Title :
Underwater optical ranging: A hybrid LIDAR-RADAR approach
Author :
Waldron, Dennis L. ; Mullen, Linda
Abstract :
A hybrid LIDAR-RADAR system is applied to optical ranging in order to achieve centimeter-type range accuracy over the distance of meters with high range resolution. The experiment is performed for NIR 830 nm, red 660 nm, green 532 nm using photomultiplier tube, interference filter, RF demodulator. An optical wavelength in the NIR region helps to protect the system against the effects of changing turbidity levels of water because NIR wavelengths absorb quickly in clean water without being affected by scattering, the components that make total attenuation. The modulation frequency of 66 MHz for NIR wavelength allowed a theoretical maximum range measurement of 1.71 m within the unambiguous range, which drops to 1.61 cm at 70 Mhz. A scheme involving chaotic modulation techniques (CLIDAR) will be studied in future.
Keywords :
demodulators; electro-optical modulation; interference filters; laser ranging; measurement by laser beam; object detection; optical radar; photomultipliers; remote sensing by laser beam; turbidity; underwater optics; CLIDAR; NIR region; RF demodulator; centimeter-type optical range accuracy; chaotic modulation techniques; distance 1.61 m; distance 1.71 m; frequency 60 MHz; frequency 70 MHz; hybrid LIDAR-RADAR system; interference filter; modulation frequency; optical wavelength; photomultiplier tube; resolution; turbidity levels; wavelength 532 nm; wavelength 660 nm; wavelength 830 nm; Demodulation; Optical attenuators; Optical devices; Optical filters; Optical modulation; Optical scattering; Photomultipliers; Protection; Radio frequency; Radiofrequency interference;
Conference_Titel :
OCEANS 2009, MTS/IEEE Biloxi - Marine Technology for Our Future: Global and Local Challenges
Conference_Location :
Biloxi, MS
Print_ISBN :
978-1-4244-4960-6
Electronic_ISBN :
978-0-933957-38-1
