TerraPoint LLC unveiled its upgraded Airborne Laser Topographic Mapping System (ALTMS) incorporating five technical advancements that enable the company to continue providing the highest quality LiDAR elevation data available on the commercial market. TerraPoint has built and upgraded four ALTMS units that are currently deployed on operational projects around the world.

“By developing and maintaining our own LiDAR systems, TerraPoint has built a reputation as a technological innovator and leader in the LiDAR industry,” said John Zeigler, TerraPoint’s Director of Engineering. “We intend to keep that technological advantage.”

As part of the upgrade, TerraPoint increased the ALTMS shot rate from 20 kilohertz to 40 kilohertz. This means the system can fly at the same altitude and get a higher density of measurement points on the ground, creating better quality data with superior feature recognition, identification and classification. Alternately, the increased shot rate allows TerraPoint to fly higher while maintaining the 20 kilohertz point density and complete the job nearly twice as fast.

“The ability to capture a higher point density while keeping costs down is of particular value in areas where penetration of dense canopy vegetation is crucial to producing an accurate bare earth elevation model,” said Jerry Harless, Coordinator for the Puget Sound LiDAR Consortium in Seattle, Wash.

The second upgrade involves a fine tuning of the ALTMS auto gain component that compensates for reduction intensity as a function of range. This results in fewer point drop-outs and sharper feature definition in extreme terrain. Thirdly, to enhance the accuracy of elevation measurement values, the TerraPoint engineering staff replaced the commercial timing circuitry with a customized component developed in-house. It more precisely measures the time lapse between laser pulse emission and return, the value of which determines ground elevation.

TerraPoint has also enhanced its all-return measurement capability, the operating feature that has traditionally given ALTMS an advantage over other LiDAR systems. While most LiDAR systems only collect first and last laser returns from the surface, TerraPoint captures up to four returns, which provides more data on intermediate structures and vegetation and, in general, a better understanding of the terrain. ALTMS is now capable of measuring the intensity of every return. This enhancement further improves the visual quality of terrain features and the end user’s ability to identify and classify them.

The fifth system enhancement is a conversion of the ALTMS onboard user interface to a Microsoft/Intel environment. The new interface makes it easier for the onboard operator to run and calibrate the LiDAR during airborne operations. In addition, the new Intel architecture provides more CPU capacity and will extend the system life cycle.

“These upgrades, combined with our advanced software calibration processes, allow us to provide the highest-quality LiDAR data available today,” says John Zeigler.

As the developer of its own LiDAR systems, TerraPoint maintains an in-house staff of engineers and scientists who continually look for ways to enhance the onboard acquisition and ground processing systems. This has enabled TerraPoint to distinguish itself in the surface mapping market with cutting-edge technology and high-quality data standards.