====== GPS Approaches ======


===== GPS CDI Scale =====


Enroute Mode - 5NM

Terminal Mode - 1NM

Approach Mode - 0.3NM

<note tip>AIM 5-4-5: Most RNAV approaches include a VDP. The VDP is only applicable to aircraft using LP or LNAV minima, not LPV or LNAV/VNAV minimums.</note>

===== GBAS - Ground Based Augmentation System =====

Ground-Based Augmentation Systems (GBAS) require no additional action on the part of the pilot other than those actions associated with instrument approach procedures. GBAS consists of ground-based equipment in the vicinity of airports that provides additional accuracy and integrity for aircraft GPS systems. This added accuracy allows for more precise GPS approaches.

GBAS only supports approaches down to Category I approach minima. The FAA intends to bolster GBAS capabilities across the country and provide Category III approach capabilities.

====== GPS Approach Minimums ======


===== LPV - Localizer Performance with Vertical Guidance =====


Uses WAAS to act like an ILS. Sensitivities change as the aircraft gets lower. Aircraft must be certified for LPV approaches (statement in flight manual or supplement).


===== LNAV/VNAV =====


Usually provided by Baro-VNAV. Internally generated glidepath.

===== LNAV =====


Lateral only. No WAAS required.