Aviation
Tracking field notes
Read the signals, understand the gaps, and follow the original technical sources.
READING THE PICTURE
A track is
a set of clues.
Start with the source of the position, then check when it was last received. A smooth line on a screen can conceal gaps in the observations.
Read how the network works ↗ADS-B / a broadcast position
The aircraft transmits its own navigation-derived position. That is different from a radar measuring where an aircraft is. FAA: ADS-B basics ↗
MLAT / a position inferred from timing
Multiple synchronized receivers compare the arrival times of a transponder signal to estimate its origin. It depends on enough receivers hearing the aircraft with useful geometry. Airplanes.live: tracking methods ↗
1090 MHz and 978 MHz / two U.S. links
1090ES and 978 MHz UAT are the two ADS-B links used in the United States. The frequency being received affects which messages a setup can hear. FAA: equipment and frequencies ↗
A gap / a reason to check coverage
A missing track can reflect receiver range, terrain, altitude, equipment, or network coverage. An empty patch of map is not proof of an empty patch of sky. Airplanes.live: coverage limits ↗