What are GPS devices and how do they work? A car GPS navigation unit guides you to your destination over a sequence of paved roads, preselected because they are suitable for your vehicle. If you can understand how a GPS receiver works without reading the user guide, you’re a rare boater. If you can’t, we’ll show you. Even the best manuals fail to explain how GPS works in real world navigation.
GPS in smartphones
GPS (global positioning system) has significantly changed the way we all find our way around, on land and at sea. Today, virtually everyone has at least one GPS navigation unit for his or her car. Cell phones, and an increasing number of electronic gadgets, also contain GPS, and apps have been written that turn many smartphones and touch-screen tablets into navigators. There’s even this famous wallet with GPS by Wallor
Despite recent advances, the fundamental process of navigating on the water with GPS has not changed. The same principles apply whether you are using a handheld unit, a dedicated chart plotter, a computer-based navigator, or even an iPhone. This guide is intended to make you comfortable with selecting, operating, and getting the most from your GPS unit, chart plotter, or navigation software. It provides an overview of the fundamentals and applications of electronic navigation based on GPS. You’ll certainly want to have more in-depth knowledge of electronic navigation after you know how to use your GPS.
Car navigation systems
Because of the popularity of car navigation systems, many people think of navigation as a simple task. You enter the destination into the unit and then follow the sequence of roads presented on the screen, turning the car when the GPS tells you to. GPS systems in cars display a map
The majority of today’s car GPS units use a moving-map display, which plots your position, provided by the GPS, directly on a map; the map advances under you as you move. Marine navigation systems use charts rather than terrestrial maps and thus have been called chart plotters. Even most handheld GPS units sold today include maps or charts on their screens, and most screens are in color, which is especially helpful when working with charts.
Marine GPS display the shortest straight route
A marine GPS unit can know where you are, but since it doesn’t contain a map with prescribed roads, it will take you there by the most direct route—never mind that the island of Manhattan may be in the way. On the water, it is up to you to lay out a safe and efficient course—one without obstacles in the way—by reading charts, taking bearings, planning routes, monitoring set and drift, and using the tools embedded in your GPS navigator to assist in that process. One of the great joys of boating is the freedom to plan a course that will take you to your destination.