Another question from me - I am learning fast, honest - when tracking an aircraft the little aeroplane label is there. Sometimes I see a circle with a cross in it. What is this?
Beta V 3.0
Jeremy
Circle/cross symbol means that Radarbox doesn't know the heading of the aircraft. Either it's not being transmitted, or the aircraft has timed-out in Radarbox.
Thanks.
Sometimes it tracks across the screen with the circle/cross so it must know the direction.
Thanks for your help.
J.
Even though it can track the change in position, that doesn't mean the aircraft is transmitting it's heading. Depending on wind direction, heading and direction of travel can be different.
Quote from: Jeremy on July 11, 2009, 12:02:56 PMSometimes it tracks across the screen with the circle/cross so it must know the direction.
The majority of ADS-B-equipped aircraft transmit "velocity over ground", from which both groundspeed and track can be calculated.
However some (for example UAL B772s) transmit airspeed and heading instead - I assume it's these that don't show up with the aircraft symbol.