This paper presents a thorough investigation into the EKF-based SoOP navigation algorithm's sensitivity to spatial parameters and receiver- and transmitter-related properties. Utilizing the innovative SoOPNE simulation platform, our study unveils significant insights. For instance, at high latitudes, Iridium-Next and Oneweb show a tenfold accuracy improvement over Orbcomm. Additionally, discrepancies between predicted and actual satellite trajectories, with a nominal drift of approximately 250 meters, result in navigation errors of around 400 meters. Our findings underscore the critical importance of addressing these factors to optimize SoOP navigation performance.