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[ By Electronics Infoline Editorial Team ]
Feature Image by Bram Van Oost on Unsplash
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Introduction
The pace of growth and expansion of new technologies in the 20th century has been unparalleled in human history. The advancements in electronics and communication technology have completely reshaped the social structure and the standard of living.
One of the areas of technology which has been absolutely crucial in the current technological revolution is the communications technology. It is this technology which has made internet, mobile telephony, and satellite communication possible.
One of the major reasons for the immense growth of the communication technology is the evolution of geo-orbital satellites. These satellites ensure very fast, reliable and wide-area communication. There are numerous purposes for which these satellites are used however one of the most well known and widely used applications of these satellites is the GPS (Global Positioning System).
Above Video Courtesy Casual Navigation, YouTube
What is GPS?
The GPS (Global Positioning System) is a satellite-based radio-navigation system developed by USA. The GPS project consists of at least 24 satellites and the project was initially named as NAVSTAR GPS. The GPS is a type of GNSS (Global Navigation Satellite System) which is capable of providing very accurate data regarding geolocation and time information to a GPS receiver located on Earth. The GPS receiver, however, should be within the line of sight of four or more GPS satellites to receive accurate signals. GPS signals loose signal strength in mountainous regions, densely populated areas and underground.
One of the benefits of GPS is that the user doesn’t need to send any data and the communication is unidirectional. Another advantage of GPS is that it does not require any telephone or internet connection for the data reception.
The GPS systems is developed, operated and maintained by the US government and free global access is provided to any user with a GPS receiver.
The major application areas of GPS technology include transportation, civil works, policing, personal navigation, outdoor sports, robotics and military applications.
History of GPS
The history of the GPS dates back to the 1960s when the US Navy carried out satellite navigation experiments to track down the nuclear submarines. Using the Doppler effect phenomena, the satellites were able to pinpoint the position of the submarine. These initial experiments eventually resulted into the creation of a robust and stable satellite navigation system in 1970s known as NAVSTAR (Navigation System with Timing and Ranging). This project was funded and developed by US Department of Defense (DoD). The present GPS system consisting of a fleet of 24 satellites became fully operational in 1993.
There are two types of navigation services which the GPS provides. These are known as SPS (Standard Positioning Service) and PPS (Precise Positioning Service). The SPS is available to all the users globally without any charges. The PPS is available to US armed forces, US federal agencies and selected allied forces.
Historical timeline of events
- 1972: First test flights of prototype GPS receivers were conducted by the US air force.
- 1978: First ever GPS satellite was launched into the orbit.
- 1983: US government announces to make the GPS technology available for civilian use.
- 1988: Satellite command and control center is established at Falcon Air Base, Colorado Springs.
- 1989: The first modern block-II satellite is launched into the orbit.
- 1993: GPS acquired IOC (Initial Operational Capability) with a fleet of 24 satellites. These satellites provided SPS (Standard Positioning Service) to the civilians.
- 2000: Selective availability of GPS is removed and non-degraded GPS signal is made available for public use.
Figure 1: Source: http://www.avionicswest.com/Articles/howGPSworks.html
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