1
general::
Phrase(s): lock in on someone or something [and] lock on(to) someone or something
Fig. to fix some kind of electronic sensing device on someone or something. • The enemy pilot was flying just ahead of us. Aiming the laser, we locked in on him and shot him down. • We locked onto the satellite and got an excellent TV picture.
McGrawhill's American Idioms And Phrasal Verbs