DEFINITIONS
For the purposes of this study, the following definitions are
used to classify the various airborne laser altimetry systems in
operation today:
Commercial: A commercial instrument is defined as any
airborne laser altimeter that is used on a "for profit" basis or an
off-the-shelf instrument bought from a commercial instrument
manufacturer but used for non-profit purposes. Examples of
the later include the systems operated by the U.S. Army Corps
of Engineers Topographic Engineering Center, the University
of Florida and the UK Environment Agency. Commercial
instruments are further divided in to two categories; Off-The-
Shelf or Proprietary.
Off-The-Shelf (OTS): An off-the-shelf instrument is defined as
any complete laser altimetry system that includes all necessary
hardware, firmware and post-processing software, and is
available from a dedicated commercial instrument
manufacturer. These instruments can be purchased by any
company or organization wanting to acquire airborne laser
altimetry capabilities. Currently the three major suppliers of
off-the-shelf instruments are Azimuth Corporation (USA),
Optech Inc. (Canada), and TopEye AB (Sweden).
Proprietary: A proprietary instrument is defined as any
custom-designed system. The instrument may incorporate
commercial off-the-shelf subsystems or components but must
essentially be designed, developed and maintained as a unique
proprietary system or systems, not available for purchase by a
third party. For the purposes of this paper, proprietary
instruments are only included if they are used for commercial
"for profit" operations. Examples include John E. Chance’ s
FLI-MAP and TerraPoint’s ALTMS. Custom-built systems
operated by government agencies, research institutes or
universities for research applications, for example LVIS, are
not considered as commercial instruments.
Only scanning laser altimeters are considered for this study as
profiling systems have limited commercial applications and are
generally not deployed in "for profit" operations. Other
airborne sensors integrating a lidar for direct single-point
elevation measurement were also not considered. Bathymetric
laser systems such as SHOALS or LADS were also excluded as
their design constraints, target applications, commercial
markets and competing technologies are considered
significantly different as to be outside the terrestrial mapping
sector covered in this paper. It should be noted however that
bathymetric lidar systems have been used for similar mapping
applications as the terrestrial systems to be discussed below and
there is growing interest in hybrid hydrographic-terrestrial lidar
instruments for coastal beach mapping, especially working in
the near-shore surf zone.
2. COMMERCIAL SECTOR
Unlike the research sector, which is primarily driven by
scientific goals and objectives, the commercial sector is driven
by the need to define and address profitable markets for the data
products. In assessing the various market opportunities for
laser altimetry, commercial organizations focus on areas that
International Archives of Photogrammetry and Remote Sensing, Vol. 32, Part 3W14, La Jolla, CA, 9-11 Nov. 1999
offer a demand for the data products that is large enough to
support a profitable business. Ideally, such markets require the
data capture and analysis capabilities provided by laser
altimetry but not readily available from other survey
technologies and are driven by various economic factors to
place a significant value on the data products. Potential
markets should also have an established client-base with the
financial resources to contract for laser altimetry survey
services at a reasonable and profitable price. Due to the
relatively recent introduction of the technology to the
commercial sector, many of these markets are still being
defined.
2 1. Commercial Markets
Depending on the survey application, laser altimetry can be
viewed as either a complementary or a competitive technology
when compared to existing survey methods. For many
applications, airborne laser altimetry is currently deployed in
conjunction with other more traditional sensors including
standard aerial film cameras, digital cameras, hyperspectral
scanners or thermal imagery. In general, laser altimetry is best
viewed as an addition to the remote sensing toolbox that can
add significant value to the data products produced, either
independently or in conjunction with other sensor systems.
Deploying airborne laser altimetry within a field survey can
provide additional value depending on project specific goals
and deliverables. Since each individual client has particular
needs and specifications that they expect to be met, laser
altimetry may not meet these expectations without support from
traditional survey methods. However, in certain applications,
such as forestry or coastal engineering, laser altimetry offers
unique capabilities not achievable with any other technology.
A brief review of the main commercial applications is provided
below. (Flood, 1999; Flood and Gutelius, 1997; Gutelius,
1998)
DTM Generation: Airborne laser mapping is a rapid, cost-
effective source of high-accuracy, high-density elevation data
for many traditional topographic mapping applications. The
technology allows large area topographic surveys to be
completed significantly faster and at a reduced cost compared
to traditional survey methods.
Forestry: The use of airborne laser mapping in the forestry
industry was one of the first commercial areas investigated.
Accurate information on the terrain and topography beneath the
tree canopy is extremely important to both the forestry industry
and natural resource managers. Accurate information on tree
heights and densities is also critical information that is difficult
to obtain using conventional techniques. Airborne laser
technology, unlike radar or satellite imaging, can
simultaneously map the ground beneath the tree canopy as well
as the tree heights. Post-processing of the data allows the
individual laser returns to be analyzed and classified as
vegetation or ground returns allowing DTMs of the bare ground
to be generated or accurate representative tree heights to be
calculated. Established techniques from the research sector
using full waveform analysis of the return laser pulse to
investigate details of canopy structure (Blair and Hofton, 1999)
are also receiving greater attention as the technology gains
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