What is the basic position-finding method used by a Global Navigation Satellite System (GNSS) receiver, as described in the material?

### Why this is right The material describes GNSS position determination as trilateration: the receiver measures distances to satellites and uses those distances to determine its position. Each measured distance constrains the possible locations of the aircraft. ### The concept A satellite signal allows the receiver to estimate the distance between itself and that satellite. Combining measurements from multiple satellites narrows the possible position. The receiver then expresses its position as geographic coordinates and can show it on a map. GNSS differs from inertial navigation, which estimates movement from onboard sensors, and from conventional radio navigation, which depends on ground-based aids. ### The other options - **B. Pilotage using visible landmarks only**: this uses recognizable ground features, not satellite-distance measurements. - **C. Timing aircraft turns from a known heading**: this is not the satellite-distance method described for GNSS. - **D. Following a ground radio route without measuring position**: this describes neither GNSS trilateration nor its position calculation. ### Terms - **Global Navigation Satellite System (GNSS)**: a satellite-based system used to determine position and support navigation. - **Trilateration**: determining position from measured distances to known points. - **Geographic coordinates**: latitude and longitude values used to specify a position on Earth. ### Remember GNSS locates the aircraft by combining measured distances to satellites.