GPS satellites in orbit around the Earth

Global Positioning System

A primary consideration in the search for acoustic targets and magnetic anomalies is positioning. Accurate positioning is essential during the running of survey track lines, and for returning to recorded locations for supplemental remote sensing and ground truthing operations. These positioning functions were accomplished on this project through the use of a Garmin 225D global positioning system. The Garmin 225D differential global positioning system (DGPS) provided navigational positioning data for the survey vessel, the G-886 magnetometer, and side scan sonar. Navigational data were recorded and updated by the Garmin 225D at the rate of twice per second.

Garmin 225D Global Positioning System.

All positioning coordinates are based upon the position of the antenna of the DGPS. Each of the remote sensing devices was oriented relative to the antenna (known as layback) in the Hypack Max software program. This information is critical in the accurate positioning of targets during the data analysis phase of the project.