Search Radar Equipment approach. Not many civvy fields do this now, more a military thing these days.
The deal is, ATC tell you which heading to fly, and what altitudes you should be at during the descent (crosschecked against distance to go) to remain on the "Glidepath".
Not as accurate as a PAR, hence classed as an airfield approach, rather than a runway approach, and can only be flown without visual reference to a minimum height above touchdown of about 450 - 500 ft.