at 50 meters ahead
can I say that " pleas turn right at 50 meters ahead " , I mean at the place such as a intersection that is 50 meters ahead of there . besides , can I say that " the station is about 100 meters ahead " , omitting the “ of XXX ” .
Please turn right in 50 metres,
or
Please turn right 50 metres ahead.
or
Please turn right after 50 metres.
"The station is about 100 metres ahead" is perfect.