What Is MLAT? Definition & Meaning in Aviation
MLAT (multilateration) is a way of finding an aircraft’s position by comparing the exact time its transponder signal reaches several ground receivers.
In plain language
Some older aircraft do not broadcast their position by ADS-B but do reply to radar with transponder signals. If at least four receivers hear the same signal, the differences in arrival time reveal where it came from.
Example
MLAT can show older aircraft in areas where several volunteer receivers overlap, for example near a busy airport with many receivers.
Why it matters
MLAT lets trackers show older aircraft and fills gaps where ADS-B is missing. Understanding it explains why some aircraft appear only in areas with many receivers, and why their positions can look less smooth.