GPS History
This U.S. government department originally developed GPS for military use
What is the Department of Defense?
GPS satellites transmit data using this type of electromagnetic wave.
What are Radio Waves?
What other data besides location does GPS provide?
What is Time?
There are at least this many active satellites in the full GPS constellation.
What is 24?
GPS specifically uses this method, which calculates position based on distance (ranges) rather than angles.
What is Trilateration?
This was the first artificial satellite launched into space (1957), which helped scientists realize they could track objects using radio signals.
What is Sputnik 1?
GPS signals travel at this specific speed, allowing receivers to calculate distance based on timing.
What is the speed of light?
This is the term for a system that uses satellites from multiple countries (like GPS, GLONASS, and Galileo).
What is GNSS - Global Navigation Satellite System?
GPS satellites orbit the Earth at approximately this altitude in miles (within 1,000 miles).
What is 12,500 miles?
This method, often used in surveying and old-school mapmaking, relies on measuring angles.
What is Triangulation?
The year the first GPS satellite launched
When is 1978?
This is the term for when a GPS signal bounces off a building or canyon wall before hitting the receiver, causing errors.
What is multipath interference?
GPS can calculate this by measuring the change in your position over a specific amount of time.
What is velocity or speed?
Each GPS satellite orbits the Earth exactly this many times per day.
What is two?
This is the minimum number of satellites required to determine a 2D position (latitude and longitude).
What is three?
This is the formal name for the American GPS system.
What is NAVSTAR?
To calculate your position, the receiver measures the time difference between when a signal was sent and when it was received, a value known as this.
What is Signal Travel Time?
This word refers to the height of an object above sea level, which 3D GPS can measure.
What is Altitude?
GPS satellites carry this many atomic clocks on board to ensure perfect timing.
What is four?
This is the minimum number of satellites required to determine a 3D position (latitude, longitude, and altitude).
What is four?
Until the year 2000, the military intentionally degraded civilian signals for security, a practice known by this term.
What is Selective Availability?
These are the primary frequencies used by GPS satellites to send data.
What are L-Band frequencies?
This correction system uses ground-based stations to improve GPS accuracy to within a few centimeters.
What is DGPS - Differential GPS?
This is the approximate speed, in miles per hour, that a GPS satellite travels through space.
What is 8,700 mph?
If you have only one satellite signal, your possible location is anywhere on the surface of this 3D shape.
What is a sphere?