The Global Positioning System (GPS) is a space-based navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil, and commercial users around the world. The United States government created the system, maintains it, and makes it freely accessible to anyone with a GPS receiver

One hazard of human existence is being geographically lost, which sometimes means the difference between life and death. The ability to know one's position was considerably enhanced on February 22, 1978, when members of the U.S. Air Force (USAF) Space Division based in Los Angeles, California, launched the first NAVSTAR (Navigation Satellite with Timing and Ranging) satellite in the Global Positioning System (GPS). This satellite-based navigation system enables users anywhere on Earth to determine their location to a high degree of accuracy.

Applications of GPS

The most obvious application for GPS is satellite navigation in vehicles, aircraft and ships. It allows anyone with a GPS receiver to pinpoint their speed and position on land, air or sea, with incredible accuracy. Drivers can use in-vehicle portable navigation devices to follow a route, find detours around traffic problems and with additional software receive traffic alerts and warnings on safety camera locations.

GPS is also available for other uses: hikers and ramblers can use GPS receivers to ensure they are following their chosen route and to mark rendezvous points along the way. While gamers can take part in geocaching, a kind of treasure hunt for the digital age, which uses precise GPS signals to help the players track down a hidden stash.

The emergency services, for instance, can use GPS not only to find their way to an incident quicker than ever before but also to pinpoint the location of accidents and allow follow-up staff to find the scene quickly. This is particularly useful for search and rescue teams at sea and in extreme weather conditions on land where time can be a matter of life or death.

Scientists and engineers also have applications for GPS receivers, in scientific experiments, and in monitoring geological activity such as earth tremors, earthquakes and volcanic rumblings. They can use strategically positioned GPS devices to assist them in tracking climate change and other phenomena. Fundamentally, GPS can now be used to produce very accurate maps.

2) Applications

The applications of the Global Positioning System fall into five categories: location, navigation, timing, mapping, and tracking. Each category contains uses for the military, industry, transportation, recreation and science.

This category is for position determination and is the most obvious use of the Global Positioning System. GPS is the first system that can give accurate and precise measurements anytime, anywhere and under any weather conditions. Some examples of applications within this category are:

1. Measuring the movement of volcanoes and glaciers.
2. Measuring the growth of mountains.
3. Measuring the location of icebergs - this is very valuable to ship captains helping them to avoid possible disasters.
4. Storing the location of where you were - most GPS receivers on the market will allow you to record a certain location. This allows you to find it again with minimal effort and would prove useful in a hard to navigate place such as a dense forest.

Navigation

Navigation is the process of getting from one location to another. This was the what the Global Positioning System was designed for. The GPS system allows us to navigate on water, air, or land. It allows planes to land in the middle of mountains and helps medical evacuation helicopters save precious time by taking the best route.

GPS brings precise timing to the us all. Each satellite is equipped with an extremely precise atomic clock. This is why we can all synchronize our watches so well and make sure international events are actually happening at the same time.

This is used for creating maps by recording a series of locations. The best example is surveying where the DGPS technique is applied but with a twist. Instead of making error corrections in real time, both the stationary and moving receivers calculate their positions using the satellite signals. When the roving receiver is through making measurements, it then takes them back to the ground station which has already calculated the errors for each moment in time. At this time, the accurate measurements are obtained. Tracking

The applications in this category are ways of monitoring people and things such as packages. This has been used along with wireless communications to keep track of some criminals. The suspect agrees to keep a GPS receiver and transmitting device with him at all times. If he goes where he's not allowed to, the authorities will be notified. This can also be used to track animals.

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Many applications use a combination of the above categories. The following is a list of some additional areas where the global positioning service is being applied:

1. precision farming
2. open-pit mining
3. oil exploration
4. airport and harbor approaches
5. animal migration and population studies
6. vehicle tracking
7. construction - tunnels, golf courses, roads, etc.
8. emergency services - the closest ambulance or fire truck is sent to an emergency, thereby saving time.
9. atmospheric studies - ozone layer, air quality, etc.
10. archaeological explorations
11. recreational activities - camping, boating, etc.
12. astronomical telescope pointing
13. networking - speed is increased, the Internet is highly synchronized because of GPS.
14. aiding the blind

