A technique that can maximize signal to noise ratio in systems that use beam steering, by steering both the transmit and receive signals. A beam splitter is used, which is positioned to receive both the light beam transmitted by the light source and the return light beam, and a scanning beam steerer, which is positioned to receive both transmitted light from the beam splitter and returning light from the target. Using a split portion of the beam, a reference signal can be provided to probe the ambient condition of the sensor, to sense conditions such as darkness and fog.