Optical time of flight sensor for navigation systems in robotic applications

A time of flight (ToF) system comprises three photoemitters, a photosensor, and a controller. The first photoemitter transmits light onto objects at first height, the second photoemitter onto objects at second, lower height, and the third photoemitter onto objects at third, lowest height. The controller causes one of the photoemitters to transmit modulated light and the photosensor to receive reflections from the scene. The controller determines a depth map for the corresponding height based on phase differences between the transmitted and reflected light. In some examples, the ToF system is included in an autonomous robot's navigation system. The navigation system identifies overhanging objects at the robot's top from the depth map at the first height, obstacles in the navigation route from the depth map at the second height, and cliffs and drop-offs in the ground surface in front of the robot from the depth map at the third height.