Global Positioning System


GPS: The Basics

What is GPS?

The Global Positioning System is comprised of satellites orbiting the Earth. The system provides geolocation and time information to GPS receivers on or near the surface. It is owned by the United States government and operated by the United States government.

History of GPS

The United States Navy successfully tested the first satellite navigation system in 1960, and in 1967 developed a satellite able to keep accurate time. In 1963, the United States Air Force conducted a study on the use of three dimensional ground based radio navigation. This study produced the concept of GPS. In 1964, the United States Army put its first geodetic surveying satellite into orbit. These technologies were combined into what ultimately became the Global Positioning System. The system was initially limited to military use. After a Korean Air Lines commercial flight was shot down when it wandered into the USSR's prohibited airspace, President Ronald Reagan issued a directive to make GPS freely available for civilian use. The signal remained intentionally degraded to everyone except the US military until May 2000 when President Bill Clinton issued a policy directive to allow the same precision to all users.

Basic Principles of Operation

GPS operates by comparing radio signals received from satellites orbiting the Earth. There are a minimum of 24 satellites providing worldwide coverage, in any weather, 24 hours a day. Each satellite completes two precise orbits of the Earth every day, and transmits a unique signal. When a GPS device receives a signal, it is able to determine the position of the satellite based on the unique signal of that satellite. The receiver determines the distance from the satellite based on the amount of time required for the signal to reach the receiver. Once the receiver acquires signals from multiple satellites, and calculates the distances of those satellites, it is able to determine its position. Signals from a minimum of three satellites are required to determine two dimensional position as well as track movement. Three dimensional (latitude, longitude, and altitude) position can be provided with signals from four or more satellites. A GPS receiver will typically track eight or more satellites depending on the time of day and its location on or above the Earth. The GPS device is able to calculate information in addition to location and movement. Devices are able to provide speed, bearing, track, distance traveled, distance remaining to the destination, and other information relating to time, speed, distance, and location. GPS receivers are capable of horizontal position accuracy of within 3.5 meters.

Uses of GPS

There are many applications of GPS in addition to the needs of the military and navigational uses of the civilian. GPS technology may be found in commercial applications to improve productivity. It is used in farming, mining, surveying, package delivery, and logistical supply chain management, to name a few. Businesses and industries which require precise time synchronization rely on GPS. Banking systems, financial markets, power grids, and communications networks are heavily dependent on GPS time. GPS assists with saving lives. It is used to help prevent transportation accidents on rail and is a vital part of the Next Generation Air Transportation System which will replace the current air traffic control system. There are also scientific applications for GPS. Weather forecasting, earthquake monitoring, and environmental protection are a few examples. GPS is used in a wide range of recreational activities, and new uses for the technology are created often.

GPS Hardware

Consumer GPS hardware, or Personal Navigation Devices (PND), continue to be a popular way for many people to take advantage of the Global Positioning System. Two of the leading GPS PND Manufacturers are:

  • Garmin
  • TomTom


Garmin is an American multinational technology company founded in 1989 by Gary Burrell and Min Kao. They specialize in GPS technology development for use automotive, aviation, marine, outdoor, and sport activities. They employ over 11,500 people in over 60 offices around the world. Garmin reported revenue and earnings growth at the end of the first quarter of 2017. Total revenue grew 2% over the prior year, to $639 million, and operating income grew 12%. Marine, outdoor, aviation, and fitness grew 12% collectively over the prior year quarter and contributed 75% of total revenue. Gross margin improved 3.8% to 58.3%, compared to the prior year quarter. The auto segment revenue declined 19% in the first quarter of 2017. This is primarily due to the continuing PND market contraction. Gross margin for this segment remained constant at 44%.


TomTom is a Dutch company founded in 1991. They produce traffic, navigation, and mapping products. The company has over 4,600 employees in over 50 offices around the world. At the end of the first quarter of 2017, TomTom reported a 2% loss in revenue at 213 million Euros. Gross margin improved to 62% from 57% the previous year. Consumer revenue decreased 16% on the year to 98 million Euros. This is mainly driven by the continued decline in the PND market.

GPS Software Applications for Smart Phones

Another option for consumers to utilize the Global Positioning System is through their smart phones. The use of GPS software applications continues to grow. The most widely used application on Android and Apple platforms is Google Maps. It is free, contains accurate traffic data, location information, and many more features. Other applications are available. Features vary between them, not all of them are free. A few of the different applications are:


  • BackCountry Navigator
  • HERE WeGo
  • MapFactor
  • MapQuest GPS Navigation and Maps
  • Scout GPS Navigation
  • Waze GPS, Maps and Traffic


  • Maps.ME
  • Waze
  • CityMaps2Go
  • Scout GPS Navigation
  • Sygic GPS
  • Apple Maps

Comparison of Personal Navigation Devices and Software Applications

PNDs and smart phones with GPS software are both excellent options to take advantage of everything the Global Positioning System has to offer. They each have their advantages as well as drawbacks. Some of the most notable pros and cons of each follow:


Dedicated PNDs have many advantages. They are designed for the purpose of navigation. The screens are generally larger than those of smart phones, and the displays are optimized for viewing at arms-length and usability while driving. They typically include a windshield or dash mount and a charger. PNDs store their map databases internally, and require updates to remain current. Maps may become outdated; however, they will continue to work in remote areas. Dedicated PNDs may or may not connect to the internet, depending on the model. Some require a subscription, and others are able to connect to a smartphone using Bluetooth to access the internet.

Software Application

GPS software applications installed on a smart phone have advantages as well. There are many to choose from, allowing the user to find the one that is right for them. Maps and points of interest are updated often, ensuring they are the latest version, and generally come from the same map databases used by PNDs. A drawback is the possibility of losing phone coverage in remote areas, causing the loss of the maps. The use of the phone network is also an advantage. It allows for real time traffic detection and avoidance, gas prices, and similar information available through the use of a web browser. One significant down side to using a smart phone application is that it is not a dedicated navigation device. If the user needs to use the phone, the navigation will most likely be suspended.


The Global Positioning System has revolutionized the way people live, work, and play. It is a part of modern everyday life and some might say is no longer a luxury, but a necessity. Manufactures of PNDs are seeing a decrease in demand of the devices. This is due in part to the increasing popularity of software applications for smart phones. They are adapting to the changing consumer market by offering new products and services and continue to have a promising future.


File: Comparison satellite navigation orbits.svg. (n.d.). Retrieved from Wikimedia Commons: Gangwar, A. (2016). 10 Best GPS and Navigation Apps for iPhone. Retrieved from Garmin | What is GPS? (n.d.). Retrieved from Garmin Revenue up 7% to $642M in Q1 2016. (2016). Retrieved from Global Positioning System-Wikipedia. (n.d.). Retrieved from Applications. (2014, November 25). Retrieved from Hindy, J. (2017, April). 10 best GPS app and navigation app options for Android. Retrieved from for-android-357870/ Pivat, L. (2016, April 19). Tom Tom Revenue up 6% in 1Q 2016. Retrieved from Tom-Revenue-up-6-in-1Q-2016_a5895.html?print=1 Top GPS manufacturers. (2009, October 26). Retrieved from ShowUhow Blog: Zahradnik, F. (n.d.). GPS: Smartphone vs. dedicated Car (PND). retrieved from