Development of an interferometric level 3 pipeline for columnar filtering, 5-fold cross-validation, and IVOA VOEvent dispatch of technosignatures in global SETI initiatives

Modern international Search for Extraterrestrial Intelligence (SETI) initiatives, such as Breakthrough Listen and COSMIC, generate petabytes of raw data daily. This paper introduces a practical, end-to-end Level 3 data processing framework optimized for distributed astronomical computing and Citizen Science paradigms. The proposed method circumvents line-by-line memory allocation, relying instead on high-speed columnar (vectorized) analysis of spectrograms via lazy loading mechanics. To eliminate artificial intelligence (AI) overfitting under extreme signal-to-noise ratios, a rigid 5-fold cross-validation algorithm is integrated directly into the sub-band parsing logic, allowing robust anomaly extraction in up to 35% Gaussian white noise profiles. The framework is coupled with an interferometric trilateration algorithm based on the Time Difference of Arrival (TDOA) across a global triad of operational radio observatories: the Green Bank Telescope (USA), MeerKAT (South Africa), and the Parkes Observatory (Australia). The architecture is natively integrated with an automated alert dissemination module compliant with the International Virtual Observatory Alliance (IVOA) VOEvent v2.0 standard over institutional SMTP gateways.