GPS Technology and Terminology

Radio Signals: Radio signals are electromagnetic waves in the approximate frequency range from 10 kilohertz (kHz) to 300 gigahertz (GHz). Television and radio stations, for example, broadcast their programs using this signals. Radio signals are sometimes (erroneously) referred to as microwaves. Microwaves are the high-frequency end (from 0.3 to 300 GHz) of the radio signals. GPS receivers: GPS receivers are apparatus that can receive the radio signals transmitted by the GPS satellites.

Range: Distance between a GPS satellite and a GPS receiver.

Mathematical Equations: Mathematics is the group of Sciences that uses numbers and symbols to study quantities, properties, measurements, forms, etc. Equations are used in Mathematics to equate two expressions.

Lock-on: A (jargon) expression used in satellite telecommunications to indicate that a receiver has established communications with a satellite. We lock-on the GPS satellites when we turn the receiver on and information about the satellites starts to appear on our display.

Network:The group of schools that participates in the ATLAS Project constitutes a network. The International GPS Service (http://igscb.jpl.nasa.gov/ is a fundamental network for GPS applications in Geophysics.

Sites:Each ATLAS school is a site.

Experiment: We are going to carry out 2 experiments as part of the ATLAS Project. The first is the Global Mapping Experiment and the second is the Community Mapping Experiment.

Elevation angle: The elevation angle of an object in the sky (in the illustration below the object is the sun) is the angle between the plane that forms the horizon and an imaginary line to the object. When the object is on the horizon (a setting or rising sun, for example), the elevation angle is nearly 0°. When the object is directly overhead, or at "zenith," the elevation angle is 90°.