# Trajectories

A transmitter can move along a defined trajectory (optional), without the need to connect it to a moving object.

If an antenna will be tied to a moving object in the time-variant geometry database, then no trajectory will be needed to describe the movement of that antenna. If a transmitting antenna will be moving without being tied to such an object, then a trajectory will need to be defined. Define a trajectory using the icon in the project toolbar.

Left-click once for each vertex in (X,Y); right-click after specifying the last vertex. Then either define the next trajectory or toggle the icon off to leave the trajectory-definition mode. Z coordinates, speed, yaw, pitch and roll can be defined later when an antenna is tied to a trajectory.

It is also possible to define a trajectory by editing the .net project file with a text editor. The format is shown in the following lines:
** Dynamic antenna [time,x,y,z,az,tilt,roll,velocity,direction] per time step *
ANTENNA 1 POSITION_TIME_VARIANT 0.000, 508276.420, 5393273.950, 30.000, 0.00, 0.00, 0.00, 10.000, 1.000, 0.000, 0.000
ANTENNA 1 POSITION_TIME_VARIANT 1.000, 508376.420, 5393273.950, 30.000, 45.00, 0.00, 0.00, 10.000, 1.000, 0.000, 0.000
ANTENNA 1 POSITION_TIME_VARIANT 2.000, 508476.420, 5393273.950, 30.000, 90.00, 0.00, 0.00, 10.000, 1.000, 0.000, 0.000