Feed MLAT

MLAT (multilateration) finds aircraft that do not broadcast a position. Radio travels at a fixed speed, so when an aircraft transmits, stations at different distances hear it at slightly different instants, a difference of millionths of a second. If three or more stations record exactly when they heard the same message, the differences place the aircraft at one point in the sky (four stations also give altitude). The same trick, run the other way, is how GPS works.

What your station does: your receiver time-stamps every message it hears with its own clock, and sends those timestamps (not your location data) to the network's MLAT server. The server compares all stations' clocks, using aircraft that do broadcast their position as reference beacons, and calculates positions for the others. The results come back to you and appear on the map labelled MLAT.

What it needs:

• An exact position. Your latitude, longitude and the antenna's altitude above sea level must be right to within a few metres, because the whole calculation assumes it. A wrong location does not just fail; it makes your station's timing look bad to the others, and the server will pause it.
• Neighbours. At least three stations must hear the same aircraft, so MLAT is best where stations overlap. Your station may sit at "connected, waiting for peers" until the next station near you joins; that is normal.
• A steady receiver. A computer that is not overloaded, a USB radio that is not dropping samples, and a network without long delays or gaps.
• The same UUID in your MLAT line as in your feed, and MLAT_USER set to your Station ID, so the portal can match your MLAT connection to your station and show you its health.

Privacy: the MLAT server needs your true coordinates. They stay on the server. The portal never publishes them: the public sees only the approximate location you chose when you claimed your station. See the MLAT network page for how stations are linked and how well.

Trade-offs: MLAT positions are less exact than ADS-B and arrive a moment later, and only aircraft heard by enough stations get one. It is an extra, not a replacement.