# Presentation: 605455

## COMMISSIONING THE WIDE AREA AUGMENTATION SYSTEM

**Jimmy R. Snow**

**COMMISSIONING THE WIDE AREA AUGMENTATION SYSTEM**

##     OVERVIEW

**  ****WAAS System/Procedures**
**  ****WAAS Commissioning Considerations**
**  ****Ohio University Study**
**  ****MITRE Computer Modeling**
**   ****MITRE/Flight Inspection Validation**
**   ****WAAS Receiver**
**   ****WAAS Limitations**
**   ****Future Challenges**

##    GNSS RNAV PROCEDURES

**LPV****	****	****	****Takes Advantage of WAAS Capability**
**  ****	****	****	****Equivalent to Localizer Lateral With Vertical ****	****	****	****	****Between ILS and LNAV/VNAV, HAT 250 ft & Up**
**LNAV/VNAV****	****	****Vertically Guided Approach With Decreasing ****	****	****	****	****Vertical Obstruction Clearance, HAT 350 ft****	****	****	****and Up**
**LNAV****	****	****	****Non-Precision Approach With 250 ft ROC, ****	****	****	****	****             Smaller Protected Area Than VOR, No ****	****	****	****Vertical Guidance**
**CIRCLING ****	****            Approach Procedure to a runway and then**
**	****	****	****Maneuver to Land on Another Runway**

## Slide 4

## Status Of FAA

**GPS Procedures (9/22/03)**

**	****	****     *****	******   ******Year*****      *****97       98        99       00      01      02******    ******03***
**GPS Proc Published  573     516     531     504    447    618   510**
**	****	****	*****	******    ***
***	******	******	******	******	******TOTAL***
**	****	****	****LPV****	****	****	****	****	****       7**
**	****	****	****LNAV/VNAV Published****	****	****   613**
**	****	****	****LNAV Published****	****	****	****3,237**
**	****	****	**_**Military/Specials**__**	**__**	**__**	**__**   237**_
**	****	****	****GPS Proc Published        ****	**** ****	****4,094****	****	****    **

## WAAS COMMISSIONINGCONSIDERATIONS

**WAAS Commissioning Date Established Approximately Two Years in Advance**
**Scheduled on Procedures Publication Date, July 10, 2003**
**Estimated Over 600 LNAV/VNAV Approaches Published for FMS Baro VNAV Operations**
**Over 3,000 LNAV Approaches Published for TSO C-129 Receivers**
**Very Limited WAAS Flight Inspection Capability (Prototype MMR Receiver in Lear 60)**
**Technical Center WAAS Coverage Chart and Outage Records Used to Restrict Certain LNAV/VNAV Approaches**
**Numerous Discussions With Certification and Flight Standards**

## WAAS COMMISSIONING OPTIONS

**No Flight Inspection or Evaluation of Procedures**
**Evaluate Each Procedure on Next Periodic (One and Half Years or Longer to Evaluate All)**
**Surge Effort After WAAS IOC (up to 1,000 Flight Hours)**
**Non-Traditional Evaluation of Existing Procedures**

## OHIO UNIVERSITY SUPPORT

**Initiated Discussions With Ohio University, Avionics Engineering Center May 2001**
**Established Procedure Parameters With FAA Working Group**
**Held Discussions With Ohio University to Evaluate WAAS Requirements**
**Established a Technical Task Directive With Ohio University July 2001 to Evaluate WAAS Commissioning Requirements**
**Study Delivery Not Later Than Nine Months After Task Signed**

## FLIGHT INSPECTION COMPARISON

**GPS/Baro VNAV**
**Obstacle Evaluation**
**Standard Instrument Approach Procedure (Section 214)**
**Procedure Design (Database, Waypoints, Accuracy)**
**Electromagnetic Spectrum (RFI)**
**WAAS LNAV/VNAV**
**Obstacle Evaluation**
**Standard Instrument Approach Procedure**
**Procedure Design**
**Electromagnetic Spectrum **
**Geosynchronous Satellite Signal**

## OHIO UNIVERSITY CONCLUSIONS

**Result**
**Inspection of GPS/Baro VNAV Procedures Should Accomplish All Anticipated WAAS LNAV/VNAV Requirements**
**EXCEPT Ensuring Adequate GEOSAT Signal Coverage**
**GEOSAT**
**Provides Integrity Information, and Differential Corrections**
**Without, WAAS Receiver Reverts to LNAV Only Capability**
**Thus, LNAV/VNAV Procedures Can Not Be Conducted**

