Satellite Navigation for Aviation

Satellite Navigation for Aviation : 

Satellite Navigation for Aviation Federal Aviation Administration By David Peterson Technology & Benefits

General Overview : 

General Overview How does it work to be sure it is safe? What can you do with it? What do you want to do? 2

Technology : 

4 Technology Satellite Navigation Global Positioning System (GPS) Wide Area Augmentation System (WAAS or SBAS) Ground Based Augmentation System (GBAS or LAAS) Receiver Autonomous Integrity Monitoring (RAIM) Connects to: Automatic Dependent Surveillance (ADS-B) Required Navigation Performance (RNP) Next Generation (NextGen)

Contrast Between Military Mission and Civil Air Navigation : 

5 Contrast Between Military Mission and Civil Air Navigation GPS is operated and maintained by the U.S. DoD “The mission of this program is to: drop 5 bombs in the same hole, and build a cheap set that navigates and don’t you forget it!” Civil requirement One accident due to navigation failure every billion landings Similar to single engine versus multiple engine aircraft Spending planned for GPS over the next 5 years: $5.8B Civil aviation wishes to leverage GPS, but must augment to improve safety even for vertical guidance, hedge against weaknesses in the number of satellites, and provide a sovereign mechanism to use GPS

Leverage GPS Investment to Reduce Existing Nav Infrastructure : 

6 Leverage GPS Investment to Reduce Existing Nav Infrastructure VORTACs (green) and TACANs (red)

Operation of One GPS SatelliteFour Essential Ingredients : 

7 Operation of One GPS SatelliteFour Essential Ingredients 1) Start time Transmission time 3) Arrival time Reception time 2) Ephemeris Satellite location 4) Distance traveled Travel time = Arrival time – Start time Range = Speed of light × Travel time

Operation of One GPS SatelliteEstablishes a Sphere of Possible Locations : 

8 Operation of One GPS SatelliteEstablishes a Sphere of Possible Locations

Operation of Three GPS SatellitesEstimate Latitude, Longitude and Altitude : 

9 Operation of Three GPS SatellitesEstimate Latitude, Longitude and Altitude

Four GPS Satellites are Needed forLatitude, Longitude, Altitude & Aircraft Clock : 

10 Four GPS Satellites are Needed forLatitude, Longitude, Altitude & Aircraft Clock Four equations are needed to solve for four unknowns.

GPS Performance (Usually) : 

11 GPS Performance (Usually)

Major GPS Faults About Twice a YearExample: Ephemeris Failure on April 10, 2007 : 

12 Major GPS Faults About Twice a YearExample: Ephemeris Failure on April 10, 2007

GPS Ground Control Does Not Provide Quick Fault Detection : 

13 GPS Ground Control Does Not Provide Quick Fault Detection Fine for military, but: Time to alarm can exceed one hour No monitoring of civil signals.

Receiver Autonomous Integrity MonitoringUtilize the Extra GPS Satellites! : 

14 Receiver Autonomous Integrity MonitoringUtilize the Extra GPS Satellites!

Receiver Autonomous Integrity MonitoringFive (or more) GPS Satellites are Needed! : 

15 Receiver Autonomous Integrity MonitoringFive (or more) GPS Satellites are Needed! all-in-view subset #1 subset #2 subset #3 subset #4 subset #5 should be close to the truth

WAAS Functional Operations : 

WAAS Functional Operations 16

Where Is WAAS Available? : 

Where Is WAAS Available? WAAS is available throughout North America. Red line – LNAV/VNAV - outlines the WAAS service area supporting vertically-guided approaches* as low as 2eet. Yellow line - LPVlpv- outlines the WAAS * These WAAS approaches are called “LPV”s.

WAAS Accuracy Compared to the Instrument Landing System (ILS) : 

18 WAAS Accuracy Compared to the Instrument Landing System (ILS)

Ground Based Augmentation System (GBAS or LAAS) : 

Ground Based Augmentation System (GBAS or LAAS) 19

WAAS & GBAS Protected Accuracy : 

20 WAAS & GBAS Protected Accuracy

Area Navigation Based on WAAS & GBAS Compared to ILS : 

21 Area Navigation Based on WAAS & GBAS Compared to ILS

Airports with WAAS LPVNo GPS Equipment Required at Airport50 Pieces of Equipment Serve the Continent : 

