Techniques to compensate for phase impairments in lidar systems

A method of light detection and ranging (LiDAR), comprising:

• emitting an outgoing optical beam towards a target and collecting light returned from the target in a target optical beam;
• redirecting a portion of the outgoing optical beam to an optical delay device to generate a reference optical beam;
• detecting a first beat frequency from the target optical beam to generate a target signal, and detecting a second beat frequency from the reference optical beam to generate a reference signal;
• processing the reference signal to generate a phase noise estimate;
• combining the phase noise estimate with the target signal in a digital time-domain computation to eliminate noise in the target signal to generate a phase corrected target signal;
• and
• determining a range of the target from the phase corrected target signal.

A frequency modulated continuous wave (FMCW) light detection and ranging (LIDAR) system, comprising:

• a processing device;
• and
• a memory to store instructions that, when executed by the processing device, cause the LIDAR system to:
• emit an outgoing optical beam towards a target and collect light returned from the target in a target optical beam;
• redirect a portion of the outgoing optical beam to an optical delay device to generate a reference optical beam;
• detect a first beat frequency from the target optical beam to generate a target signal, and detect a second beat frequency from the reference optical beam to generate a reference signal;
• process the reference signal to generate a phase noise estimate;
• combine the phase noise estimate with the target signal in a digital time-domain computation to eliminate noise in the target signal to generate a phase corrected target signal;
• and
• determine a range of the target from the phase corrected target signal.