The rules that use the vocabulary item "on" are:

<zoom_operation>

zoom closer in on <zoomable_thing>

zoom in closer on <zoomable_thing>

zoom in on <zoomable_thing>

<proceed_verb>

go on

<center_operation>

center in on <zoomable_thing>

center on <zoomable_thing>

<display_verb>

turn on

<location_mod>

on <point_loc>

<guide_command>

guide on <unit-sing>

<h_hour>

time on target

<take_station_command>

take station on <guide_ship> <ship_bearing> <ordered_distance>