Understanding the location on the planet Earth is always been important for human beings. In ancient time humans were using celestial objects or astronomical observations to determine their location and navigation. Sailors roam around the world and started map making. Since then map has been an integral part of human history, possibly up to 8,000 years.
With the changes in technology, methods of navigation have revolutionized the way the humans used to navigate. In the year of 1970, a satellite based navigation system “GPS – Global Positing System” came into the existence. GPS is a constellation of 24 satellites that orbit the earth at a distance of 20, 200 km (12, 550 miles). Each satellite broadcast signal to the earth, and these signals carry a timecode and geographical data point that allows the user with GPS receiver to pinpoint their exact position, speed and time anywhere on the planet.GPS began its life as a military technology, then everything changed in the late 80s when the US government decided to allow civilian use of the satellite network.
The fact that GPS is driven under the control of USA Government, reliability of such system is not guaranteed in hostile situations. This led to the necessity of other satellite based navigation and positioning system such as GLONASS (Russia), Galileo (Europe), BeiDou ( China), and Quasi-Zenith from Japan. India is set to have its own regional navigational satellite system by the middle of 2015 as reported by ISRO.
The satellite based navigation system provides global navigation (provided the system has global coverage) and whether it’s day or night. But satellite based navigation system has certain limitations. The positioning of satellite system highly depends on the satellite signals strength received at the receiver. Satellite signals availability is limited to clear sky, deep canyons or dense vegetation, high rise building group together, poor weather condition (heavy rainfall) may cause the degradation of satellite signal and the receiver system may not provide location information. Other limitations to the GPS/GNSS system are such as bad satellite geometry and GPS/GNSS jamming.
The UK Ministry of Defence is investing millions of pounds in the research of Quantum Compass – a device which measures the relative position using sub-atomic particles. Based on the research that shows that atoms can be frozen by lasers to a temperature just above absolute zero (−273.15 °C), becoming a billion times colder than the temperature of the universe. The sub-atomic particles at frozen state are extremely sensitive to the magnetic and gravitational field of the Earth and making them ideal for more accurate atomic clocks. Another interesting phenomenon that frozen atoms exhibit is entanglement, a physical phenomenon that occurs when pairs or groups of particles are generated or interact in ways such that the quantum state of each particle cannot be described independently—instead, a quantum state may be given for the system as a whole.
The prototype compass built by the Ministry of Defence resembles a 1-meter-long container containing clouds of rubidium atoms frozen using lasers. Three such devices could be placed at right angles to each other to measure movement along all three axes. By measuring the movement of these frozen particles over precise periods of time the motion of the device can be calculated or its proximity to areas of high gravity. Measurements of physical properties such as position, momentums etc performed on entangled particles are found to be appropriately correlated. Such atom interferometers theory improvises better navigation technology than GPS/GNSS navigation.
The fact that GPS/GNSS does not work underwater, the Quantum TNS (timing, navigation and sensing) will very useful for submarines which uses GPS/GNSS signals while surfaced but rely on crude accelerometers when underwater to track position with dead reckoning. But spending just one day underwater can lead to inaccuracy of up to a kilometer. With Quantum TNS this error could be kept to as little as one meter. Moreover unlike GPS/GNSS signals subatomic particles are not vulnerable to the attack of interfering with or hijacked to corrupt location information.
Now the biggest challenge of the scientist is to create miniature, perhaps which could be fixed in our smart phones and paired GPS/GNSS chips. Then all is needed only a reference to calculate your position with those super-cooled atoms.
Reference: New Scientist