Global Positioning System Advantages And Disadvantages

Global Positioning System

Himangshu Sarma1, Monalisha Goswami2

1,2Department of Electronics, Lalit Chandra Bharali College, Maligaon, Guwahati -11 E-mail: [e-mail]

Abstract

GPS or Global Positioning System is a network of orbiting satellites that send precise details of their position in space back to earth. The signals are obtained by GPS receivers, such as navigation devices and are used to calculate the exact position, speed and time at the vehicles location. The 24 satellites that make up the GPS are orbiting the earth about 12,000 miles above us. They are constantly moving, making two complete orbits in less than 24 hours. These satellites are travelling

• Satellite geometry/shading - This refers to the relative position of the satellites at any given time. Ideal satellite geometry exists when the satellites are located at wide angles relative to each other. Poor geometry results when the satellites are located in a line or in a tight grouping.

• Intentional degradation of the satellite signal - Selective Availability (SA) is an intentional degradation of the signal once imposed by the U.S. Department of Defense. SA was intended to prevent military adversaries from using the highly accurate GPS signals. The government turned off SA in May 2000, which significantly improved the accuracy of civilian GPS receivers.

6. Advantages and Disadvantages of GPS

There are several advantages of GPS following with some usual disadvantages [6] [7]. These are mentioned at below -:

Advantages

• GPS is able to work in all weather. Here one need not worry about the climate. • It is less costly than the other navigation systems.

• The system is updated in a regular basis by the authorities and hence it is more

WAAS consists of a network of ground based reference stations to measure small variations in the GPS satellite’s signal. It has 2 master stations which arrange the correction messages properly and send them to the geostationary WAAS satellites. The satellites broadcast the correction messages back to the earth. [8].

8. Application of GPS

GPS is an essential element of the global information infrastructure. GPS is used for a wide variety of purpose for both military and civilians [9]. Some application where commonly used GPS are given below –:

• Road Transport- Road transport applications are the majority users of GPS. It includes mainly taxi service, public transport, emergency vehicle location etc.

• Marine and Rail Transport -Marine applications include ocean navigation, port approaches, harbour entrance, automatic identification etc.Whereas the rail transport application includes the passenger’s information, trains position, level crossing approach etc.

• Security- Security application includes tracking of vehicles, tracking of suspect etc. It acts as a guard against auto and mobile thefts. If GPS is installed then the stolen material can be easily traced even if these are stolen and being sent to