UAV-R21-1 is a lightweight millimeter-wave radar sensor developed and produced by Microbrain Intelligent Technology Co., Ltd. The sensor has high measurement accuracy, small size, high sensitivity, light weight, easy integration and stable performance. The product can detect whether there is aobstacle in front by sending 77GHz sector electromagnetic wave to the front and processing the echo signal, and feedback the relative distance, speed, azimuth and other information between obstacles and radar, and guide drone to avoid obstacles to ensure safe operation.