GPS Coordinate Systems

GPS coordinate systems are very important in terms of navigation and positioning in a variety of different situations. In this guide we shall look at what GPS coordinate systems are and some extra information about them.

What are GPS Coordinate Systems?

Geographic coordinate systems refer to a coordinate system that enables all locations on the Earth to be specified using three coordinates – largely using the spherical coordinate system.

As the Earth is not a sphere it has made it incredibly difficult to define a coordinate system that can accurately state topographical data. However geographic coordinate systems have provided the best possible solution to this challenge and are widely used.

GPS coordinate systems refer to devices that utilize the Global Positioning System (GPS) to determine geographic coordinates. The global positioning system is a set of 27 (24 active and 4 back-ups) U.S. based space satellites that send signals to GPS receiving devices to pinpoint a specific location on the Earth.

What are GPS Coordinate Systems used For?

GPS coordinate systems have a huge range of uses both in military and civil situations. The military regularly use GPS coordinate systems both in war and standard search and rescue missions – if a pilot is downed a GPS can help locate them much faster than traditional methods. They can use GPS coordinate systems for navigation in the dark or in unfamiliar territory as well as to coordinate the movement of troops and supplies.

The military also use GPS coordinate systems extensively to help with mapping and reconnaissance. Artillery projectiles are often embedded with GPS coordinate system receivers that are able to withstand accelerations up to 117,600 meters per second.

Civilians also regularly use GPS coordinate systems – most commonly as in-car navigation systems and on their cell phones. Many cell phones these days have GPS coordinate systems built into them – largely to help emergency services locate a person in a critical situation. Modern cell phones have in-built GPS navigation that can double up as in-car navigation systems. The Apple iPhone is a well known device that facilitates GPS coordinate system technology.

Those who enjoy the great outdoors also get great benefits from GPS coordinate systems by using them as accurate navigation tools to make sure they do not get lost in unknown territory.

GPS Coordinate Systems

The Shape of the Earth and its relevance to GPS Coordinate Systems

As we mentioned before, the irregular elliptical shape of the Earth poses many problems when it comes to GPS coordinate systems. The Earth has a bulge at the equator meaning that the radius at the equator is 0.3 percent larger than that measured through the poles. Map makers will usually use the true ellipsoid that best fits the area in which they are working with.

GPS coordinate systems have largely covered the problems related to the irregular shape of the Earth – however it can pose difficulties when trying to get exact coordinates – particularly near the equator.

The Earth is constantly moving due to plate movements and diurnal movements caused by the moon. Continents can move as much as 10cm a year, and Scandinavia, for example, is rising by 1cm a year as a result of melting ice caps. This can affect the accuracy of GPS coordinate systems, however these changes are insignificant if local datum is used as opposed to global GPS datum that can be inaccurate.

GPS Coordinates

Geodesic Height and GPS Coordinate Systems

One of the three main coordinates required to get a full reading on a GPS coordinate system is the geodesic height. Geodesic height measures the vertical distance from the centre of the sphere or from the surface of the sphere. It is essential in completely specifying a location of a topographical feature on the Earth.

Due to the irregular shape of the Earth, each country has its own set of datum, for example the reference point for England is in Newlyn.

We hope you have found this guide on GPS coordinate systems helpful. While we have just touched on the basics, it is a very complex and in depth subject that is very interesting to learn more about.