Saturday, November 7, 2015

UNSY 605, Assignment 3.5, UAS Sensor Placement



The placement of sensors on an unmanned aerial system (UAS) is an extremely important design aspect of the system.  The location of a camera in relation to the airframe will affect the field of view (FOV) of the sensor.  The placement of the camera will also determine additional equipment requirements to adjust the FOV, if necessary, during the platform’s mission.  Depending on the placement and types of the aircraft’s engines and the design of the UAS’ airframe, the camera may also require buffer equipment to ensure vibrations during the platform’s operation does not interfere with the imagery collected by the camera.  These factors will be significant considerations in the types of missions suitable for the UAS.
The DJI Inspire-1 Model T600 quadcopter would be a suitable platform to conduct aerial photography services.  The Inspire-1 can climb to over 14,000 feet but features a software limiter to keep the aircraft below 400 feet to comply with current Federal Aviation Administration (FAA) regulations (FAA, 2015).  The UAS weighs only 6.5 pounds and measures only 17.25 inches by 17.75 inches by 12 inches in size.  The quadcopter can reach speeds of 50 mph and has an endurance of approximately 18 minutes of continuous flight.  The Inspire-1 can also withstand winds up to 22 mph.  The imagery sensor mounted on the UAS is a 12.4 megapixel camera featuring a 94 degree FOV and capable of still image capture and video recording.  The camera is mounted on a stabilized gimbal to ensure maximum range of view and stability of image.  The gimbal enables the camera to pitch from -90 degrees to +30 degrees and can pan +/- 320 degrees.  The imagery system supports common jpeg, dng, mp4, and mov image and video formats.  Micro SD data cards of up to 64 GB are also supported.  The Inspire-1 also features a control mode that allows one operator to fly the aircraft and another operator to control the camera system.  The unique design of the Inspire-1 features engines mounted on hinged arms that swing up and down.  The arms pivot to the down position with the landing legs resting on the ground while the quadcopter prepares for take-off and for landing.  Once airborne, the arms pivot up to provide the camera mounted underneath the fuselage an unobstructed view (DJI, 2015).  The video below demonstrates the ease and utility of Inspire-1 operations.


Figure 1.  The DJI Inspire-1 is reviewed and test flown by “Mythbusters” co-host, Adam Savage.
 The Blade FPV Nano QX quadcopter is a suitable choice for first person view (FPV) UAS competitive racing.  The Nano QX weighs only 0.77 ounces and features excellent maneuverability and handling characteristics.  The Spektrum ultra micro camera is mounted at the front of the quadcopter between two of the arms supporting two of the motors.  The positioning of the camera and the angle of the arms of the airframe ensure an unobstructed, wide FOV the operator.  The video below demonstrates the excellent visibility transmitted to the operator’s Fat Shark Teleporter V4 headset (Horizon Hobby, n.d.). 
A wide range of platforms are available for aerial photography services and competitive FPV UAS racing.  The quality of the imagery systems and the FOV afforded by the design of the aircraft are extremely important aspects.  These characteristics will factor significantly in platform selection for the respective roles.  The DJI Inspire-1 and Nano QX UAS are well suited for their respective, intended roles.



References

DJI.  (2015).  Inspire-1 [Fact sheet].  Retrieved from http://www.dji.com/product/inspire-1

Federal Aviation Administration.  (2015).  Model Aircraft Operations.  Retrieved from https://www.faa.gov/uas/model_aircraft/

Flying the DJI Quadcopter with Adam Savage [Video file].  Retrieved from https://www.youtube.com/watch?v=nT5U9T9Uyok

Horizon Hobby.  (n.d.).  Nano QX FPV RTF with SAFE Technology [Fact sheet].  Retrieved from http://www.horizonhobby.com/nano-qx-fpv-rtf-with-safe-technology-blh7200  

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