28th Apr 2005

About GPS

GPS stands for Global Positioning System. It’s an international navigation system that allows you to ascertain your location, navigate a course, or track the progress of others, from anywhere in the world.

How Does GPS Work?

First of all, a process of triangulation narrows down the location of the receiver to somewhere between a group of 3 satellites. Then, using the calculation - speed x time = distance – a group of satellites above the earth calculate the user’s distance from the satellite. Speed is ascertained by calculating how long it takes the satellite signal to reach the receiver, with the aid of a 4th satellite to make sure it’s an accurate measurement. This narrows down the location of the user to a perfect location in longitude and latitude – and that’s GPS!

How To Access GPS

There are as many ways to access GPS as there are uses for it. Complex computer systems used to form the bulk of GPS receivers, but today, anything from a watch, to a PDA, to a hand-held system, to a state-of-the-art ship navigation system can tap into the potential of the GPS.

Here, we’ll look at the various types of unit available, before moving on to describe the various uses for consumer GPS products, what type of unit is best suited for these, and the various features you can expect from them.

Marine (Ship) GPS

Probably the most common type of GPS system, all working ships and almost all modern pleasure vessels utilise GPS technology. The large, complex systems used on fishing vessels, cargo ships or other professional capacities often cost thousands of pounds and are directly linked to the ship’s control system. For the amateur seaman, however, more affordable options are available.

Ship GPS can be fixed into any craft of any size, or for more flexibility hand-held GPS devices can be used in marine situations. Most come with a map system, with only budget devices relying solely on longitude and latitude coordinates. In addition to maps, some more advanced GPS devices offer depth sounding, and even fishing aids for offshore fishing expeditions.

Laptop GPS

Your laptop can be turned into a GPS device: just fit it with an external antenna and use some GPS software. Most CD-ROM-based maps offer a GPS function; for those that don’t, GPS software is available for purchase along with a new set of maps. This can be used in any situation – even light aircraft pilots can use Civil Aviation Authority maps to chart their progress in-flight. For those at ground level, drivers, train passengers and other travellers may find this useful. It can also be used for planning journeys in a reliable and accurate fashion.

Watch GPS

GPS technology isn’t restricted to computers or large-scale units: it can fit on your wrist. This is great for anyone who wants fast, accurate and straight-to-the-point information on any GPS-related statistic, such as distance, speed, or timing, or any combination of the three. Walkers and hikers can use it to calculate progress made; golfers can store information on shots, course length, or how far it is to any hazards or fairway shots. People sailing on craft too small to fit a GPS system onto may find a sailing watch GPS handy for anything from a basic navigation aid to a comprehensive keeper of timing, speed and wind direction information.


The ultimate in PDA potential is reached by turning your PDA into a compact yet powerful navigation aid. Most of the major PDA manufacturers have at least one GPS device available for their range of products. Most of these work by attaching an external antenna to your PDA to pick up the GPS signal, and by running some GPS software specially made for your system. The software will provide maps for various locations (with more available to order should you be travelling further afield), and allow you to carry out all the usual GPS tasks: charting a course, plotting your current location, calculating speed and journey time etc. In common with Laptop and Vehicle GPS solutions, it’s even possible to navigate through cities with the greatest of ease: enter where you are and where you’re going, and you’ll be given the route to get there, complete with a real-time map guidance system displaying everything from one-way streets to points of interest.

Vehicle GPS

A vehicle GPS includes a mirror assembly having a reflective element and a housing for the reflective element that is made from a material that is electrically substantially non-conducting. The system further includes a global positioning system (GPS) receiver and control module and at least one receiving antenna. The vehicle GPS is adapted to receive earth satellite signals with the receiving antenna and to convert the signals to location, velocity and/or time parameters.

Types of GPS

In this section, we’ll review the main types of GPS use in detail, with suggestions as to which type of GPS system is best for each type of user. If you fit into one of the categories below, it’s definitely worth getting a GPS system if you’re at all interested in the numerous advantages they have to offer.

  • Outdoor/Map GPS (hand held)
  • Car and Vehicle GPS Navigation
  • Golf GPS
  • Marine GPS

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