Definition
NAVSTAR is the official name of the satellite constellation operated by the United States that provides the Global Positioning System (GPS) signals used for worldwide navigation. The system determines a receiver's position by measuring the precise time it takes for radio signals to travel from multiple satellites to the receiver, then using those timing measurements to calculate the distance (range) to each satellite.
Plain English
NAVSTAR is the formal name for the group of U.S. satellites that broadcast the signals your GPS receiver uses to figure out where you are. It works by timing how long signals take to reach you from several satellites and using those times to work out your position.
Context Anchor
Seen in instrument flying discussions of GPS components and how GPS receivers determine aircraft position.
Derivation
The name is built from the two physical quantities the system relies on: timing (how long the signal takes to arrive) and ranging (the distance that timing reveals). Knowing both, from several satellites at once, lets the receiver pinpoint a location.
Why Pilots Care
NAVSTAR satellites supply the signals that allow GPS receivers to give accurate position, altitude, and timing data for instrument navigation and approaches.
Intuition Check
NAVSTAR is not a separate cockpit instrument. It is the satellite system that GPS receivers use to calculate position.
Example Sentence 1
The GPS receiver in the panel uses signals from the NAVSTAR satellite constellation to display the aircraft's position.
Example Sentence 2
Before GPS became common, pilots trained with the understanding that NAVSTAR was the underlying satellite system supporting all satellite navigation.