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2001
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Pipeline R-O-W management at light speed
B. Carl Kuhnke
Director of Business Development
Terra Remote Sensing Inc.
Sidney, British Columbia,
Canada V8L 5Y3
Tel. (250) 656-0931 Fax (250) 656-4604
Website:www.terraremote.com
Geographical information has long been seen as a useful adjunct to the core business needs of large
corporations. Today, however, technology advances and management requirements are transforming
the previously specialized GIS world into a core enterprise function that integrates engineering detail,
geospatial information, and strategic planning. This paper examines an industry in explosive growth
B oil and gas transmission – and how the application of a new airborne remote sensing technology,
LIDAR, can cost-effectively provide the simple, transparent management tools needed to design,
build, manage and value the billions of dollars in pipeline infrastructure currently underway.
The Need
Power crisis. Lights out in Silicon Valley. Cold pools in Palm Springs……….
A combination of well-intentioned but badly-implemented utility deregulation, enormous economic
growth, and an insatiable North American appetite for new energy capacity has led to a crisis
situation, not only in the west, but across North America. National, state and provincial governments
are wrestling with the conflicting ideals of environmental stewardship and the need to design and
build generation capacity to keep up with demand and prevent the huge economic ramifications that
will result from a failure to do so.
At the same time, the corporations charged with the responsibility to develop and provide the critical
energy supplies must speed the process with not only these priorities in mind, but also stakeholder
accountability. They are required to effectively manage and value these increasingly large assets once
they are in the ground.
As a result, the “Enterprise GIS” is no longer a ‘wish list’ item, but a necessity. Hydrocarbon
producers and purveyors are moving to quickly integrate their existing, fractious systems in
inventory, design, construction and maintenance, while simultaneously focusing on the bottom line.
A fast, simple and cost-effective means to plan new construction and manage existing assets is
needed - one that can reduce deployment and reporting costs while providing more and better data
for implementing those functions.
Two traditional methodologies - aerial photomapping and ground surveys - have proven
cumbersome, slow, and expensive. While satellite imagery has recently become ‘en vogue’, even the
best one meter resolutions are not sufficient for more than a cursory view of assets from a
management perspective. However, sophisticated airborne scanning LIDAR devices integrated with
digital imagery and GPS/IMU systems can provide rapid and precise (to 15 cm absolute) x, y and z
positioning and detailing, with considerable cost savings. Its ease of integration into any existing
GIS brings both strategic and financial benefits.
WHAT IS LIDAR ?
Quite simply, LIDAR is the use of light to measure distance. Everyone is familiar with the more
common acronym RADAR (RAdio Detection And Ranging). LIDAR (LIght Detection And
Ranging) is simply a substitution of light's frequency band for slower radio waves in the
electromagnetic spectra. Public awareness of this terminology has grown as LIDAR (‘laser’) speed
guns have replaced traditional radar guns in traffic speed enforcement. LIDAR simply uses a laser
pulse to determine distance by measuring the time it takes for the laser pulse to reflect back from a
"ground hit" (or other object).
The key to the effective use of LASER/LIDAR in mapping lies not in the light pulse itself, which is a
decades-old technology, but in the sophisticated georeferencing algorithms that enable us to know
precisely where the target object is in time and space. Current laser technology provides an accuracy
of 5 cm or less from an airborne platform. The aircraft’s Inertial Reference or Measurement Unit
(IRU/IMU) provides the directional vector of the laser fire. Coupled with a Differential Global
Positioning System (DGPS), they provide a position for the laser within 5 -10 cm.
Terra has been in the LIDAR business for almost 20 years, having co-developed the world’s first unit
to perform airborne coastal bathymetry at efficiencies far exceeding the capabilities of surface
vessels. The LARSEN 500 marine LIDAR bathymeter has been performing bathymetry around the
world for over 15 years. Based on the time differential of the water surface reflection pulse and the
seafloor reflection the airborne scanning bathymeter can collect water depths down to 50 meters at a
rate of 50 sq km/hour. Based on an Nd:YAG laser with a wavelength of 1064 nm, it is frequency
doubled to also produce a blue-green wavelength signal (532 nm) which penetrates to the ocean
floor. The water depth is derived from the time differential of the seabed reflection and the water
surface reflection of the infrared signal. (Figure 1). Combine the LIDAR bathymeter with georeferenced
imagery flown simultaneously, and the integrated end product provides a powerful tool
for coastal management around the world (Figure 2).
New Technological Development
Continuing technological advances, miniaturization and industry needs have pushed suppliers of
LIDAR technology to ‘go faster and smaller’ in their product offerings. Marine bathymeters require
a high-energy laser pulse to be able to transit the water column and return some photons to the
airborne detectors. This energy requirement dictates a finite limit to the system's Pulse Repetition
Frequency, or PRF. The laser systems are quite bulky, consume kilowatts of power and need liquid
cooling.
Growing terrestrial needs for precise mapping, digital elevation models, and the advent of GIS have
demanded more precise measurements from the supplier community. The demands on a terrain
LIDAR system are such that low power diode or diode-pumped YAG lasers can fulfill the task. This
laser technology permits the very high PRFs needed for the decimeter level terrain detailing. So, too,
the requirement for visual imagery to which senior management can easily relate has become an
important feature (Figure 3).
Many companies have responded by integrating one or more sensors on an airborne platform that can
be moved to a project quickly and inexpensively. Some firms, Terra included, chose a helicopter
platform that provides a combination of versatility and low cost, with a specific target market of
linear corridors (Figure 4). Others have selected fixed wing aircraft flying at higher altitudes for the
mapping of large urban or rural areas. In all cases, the LIDAR sensors now feature pulse repetition
frequencies in the order of 5000 - 25,000 Hz, permitting the collection of up to one million data
points per minute. This presents its own software challenges for data acquisition and processing, all
of which are manageable in today’s technology environment.
Today’s GIS has to support a wide range of clients and is challenged by diverse management
demands. Typically, management needs a combination of data outputs that satisfies not only
engineering design and maintenance, but also strategic planning, all for the same asset or set of
assets. Ten years ago this would have been technically unthinkable, cost-prohibitive, or both. Today
it is not only a technical reality, but also a cost-effective investment that brings more to the bottom
line.
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