Cartography and Navigation_Assignment 3

1. hey everybody!.This is my third post on remote sensing assignments.This time it is gps and its applications.First we need to get some idea about gps and how it works.

Global Positioning System or GPS is a constellation of 27 satellites orbiting the earth at about 12000 miles. These satellites are continuously transmitting a signal and anyone with a GPS receiver on earth can receive these transmissions at no charge. By measuring the travel time of signals transmitted from each satellite, a GPS receiver can calculate its distance from the satellite. Satellite positions are used by receivers as precise reference points to determine the location of the GPS receiver. If a receiver can receive signals from at least 4 satellites, it can determine latitude, longitude, altitude and time. If it can receive signals from 3 satellites, it can determine latitude, longitude and time. The satellites are in orbits such that at any time anywhere on the planet one should be able to receive signals from at least 4 satellites. The basic GPS service provides commercial users with an accuracy of 100 meters, 95% of the time anywhere on the earth. Since May of 2000, this has improved to about 10 to 15 meters due to the removal of selective availability. 


Applications of GPS
1)GPS Vehicle Tracking-Vehicles can be tracked if they have a gps equipment fitted with a radio or cell phone transmitter to broadcast their position and velocity information.
2)Fishing application-Can be used to find the position of boats used for fishing purposes
3)Forestry
a)Forest fire monitoring
b) Forest resource monitor
4)Balloons fitted with camera can be monitored from the ground with gps equipment fitted with them used for remote sensing 

hey!everybody,this is my second post as part of our remote sensing assignments and activities.We performed an exciting experiment with a GPS equipment in our campus.We were divided into 2 groups of 6 people each.Our remote sensing teacher introduced us to the basics of the equipment and told us to find the distance between our academic block and the aerospace block and also to use the gps equipment to get the route to the starting point from the final point.We marked the starting point coordinates (latitude and longitude and also the elevation) and proceeded to the final point.On our way we could also see the speed with which we were travelling.To our surprise we were at an elevation of more than 100 metres.On reaching the final point we marked that point and also noted its coordinates.There was an option to find routes.In that option we selected the starting waypoint.It showed the routes and us to the starting point with the help of an arrow that guided us with direction.We also explored various other features that were available in the gps.Some features were -
1)Sun-set and sunrise time
2)Routes
3)Waypoints
4)Odometer
5)Elevation
6)No of satellites

initial position coordinates are:

N 08D 37' 29.7"
E 077D 01' 56.3"

elevation 102m

final position coordinates are:

N 08D 37' 32.2"
E 077D 02' 02.5"

elevation 107m

1 degree of latitude corresponds to a distance of 111 km on the ground.
1 degree of longitude corresponds to a distance of 111*cos(latitude) on the ground.
North South distance is 77.08 metres
East West distance is 189.3 metres.
The actual straight line distance between the two points is 204 metres

This is a physical map of South America with physical features like roads ,rivers along with countries and their international borders shown.It extends from around 12 degree north to around 54 degree south

Advantages:

 1) It shows the physical features like roads ,rivers along with countries and their international boundaries.

2)It shows the scale in bar form which can be used to estimate distances.

3)It shows the latitudinal and longitudinal extent of the continent.

4)It shows the national capitals along with important cities.

5)Adjoining oceans and seas shown.

6) Index is included.

7) Different colours are used to distinguish between countries.

Disadvantages:

1)    Only rivers are shown, mountain ranges r not shown (topography is not represented).

2)    Only roads are represented (other modes of transport are not represented).