The Global Positioning System, also called NavStar, that we use was built by the US military and has been fully operational since 1995. Many modern GPS receivers use a combination of both GPS and the RussianGLONASS satellites for improved coverage and accuracy.The GPS system currently has 31 active satellites in orbits inclined 55 degrees to the equator. The satellites orbit about 20,000km from the earth's surface and make two orbits per day. The orbits are designed so that there are always 6 satellites in view, from most places on the earth.GPS uses a lot of complex technology, but the concept is simple.The GPS receiver gets a signal from each GPS satellite. The satellites transmit the exact time the signals are sent. By subtracting the time the signal was transmitted from the time it was received, the GPS can tell how far it is from each satellite. The GPS receiver also knows the exact position in the sky of the satellites, at the moment they sent their signals. So given the travel time of the GPS signals from three satellites and their exact position in the sky, the GPS receiver can determine your position in three dimensions - east, north and altitude.There is a complication. To calculate the time the GPS signals took to arrive, the GPS receiver needs to know the time very accurately. The GPS satellites have atomic clocks that keep very precise time, but it's not feasible to equip a GPS receiver with an atomic clock. However, if the GPS receiver uses the signal from a fourth satellite it can solve an equation that lets it determine the exact time, without needing an atomic clock.If the GPS receiver is only able to get signals from 3 satellites, you can still get your position, but it will be less accurate. As we noted above, the GPS receiver needs 4 satellites to work out your position in 3-dimensions. If only 3 satellites are available, the GPS receiver can get an approximate position by making the assumption that you are at mean sea level. If you really are at mean sea level, the position will be reasonably accurate. However if you are in the mountains, the 2-D fix could be hundreds of metres off.A modern GPS receiver will typically track all of the available satellites simultaneously, but only a selection of them will be used to calculate your position.

The GPS is a very common technology in todays world. When I chose this as my topic for the project I realized that the internet had plenty of information. But for the authenticity I searched for a few journals on GPS. I came across Wikihow, springer(the one which I used finally), and also the online library of our college.

A few papers were interesting but I could not read them all, and so I decided to go with the journal above as it was comprehensive and was perfect for those who do not know much about GPS.

Since the journal is quite big as you see, I used youtube as a source of my information. The written word does not suit many people(one of them being me) so these videos very helpful.

I have put them up at the top of this Padlet.

The GPS uses the concept of trilateration and triangulation. The working of this technology has been explained in the videos given above. Basically , triangulation and trilateration requires three satellites. These three satellites are co-ordinated by the 'control' and a specific location is thus acquired.

For better understanding please refer to the 2nd and 3rd video above.

The GPS uses the concept of trilateration and triangulation. The working of this technology has been explained in the videos given above. Basically , triangulation and trilateration requires three satellites. These three satellites are co-ordinated by the 'control' and a specific location is thus acquired.

For better understanding please refer to the 2nd and 3rd video above.

1)Declination Setting - GPS units can be adjusted to the amount of magnetic declination in the area of use. Differential GPS (DGPS) - An extension of the GPS system that uses land-based radio beacons to transmit position corrections to GPS receivers. DGPS reduces the effect of selective availability, propagation delay, etc. and can improve position accuracy to better than 10 meters

2)Latitude - A position's distance north or south of the equator, measured by degrees from zero to 90. One minute of latitude equals one nautical mile

3)Autonomous Positioning The least precise form of positioning that a GPS receiver can produce. The position fix is calculated in real time from satellite data alone. Autonomous positions are generally accurate to within 10 meters.

4)Multipath Interference, similar to ghosts on a television screen, which occurs when GPS signals arrive at an antenna after traversing different paths. The signal traversing the longer path will yield a larger pseudorange estimate and increase positional error. Multipath occurs when GPS signals reflect off a surface before reaching the GPS antenna.

5)Ellipsoid An ellipsoid is the three-dimensional shape that is used as the basis for mathematically modeling the earth’s surface. The ellipsoid is defined by the lengths of the minor and major axes. The earth’s minor axis is the polar axis and the major axis is the equatorial axis. Ephemeris The current satellite position predictions that are transmitted from a GPS satellite in the NAVDATA message

6) SOME ABBREVIATIONS

AOL- AIRBORNE OPTICAL LASER

CDU-CONTROL DISPLAY UNIT

MOU - MEMORUNDUM OF USER

HAE- HEIGHT ABOVE ELLIPSOID

I think that all the applications of the GPS mentioned above are feasible.

One reason being that many of these have actually been developed and are contributing towards its widespread use.

The applications of GPS which I could relate with the best is networking(The one where GPS increases the speed of the internet)

Other applications of GPS are-

1) Vehicle tracking and other navigation techniques(which is also the most common one)

2) recreational activites mentioned above

The best application which I think me and my team can conduct is AIDING THE BLIND

The reason being this does not require much skill or knowledge of the concept

and thus can be conducted smoothly at college level