Resetting signal between GPS updates (Simulink)

I am using Simulink to estimate the Euler angles etc of a UAV in motion. I am trying to correct for bias errors and if there is no new velocity update from the GPS, I should send a 3x1 zero vector as the correction from the aaccelerometer. What I do now is that I hold the last sampled correction value and send that between updates. How do I reset the error correction? I assume I should use a switch somehow.