Global Positioning System (GPS) has completely altered our lifestyles. The introduction of this technology in smartphones and cars led almost all sectors to depend on geopositioning for their routine transport. The tracking system has truly revolutionized the lives of people.
Nonetheless, the phenomenon called continental drift makes a person question the system’s prudence and accuracy. We know that Earth’s solid surface is not static. Instead, it is moving very slowly in a way that may not affect your daily life but would change the location of your continent in a several thousand years.
For example, the Australian continent sits on the planet’s fastest moving tectonic plate and is estimated to be drifting at about seven centimeters per year to the northeast.
So the question that, whether this phenomenon is catered in the coordinates provided by the global navigation satellite systems (GNSS) such as GPS or not, is a quite intriguing one. Wonderful Engineering, today, gives you the answer to this query.
To understand how this change is catered for, you first need to know how the geolocation devices work. Usually, the system employs reference points which are stable survey marks that are fixed to the ground to be precisely measured. These reference points along with the coordinate system of latitudes, longitudes, and heights are known as a geodetic datum, with every country having its datum,
For example, the Australian one is called the Geocentric Datum of Australia 1994, or GDA94. The coordinates of fixed landmarks such as roads, buildings, and utilities along with the coordinates of moving objects are all based on GDA94.
The GDA94 in the early 90’s was made to move with the drift, thus resulting in an unchanging three-dimensional coordinate system. But today, the GNSS devices use a different datum to determine their coordinates.
The Great Problem!
Satellite positioning systems like GPS, the Russian GLONASS, China’s BeiDou and the European Union’s Galileo use coordinates not based on a continent fixed datum but rather the average of all continents.
The Australian GDA94 coordinates are moving about Australia’s movement. This would not have been a problem earlier since our positioning systems were not accurate enough to notice the change. But today’s devices show that by 2020, Australia will have moved 1.8 meters away from its original position, and with real-time access to GPS that we have today, this discrepancy will be easily noticeable.
The Solution
To cater for this, the Intergovernmental Committee on Surveying and Mapping (ICSM) Australia’s is now looking to modernize the GDA, which will be called GDA2020. The latest system will involve defining a new datum calculated on average shifts of all coordinates in Australia by 1.8 meters to the northeast, which will bring the coordinates of Australia back into line with the global systems.
In 2020, the second stage of this modernization will launch a new location reference system, akin to the global one, that will keep on measuring and modeling Australia’s movement. The new system will cater for the continental drift phenomenon by syncing with the satellites that provide all our current positioning.
So, the next time you tap open your google maps, remember to appreciate the hard work and the thought process which goes into designing the astonishing technology.
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