EXPLORING THE UNEXPLORED
GPS
The other application can be of using the gps system in locating the different houses during the time of census and fixing the coordinates of the place.
GPS
The Global Positioning System (GPS) is a space-based global navigation satellite system (GNSS) that provides reliable location and time information in all weather and at all times and anywhere on or near the Earth when and where there is an unobstructed line of sight to four or more GPS satellites.
It uses between 24 and 32 Medium Earth Orbit satellites that transmit precise microwave signals. This enables GPS receivers to determine their current location, time and velocity.
The GPS satellites are maintained by the United States .
GPS is often used by civilians as a navigation system. On the ground, any GPS receiver contains a computer that "triangulates" its own position by getting bearings from at least three satellites. The result is provided in the form of a geographic position - longitude and latitude - to, for most receivers, within an accuracy of 10 to 100 meters. Software applications can then use those coordinates to provide driving or walking instructions.
Basic concept of GPS
A GPS receiver calculates its position by precisely timing the signals sent by GPS satellites high above the Earth. Each satellite continually transmits messages that include
- the time the message was transmitted
- precise orbital information (the ephemeris)
- the general system health and rough orbits of all GPS satellites (the almanac).
The receiver uses the messages it receives to determine the transit time of each message and computes the distance to each satellite. These distances along with the satellites' locations are used with the possible aid of trilateration, depending on which algorithm is used, to compute the position of the receiver. This position is then displayed, perhaps with a moving map display or latitude and longitude; elevation information may be included. Many GPS units show derived information such as direction and speed, calculated from position changes.
Three satellites might seem enough to solve for position since space has three dimensions and a position near the Earth's surface can be assumed. However, even a very small clock error multiplied by the very large speed of light — the speed at which satellite signals propagate — results in a large positional error. Therefore receivers use four or more satellites to solve for the receiver's location and time. A few specialized GPS applications do however use the time; these include time transfer, traffic signal timing, and synchronization of cell phone base stations.
GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is.
Survey using GPS(Global Positioning System)
Few days back we did a survey of our college with the help of our gps device.
It was a small portable device easy to handle in our hands and easy to take anywhere .
We were divided into two groups of 6 people each. With the help of the device we surveyed a part of our campus from our d2 block to a place which took us near the girls hostel.
The other group went to the d4 block from our d2 block.
It was our 1st field trip.It was a nyc experience to explore the unexplored paths of d campus.
In future it might be of great help for the people coming frm that side.
We took the reading of the latitude and longitude of 3 locations.
The starting point, end point and one point in between.
Point 1 : 8° 37′ 29.7′′ N, 77° 01′ 56.4′′ E
Point 2 : 8° 37′ 35.1′′ N, 77° 01′ 55.35′′ E
Point 3 : 8° 37′ 37.633′′ N, 77° 02′ 00.05′′ E
We also measure the altitude of the different places which fluctuated due to uneven elevation of the land.
Now from these three points we can calculate the distance between any two points.
Distance between point1 and point2:
8° 37’ 35.1′′ N, 77° 01′ 55.35′′ E - 8° 37′ 29.7′′ N, 77° 01′ 56.4′′ = 5.4′′ N, -1.05′′ E
Therefore distance between point1 and point2(in km/m) is:
N = 5.4 * 111/3600 ≈ 0.1665km ≈ 166.5m
E = 1.05* 111/3600 ≈ -0.032375km ≈ 32.375m
Distance between point2 and point3:
8° 37′ 37.633′′ N, 77° 02′ 00.05′′ E - 8° 37′ 35.1′′ N, 77° 01′ 55.35′′ E = 2.533′′ N, 4.7′′ E
Therefore distance between point2 and point3(in km/m) is:
N = 2.533*111/3600 ≈ 0.0781km ≈ 78.1m
E = 4.7*111/3600 ≈ 0.1449166km ≈ 144.9166m
Therefore,
The total distance travelled North ≈ [ 166.5+78.1 ]≈ 244.6mN
And total distance travelled East ≈ [ 144.9166-32.375 ] ≈ 112.5416mE
Noble applicaton of gps
Tracking of prisoners or other offenders
In this if a gps device is fitted in those people who volunteerily wants to leave the prison and go home then they can used this device.
This device can be fitted on their body and their location can be tracked.
They can be volunteerily allowed to wear this GPS BELT and the locations in which they will be moving can be fed before with some fluctuations if needed.
Or their path can be fixed as given by them. If they deviates from their path then the police can be alerted.
The other application can be of using the gps system in locating the different houses during the time of census and fixing the coordinates of the place.
Though the cities nowadays are planned but it is very helpful in keeping the data of the new locations coming and the scattered locations.
GPS technology allows us to reduce the amount of time spent by census workers in locating addresses. The new electronic technology replaces a paper-based operation, providing faster, more accurate and secure collection of information.