## OHIO UNIVERSITY STUDY ASSUMPTIONS

** ****Assumptions**
**The inherent WAAS monitoring is capable of detecting system faults within the required time-to-alarm**
**The WAAS receiver reverts to a GPS-only capability in the absence of a GEOSAT signal**
**The FAA has authorized WAAS for supporting LNAV/VNAV approach procedures**
**The SIAP procedure has been previously commissioned for GPS/Baro VNAV**
**The availability of GPS/Baro VNAV and WAAS LNAV/VNAV is at least 95 percent**
**The descent altitude is the same for the WAAS LNAV/VNAV and GPS/Baro VNAV procedures**
**There is a high-correlation between predicted (monitoring) and actual WAAS system performance**

## STUDY CONCLUSIONS

**~ 6****00 GPS/Baro VNAV Procedures Expected to be Commissioned Before WAAS IOC**
**Inspection of GPS/Baro VNAV Procedures Should Accomplish All Anticipated WAAS LNAV/VNAV Requirements EXCEPT Ensuring Adequate GEOSAT Signal Coverage**
**Computer-based GEOSAT Coverage Screening Models May be Used to Streamline Flight Inspection Process ****(****To determine if GEOSAT is shadowed on final approach segment****)**

## STUDY RECOMMENDATIONS (1)

**The Comparison of GPS/Baro VNAV and WAAS LNAV/VNAV Flight Inspection Requirements Should Be Repeated Once Formal Criteria Are Available in FAA Order 8200**
**The Feasibility and Benefit of Developing a Screening Model for Assessing GEOSAT Signal Coverage Should Be Assessed Further**
**Low Confidence Cases, the WAAS LNAV/VNAV Procedure Should Be Flight Inspected Before Being Authorized for Use,**** ****Low Priority**

## STUDY RECOMMENDATIONS (2)

**Marginal Confidence Cases, the WAAS LNAV/VNAV Procedure Should Be Flight Inspected Before Being Authorized for Use, High Priority**
**High Confidence Cases, WAAS LNAV/VNAV Operations Authorized and Inspection Performed During Next Periodic Inspection of GPS/Baro VNAV Procedure**
**For WAAS Procedures Authorized Prior to Formal Flight Inspection, Authorization Should Be Withdrawn if a “Problem Report” Is Received**

## SECOND PHASECOMPUTER MODELING

**FAA Contacted MITRE, Center for Advanced Aviation System Development For Assistance (CAASD)**
**MITRE Advised They Could Modify an Existing Software Program to Do What Ohio University Recommended**
**Meetings Were Scheduled to Discuss****:**
**Establishing an Agreement Between FAA and MITRE**
**Delivery Schedules**
**Evaluation Requirements**
**Data Requirements**

## FAA-MITRE AGREEMENT

**AVN Would Provide MITRE the Following:**
**Airport Identifier**
**Airport Reference Point (latitude/Longitude)**
**Airport Elevation**
**Airport Priority for Screening**
**If Available Airport Name and Location**
**MITRE Will Evaluate Each Airport Using the Following Criteria:**
**Evaluate a point 250 ft Above the ARP From 090 to 270 Degrees**
**At Least One WAAS GEO is More Than 10 Degrees Above the Horizon**
**No Terrain Within 40 nm of the ARP More Than 5-deg Elevation Angle Viewed From 250 ft Above the ARP**
**MITRE Would Use Worst-case WAAS GEO Positions**
**MITRE Would Validate the Computer Model and Peer Review Results **

## Elevation Angles in USA and Canada(POR and AOR-W)

**Elevation Angles in USA and Canada****(POR and AOR-W)**

## TERRAIN MASKING:Forty Nautical Miles

**10 nm**

**30 nm**

**Mount**
**Ranier**
**(14,400 ft)**

**4.5°**

**ARP (Sea Level)**

**FAF (Sea Level)**

**Geo**

**10° (minimum)**

## TERRAIN MASKING:Results

**A detailed look at the airport is not required**
**  ****Failure of the Screening Does Not Necessarily Imply That GEO Masking Will Occur During an Approach to that Airport**
**Failure implies that a closer look at the airport is warranted**
**  ****Availability of LNAV/VNAV Approaches Was Not Addressed**

