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