Topic > The Global Positioning Satellite System (GPS)

Since the beginning of navigation, sailors have relied on the sky to determine their direction, using visual indicators such as the North Star and celestial poles to locate their position . Today we no longer struggle with this problem so much, since we have the Global Positioning System of satellites (GPS) that we use daily in our cars and smartphones. However, this technology relies on humans to make changes every single day, and the further away you get from satellites, the harder it becomes to pinpoint your location. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay While GPS is precise enough to allow us to navigate Earth, it is not precise enough to take a spaceship to Saturn. Based on recent research by Science News and WIRED, a new solution has been introduced: a stellar GPS network, or pulsar positioning system. The premise of the pulsar positioning system is that, similar to the way GPS uses the coherence of satellite signals to determine its area, spacecraft would be able to receive radio signals from dead stars that emit radiation at constant intervals, known also as a pulsar. Instead of having to rely on radio telescope communications far from Earth, spacecraft could venture farther without having to worry about inaccurate coordinate readings. Using the GPS system, the receiver, like a car or telephone, receives radio signals from satellites in Earth's orbit. These satellites are set with atomic clocks to radiate signals simultaneously. These satellites are all at separate distances from the receiver and therefore each transmission reaches the device at different times. From these differences in duration the GPS system deduces its position. The highest-quality consumer devices can estimate your location to within about a meter in the best situations, but tall buildings and interference can easily disable the system by 20 meters or more. Because these GPS satellites orbit the Earth so rapidly (they complete two orbits per day), Einstein's special theory of relativity requires the clocks to tick more slowly than the Earth's. For example, after two minutes the GPS satellites have already diverged from the earth's clocks. The only way to send the correct time to satellites is to determine the actual time from clocks on Earth and transmit the information to each satellite, which is a perpetual obligation for the Department of Defense. In contrast, even though a pulsar's uniform signals are used to keep time just like the GPS system, calculations in the pulsar positioning system already take relativity into account. Therefore, the constant review associated with GPS is avoided. Pulsars have a very advanced ability to keep time similar to atomic clocks and do not move between intervals very often relative to Earth. Even when they do this, it is possible to predict the distance they travel. To prove that the pulsar positioning system can navigate on its own, several researchers experimented with their radio signals. Angelo Tartaglia, a physicist at the Polytechnic University of Turin in Italy, conducted a study on software that imitates pulsar transmissions. Tartaglia and his team tracked the observatory's trajectory with an accuracy of several nanoseconds. Additionally, researchers from the Station Explorer for.