A method and apparatus for finding a relative direction to, a radial speed of, and a distance to a target is described. A laser source illuminates the target and the Doppler shifted return beam is incident upon a window system at an angle and is transmitted therethrough. The magnitude of the transmitted Doppler shifted beam decreases due to Fresnel transmittance. Opposing photomixers then detect this transmitted Doppler shifted beam, thereby creating a pair of detection signals that are mixed with a local oscillator signal. The mixing process creates Doppler frequency signals that are subsequently processed to determine the radial speed of the target. Due to the Doppler frequency component of the signals, objects in the same direction, but moving at different radial speeds, can be discriminated, as the relative direction processing occurs after the Doppler processing.