for selecting sensors that detect obstacles and people. To determine the applicable fields of a sensor, measurement resolution is evaluated by its effectiveness in recognizing thin objects. The mapping performance test constructs a 2D map from the point cloud obtained from the lidar sensor mounted on a mobile robot. This evaluation is important for selecting sensors with the required accuracy for safe driving when used in mobile applications. Environmental robustness is evaluated and compared in foggy and glass environments, which pose difficulties for range sensors during measurement. To summarize Laser Emitters Collimating Lenses Laser Emitters Laser Receivers Motor MEMS Mirror (b) (a) TransmitterTransmitter Beam Spreader Laser Emitters Receiv rReceiver Target Targett tt t Array of Receivers (c) CW Radar (d) FIGURE 1. The operation mechanism of lidar and radar sensors. (a) A mechanical lidar system, (b) an MEMS lidar, (c) a flash lidar system, and (d) FMCW radar and pulse radar systems. Pulse Radar t Long Range Velodyne VLP-16 IWR 1443 Midrange HPS-3D160-U Short Range Solid State MEMS CE30-D RPLIDAR-A2 Mechanical FIGURE 2. Representative sensors based on beam steering technology and measurable ranges. 30 IEEE ROBOTICS & AUTOMATION MAGAZINE SEPTEMBER 2023 X4M03 Radar Frequency Amplitude Amplitude