In urban environments, standalone GNSS receivers can be strongly affected to the point of not being able to provide a position accuracy suitable for use in vehicular applications. In this paper, a vector delay/frequency-locked loop (VDFLL) architecture for a dual constellation L1/E1 GPS/Galileo receiver is proposed. In this implementation, the individual DLLs and FLLs of each tracked satellite are replaced with an Extended Kalman filter (EKF), responsible for both estimating the user's position, velocity and clock bias and closing the code/carrier updates for each GPS L1 and Galileo E1 tracking channels. In this work, a detailed performance comparison between the scalar tracking and VDFLL configuration is assessed under signal outages and significant power drops conditions that are simulated in different satellite channels. Contrary to the conventional tracking, the L1/E1 VDFLL loop is able to recover the frequency and code-delay estimation at the end of the simulated outages without the requirement of signal reacquisition process.