LiDAR system and method employing late-lock Geiger mode detection

1. A LiDAR system comprising:

a pulsed laser for providing and transmitting towards an object an optical signal which is reflected from the object thereby producing a reflected signal;

an avalanche photodiode (APD) photodetector for detecting the reflected signal;

a processing system for determining a time difference between when the optical signal is transmitted and when the reflected signal is detected;

SAID LiDAR SYSTEM CARACTERIZED BY:

a synchronization delay between APD quench and APD arm, the synchronization delay defined by the following relationship

Synchronization Delay=(Duration LPP −Duration HO )

wherein Duration LPP is the duration of the laser pulse period and DurationHO is the duration of a holdoff time; and

wherein laser pulse period is the time period between transmission of optical signal pulses, holdoff time is a time period before the end of a detection frame during which GmAPD photodetector elements are disarmed and trapped charges in the GmAPDs can detrap and recombine.

2. The system according to claim 1 further CHARACTERIZED BY:

the difference between the holdoff time and laser pulse period is<10 nsec.

3. A method of operating an avalanche photodiode (APD) LiDAR system comprising:

operating a pulsed laser such that an optical signal is directed towards an object and subsequently reflected from the object thereby producing a reflected signal;

detecting the reflected signal by a photodetector;

determining a time difference between when the optical signal is transmitted and when the reflected signal is detected;

SAID METHOD CHARACTERIZED BY:

a synchronization delay between APD quench and APD arm, the synchronization delay defined by the following relationship

Synchronization Delay=(Duration LPP −Duration HO )

wherein Duration LPP is the duration of the laser pulse period and DurationHO is the duration of a holdoff time; and

wherein laser pulse period is the time period between transmission of optical signal pulses, holdoff time is a time period before the end of a detection frame during which GmAPD photodetector elements are disarmed and trapped charges in the GmAPDs can detrap and recombine.

4. The method according to claim 3 further CHARACTERIZED BY:

the difference between the holdoff time and the laser pulse period is adjusted to be<10 nsec.

5. A non-transitory computer storage medium having computer executable instructions which when executed by a computer cause the computer to perform operations comprising:

operating a pulsed laser such that an optical signal is directed towards an object and subsequently reflected from the object thereby producing a reflected signal;

arming an avalanche photodiode (APD) photodetector to detect the reflected signal;

determining a time difference between when the optical signal is transmitted and when the reflected signal is detected; and

a synchronization delay between APD quench and APD arm, the synchronization delay defined by the following relationship

Synchronization Delay=(Duration LPP −Duration HO )

wherein Duration LPP is the duration of the laser pulse period and DurationHO is the duration of a holdoff time; and

wherein laser pulse period is the time period between transmission of optical signal pulses, holdoff time is a time period before the end of a detection frame during which GmAPD photodetector elements are disarmed and trapped charges in the GmAPDs can detrap and recombine.

6. The non-transitory computer storage medium according to claim 5 having computer executable instructions which when executed by a computer cause the computer to additionally perform operations comprising:

adjusting the holdoff time such that the difference between the holdoff time and the laser pulse period is adjusted to be<10 nsec.