UAS Sensor Placement

            Sensor placement is a critical design decision based on the objective that an unmanned aerial system is tasked to perform.  In this paper, two commercial aerial systems are discussed.  The first is the Yuneec Typhoon H, which is used for aerial photography services to include full motion video and still pictures below 400 Above Ground Level (AGL).  The Second UAS is the First Person View (FPV) Storm Type-A V2 racer to compete on a racing circuit.  For the selection of these two drones the blogs posted by Alexander Nixon about the two types of systems were very informative and assisted in the evaluation of the various options.

Yuneec Typhoon H

            The selection of the Yuneec Typhoon H is made after the review of twelve (12) systems with similar capabilities in the category of ‘Best Drones for Professional Film Making’ (Nixon, 2016b).  Among the reasons for the choosing this aircraft was the unobstructed 360-degree camera view, simplicity of operation, and cost.  This system has capabilities found in more expensive professional solutions, but at a consumer price point. This drone is suitable for both amateur and professional applications. 

Vehicle

            The vehicle is a six-rotor design that has a range of one kilometer.  The maximum speed is 22 mph.  The six-rotor configuration make the vehicle more reliable in case of a motor or propeller failure, making it safer to use over crowds. 

            Specification of the vehicle:

                        Material: Carbon Fiber

                        Wingspan: 16.1 inches

                        Weight: 4.1 pounds

                        Max speeds: up to 43.5 mph

                        Flight distance: 3000 feet

                        Battery charging time: 2 hours

                        Endurance:  Up to 25 minutes

ST-16 Controller

            The seven-inch Android based 720p display works well in direct sunlight.  The user interface is rated as ‘excellent’ and is as good as the DJI’s being responsive and intuitive (Nixon, 2016a).  You can control both the vehicle and the camera using the touch screen. The flight control settings come preset. However, you can set and save new flight control settings depending on your desired style. It has a HDMI output for those that prefer to fly the vehicle with First Person View (FPV) googles.

Camera

            The camera is a CGO3+ 4K Camera Gimbal. It takes high quality and stable 4K video, and 12.4 megapixel still images.  The gimbal rotates through 360-degree range of motion.  The camera is capable of 98-degree field of view. Camera setting are adjustable with the controller in-flight.

            A unique feature of this system is that the vehicle retracts its landing gear allowing a full 360-degree unobstructed view, a significant feature for a system in the under $1500 price range.  This capability allows for the way-point driven shooting, which is much easier to plan and execute (Nixon, 2016a).

            Specifications: 

                        Video: 4K UHD 30 frames per second, HD 1080p at 120 fps, 100MB Video capture at 30 fps.

                        Camera: 12.4 MP, not geotagged

                        Live View:  720 frames per second over a 5.8 GHz channel.

                        Gimbal:  3 axis anti-vibration with full 360-degree rotation

                        Digital video downlink:  up to one mile.

Safety and Redundancy

            In making an investment in these types of aerial vehicle, safety and redundancy is important to secure the investment.  The Typhoon H has several unique feature that distinguishes it from other systems.  These features include: real-time object detection and collision avoidance using Intel Sense Technology 3D; automated flight modes; and two operator mode.

            Intel Sense Technology 3D

            Automated flight modes allows the use of preprogram flight modes to best position the camera.  These flight modes include:

            Journey:  This allows the vehicle to operate as far as 150 feet to take a selfie.

            Orbit Me: The vehicle flies a circular path, keeping the camera pointed at the center point.

            Point of Interest:  It will fly around a geographic position based on GPS.

            Curve Cable Cam: Vehicle flies between pre-set coordinates, while the operator controls the camera. The pre-set coordinates are both GPS and altitude. This is a preferred operating mode of these vehicle as it allows for be best shot angles and easy transitions during flight.

            Follow me/Watch me:  In this mode, the vehicle follows the operator, while maintaining the camera fixed on their position.

            Return to Home: The vehicle returns and lands within 26 feet of the operator’s position. 

            Two-mode operation: Allows for the vehicle and camera to be operated by different persons using a smaller special-purpose controller (Nixon, 2016a, Typhoon, 2016).

Summary

        The Typhoon H designed to provide the sensor a full 360-degree gimbal rotation with 98-degree coverage is an excellent platform for taking video and still photograph, all at a reasonable price point. 

