GPS (Global Positioning System) is the first piece of equipment acquired if you are going to search for shipwrecks.  You need to know where you are, and you need to be able to go back to the same place.  As you will see below, most of today’s remote sensing equipment requires the use of a GPS in order to perform properly.  The current GPS offerings include WAAS support, but this only functions in North America as of the writing of this document.  In other areas of the world, the GPS will function properly, but without the WAAS feature.