Design Decisions

Key architectural and implementation decisions in libgnss++.

Explicit State Management

All solvers maintain explicit state structures (RTKProcessor, PPPProcessor) rather than global runtime singletons. This makes testing deterministic and state transitions auditable.

Modular RTK Pipeline

The RTK solver is decomposed into discrete stages: selection (reference satellite and DD pair construction), measurement (residual and covariance assembly), update (Kalman filter), and validation (fix validation with conservative hold policy).

Centralized Signal Policy

signal_policy.hpp provides a single source of truth for band mapping and constellation priority, preventing code duplication across solvers and I/O modules.

Protocol-Agnostic Solver Layer

Solvers accept canonical ObservationEpoch and NavigationProducts structures, remaining independent of the input format (RINEX, RTCM, UBX, QZSS L6).

Sign-off Framework

Every validation gate produces a machine-readable JSON summary so CI can enforce regression thresholds without human inspection.