How to alignment? (Radar target & FLIR)

Hi !

Some time ago, I read a alignment at ship's surveillance,tracking
radar,EOTS and Gun with TV camera and slave function, I understand
well, because tracking radar have a elevation information.
However in the air, helicopter(Lynx) with Seaspary surveillance radar,
Seaspray also have a slave function but can't understand.
How to align a FLIR with the target detected by the radar without
elevation info? and How to compensate angles whenever copter move fast?


Please solve my curiosity! expecting yours guides!