The goal of this project is to help to maintain the safety, reliability, and integrity of the nation's natural gas infrastructure by the development of a handheld, light weight, easy to use, inexpensive line location device. The design of the device will use the ground penetrating radar technology developed for the US Army handheld standoff mine detection system.
CyTerra Corporation – project management and research product
Every day in the United States an average of 55 billion cubic feet of natural gas moves through more than 1.2 million miles of underground pipe and thousands of compressor stations to virtually every home and nearly 5 million businesses across the country. For the most part, this flow of natural gas is uneventful – in fact, America's pipeline system is unequaled in its efficiency and safety. But the current gas infrastructure is aging and leaks or breakages can occur. Moreover, as the Nation's consumption of natural gas increases, at least 300,000 miles of new distribution and transmission pipelines will have to be built by 2015.
The objective of this project is to design, fabricate, and test Ground Penetrating Radar (GPR) systems for both low and high frequencies (200 to 1600 MHz) based on the military Handheld Standoff Mine Detection System (HSTAMIDS) hardware and software. The system, named LULU - for Low-Cost Utility Location Unit, will, in real time, produce a sound as the radar unit is passed over utility lines or other subsurface facilities (including non-metallic pipe), alerting the operator to the presence of a buried object. The result will be a portable, low-cost, real-time, and user-friendly subsurface pipe and utility line locater. This relates to the goal of maintaining the integrity and reliability of the nation's natural gas transmission and distribution network by preventing third party damage, through the development of sensors to detect potential infringements.
The new detector is expected to be especially beneficial in preventing “third party” damage. While not common, third party damage occurs when construction or excavation crews inadvertently strike underground utility lines. In 2002, according to the federal Office of Pipeline Safety, third party damage caused nine fatalities, 45 injuries, and an estimated $23 million in damage costs. It is by far the most dangerous and costly type of accident caused by the inability to detect gas pipes, especially older pipes that may not be correctly marked on the surface.
Like its military version, the LULU technology relies on ground penetrating radar. To make it suitable for pipeline detection, Cyterra engineers altered the frequency band and antenna size of the system to increase the depth detection range from shallow mine depths of inches up to10 feet for pipeline detection. When the radar passes over a buried pipeline, signal-processing techniques provide real-time output by producing a series of beeps to alert an operator.
A key advantage of the technology is its capability to discriminate between metal and plastic pipes. Current commercial detection methods rely on magnetic devices and cannot detect plastic pipelines. Increasingly, newer gas distribution pipes are being constructed of plastic and ceramic materials.
In fact, the Gas Technology Institute estimates that 72 percent of all 3-inch-diameter natural gas distribution pipes in the United States are plastic. These pipes are commonly used for the service lines that deliver natural gas from the gas main to the meters of homes and businesses.
By incorporating existing, proven man-portable, user-friendly, plastic mine detection technology, only minor modifications to the hardware and algorithms were necessary to produce real-time operator audio feedback when detecting buried plastic or metallic pipe. CyTerra developed, updated and correlated mathematical models of GPR performance for different soil and target characteristics, and extended the HSTAMIDS model to different depth and target types. The two models include cross-range as well as depth resolution, and can potentially be used to produce algorithm receiver operating characteristic curves.
Using existing HSTAMIDS equipment (the GPR and the portable data recorder), CyTerra collected buried plastic pipe signatures in various soils and depths. The hardware was developed from off-the-shelf components that meet the low and high frequency band specifications and included redesign and re-layout of the proven HSTAMIDS RF module in two designs, to meet the frequency requirements. Two derivative RF modules were fabricated in the two frequency levels, including spare boards and housings. Housings, antennas, electronics, control software and algorithm (target detection) software were integrated and lab tested against sandbox targets for functionality. CyTerra conducted tests against a different set of targets at a field location to validate the lab and sandbox tested code and hardware.
Two sets of antennas were designed and fabricated: one for the low frequency system and the second for the high frequency system. Except for size, they are copies of the proven spiral antenna design from the HSTAMIDS. The LULU algorithms were developed from redefined HSTAMIDS algorithms to include the selected targets at selected depths and soils.
The LULU system is user-friendly; unlike existing depth plots that require operator interpretation to both detect and range the pipe location, the CyTerra system alerts the operator to the location through audio. A 2-D off line image indicates the depth of the detected pipe.
Real-time audio detection is possible because the multi-threaded processing permits simultaneous operation of the HSTAMIDS advanced ATR algorithms along with the GPR control code and other tasks. The current HSTAMIDS processing of GPR data relies on Principal Component Analysis (PCA) performed automatically upon appropriately selected and conditioned features of the GPR response in clutter and mine environments. As compared to earlier work, CyTerra has seen significantly better performance with this system because of the length of the pipe targets versus the smaller mine targets.
This project is complete and all deliverables have been received.