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Required Navigation Performance (RNP, RNP RNAV). AFFSA. Overview. RNP, RNP RNAV In CNS/ATM (GATM) Equipage The Big Four Regional Requirements RNP-10 and BRNAV Summary. RNP-X. X NM. Desired Position. Indicated Position. 95 % Position Error. Actual Position. What is RNP?.
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Overview • RNP, RNP RNAV In CNS/ATM (GATM) • Equipage • The Big Four • Regional Requirements • RNP-10 and BRNAV • Summary
RNP-X X NM Desired Position Indicated Position 95 % Position Error Actual Position What is RNP? RNP is a statement of navigation performance (accuracy, availability, continuity, and integrity) necessary for operation within a defined airspace. RNP airspace requires that an aircraft be within a specified distance of its cleared flight path 95% of the time. It is anticipated that RNP will eventually include vertical position (3D) and time (4D) accuracy as well. Where X =12.6 10 5 4 2 1 0.3
What is RNP RNAV? • RNP RNAV (as defined by RTCA DO-236A) • RNP RNAV merges the standard in the ICAO Manual with the containment requirements and the area navigation functional and performance standards in this MASPS. Additionally, the terms "VNAV" and "Time of Arrival Control (TOAC)" have been developed to address the vertical and time aspects of RNP operations • RNP RNAV AIRSPACE [RTCA SC- 1 8 1 /EUROCAE WG- 131] • Generic term referring to airspace, route(s), leg(s),. where minimum navigation performance requirements (RNP) including containment integrity and containment continuity have been established and aircraft must meet or exceed that performance to fly in that airspace • RNP-(x) RNAV [RTCA SC- 18 1 /EUROCAE WG- 131] • A designator used to indicate the minimum navigation system requirements needed to operate in an area, on a route or on a procedure (e.g., RNP-1 RNAV, RNP-4 RNAV)
RNP RNAV – Containment Assurance Containment Limit = 2 x RNP (8 NM) Containment Integrity 99.99% RNP-4 (4 NM) Accuracy 95% Defined Path RNP-4 (4 NM) Containment Limit = 2 x RNP (8 NM)
Equipage • RNP DOES NOT equate to equipage • RNP is based on the total system accuracy, integrity, availability, and continuity, required for operations in a define airspace • But the navigation subsystems and their integration into the system do determine the RNP capability of a given aircraft • Equipage used to meet RNP: • Flight Management System (FMS) • GPS • INS\IRS • EGI (Embedded GPS INS) • Other • Air Crew training is also needed • If the aircraft is properly equipped, but the crew is not trained then the aircraft should not fly in RNP RNAV airspace
The Big Four • Accuracy • Integrity • Continuity • Availability
The Big Four - Accuracy • Accuracy - RNP X: total system error must be less than X nautical miles 95% of the time • Total System Error (TSE) is comprised of: • Path Steering Error - (PSE) The distance from the estimated position to the defined path. (Centering Error) • Path Definition Error - (PDE) The difference between the defined path and the desired path at a specific point. (Use of Different coordinate systems) • Position Estimation Error - (PEE) The difference between true position and estimated position. ( Navigational Avionics errors) Desired Path PDE Defined Path TSE PSE Estimated Position PEE True Position
The Big Four - Integrity • Integrity -The ability of a system to provide timely warning to users when the system should not be used for navigation • The Probability of Hazardous Misleading Information (HMI) should be included in the Integrity analysis • HMI is an undetected or undetectable error that is displayed to the pilot
The Big Four - Continuity • Continuity - probability that navigation capability is supported for the duration of the intended operation • Assumes system was available at the beginning of the operation and determines the probability that it will continue to provide the needed functionality for the entire operation • Looks at the total system • Avionics and sensors • Ground and Space based Navaids • Probability is based on nonscheduled interruptions • Nonscheduled interruptions = a failure in the system
The Big Four - Availability • Availability - Percent of time all system elements are operational and available for use at user location • Is a function of: • The technical capabilities of the transmitter facilities • The physical characteristics of the environment • Reliability of applicable avionics
