Validation Methodology & Reference Implementation
A six-tier validation pyramid for the HAPIS Link Budget API — code verification, ITU-R / 3GPP reference cases, cross-tool checks, empirical comparison, sensitivity analysis, and continuous integration. v1.0 runs a mandatory itur cross-tool oracle per commit at Tier 3 for ITU-R P.676 (±0.05 dB typical tolerances), and § 11 documents a candid Cat 4 reclassification case study of how the methodology caught and corrected multi-dB catalogue errors. Explicit about which tiers are operational today and which are on the roadmap.