Introduction
In olden days, our ancestors used many different measures to find their way around the Earth. They used the positions of stars, landmarks were put up and detailed maps were drafted in order to prevent themselves from getting lost. In today’s day and age, it is much easier to know exactly where on Earth you are and find your way around without ever getting lost again - as long as you have a handy device known as a GPS.
I knew that GPS’s could be found in cars, boats, planes, computers and other new devices, but my interested in how exactly this system worked was aroused when I was listening to my dad teaching his friend, who had recently bought a GPS, how to use it.
After doing some research, I found that the GPS that my dad’s friend bought is not really a GPS, but a GPS receiver. The Global positioning System (GPS) is actually a “worldwide radio-navigation system” that consists of 24 satellites (27 in total - 24 operating and 3 as back-ups) that orbit the Earth. This satellite network was originally developed by the U.S military navigation system, which was later available to common people as well. The satellites, weighing 3,000 to 4,000 pounds each, are orbiting 11,000 nautical miles above the Earth’s surface, with five ground stations keeping them in check and in working condition. Each of the satellites makes two complete rotations every day, all of them positioned so that at least four satellites are “viewable” in the sky.
The GPS receiver uses four or more of these satellites to calculate its position by figuring out the distance of each of the satellite and using that information to deduce its own location. This mathematical principle is called trilateration, which is the process of finding the absolute or ...
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... of receiver clock when signal received
TS = reading of satellite clock when signal transmitted c = speed of light (in a vacuum) = 3.0 x 108
Fig 5: A diagram showing how the GP pseudorange observation is related to the satellite and receiver clocks
Works Cited
http://geoweb.mit.edu/~tah/12.540/ http://gps.about.com/lr/gps_tracking/1769939/1/ http://www-gpsg.mit.edu/~tah/12.540/12.540.Lec06.pdf http://electronics.howstuffworks.com/gadgets/travel/gps2.htm http://www.math.tamu.edu/~dallen/physics/gps/gps.htm http://gauss.gge.unb.ca/gpsworld/EarlyInnovationColumns/Innov.1991.07-08.pdf http://mathworld.wolfram.com/SphericalTrigonometry.html http://gps.about.com/od/gpsproductoverview/a/How-GPS-Tracking-Works.htm http://www.nbmg.unr.edu/Staff/pdfs/Blewitt%20Basics%20of%20GPS.pdf
Interferometers: http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-20-3-2725&id=226739
on this built in compass sense to guide them in the open ocean. Another use for
Eric Bland a journalist for NBC News covered an investigative article on the vulnerabilities of GPS devices that everyday citizens have become accustomed. Bland uncovered that a spoofer can jam GPS signals thereby rendering a device with GPS inactive, more interestingly is that a spoofer can create a false signal that overpowers the actual real signal. The false signal transmits like the original signal but offers incorrect and or fabricated destination to the GPS receiver. In such an instance the spoofer would control the victim’s time and destination. While the thought of driving or arriving into an unknown location is frightening and might threaten safety, it is the number of national infrastructure reliant on GPS and vulnerable to spoofers that raises genuine concern and fright in regards to national security. The country’s electrical power grids, generators, airports and law enforcement are examples of infrastructures and institutions that relay on the GPS for daily functioning. Brent Levina adjunct professor at Virginia Tech decide to build a spoofer to better highlight the weaknesses of the GPS (Bland,
Now that we’ve made our way through the journey of Ken Jennings’ incredible book I feel as if it’s important for me to try to sway you to become more involved in geography. It’s a truly fascinating subject and can take you places you never thought you could ever visit. If you don’t want to leave your home, at least buy an atlas, map, or visit Google Earth. You never know what you could discover in your journey. If you don’t think maps or an atlas is your thing, you never know if you never try. Jennings created a journey, for me I would have never cared to take had it not been assigned as a college class assignment, but now I’m so glad I did. Jennings shined a different light on geocaching, and map hunting. He made it fun, interesting, and overall thrilling.
