Drone Autommatic Flight
This video shows that automatically obstacle avoiding flight by Drone. Detect height by pressure sensor and detect obstacle by SMD type of Ultrasonic sensor.
In Ultrasonic Sensors
Example application using an SMD ultrasonic sensor to detect objects
You can see a drone (equipped with an SMD ultrasonic sensor) flying autonomously, and can also check the ultrasonic sensor waveform when an obstacle is detected. This could also be used for applications such as detecting objects or people.