RNP RNAV (NAM & CAR) Proposed Implementation 2005 >> 2025 Current RNP-12.6 North Atlantic RNP-10 (North Pacific – Apr 98) (Central Pacific – Dec 98) (Central-East Pacific – Feb 00) (NOPAC/Anchorage/Japan – Oct 00) (S.China Sea/Australia – Nov 01) Future RNP-4 2005 RNP-1 PRNAV (Europe) 2005-10 Future RNP-10 Eur/SAM routes 01 Regional Requirements BRNAV (Europe) 23 Apr 98 Future RNP-5/10 Mid East
RNP-10 • RNP-10 Fundamentals • RNP-10 is oceanic airspace that requires + 10 NM accuracy 95% of the time • The probability of loss of long range navigation capability shall be less than 10-5 per flight hour • Dual long-range sensor equipage is accepted as meeting the 10-5 availability requirement • Extensive analysis needed for less than dual equipage • Certification dependent on quality of analysis • Acceptable Long Range Sensors Include • GPS • INS (with time limits) • 6.2 hrs in “nav” mode unless sufficient data provided to support extending the limit
BRNAV • BRNAV Fundamentals • BRNAV is European airspace that requires + 5 NM accuracy 95% of the time. • BRNAV was designed to allow implementation of reduced lateral spacing using existing technology • For ground based navaids, integrity and continuity of service are covered by manufacturing standards for the navaids and the airborne avionics • Aircrew is required to determine availability of ground based navaids/receivers needed to support navigation in BRNAV airspace • For space based navigation systems (GPS) the avionics system design must include the functionality needed to assess and assure accuracy, integrity, availability, and continuity across the entire route of flight • BRNAV does not necessarily qualify you for RNP-10
BRNAV (cont) • Functionality/equipment specified for BRNAV consists of: • RNAV Function supported by one or more of the following sensors: • DME/DME (Distance Measuring Equipment) • VOR/DME (VHF Omni Range) • INS (Inertia Navigation System) • 2 hr time limit without automatic radio updates or additional data showing enhanced accuracy • GPS (Must have the following) • RAIM (or sensor equivalent integrity) • FDE • Pseudo-range step detection • Health word checking • VOR, DME, or ADF installed and operative to use as an alternate navigation source should GPS RNAV fail • LORAN C (with limitations)
Summary • RNP and RNP RNAV are found in the Navigation part of CNS/ATM • RNP is a statement of navigation performance • Accuracy, Integrity, Continuity and Availability • RNP RNAV adds Containment Integrity • RNP Attainable • Depends on aircraft equipage and NavAid coverage • RNP RNAV Regional Requirements • RNP-10 and BRNAV
RNP and RNP RNAV Definitions • RNP (as defined by ICAO Doc. 9650): • A statement of the navigation performance (accuracy, integrity, continuity and availability) necessary for operations within a defined airspace • The ICAO Manual also states: While the navigation performance accuracy is the basis for defining an RNP type, the other navigation performance parameters of availability, coverage, reliability, fix rate, fix dimension, capacity, time to recover and integrity determine the utilization and limitations of the individual navigation systems, both ground and airborne, and characterize the means by which a user derives navigation information within an RNP type airspace • RNP RNAV (as defined by RTCA DO-236A) • RNP RNAV merges the standard in the ICAO Manual with the containment requirements and the area navigation functional and performance standards in this MASPS. Additionally, the terms "VNAV" and "Time of Arrival Control (TOAC)" have been developed to address the vertical and time aspects of RNP operations
RNP RNAV Definitions (cont) • RNP RNAV AIRSPACE [RTCA SC- 1 8 1 /EUROCAE WG- 131] • Generic term referring to airspace, route(s), leg(s),. where minimum navigation performance requirements (RNP) including containment integrity and containment continuity have been established and aircraft must meet or exceed that performance to fly in that airspace • RNP-(x) RNAV [RTCA SC- 18 1 /EUROCAE WG- 131] • A designator used to indicate the minimum navigation system requirements needed to operate in an area, on a route or on a procedure (e.g., RNP-1 RNAV, RNP-4 RNAV)
HMI Examples • If there are two displays of heading from different sources which display different values that are both visible to the pilot, the display of the erroneous value is not HMI since the pilot can detect the difference • If there are two displays of heading that both display the same erroneous data to the pilot at the same time and there is no other display of heading in the cockpit at that time, the displayed heading is HMI if using it leads to a Hazardous situation