Read 2%20-%20GBAS%20A%20Users%20Perspective%20rev%2016%20Apr%2007%20(CNS_ATM%20Conf).pdf text version

GBAS...A User's Perspective

Colonel Chris Ceplecha Commander Air Force Flight Standards Agency


· · · · · · · GBAS Technology Primer Boeing Visit/Flight Demo A Pilot's Perspective of GBAS Military Applications Other Potential Applications The Military GBAS Summary

GBAS Technology Primer

· Ground Based Augmentation System

­ Enhances GPS performance to provide state-of-the-art Precision Approach and Landing capabilities ­ LAAS is FAA term

· GBAS Components:

­ GPS satellites ­ Ground Station

· Monitors GPS signals and corrects to ensure accuracy & integrity · Entire approach procedure & GPS accuracy/integrity data transmitted to airborne receiver via a datalink

­ Airborne Receiver

· · · · Data from ground station is decoded by datalink receiver GPS receiver applies accuracy & integrity data Displayed to pilot identical to ILS, labeled "GLS" Can be hand flown or via autopilot

Boeing Flight Demo

· February 12, 2007 · Operated from Boeing Field · Airborne System

­ TUIfly B737-800 (737NG)

· Just arrived from factory, awaiting customer acceptance · GBAS precision approach capability, fully integrated with glass cockpit and autoflight

· Ground Stations

­ Honeywell SLS-3000

· Moses Lake · SEA-TAC

Honeywell GBAS Ground Station

Full IFR certification for Honeywell GBAS ground stations expected 2008, starting with systems at Memphis & Sydney Australia

Approaches using GBAS at Moses Lake

· Ephrata (KEPH)

­ 10 nm from Moses Lake GBAS ­ Two approaches ­ Continuous GBAS signal reception down to well below Cat I minima


GBAS system at Moses Lake

­ GBAS signal received at altitude beyond 90 nm range


Moses Lake (KMWH)

­ Nine approaches ­ Multiple runway ends, including tactical runway ­ Varying glidepath angles ­ Normal and displaced thresholds ­ Mix of coupled and hand-flown approaches

Approaches using GBAS at SEA-TAC

· Boeing Field (KBFI)

­ 6 nm from SEA-TAC GBAS ­ Approach to displaced threshold ­ "Short field" landing

· ·

GBAS system at SEA-TAC Tacoma Narrows (KTIW)

­ 18 nm from SEA-TAC GBAS ­ One hand-flown approach


McChord AFB (KTCM)

­ 23 nm from SEA-TAC GBAS ­ Two approaches ­ Continuous GBAS signal reception down to below 90 ft AGL

A Pilot's Perspective on GBAS

· Guidance quality

­ Relative to ILS, GBAS provides more stable guidance

· Pilot Workload

­ Same as current ILS, loading and flying ­ Far less pilot workload vs WAAS/SBAS receivers ­ Excellent solution for single pilot IFR

· Military single seat fighter ops · Very Light Jets · General Aviation

· Range of Military Utility was evident · Demo experience showed technology to be mature

Potential Military Applications

· · · · · · · · · Rapid deployable Fraction of cost of ILS, no complex antennas Multiple runway ops Adjacent airfield ops Separation of Dissimilar Traffic Flows Curved and Segmented Approaches Tactical Operations, approach of the day Reduced flight inspection time/cost Future growth

­ Precision Air Drop ­ Precision Air to Air Refueling

· Manned Aircraft · Unmanned Aircraft

Multiple Runway Operations

· Single GBAS ground station

­ ­ ­ ­ Cover multiple runway ends from single location Cover multiple airports with 25 NM No need to reposition ground equipment Landing traffic patterns can be kept separate

· Approach parameters are sent over the GBAS datalink

­ No need for aircraft to store approach data, (e.g. FMS) ­ Ground Station can broadcast multiple sets of approach parameters (e.g. variable glidepaths, guided departures)

· Supports deconfliction of rotary-wing traffic from fixed wing traffic

Adjacent Airfield Operations

· Single GBAS ground station will cover adjacent airfields, subject only to terrain and line-of-sight limitations

­ GBAS at Eglin could cover Duke Field and Hurlburt ­ GBAS at Baghdad Intl could cover surrounding area

· Same ground station could cover numerous helicopter landing sites around primary airfield

­ Medical and combat operations ­ Safe vertical descent in obstacle rich environments

Curved and Segmented Approaches

· GBAS approaches do not need to be a straight line

­ Approach parameters from ground station can define Terminal Area Path (TAP) segments

· · · · Initial Fix Track-to-Fix Radius-to-Fix Dynamic Downwind


5.0 NM


3.0 NM

14 3. M N




6.5 NM

­ TAP segments provide continuous guidance to the Final Approach Segment ­ Also supports guided Missed Approach ­ Environmental Benefits

· Reduced emissions (Greenhouse mandate) · Reduced noise impact


2.0 2N M


Holly Springs 112.4 HLI Chan 71X

2° M 30 . 7 N




Tactical Operations

· Tactical/Unimproved Runways

­ ­ ­ ­ ­ ­ ­ ­ GBAS ground station can be at a location remote from the runway Dimensions/configuration of runways and taxiways are not a factor No "sensitive areas" to be kept clear while aircraft are on approach No expensive, difficult to construct antenna Approach parameters can be rapidly generated and validated Supports temporary runways and/or displaced threshold Supports "approach of the day" concept Supports tactical missions (threat avoidance, deception)

· Configurable Approaches

· Spare Datalink Bandwidth

­ Can be used to pass other tactical information (e.g. NOTAMS, Wx, Airfield status, etc)

Potential Additional Applications

· Remote maintenance, remote support potential

­ Upload new approach from remote location ­ Flight inspection support from remote location

· Unmanned aircraft landing · Precision Air-to-Air Refueling

­ Manned/unmanned

· Night/Adverse wx airfield surface movement · Precision Station Keeping · Smart Weapon High Precision Updates

The Military GBAS - JPALS


­ Joint Precision Approach and Landing System

· Civil Interoperable Mode

­ Based on Civil GBAS (LAAS)

· Military Mode

­ ­ ­ ­ Shipboard, Fixed Base and Tactical Environments Anti-Jam GPS Systems UHF Encrypted Data Link Small Footprint, Much Less than 1 C-130 for transport

· Technology is Mature, 12 Years of DoD Investment


· Commercial aviation is embracing GBAS technology today through ground systems and avionics · Provides tremendous capabilities over today's civil legacy systems · Significant flexibility to the warfighter over existing systems

­ Secure network supportability ­ Load new approach from distant location



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