Characterized by several stages of development, the modern state of California witnessed a myriad of hurdles during the period of Spanish and Mexico invasion. The predicaments faced by the Native Americans are seen to have accelerated with the intrusion of the Spanish rule and its exercise of colonial power over the Mission Indians. Although the native dwellers of California did not a lead a politically stable life before its colonization, Mission Indians enjoyed a period of social stability with strength in local governance. The onset of the Spanish and Mexico rule saw the opening up of the state to more immigrants and imperialist through routes that were created
The advanced technology that XM Radio uses is a big change from the old fashioned ways that FM and AM radio are broadcasted. XM Radio uses satellites in order to broadcast across the entire country with a clear signal. “XM satellites’ fixed orbits ensure a focused and consistent signal” (“Satellites” 2002). If the satellites need to be moved for any reason, no problems will occur with the broadcasting and ensures that the signals will not be lost (“Satellites” 2002). The ways in which were they were manufactured plays a big role in the quality of the signals that are sent to Earth. “The satellites were built by Boeing Satellite Systems, which is the world’s leading commercial manufacturer of satellites” (“Satellites” 2002). This was a smart decision by the makers of XM Radio because Boeing is such a well-respected company that it will ensure the confidence of needed consumers.
Christopher Columbus was known as a “dead reckoning navigator”[2]. Dead Reckoning Navigation, or also known as Deduced Navigation, was used by an umpteen of sailors. In Dead Reckoning Navigation the helmsman can find his locus by measuring the distance he has sailed to a known point. Each day, the ending position was the starting point for the next day. However, this method is not as elementary as it sounds. In order for this tactic to work, the helmsman needs to measure his course and distance sailed. Therefore, a course is measured by a magnetic compass, and distance with a time and speed calculation. One can conclude then that this was a nettlesome process. Of course, since then humans have immensely improved in this area. Today, there is a way to know where one is at while at sea that is much less problematic.
In 2010, Google broadcasted that they created an archetype of a car that can drive itself; its purpose, to avert collisions, allow citizens more time, and cut down on harmful pollutants that vehicles produce (Poczter & Jankovic, 2014). The heart of the self-driving automobile is lasers that are mounted on the roof of a modified Toyota Prius that produces a precise three-dimensional atlas of the area surrounding the car. Furthermore, the automobile is outfitted with four radars, and another laser around the vehicle that allows it to precisely create a 3-D map of its surroundings (Poczter & Jankovic, 2014). The vehicle calculates the laser dimensions with high-resolution maps of the globe, which allows it to drive itself without human intervention, while evading obstacles and obeying traffic laws (How Google’s self-Driving Car Works, 2011).
When looking at “Itinerary” by Eamon Grennan, one can see “a passion for invisibility, be a fly on the wall” is important because of the metonymy between feeling invisible and being a fly on the wall. This shows how they felt because they wanted to be or experience “invisibility” and insignificance. To add onto that “the pitchers ear, the child in the corner” shapes how you can be an introvert and listen to people rather than ever being in the center of attention. To expound, “You circle a space you’ve come back to, trying to find some comfort” this person is caught in a cycle that doesn't seem to end. Even though she can't seem to stop, they deep down wants to. To add to that, “something that says you’re at home now” they are hoping they can find
with a digital map, who shows the position of the car. Based on the position of
The GPS is sensing knowledge to help with navigation with the car and destinations. Autonomous cars are not yet available on a large scale of the world such as out of the United States of America, but have been programmed and developed to travel along the roads of America. Most autonomous cars are programmed only for American roads, we have made a big step towards the future with autonomous cars, with them being only available mainly in America, they are a luxury. They are making their way to larger scale autopilot features, and will eventually be available on a larger scale.(Ali
Google maps an application that helps you to find any place in the world because it provides you with a map.
have the capability to let you talk with someone across the nation or let you
There was a time a person would use a roadmap to get from one location to another. Some also would stop and ask for directions. Today, you seldom see paper maps and people stopping at a local gas station for directions. Many vehicles come with a navigation system that provides a real-time map of the vehicle’s current location as well as systematic directions to requested destination.
GPS is a system of satellites radio-transmitters that orbit the planet in great numbers; their purpose is to be able to pinpoint the exact location of an individual or any type of vessel that is equipped with a receiver transmitter within a very small radius. GPS navigation has had a great impact upon society in general as well and its commercial and military applications. Global Positioning is made available at no cost to anyone who has a GPS receiver unit anywhere on the planet. A GPS unit is able to give the user longitude/latitude information as well as, altitude, traveling speed, distance traveled, distance remaining and time in any type of weather conditions imaginable.
A satellite is defined as an object that orbits or revolves around another object. In basic terms, this relationship is due to the gravitational pull of the larger object while the smaller one has enough velocity and momentum to circle the larger one (Fitzgerald &Dennis). This is a good definition if one is only speaking of the broad principles of why and how objects attract one another and where in nature this occurs. The billions of stars and planets together make up a vast network of orbiting objects that each can rightfully be called satellites. By studying the way the Universe and Solar System works, scientists have been able to send man made devices into earth's orbit to serve the needs of a technologically developing world.