Dynamic receiver gain control for LiDAR system

A receiver in an optical sensing system, comprising:

• a detector configured to detect light beams returned from an object scanned by the light beams emitted at a plurality of vertical detection angles;
• and
• a controller configured to dynamically vary a gain of the detector based on a predetermined look-up table mapping the respective vertical detection angles to target detector gains, wherein the target detector gains are proportional to a square of detection distances determined based on an elevation of the optical sensing system positioned above a ground and the respective vertical detection angles, and wherein the controller is further configured to determine a first reflectivity of the object based on the light beams received by the receiver and adjust the gain of the detector by the ratio of the first reflectivity and a second reflectivity of a ground.