• SJU reference # PJ.14-03-04 /Release 2019
  • Stakeholders
  • Benefits Operational efficiency
  • Status Available for industrialisation/deployment

PBN procedures rely on the availability of GNSS constellations, such as Galileo, around the clock. The candidate solution alternative position, navigation and timing (A-PNT) pursues fallback capabilities in case of GNSS unavailability for the short, medium and long term.

The short-term alternative A-PNT only considers requirements related to the navigation domain due to the brief timeframe and unlikelihood of changes to airborne or ground systems. It aims to support RNP-1 operations in those terminal manoeuvring areas where RNP-1 has been implemented with limited or no impact on the continuity of essential operations, as mandated by an European Commission Implementing Rule. The backup is provided by current terrestrial navigational aids, mainly distance measuring equipment (DME), enhanced or complemented by VHF omni range (VOR), or VOR/DME minimum operational network (MON).

The medium-term alternative A-PNT is a standalone aircraft upgrade that supports RNP-based operations in the terminal manoeuvring area. It operates with Standard Instrument Arrival (STARs) and standard instrument departure (SIDs) procedures.

To meet long-term outages, SESAR is researching a number of existing and new technologies capable of supporting more demanding operational positioning and navigation requirements. These include multi-DME coupled with receiver autonomous integrity monitoring (RAIM) algorithm, enhanced DME, the future LDACS for navigation, enhanced low frequency radio navigation (eLORAN), and Mode N. The long-term A-PNT airborne solution is expected to support RNP-1 arrivals and departures, RNP-defined routes, and RNP approach procedures with lateral and vertical guidance supposing appropriate ground infrastructure.

SJU references: #PJ.14-03-04/Wave 2


  • Enhanced safety, security resiliency
  • Interoperability
  • Increased cost efficiency