UAS Sensor Placement

The unmanned aviation domain is growing exponentially every day and becoming available for personal and professional use by the average person. However, not all unmanned aerial systems (UAS) are built alike. Besides differences in their physical appearances, the sensor placement and integration can change how effective an UAS can be for a particular task. This paper will discuss the selection of two different commercially available UAS systems designed to complete two different tasks while comparing the sensors onboard each system. The first system must be able to provide aerial photography and full motion video below 400 feet above ground level (AGL) and the second system needs to be able to perform as a racing drone with a first person view (FPV).

DJI Phantom 4 Pro

The DJI Phantom 4 Pro is the most recent edition of the Phantom series and was launched in March of 2016 by the DJI company (Perlman, 2017). Amongst the newest changes of the Phantom 4 is that it is lighter and can stay up in the air for up to 28 minutes, has updated obstacle avoidance, and a new camera lens (Perlman, 2017). The camera onboard is a professional quality 4K 20 mm lens that is capable of a 94˚ field of view that is capable of capturing 30 frames per second (fps) in camera mode and high definition video in 1080p at 120 fps (DJI, n.d.a). The camera has a range of 100-3,200 m for video and 100-1600 m for still photos which allow it to take ideal panoramic photos (DJI, n.d.b). The camera is installed underneath the airframe using a 3-axis gimbal to eliminate vibrations and in-flight movement in order to capture clear, smooth images (DJI n.d.a). Between the two positioning systems and the vision system onboard, the Phantom 4 can easily be flown at altitude with comfort and ease. The Vision Positioning System (VPS) onboard the Phantom 4 includes a forward vision system and a downward vision system (DJI, n.d.a). The forward vision system acts as the primary sensor for the Phantom 4 to detect and avoid obstacles in different flight modes while the downward facing system uses dual cameras and ultrasonic sensors to determine position accuracy when flying indoors or at low altitudes (DJI, n.d.a). On top of the vision system, the Phantom 4 also is equipped with not only a Global Positioning System (GPS) and also a Global Navigation Satellite System (GLONASS) (DJI, n.d.a).  These sensors allow the Phantom 4 to always be connected to satellites in order to maintain a precise accurate position while in the air. The Phantom 4 also has several redundant systems, including two compass modules and dual Inertial Measurement Units (IMUs), so that the system can internally check and verify information that it is receiving (DJI, n.d.a). To give more variety to the types of tasks the Phantom 4 can complete it offers three flight modes: position mode, atti mode, and the new sport mode (DJI, n.d.a).

Aerodyne RC Nimbus 195

The Nimbus 195 is one of the newest FPV racing drones on the market, by Aerodyne RC (Aerodyne RC, n.d.a). What makes this vehicle unique compared to any other is that the frame is from a carbon fiber material that allows it to be virtually indestructible and can handle operating in inclement weather (Aerodyne RC, n.d.a). The Nimbus is available to pre-order in both Ready-to-Fly (RTF) and Bind-and-Fly kits as well as just the frame (Liszewski, 2017). The drone that is included with the kits is fully assembled drone and equipped with the essentials needed for an effective racing drone. Sensors on this system include a Typhoon 4-in-1 electric speed controller (ESC), an Omnibus F4 flight controller with onscreen display, a 5.8 GHz Tramp HV video transmitter, SBUS radio control receiver, and a video transmitter (VTx) antenna (Aerodyne RC, n.d.b). The key visual sensor to this system is the adjustable FPV Foxeer Arrow V3 camera (Aerodyne RC, n.d.b). It is installed onto the front of the system and is adjustable to 30, 45, and 55 degree angles in order to assist with situational awareness as the vehicles races through any course (Aerodyne RC, n.d.b). The other benefit to this camera is that is it allows for the smallest delay possible, which due to the necessity of the operator needs to be able to quickly respond to obstacles on the course. Another reason this system is a recommended system for drone racing is because it is not equipped with unnecessary sensors such as a GPS, but has a gyroscope, accelerometer and an added barometer in order to maintain situational awareness of the position of the vehicle (Aerodyne RC, n.d.a; InvenSense, 2013; Aerodyne RC, n.d.c).

Even though both of these systems are examples of UAS, they both demonstrate that depending on how they were built they can serve completely different purposes. The most significant difference between the two is the camera system setup. The Nimbus is equipped with a FPV camera in order to provide the operator a first person experience with the least amount of drag possible, while the Phantom 4’s camera is installed with a gimbal to guarantee that the camera stays stable as it takes images. The breakdowns of both of these systems demonstrate that the design and placement of key components can completely change how the system functions and can serve a specific mission.

References

Aerodyne RC.  (n.d.a). FPV Racing Drone NIMBUS 195. Aerodyne RC.  Retrieved from http://aerodyne-rc.com/

Aerodyne RC. (n.d.b). Nimbus – BNF kit. Aerodyne RC.  Retrieved from http://aerodyne-rc.com/product/nimbus-bnf-kit/

Aerodyne RC. (n.d.c). Omnibus F4. V3 Flight Controller. Aerodyne RC. Retrieved from http://aerodyne-rc.com/product/omnibus_f4/

DJI. (n.d.a). Phantom 4. DJI. Retrieved from https://www.dji.com/phantom-4

DJI. (n.d.b). Phantom 4 Specs. DJI. Retrieved from http://www.dji.com/phantom-4/info#faq

InvenSense. (2013, August 19). MPU-6000/MPU-6050 Product Specification Revision 3.4. Retrieved from https://www.invensense.com/wp-content/uploads/2015/02/MPU-6000-Datasheet1.pdf

Liszewski, A. (2017, January 11). This Unbreakable Racing Drone is Perfect for Terrible Pilots. GIZMODO. Retrieved from http://gizmodo.com/this-unbreakable-racing-drone-is-perfect-for-terrible-p-1791069907

Perlman, A. (2017, January 3). 10 Best RC Drones with a Camera. UAV Coach. Retrieved from http://uavcoach.com/drone-with-camera/

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