22 Airports with WAAS LPVNo GPS Equipment Required at Airport50 Pieces of Equipment Serve the Continent As of May 7, 2009 1595 LPVs serving 872 airports 588 Non-ILS Airports 911 LPVs to non-ILS runways

GBAS Technical Strengths : 

23 GBAS Technical Strengths One GBAS serves all runway ends Procedures uplinked from airport Internationally available (with local ionospheric studies) Upgradable to CAT II/III (2012 timeframe) Boeing & Airbus Over 1000 aircraft orders include GBAS avionics B-737NG, B-787, B-747-8, A-320 & A380 Ground system manufacturers U.S. Honeywell (SLS series) & Raytheon (for DoD) Korea, France, Russia, Denmark & Japan FAA SLS-3000 installed in Memphis & FAATC SLS-4000 System Design Authorization in August 2009

Comparison : 

24 Comparison

RNAV (Area Navigation) : 

25 RNAV (Area Navigation) Tracks independent from ground based equipment. Automated nav. for reduced workload & better awareness. Same path every flight.

Required Navigation Performance (RNP) : 

26 Required Navigation Performance (RNP) Performance based navigation Classify aircraft & operations based on nav. capability Area navigation (RNAV) plus onboard monitoring alerting to within 2 times RNP value graphic from Boeing

WAAS & GBAS : 

27 WAAS & GBAS Technical Summary Handle the billions of fault modes hypothesized by the full aviation community Provide alarms to the pilot within seconds Hedge against constellation shortfalls Enable sovereign control over navigation Foreshadowing of benefits: Support vertical guidance Critical technology for ADS-B and RNP

Benefiting User Groups : 

28 Benefiting User Groups Airspace User Society ATC/FAA Airport Operators

What does a WAAS-enabled LPV approach mean to the users? : 

29 What does a WAAS-enabled LPV approach mean to the users? Example: Half Moon Bay Airport 9 nm SW from SFO 15 nm from San Francisco

From the air : 

30 From the air

Historically underused, in part due to weather : 

31 Historically underused, in part due to weather View looking East 300 ft overcast Clear

Looking West : 

32 Looking West There are obstructions on both sides of the runway, thus the Decision Height is higher than 250 ft.

Comparison of Approaches (Horizontal Path) : 

33 Comparison of Approaches (Horizontal Path) LNAV (GPS-RAIM) LPV (WAAS)

Comparison of Approaches (Vertical Profile) : 

34 Comparison of Approaches (Vertical Profile) Minimum Descent Altitude: 746 ft Vertical guidance from barometric altimeter Decision Altitude: 309 ft Vertical guidance from WAAS Identical to ILS LNAV LPV

LNAV (GPS-RAIM) LPV (WAAS) : 

35 LNAV (GPS-RAIM) LPV (WAAS)

WAAS Enables LPV Approaches : 

36 WAAS Enables LPV Approaches ILS-like capability with same minimums (200’) Better access to all-weather approaches for all users – now 1698 approaches published Allows better flexibility for users to select primary and alternate destinations ILS requires periodic flight inspection, much less LPV flight inspection is indicated WAAS-enabled LPV approaches are straighter than ILS, hence easier to fly Approximately 50,000 aircraft now equipped FedEx has equipped 256 aircraft for regional deliveries

Potential WAAS Benefits : 

37 Potential WAAS Benefits WAAS provides greater vertical accuracy than barometric pressure-based altitude, hence provides lower minimums compared to GPS-RAIM-based RNP approaches Current developments in RNP approach designs will enable lower minimums for aircraft upgraded to WAAS

Noise reduction at Jackson Hole : 

Noise reduction at Jackson Hole 38

Juneau Approach : 

Juneau Approach

Benefits of flexible approaches enabling improved capacity of a single runway : 

40 Benefits of flexible approaches enabling improved capacity of a single runway

Slide 41: 

24 Hours of New York TRACON Traffic

Terminal area with an RNP curved approach : 

43 Terminal area with an RNP curved approach

Benefits of GBAS and ADS-B on Parallel approaches : 

Benefits of GBAS and ADS-B on Parallel approaches 44

Summary - WAAS Benefits : 

47 Summary - WAAS Benefits More precision approaches Safer and lower minimums More options on selecting primary and alternate destinations More reliable use of GPS for non-radar areas compared to GPS-RAIM Gulf of Mexico and polar regions Reduced enroute separation Lower IFR altitudes

Questions? : 

Questions?