2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228655This paper reports the results of an analysis of the Doppler tracking data of Pioneer probes which did show an anomalous behaviour. A software has been developed for the sake of performing a data analysis as independent as possible from that of J. Anderson et al. \citep{anderson}, using the same data set. A first output of this new analysis is a confirmation of the existence of a secular anomaly with an amplitude about 0.8 nms$^{-2}$ compatible with that reported by Anderson et al. A second output is the study of periodic variations of the anomaly, which we characterize as functions of the azimuthal angle $φ$ defined by the directions Sun-Earth Antenna and Sun-Pioneer. An improved fit is obtained with periodic variations written as the sum of a secular acceleration and two sinusoids of the angles $φ$ and $2φ$. The tests which have been performed for assessing the robustness of these results are presented.13 pages, 6 figures, minor amendmentsGeneral Relativity and Quantum CosmologySpace Physicstext