Aug 31 2015
Through a recent contract awarded to two evaluating companies, the United States Geological Survey has requested from Sigma Space the collection and processing of Single Photon LiDAR (SPL) in a test area in upper Connecticut.
SPL is a disruptive LiDAR technology created by Sigma, which enables collection of elevation data at much higher speeds and resolution than conventional LiDAR systems. While SPL is by now a well developed technology in use by the US DoD and in commercial data acquisitions, this is the first attempt by USGS to validate the technology as an enabler for its 3DEP program. The 3DEP program by USGS aims to create a comprehensive 3D map of the US. If done at the highest quality level, but using conventional LiDAR technology, such program could cost more than $ 1.5 billion and take 8 years to complete, according to the National Enhanced Elevation Assessment. However using SPL the cost could be reduced by up to a factor of ten and completed in one year.
“The key concept behind the high efficiency of SPL is the ability to use single photons, elementary light particles, to make a range measurement,” explains Dr. Marcos Sirota, CEO of Sigma Space. “Conventional LiDARs use hundreds or thousands of photons per measurement. That is why our system is so much faster. Furthermore, the detector physics and associated electronics enables our system to operate in full daylight, in comparison to other photon-sensitive technologies that can operate only at night,” he added. Also, because SPL uses green laser light it has both topographic and bathymetric capabilities in a single LiDAR.
After receiving the request, and one coordination phone call with USGS and the evaluating companies, Sigma Space personnel were able to collect SPL data for the entire 500 square mile test area in one weekend, with densities in excess of 20 points per square meter. In addition, they simultaneously collected RGB imagery for a large part of the test area at 4 cm resolution, using a MIST camera, courtesy of Visionmap.
SPL technology is also to be proven soon in space. NASA’s ICESat II mission, to be launched in 2017, adopted SPL as the LiDAR technique for its Advanced Topographic Laser Altimeter. The primary objective of the mission is to measure polar ice sheet elevation change and sea ice thickness. Sigma provided the timing and on-board processing electronics for the 64 channel, single photon LiDAR system. Sigma also provided the optical assembly for the pointing determination system which tracks the laser and telescope pointing with respect to the star field, in the instrument.