There are three categories of instrument approach procedures: precision approach (PA), approach with vertical guidance (APV), and non-precision approach (NPA). A precision approach uses a navigation system that provides course and glidepath guidance. Examples include precision approach radar (PAR), instrument landing system (ILS), and GBAS landing system (GLS). An approach with vertical guidance also uses a navigation system for course and glidepath deviation, just not to the same standards as a PA. Examples include baro-VNAV, localizer type directional aid (LDA) with glidepath, LNAV/VNAV and LPV. A non-precision approach uses a navigation system for course deviation but does not provide glidepath information. These approaches include VOR, NDB and LNAV. PAs and APVs are flown to a decision height/altitude (DH/DA), while non-precision approaches are flown to a minimum descent altitude (MDA).