Saturday, 17 September 2016

6.5 - Research: UAS Mission

      Introduction
            In Malaysia, the mobile communication coverage is relayed via communication towers. Before building a tower, site survey of panorama view at 200 to 300 feet above ground level is needed to find out any obstructions along line-of-sight. Most of the time, the surveyor will engage crane service to lift a person to the height and take pictures of panorama view. Similar practices are conducted for regular inspections and maintenance works. The crane has its limitations. The solution to this is to deploy UAV to perform site survey, inspection and maintenance of tower structure s and antennas. There are two advantages. First, it is more cost effective. Second, the portability and mobility of UAV enables the operation to be carried out anywhere with the permission from local aviation authority.
UAV Platform
There are two types of UAV commonly used in commercial sector. Fixed wing is powered by engine to move its propellers. The advantage is higher power to weight ratio than a comparable electric motor leading to higher payload capability and long-range operation. The actual payload capacity allows for the installation of instrumentation and sensors needed to fulfill the requirements of the mission. The long-range operation will allow for wider area surveillance (Jaimes, Kota, & Gomez, 2008).
            On the other hand, a quad-rotor UAV are highly maneuverable. It has the potential to hover at required altitude, able to take-off and land vertically within small areas. This capability has huge advantage for commercial applications as long runway is not necessary for the mission. Quad-rotor UAV has four motors located at the front, rear, left and right ends of across frame. Changing the speed of rotation of each motor controls the quad-rotor. The front and rear rotors rotate  in a counter-clockwise direction while the left and right rotors rotate in a clockwise direction to balance the torque created by  the spinning rotors (Jaimes, Kota, & Gomez, 2008).
            For site survey and maintenance purposes, the recommended platform is quad-rotor UAV. The most important attribute is its hovering property. Visual inspection of tower structures, line transmission and antenna discs requires the UAV to be hovered at certain altitude and remains static so that the controller on ground is able to zoom and focus the camera on defective areas for detail analysis. As for the site survey, the UAV is used to hover and to remain static at 200ft to 300ft above ground level in order to take panorama view of the site surrounding. It is important to ensure that there is no obstructions along the line-of-sight of the communication tower so that the transmission of signals can be received by all mobile phone users in the future.
Legal Issues
            According to Department of Civil Aviation (DCA) of Malaysia, the controller of UAV, also known as UAV pilot must be a private pilot license (PPL) holder for the UAV with weight more than 20kgs (DCA, 2016). In view of this, it is mandatory to deploy UAV with weight less than 20kgs for site survey and maintenance purposes so that the controller may not be PPL holder. The idea of deploying UAV is to reduce high cost of engaging crane services and also to reduce the time taken to take videos and photos of the site in order to achieve cost efficiency. Nevertheless, it is important to demonstrate to aviation authority that the UAV controller with the weight of UAV less than 20kgs is well trained with basic flight knowledge, human factors and situational awareness. It is mandatory to educate the controller that safety is paramount for any flight operations.
Conclusion
The use of UAV to carry out site survey and inspections on communication tower is inevitable. It is the only way to achieve cost efficiency and increase productivity. Equally important is to enhance overall safety of tower inspection. Climbing on the communication tower and to perform inspection to locate defects at the same time requires experience technicians and inspectors. Proper safety measurements such as safety harness, wind conditions must be observed. Liability is too great for any company if someone fall from the tower accidentally. UAV is the only solution to perform general inspection quickly. If defects are found, inspector can target on them and time taken to repair will be relatively shorter.















Reference
Department of Civil Aviation. (2016, September 12). Aeronautical Information Services. Retrieved from http://aip.dca.gov.my/aip%20pdf%20new/AIC/AIC%20200804.pdf
Jaimes, A., Kota, S., & Gomez, J. (2008). An approach to surveillance an area using swarm of fixed wing and quad-rotor unmanned aerial vehicles UAV(s). IEEE.


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