Read the passage below and asnswer the following questions
There is always implication of one scien-tific invention in other areas, sometimes least expected. In this context the use of local GPS technology that has become so ubiquitous among the earth people has been taken to decipher mysteries of the universe. Cosmic GPS would employ pulsing stars, not satellites, as celestial beacons and this will be done by the frequency "fingerprints" that are left by the massive electromagnetic disbursals that are emitted in the region of pulsars. This is quite similar to finding your favourite coffee shop in an unknown city, getting directions via satellite. The analogy works in the same way by a positioning system based on blinking stars instead of satellites,
The Principle behind the pulsar positioning is not too different from ordinary GPS. The GPS receiver in a car or phone receives radio signals from satellites orbiting the earth. The satellites are synchronized with atomic clocks to emit signals simultaneously. Because the satellites are all at different distances from the receiver, each message reaches the device at a different time. From these time differences, a GPS device infers the distance to each satellite, and hence can calculate its own position.
The best devices can pinpoint your loca-tion to within one metre under ideal condi-tions, but tall buildings or other interference can throw them off by 10 to 20 metres or more. Though, the navigation system pro-posed by Italian scientist Tartaglia and col-leagues is just a proof of the concept, a GPS-like system under construction in Europe called Galileo could implement the ideas within a decade, he says.
There are but few technical glitches that arise, ironically due to scientific anomalies. Because the satellites move so fast (they orbit the earth twice every day), Einstein's special theory of relativity must be considered. Relativity requires that clocks on board tick slower than those on earth. After two minutes, the satellite's clocks are already out of sync with earth clocks. Transmitting the correct time to each satellite is a constant chore of the De-partment of Defense, which determines the real time from an ensemble of clocks on earth.
A pulsar's regular blips can be used to tell time just like the signals received from GPS satellites. But the math in the new pulsar-based system already accounts for relativity, so these corrections are not necessary. Further, pulsar based systems may not be as precise as GPS, but they could be a backup system for GPS if the ground control for the satellite fails.