Collaborative Research: Facility Support to Renew Operation of the National Center for Airborne Laser Mapping (NCALM)

点击翻译按钮获取中文摘要

1339015ShresthaThis grant provides five years of operational support for the National Center for Airborne Laser Swath Mapping (NCALM). NCALM is a collaborative Facility with two nodes. The acquisition node and initial flight line trajectory calculations and ALSM data calibration functions are now located and performed at the University of Houston (UH) and the data processing, archival and distribution node is at the University of California at Berkeley (UC-B). Also known as airborne Light Detection and Ranging (LIDAR), ALSM allows for the measurement of surface topographic features with decimeter-level accuracies and meter to sub-meter spatial resolution. High resolution, georeferenced, digital elevation models (DEMs) processed from raw ALSM data (point clouds) offer unprecedented observations of a multitude of geomorphic features at the scales at which fundamental shaping processes operate. Examples include, fault scarps, hill slopes, river channels, barrier beaches and sand dunes, mountain and continental glaciers, volcanic edifices and vegetative canopy structure. DEMs developed from ALSM can be used to model and advance understanding of the dynamics of surface landforms and the underlying processes responsible. The technique also has a wide range of applications in civil engineering and hazards assessments and for archaeological investigations of past civilizations modification of landscapes, especially in tropical environs where such structures are invisible via airborne photogrammetry. ALSM systems fire laser pulses (typically Nd:YAG at milliJoule powers) at high frequency from an aircraft whose position and orientation are accounted for via on board and ground GPS control and an aircraft IMU. The ALSM system measures the round trip travel time for individual pulses to reflect off encountered surfaces and return to a detector. The intensity of returns is also recorded on the UH GEMINI system. Raw ALSM travel time data is combined with ground Global Positioning System (GPS) receiver phase data and aircraft GPS and IMU data to generate xyz georeferenced coordinates of each laser return from the surface or ?point clouds.? The GEMINI system?s high frequency laser postings allows for penetration of dense vegetative canopies and, with developed post processing routines, can yield maps of both the upper surface of vegetative canopy and the bare Earth surface that is obstructed from a bird?s eye view. NCALM is dedicated to meeting three goals: 1) providing research-quality LiDAR data to the scientific community, 2) advancing the state of the art in airborne laser mapping, and 3) training and educating graduate students to meet the rapidly growing needs of academia, government, and the private sector. ***