Geiger-Mode: The Latest and Greatest in LiDAR
The International LiDAR Mapping Forum (ILMF), held in Denver in February, is never at a loss for big announcements about ground-breaking technology, and this year was no exception. Four companies — 3DEO Inc., Harris Corporation, Princeton Lightwave and Sigma Space Corporation — presented their research on different variations of Geiger-mode LiDAR systems. Harris Corporation announced the upcoming availability of high-quality commercial geospatial data from the IntelliEarth Geospatial Solutions Geiger-mode LiDAR sensor.
Harris is the furthest along in the development of solutions based on Geiger-mode LiDAR data, a benefit of having delivered these types of products to the
|Geiger-mode LiDAR produces highly detailed topography, such as this scan of the Grand Canyon. Courtesy: Harris Corporation.|
Department of Defense (DoD) for the past 15 years. In conjunction with Lincoln Laboratories at MIT, Harris developed the Geiger-mode Avalanche Photodiode (GmAPD) LiDAR sensor and the automated processing techniques now being used to offer solutions to civil and commercial customers. DARPA funded the technology transfer from DoD around 2011; however, the original commercially available Geiger-mode with a 32x32 detector array did not gain traction in the market. Now, IntelliEarth boasts a 32x128 array and the ability to collect high-quality, wide-area elevation data 10 times faster, thus reducing costs. Test flights with the sensor will be held in March and the system should be ready for commercial operations in the summer of 2015.
In addition to the technology not being available to commercial industries, one of the obstacles to widespread use of Geiger-mode LiDAR has been processing issues resulting from the high sensitivity of the detector array, which results in misaligned noisy data that must be tightly registered to be accurate. Over the years these challenges have been addressed and the advantages of GmAPD are now evident. The higher altitude, wider swath width, higher density point cloud, and lower laser power results in faster acquisition time and reduced costs of acquiring and processing LiDAR data.
The higher point density improves foliage penetration to better sample bare Earth and more clearly defines infrastructure details. The tradeoff is the large amount of data that must be processed, so automated production is a crucial part of producing a commercially viable Geiger-mode LiDAR product. By reducing hands-on analyst time, the necessary volumes of data can be processed more quickly, with human intervention needed only at the QA/QC stage to address issues like hydro-enforcement.
“The IntelliEarth system collects 1,000 square kilometers per hour, with a minimum 50-percent overlap for uniform density,” says Phil Smith, PhD., advanced programs engineer, Harris. “That is 10 times faster than the traditional linear-mode LiDAR sensors, and at much higher densities. Although we faced some unique technical obstacles over the years due to the high sensitivity of the sensor, our automated production methods now allow us to deliver high-resolution, high-accuracy LiDAR-based solutions at a significantly lower cost.”
|At 20 points per square meter, infrastructure details are much better defined.|
Due to the complexity of the Geiger-mode system and the large volume of data that it is capable of producing, Harris will operate the sensor and offer the processing as a service, and deliver end products and analysis to its customers.
“After 15 years of collecting Geiger-mode LiDAR data and delivering solutions to the federal government, Harris is the only large-volume processor ready to serve the commercial geospatial community,” says David Kornick, eirector of geospatial for Harris. “We look forward to working with our government and commercial customers to develop custom elevation and imagery products and services that meet their needs. We envision demand coming from the USGS 3DEP Program, as well as other civil agencies like FEMA and NOAA, state and local government for transportation and infrastructure planning, and commercial entities such as utilities.”