Please try to be helpful and informative
the question by itself was really answered in the first respond.
ok, i try to explain a bit more this .first- a straight in is of course an instrument approach.
in general : when cleared for an approach
with previous radar vectors you should be on extended centerline or interception course to it and at an altitude where the approach is published or at least on the way to this altitude. the importnat thing is : after being cleared for an approach NO more radar vectoring is given, atc expect that you by yourself intercept finalcourse and follow it. reporting established is always exepted- because thats the moment he can give you a freq change to tower.
a straight in here is when
you are already more or less at extended centerline and no vectoring is needed. so like written above : position yourself and report when established. the "report established" is not always called by atc, but of course they expect a call from you like e.g tower expects a call from you when you are ready for departure being on taxi- even when you are not advised "report ready for departure"
whithout radar coverage the normal approach would be to fly the published standard procedure. when cleared for a straight in you are cleared to position yourself by own navigation on final without flying the full published procedure.
that is a straight in approach-not more not less. its everyday business.
hope this helped
cheers