Two different wireless protocols can be used for ranging between a mobile device and an access control system (e.g., a vehicle). The first wireless protocol (e.g., Bluetooth®) can be used to perform authentication of the vehicle and exchange ranging capabilities between a mobile device (e.g., a phone or watch) and the vehicle. The second wireless protocol (e.g., ultra-wideband, UWB) can use a pulse width that is less than a pulse width used by the first wireless protocol (e.g., 1 ns v. 1 μs). The narrower pulse width can provide greater accuracy for distance (ranging) measurements.