hi there, from ATC Side, (apart from having navaids such as ILS Consisting of Localiser & G/S & if any DME), normally from ATC side, we Vector a/c on a closing Heading of 30' degrees from rwy centreline, if its rwy 36, 360' degrees + or - 30 degrees, to capture Localiser, in some cases the 30' degrees capture can go as high as 45' degrees, but ll this depends on Local ATC Instructions. Now to Capture the G/S, it is normally a 3' degree glide, so 1nm for every 300ft. So to conclude, if at 1500ft amsl, u need 5nm + 2nm (=7nm) extra for the a/c to continue on the ILS.
hope this is enough for you to understand.
Cheers
