Where GPS Technology Is Actually Used

The Global Positioning System (GPS) is a US-owned utility. It gives positioning, navigation and timing, says gps.gov. Billions of users rely on apps built on it. GPS sits in cell phones, wristwatches, bulldozers, shipping containers and ATMs.

What does GPS give besides location?

• gps.gov says GPS gives a fourth dimension, time, besides longitude, latitude and altitude.
• Each GPS satellite carries multiple atomic clocks.
• Receivers sync to those clocks. They get time within 100 billionths of a second, without owning an atomic clock.

Which systems depend on it?

• gps.gov says communications networks, banking systems, financial markets and power grids depend heavily on GPS.
• They use it for precise timing and time synchronisation.
• So phones, banks and grids all use GPS. Many of them use it for time, not for a map.

The Civil Services Preliminary Examination 2018 (General Studies Paper I, Q55) asked this question, word for word:

“In which of the following areas can GPS technology be used? 1. Mobile phone operations 2. Banking operations 3. Controlling the power grids”

The options were (a) “1 only”, (b) “2 and 3 only”, (c) “1 and 3 only”, and (d) “1, 2 and 3”. UPSC’s official key is (d).

Why is (d) right?

• Mobile phone operations: gps.gov says GPS sits in cell phones, and networks use it for timing.
• Banking operations: gps.gov says banking systems and financial markets depend heavily on GPS for timing.
• Power grids: gps.gov says power grids use GPS to synchronise their timing.
• All three statements are true. So the answer is “1, 2 and 3”.

What is the trap?

• A student who thinks GPS means maps only may pick “1 only”.
• The question tests the timing idea from card 1.

GPS has three parts, says gps.gov. They are the space segment, the control segment and the user segment.

What does each part do?

• Space segment: a nominal constellation of 24 operating satellites. They send one-way signals with their position and time.
• Control segment: ground stations track the satellites. They upload fresh data and watch the health of the constellation.
• User segment: receivers, like the one in your phone. They calculate three-dimensional position and time.

How is the distance found?

• NASA says each satellite transmits its position and time at regular intervals.
• The receiver works out its position by calculating how long the signals took to reach it.
• NOAA says the radio signals travel at 186,000 miles per second.
• NASA Space Place says a receiver that knows its distance from four or more satellites can figure out where you are.

Do the satellites track your phone?

• No. gps.gov calls the satellites beacons, like lighthouses.
• They broadcast one-way signals. The satellites do not track anything on the ground.

The United States commits to keep at least 24 operational satellites, 95% of the time, says gps.gov. In practice more fly. As of 3 July 2023, gps.gov counted 31 operational satellites. NASA says there are over 30.

What is the orbit?

• GPS satellites fly in medium Earth orbit, at about 20,200 km.
• Each satellite circles the Earth twice a day.
• The satellites sit in six equally spaced orbital planes. Each plane has four baseline slots.
• This 24-slot layout lets users view at least four satellites from virtually any point on the planet.

Who runs it, and what does it cost users?

• The US Space Force operates and maintains GPS. The National Coordination Office maintains GPS.gov.
• The control segment has a master control station, an alternate master station, 11 antennas and 16 monitoring sites.
• US law and policy require the civil GPS service to be free of direct user fees.

When did GPS become operational?

• NASA says the first NAVSTAR satellite launched in 1978. It says the 24-satellite system became fully operational in 1993.
• gps.gov says GPS was declared operational in 1995. The two sources differ, so learn both dates.

gps.gov lists a timing benefit: precise synchronisation of communications systems, power grids, financial networks and other critical infrastructure. That is why the UPSC question had three uses.

How do power grids use it?

• NIST says utilities rely on GPS for wide-area time synchronisation.
• It brings a standard reference atomic time signal into substations and field equipment.
• NIST says alternatives to satellite timing are few and costly.
• NIST also reports a test where a receiver locked to a single satellite. That led to the loss of two 500 kV transmission lines.

How do banks and markets use it?

• gps.gov says GPS time makes traceable time tags possible for financial transactions and billing.
• NIST says it delivers UTC(NIST) to NASDAQ and other financial markets. The uncertainty is about 10 billionths of a second.
• NIST time reaches users through common-view observations of GPS satellites.

How good is GPS timing?

• gps.gov says users can get time within 100 billionths of a second.
• The US commits to time transfer within 30 nanoseconds of UTC(USNO), 95% of the time.

gps.gov says precise positioning boosts productivity across the economy. Here are the main uses.

• Farming: precision farming combines GPS and GIS. It covers tractor guidance, soil sampling and yield mapping.
• Farming in low visibility: GPS lets farmers work in rain, dust, fog and darkness.
• Aviation: GPS gives three-dimensional position for all phases of flight. It also supports the Enhanced Ground Proximity Warning System.
• Rail: railways use GPS to track locomotives and rail cars in real time.
• Surveying: a single surveyor can now do in one day what once took a team weeks.
• Rescue and disasters: GPS helps search and rescue, and speeds emergency services and disaster relief.
• Hazards: GPS gives early warning of tsunamis and rapid monitoring after earthquakes. NASA says it also helps monitor volcanoes.
• Environment: GPS tracking helps follow fires and oil spills more efficiently.

gps.gov says GPS-enabled smartphones are typically accurate to within 4.9 m under open sky. Their accuracy worsens near buildings, bridges and trees.

Can GPS be more precise?

• gps.gov says better receivers with augmentation can reach a few centimetres in real time.
• Until May 2000, the US limited civil accuracy on purpose. President Clinton ended that feature, called Selective Availability.
• gps.gov says civil accuracy improved tenfold on that day.
• The US also warns that signal-in-space error is not user accuracy.

What can go wrong?

• gps.gov says GPS faces interference from natural and human-made sources.
• Solar flares can disrupt GPS equipment.
• NIST names jamming and spoofing as concerns for grid timing.
• The US strongly encourages users to keep backup positioning, navigation and timing.
• The US Space Force publishes daily heat maps of interference and spoofing.

Why does a backup matter?

• Many systems rely on GPS timing at once.
• Backups exist because GPS signals can be jammed or spoofed.
• That is why backups matter.

GPS is only one satellite navigation system. ISRO lists four global systems and two regional ones.

Which systems exist?

• Global: GPS (USA), GLONASS (Russia), Galileo (European Union) and BeiDou (China).
• Regional: NavIC (India) and QZSS (Japan).
• gps.gov uses the term GNSS for any such constellation.

What is NavIC?

• ISRO calls NavIC the independent stand-alone navigation system of India. It was earlier named IRNSS.
• It was designed with 7 satellites. It covers India and up to 1500 km beyond.
• NavIC offers a Standard Position Service for civilians and a Restricted Service for strategic users.
• PIB reported on 29 July 2026 that three satellites now give position, navigation and timing. They are IRNSS-1B, IRNSS-1I and NVS-01.
• Four satellites are needed for basic positioning. So NavIC cannot give standalone positioning now, but its timing service works.
• NVS-02 launched on 29 January 2025. Its orbit raising failed because the pyro valve of the oxidizer line did not receive its drive signal.
• PIB says NVS-03 is ready for launch.

What is GAGAN?

• PIB says GAGAN is India’s satellite-based augmentation system. ISRO and the Airports Authority of India built it.
• It improves GPS accuracy and gives integrity information for safer aircraft navigation.
• It has been fully operational since 2015. It uses payloads on GSAT-8, GSAT-10 and GSAT-15.
• In June 2026, PIB says, DGCA made India’s first satellite-based landing system approach on a commercial jet using GAGAN.
• NavIC is a separate system. GAGAN enhances GPS signals.