A system and method for sidelobe suppression in phase-encoded Doppler LIDAR to support the operation of a vehicle includes determining a sequence code that is indicative of a sequence of phases for an optical signal; modulating an optical signal based on the sequence code to produce a phase-encoded optical signal; transmitting the phase-encoded optical signal to an environment; receiving, from the environment, a returned optical signal in response to transmitting the phase-encoded optical signal; generating, based on the returned optical signal, an electrical signal; and determine a Doppler frequency shift in the returned optical signal.