owned decision	not owned here
runtime setup	assemble config, ports, sinks, support inventory, capture timing	command UX and persisted run layout
acquisition	choose requests, search windows, ranking, ambiguity state, candidate reports	signal-code definitions and reusable DSP primitives
tracking	maintain channel lifecycle, lock evidence, loop state, reacquisition, fade handling	generic loop math outside receiver context
observations	turn tracking state into observation epochs with residual and quality evidence	cross-crate field meaning owned by core
navigation handoff	call navigation solvers or filters from receiver config and observations	standalone orbit, correction, PPP, RTK, or estimator science
validation	compare receiver outputs to reference truth at receiver boundary	repository artifact inspection and persisted manifest policy

State Handoff Rules

• A stage may enrich evidence; it must not silently reinterpret the previous stage's status.
• Degraded acquisition or tracking state must stay visible long enough for downstream artifacts and reports to explain it.
• Runtime sinks record events, traces, and metrics; they do not own the scientific meaning of the values they observe.
• Optional navigation is a receiver execution branch, not a transfer of navigation-domain ownership into the receiver crate.

First Proof Check

Use crates/bijux-gnss-receiver/src/pipeline/mod.rs to find the stage owner, then inspect the specific stage module and its integration tests. For runtime composition, start with crates/bijux-gnss-receiver/src/engine/receiver.rs, crates/bijux-gnss-receiver/src/engine/engine.rs, and crates/bijux-gnss-receiver/src/engine/runtime.rs.