A system comprising: a photodetector (130; 230), wherein the photodetector is configured to receive light from an environment of the system; a laser light source (110; 210), wherein the laser light source is configured to emit laser light into the environment, wherein the laser light source is configured to provide a local oscillator signal to the photodetector; and a controller, comprising at least one processor and a memory, wherein the at least one processor is configured to execute instructions stored in the memory so as to carry out operations, the operations comprising: causing the laser light source to emit a first light pulse, wherein the first light pulse is an incoherent light pulse, wherein the first light pulse interacts with the environment to provide a first reflected light pulse; causing the laser light source to emit a second light pulse, wherein the second light pulse is a coherent light pulse with a coherence length longer than the incoherent light pulse and a pulse length longer than the incoherent light pulse, wherein the second light pulse interacts with the environment to provide a second reflected light pulse, and wherein the first light pulse and the second light pulse both form at least a portion of a pulse train, wherein the pulse train comprises an interleaved pattern of coherent light pulses and incoherent light pulses; receiving, at the photodetector, the first reflected light pulse, the second reflected light pulse, and the local oscillator signal; determining, based on the first reflected light pulse, a presence of an object in the environment; and determining, based on the second reflected light pulse and the local oscillator signal, a relative speed of the object with respect to the system. a photodetector (130; 230), wherein the photodetector is configured to receive light from an environment of the system; a laser light source (110; 210), wherein the laser light source is configured to emit laser light into the environment, wherein the laser light source is configured to provide a local oscillator signal to the photodetector; and a controller, comprising at least one processor and a memory, wherein the at least one processor is configured to execute instructions stored in the memory so as to carry out operations, the operations comprising: causing the laser light source to emit a first light pulse, wherein the first light pulse is an incoherent light pulse, wherein the first light pulse interacts with the environment to provide a first reflected light pulse; causing the laser light source to emit a second light pulse, wherein the second light pulse is a coherent light pulse with a coherence length longer than the incoherent light pulse and a pulse length longer than the incoherent light pulse, wherein the second light pulse interacts with the environment to provide a second reflected light pulse, and wherein the first light pulse and the second light pulse both form at least a portion of a pulse train, wherein the pulse train comprises an interleaved pattern of coherent light pulses and incoherent light pulses; receiving, at the photodetector, the first reflected light pulse, the second reflected light pulse, and the local oscillator signal; determining, based on the first reflected light pulse, a presence of an object in the environment; and determining, based on the second reflected light pulse and the local oscillator signal, a relative speed of the object with respect to the system. causing the laser light source to emit a first light pulse, wherein the first light pulse is an incoherent light pulse, wherein the first light pulse interacts with the environment to provide a first reflected light pulse; causing the laser light source to emit a second light pulse, wherein the second light pulse is a coherent light pulse with a coherence length longer than the incoherent light pulse and a pulse length longer than the incoherent light pulse, wherein the second light pulse interacts with the environment to provide a second reflected light pulse, and wherein the first light pulse and the second light pulse both form at least a portion of a pulse train, wherein the pulse train comprises an interleaved pattern of coherent light pulses and incoherent light pulses; receiving, at the photodetector, the first reflected light pulse, the second reflected light pulse, and the local oscillator signal; determining, based on the first reflected light pulse, a presence of an object in the environment; and determining, based on the second reflected light pulse and the local oscillator signal, a relative speed of the object with respect to the system.