Fixed nadir payload mounting means that the payload is attached to the belly of the aircraft, pointing straight down at the earth in a static position.
This mounting is useful for mapping and surveying applications. Fixed nadir payload mounting is the lightest weight solution and yields longer flight times. This is because you do not need to carry the extra weight of the gimbal. However, if you’d like to perform other applications, such as inspection, you will need a gimbal. A gimbal will provide stabilized orientation control over the camera direction and functions.
Vision Aerial drones come with a Payload Connection System (PCS) that allows you to easily switch between a nadir mounted payload and gimbal-mounted payloads. All it requires is the twist of a locking mechanism and plugging in the electrical components.