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Linear FMCW Laser Radar for Precision Range and Vector Velocity MeasurementsAn all fiber linear frequency modulated continuous wave (FMCW) coherent laser radar system is under development with a goal to aide NASA s new Space Exploration initiative for manned and robotic missions to the Moon and Mars. By employing a combination of optical heterodyne and linear frequency modulation techniques and utilizing state-of-the-art fiber optic technologies, highly efficient, compact and reliable laser radar suitable for operation in a space environment is being developed. Linear FMCW lidar has the capability of high-resolution range measurements, and when configured into a multi-channel receiver system it has the capability of obtaining high precision horizontal and vertical velocity measurements. Precision range and vector velocity data are beneficial to navigating planetary landing pods to the preselected site and achieving autonomous, safe soft-landing. The all-fiber coherent laser radar has several important advantages over more conventional pulsed laser altimeters or range finders. One of the advantages of the coherent laser radar is its ability to measure directly the platform velocity by extracting the Doppler shift generated from the motion, as opposed to time of flight range finders where terrain features such as hills, cliffs, or slopes add error to the velocity measurement. Doppler measurements are about two orders of magnitude more accurate than the velocity estimates obtained by pulsed laser altimeters. In addition, most of the components of the device are efficient and reliable commercial off-the-shelf fiber optic telecommunication components. This paper discusses the design and performance of a second-generation brassboard system under development at NASA Langley Research Center as part of the Autonomous Landing and Hazard Avoidance (ALHAT) project.
Document ID
Document Type
Conference Paper
Pierrottet, Diego (Coherent Applications, Inc. Hampton, VA, United States)
Amzajerdian, Farzin (NASA Langley Research Center Hampton, VA, United States)
Petway, Larry (NASA Langley Research Center Hampton, VA, United States)
Barnes, Bruce (NASA Langley Research Center Hampton, VA, United States)
Lockhard, George (NASA Langley Research Center Hampton, VA, United States)
Rubio, Manuel (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 24, 2013
Publication Date
March 24, 2008
Subject Category
Communications and Radar
Meeting Information
Material Research Society (MRS) 2008 Spring Meeting(San Francisco, CA)
Funding Number(s)
WBS: WBS 699152.
Distribution Limits
Public Use Permitted.

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