Optical intensity control of a high-gain LiDAR for autonomous driving

Abstract

LiDAR (Light Detection and Ranging) is a sensor that uses lasers to measure distance and create high-resolution 3D maps of the surrounding environment. It is considered a key technology for autonomous driving because it can provide accurate and detailed information about the environment, including the location and shape of objects, the distance between them, and the surface characteristics of the ground.

Today, various types of automotive LiDAR are being researched and developed. Some automotive LiDAR products meet most of the performance specifications (range, field of view, frame rate). However, a standardized system configuration that satisfies both performance specifications and requirements (unit price, volume, power consumption) has not emerged. This makes it difficult for users to select the most appropriate configuration and technology among various competing alternatives in terms of cost and functionality. Such uncertainty slows down the development of autonomous driving and causes economic losses. Therefore, one of the challenges in the development of automotive LiDAR is finding a configuration that meets the necessary performance specifications and requirements for cost, size, and power consumption. In this thesis, automotive LiDAR for autonomous driving is discussed through a system-based technical approach. Firstly, Optical distance measurement methods are discussed. Secondly, the LiDAR system configuration based on the time-of-flight method is discussed. Thirdly, considerations for achieving the target performance of automotive LiDAR are discussed. Finally, a high-gain LiDAR for autonomous driving is presented. The performance of the high-gain LiDAR can be greatly degraded by ambient light. Accordingly, the ambient light effects on the high-gain LiDAR are analyzed. In addition, to suppress the effects of ambient light, an optical intensity control method is proposed to control the incident optical power on the LiDAR, and it is experimentally demonstrated that the performance degradation can be improved.