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Chadwell, CD.  2003.  Shipboard towers for Global Positioning System antennas. Ocean Engineering. 30:1467-1487.   10.1016/s0029-8018(02)00141-5   AbstractWebsite

Two 12.2 m-high towers for mounting Global Positioning System (GPS) receiver antennas were designed and constructed to provide millimeter-level stability while maintaining portability and accessibility to satellites and deck spaces. A combination of guys and a 3-m horizontal strut provide roll and pitch stability of 2-3 rum observed from 0.1 seconds to 12 days using a combination of GPS and optical/laser devices. The shipboard antenna mounts connect sub-aerial GPS positioning to underwater acoustic ranging that determine the centimeter-level location of seafloor transponders. Observed annually, these seafloor geodetic positions measure seafloor crustal motion for geophysical studies. (C) 2003 Elsevier Science Ltd. All rights reserved.