Thursday, December 9, 2010

Unmanned Aircraft System (UAS) HIgh Technology Gps and Laser Sensor Sytem

The antiquated pipeline network in Iran often results in the occurrence of leakage. Damages caused by third parties also cause growing leakage in pipeline network in Iran. Perusal of the current condition of pipelines in Iran shows that prevalent methods for leak detection are not suitable and effective for today’s needs. A representative of the Iranian Offshore Engineering and Construction Company (IOEC) indicated at the UVS Tech 2009 conference in Moscow, Russia in January 2009 that, according to their studies, aerial monitoring of the pipelines with UAS would improve Iranian pipeline network operations and would be more efficient and effective than the methods currently used.

Flexibility, short response time, and more accurate leak detection were stated as some of the advantages of this method. Using UAS would result in decreasing environmental pollution, increase quick response to third party damage and enhance maintenance of pipelines against corrosion by identifying potential places of corrosion. Moreover, it was stated that aerial survey by UAS can be an efficient solution for offshore inspection.

The IOEC representative furthermore stated that UAS seem to be suitable airborne platforms for the task of regular inspections of gas pipelines. According to Iranian feasibility studies, two different scenarios for UAS-based pipeline monitoring systems are considered:
• Small and lightweight, low-altitude UAS with a limited sensor and weight capacity;
• Small-size, low-altitude rotary wing UAS with a weight capacity sufficient for multi-sensor applications.

It was mentioned that such UAS would be operated in the uncontrolled (lower) airspace and, therefore, would require appropriate collision avoidance technology to avoid obstacles such as buildings, electrical power lines or low flying objects (balloons). For the purpose of pipeline inspection, a flight altitude of 100 m above ground level might be appropriate, which is generally below clouds. In this case, an optical/IR
sensor system would be sufficient.

The standard maximum resolution is currently <=0,5m/pixel @100m altitude above ground level. For high resolution, there is a need for terrain following in altitude. Precise mission planning with enough waypoints is a must. A solution has been proposed by offering an onboard application, which includes a microprocessor board which takes the (GPSreferenced) picture samples (Photon IR & standard video in parallel). The pictures would be stored on an onboard standard compact flash 8-32 Giga Byte.

The pictures could then be downloaded after the flight and be processed by an additional application to one big composite picture. There are further possibilities to highlight leakages by additional picture processing algorithms (e.g. colouring leakages in red). Handlaunch, autonomous flight, and autonomous landing are
considered necessary to lower personnel training needs.

The IOEC representative further indicated that for a point survey in a specified location that early survey shows has potential of leakage, or on locations where higher resolution imagery is required, rotary wing UAS are being investigated. A high resolution thermal imaging system like the FLIR Photon Thermal Imaging Camera allows entire areas to be scanned and the resulting data to be displayed as pictures with areas
of differing temperatures designated by differing color tones that help to identify areas of concern – both above and below the ground.

The first in the FLIR Photon Thermal Imaging Camera obtains sensitive imaging based on variant heat signatures (as seen in the photograph above). The second component is the Micro Epsilon Laser Range Finder which helps to keep the helicopter at constant altitude above the ground while the GPS-based
autopilot autonomously guides the vehicle along the pipeline route.


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