Techniques for identifying true signals in coherent LIDAR systems

A light detection and ranging (LIDAR) system, comprising:

• an optical scanner to transmit an optical beam toward a target and receive a returned optical beam, wherein the optical beam comprises an up-chirp frequency and a down-chirp frequency, and wherein the optical beam is modulated to have phase non-linearities;
• an optical processing system coupled to the optical scanner to generate a baseband signal in a time domain from the returned optical beam, wherein the baseband signal comprises a plurality of peaks corresponding with the up-chirp frequency and the down-chirp frequency;
• and
• a signal processing system coupled to the optical processing system, comprising:
• a processing device;
• and
• a memory to store instructions that, when executed by the processing device, cause the LIDAR system to:
• identify, among the plurality of peaks, a first true peak in the baseband signal;
• identify, among the plurality of peaks, a second true peak in the baseband signal based, at least in part, on a spectral shape of the second true peak caused by the phase non-linearities;
• and
• determine a location of the target using the first true peak and the second true peak.

A light detection and ranging (LIDAR) system, comprising:

• an optical scanner to transmit an optical beam toward a target and receive a returned optical beam, wherein the optical beam comprises an up-chirp frequency and a down-chirp frequency, and wherein the optical beam is modulated to have phase non-linearities;
• an optical processing system coupled to the optical scanner to generate a baseband signal in a time domain from the returned optical beam, wherein the baseband signal comprises a plurality of peaks corresponding with the up-chirp frequency and the down-chirp frequency;
• and
• a signal processing system coupled to the optical processing system, comprising:
• a processing device;
• and
• a memory to store instructions that, when executed by the processing device, cause the LIDAR system to:
• determine whether close-range ghosting or far-range ghosting is detected based on the plurality of peaks;
• identify, among the plurality of peaks, a first true peak in the baseband signal based, at least in part, on whether close-range ghosting or far-range ghosting is detected;
• identify, among the plurality of peaks, a second true peak in the baseband signal based, at least in part, on a spectral shape of the second true peak caused by the phase non-linearities;
• and
• determine a location of the target using the first true peak and the second true peak.