Phasor Measurement Units (PMUs) provide time-synchronized, accurate and precise measurements of instantaneous voltages and currents at many locations across the electrical power system. The current state-of-the-art time transfer architecture for PMUs uses GPS time synchronization. The dependence on GPS for time synchronization introduces new vulnerabilities to a power system utilizing PMUs. Thus, in our prior work, we proposed and verified with experimental data the concept of using multi-receiver position-information-aided vector tracking (MRPIAVT) to provide accurate, robust and reliable GPS time transfer for PMUs . The MRPIAVT architecture is improved upon in this paper, leading to Advanced MRPIAVT. Improvements include modification of the state estimation equations such that the state vector contains only the clock bias and clock drift states. Updated clock dependent process noise covariance matrix used in the Extended Kalman Filter (EKF). Increased pre-detection coherent integration timing. Hardware timing synchronization, additional sub-sample software timing synchronization and an increased sampling rate. We demonstrate with further experiments, the enhanced performance of Advanced MRPIAVT with respect to timing accuracy, jamming, multipath and data-level spoofing.