Storm Type A V2 RTF

            There are as many choices for the First Person View (FPV) racing drone.  The decision on which type of drone to select is a bit more complex than for photography.  There are several considerations that must be thoroughly researched and decided before the selection can be made.  These includes deciding on what type of racing you desire, and whether you will formally compete in a racing league or other informal events.  There are several different types of racing leagues for indoor and outdoor racing.  There are also rotor-cross, drag and time-trail racing.  Rotor-cross is popular because it involves two or more drones on a racetrack at the same time (Dixon, 2016c).

            For most racing circuits, the 250 mm (5-inch) mini-drones are the most popular.  This is not so surprising, since the smaller the drone, the more maneuverable they can be.  There are lot of parameters that go into making a multi-rotor vehicle agile.  The most important parameter that changes the performance of the vehicle is the radius of the vehicle.  Vijay Kumar in this famous Ted video explains that the inertia of the vehicle is related to the angular motion of the vehicle, which scales to the fifth power of the radius. The more you reduce the radius, the more the inertia reduces.  Concurrently, the angular acceleration of the vehicle is inversely proportional to the radius of the vehicle. As you reduce the radius the quicker the vehicle can turn (Kumar, 2012). 

            You can only go so far in making the radius of the multi-rotor small and also have enough lift and power to have a viable drone.  Manufactures have found the radius to be about 125 mm. That’s one reason the 250 mm class of multi-rotors is a viable size for racers.  They can make the vehicle fast and agile for the rigors of aero racing.

            Since the author has no experience in racing drones, the choice for this paper is the popular, affordable, and ready-to-fly, Storm Type A S3 in the 250 mm class.  There were other choices in the beginner to intermediate level of proficiency level that also are great choices.  They include Vortex 250PRO which is also inexpensive, but requires assembly.  At the higher end, there is the Luminiere QAV250 G10, but you need to be an experienced operator to fully appreciate the vehicle’s capabilities (Nixon, 2016c)

Vehicle

            The vehicle has plenty of power and endurance for its size.  The flight controller module (CC3D) onboard is responsive with minimal lag between the controller and the motor sensors. This allows for direct response, which makes the vehicle very agile. The specifications for the vehicle are:

            Size: 230mm x 245mm x 60mm

            Weight: 482 grams, 677 gram including battery

            Endurance 10.5 mins with standard batteries

Communication

            The vehicle control is on a 2.4 GHz unlicensed frequency channel, while the data link is on a 5.8GHz channel.  Each channel has sub-channels to avoid interference from other vehicles operating in the same area.  The communication channels operate up to 300 feet. 

Controller

            The RadioLink AT9 controller system has 9 channels.  It has preloaded modules for easy setup.  There is an optional 4.3 inch First Personal View monitor that attaches to the controller. It has a 5.0 Mhz bandwidth using DSSS spread spectrum protocol. The control range is up to 1.5 miles.

Camera

            An unique feature to this vehicle is the adjustable tilt angle camera with 700 TLV 90-degree field of view.  The datalink transmit at 200 mwatt power, allowing real-time video feeds of 300 ranges of 300 meters.  The placement of the camera, and the adjustable tilt angle option makes this vehicle a preferable option for those that use the vehicle for FPV racing. 

   Summary

            The Storm Type A is a good candidate as a first buy racer because it is ready to go out of the box.  There is an upgrade to the Type A Pro for those that want a faster and more responsive vehicle, which may be more appropriate for someone with experience flying in the FPV mode. The unique camera with adjustable tilt angle camera make it the appropriate choice for a first-time FPV drone racer.

References

Kumar, V. (2012, March 01). Vijay Kumar: Robots that fly ... and cooperate. Retrieved June 16, 2016, from https://www.youtube.com/watch?v=4ErEBkj_3PY

Nixon, A. (Ed.). (2016a). Yuneec Typhoon H Review: 6 is Better Than 4. Retrieved June 16, 2016, from http://bestdroneforthejob.com/drone-reviews/yuneec-typhoon-h-review/

Nixon, A. (Ed.). (2016b). Best Drones for Video & Film Making. Retrieved June 16, 2016, from http://bestdroneforthejob.com/product-category/work-drones/pro-film-video-drones/

Nixon, A. (Ed.). (2016c, May 01). Want to Race Drones? Read This Guide First! Retrieved June 16, 2016, from http://bestdroneforthejob.com/drones-for-fun/racing-drone-buyers-guide-2/

STORM Racing Drone (RTF / Type-A V2). (n.d.). Retrieved June 16, 2016, from http://www.helipal.com/storm-racing-drone-rtf-type-a.html

Typhoon H. (2016, June 05). Retrieved June 16, 2016, from http://www.yuneec.com/Typhoon-H