**TERRAIN MASKING:****Results**

## VALIDATION EFFORTS

**   ****Jeppesen and Other Databases **
**GEO Angles Were Computed by Several Methods With No**
**    ****Significant Differences Between Methods**
**Terrain Masking Code Was Checked Independently**
**Terrain Results Were Spot Checked With Sectional Charts**
**AVN Will Spot Check Some Airports During a Later**
**   ****Validation Check **

**VALIDATION EFFORTS**

## AIRPORT GROUP ONESummary

**223 Total Airports With RNAV (LNAV/VNAV) Approaches Developed by AVN**
**215 Airports Passed Screening**
**GEO > 10 Degrees Elevation and**
**Terrain to South < 5 Degrees Elevation**
**8 Airports Failed Screening**
**3 Failed for Terrain**
**5 Failed for GEO Elevation**
**3 in Northern Alaska**

## AIRPORT GROUP TWOSummary

**155 Total Airports With RNAV (LNAV/VNAV) Approaches Planned by AVN**
**142 Airports Passed Screening**
**GEO > 10 Degrees Elevation and**
**Terrain to South < 5 Degrees Elevation **
**13 Airports Failed Screening**
**12 Failed for Terrain**
**1 Failed for GEO Elevation**

## AVN VALIDATION

**MITRE Evaluated 378 Airports/AVN Flight Inspected 65 Airports To Validate MITRE results**
**11 of the 21 Identified by MITRE Did Not Have GEO Coverage**
**2 Additional Airports of the 65 Would Not Support VNAV For Geo Coverage **
**AVN Accepted the Results As Satisfactory**

## Slide 25

## WAAS MMR RECEIVER

**Have Six Collins MMR Receivers With WAAS and LAAS**
**Two Lear 60s Have WAAS Capability**
**Due to No TSO Receiver and No STC, Aircraft in Experimental Status**
**Currently in a MOPS “Beta” Configuration**
**With the FMS We Must Change the MMR Into “Delta” Configuration, Estimate 2 Years**
**LPV and LAAS Have FAS Datablock That the AFIS Reads**
**Aircraft Flying LNAV/VNAV While AFIS Evaluates LPV**
**New Contract Let to Complete VFR STC (estimate completion January 05)**

##                          LPV 

**FLIGHT INSPECTION RESULTS**

| Site | HPL
Meters | VPL
Meters | XTK
Error
Feet | ATK
Error
Feet | SNR | Below Path SNR | Worst
SNR |
| --- | --- | --- | --- | --- | --- | --- | --- |
| KFDR 23 | 16.7 | 22.4 | -3 | -8 | 41 | 42 | 39 |
| KCHK 16L | 14.2 | 23.2 | -4 | -3 | 42 | 42 | 40 |
| KTYO 17 | 14.5 | 19.9 | 3 | -7 | 41 | 42 | 40 |
| KGAI 14 | 16.5 | 21.1 | 6 | 0 | 41 | 41 | 41 |
| KOKC 17R | 12 | 21.5 | -3 | 7 | 40 | 41 | 40 |
| KOKC 35R | 10.5 | 19 | 1 | -6 | 40 | 40 | 40 |
| KOSH 36 | 12.6 | 18.6 | 4 | -17 | 40 | 41 | 38 |
|  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |

##             ILS vs WAAS LPV

**WAAS Approach**

**ILS Glideslope**

**            ****ILS vs WAAS LPV**
**Flight Inspection Comparison**

## WAAS LIMITATIONS

**  ****Inverse W          on RNAV Approach Charts/Limitations**
**  ****Indicates WAAS Outages May Occur Daily (32 airports)**
**  ****WAAS NOTAMS Are Not Provided For the Procedure**
**  ****Use LNAV Minima For Flight Planning (Destination or**
**   ****Alternate) **
**  ****If Receiver Indicates LNAV/VNAV or LPV Available**
**   ****Guidance May Be Used**
**  ****If WAAS Is Lost Revert to LNAV Minima If Receiver**
**   ****Allows or LNAV Data Is Available**
**  ****WAAS VNAV NA**** on RNAV Charts That Did Not Pass **
**     ****MITRE Modeling and Flight Inspection**
** **

## INMARSAT III COVERAGE

**INMARSAT III COVERAGE**

##                             Jimmy Snow

**                                ****NAVIGATION CONSULTANT      **
**                     ****405-249-4329**
**                     ****cjsnow@cox.net**