WIDE AREA AUGMENTATION SYSTEM PERFORMANCE ...and Multipath analysis, WAAS reference station survey...

Satellite Navigation Branch, ANG-E66 NSTB/WAAS T&E Team

WIDE AREA AUGMENTATION SYSTEM PERFORMANCE ANALYSIS REPORT

April 2020

Report # 72 Reporting Period: January 1 to March 31, 2020

http://www.nstb.tc.faa.gov/

FAA William J. Hughes Technical Center Atlantic City International Airport, New Jersey 08405

WAAS Performance Analysis Report April 2020

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DOCUMENT VERSION CONTROL

VERSION DESCRIPTION OF CHANGE DATE

0.1 Initial Version of Document 04/16/2020

0.2 Technical Edit 04/17/2020

0.3 Peer Review 04/28/2020

1.0 Final 04/29/2020


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Executive Summary

Since 1999, the Wide Area Augmentation System (WAAS) Test Team at the FAA William J. Hughes Technical Center has reported GPS performance as measured against the GPS Standard Positioning Service (SPS) Signal Specification in quarterly GPS Performance Analysis Network (PAN) Reports. In addition to the GPS PAN reports, the WAAS Test Team has provided quarterly reports on WAAS performance. The current WAAS PAN Report #72 provides WAAS performance data from the January 01 through March 31, 2020 reporting period. This report provides the following results: accuracy, availability, coverage, safety index, range accuracy, WAAS broadcast message rates, geostationary satellite ranging availability, WAAS airport availability, WAAS Code Noise and Multipath analysis, WAAS reference station survey validation, and WAAS Signal Quality Monitoring. The following table shows observations for accuracy and availability made during the reporting period for Continental United States (CONUS) and Alaska sites (the international sites are presented in the body of this report). Localizer Performance (LP) service is available when the calculated horizontal protection level (HPL) is less than 40 meters. Localizer Performance with Vertical Guidance (LPV) service is available when the calculated HPL is less than 40 meters and the Vertical Protection Level (VPL) is less than 50 meters. Localizer Performance with Vertical Guidance to 200-foot decision height (LPV200) service is available when the calculated HPL is less than 40 meters and the VPL is less than 35 meters. The FAA’s National Satellite Test Bed sites—Grand Forks, North Dakota, Atlantic City, New Jersey, and Arcata, California—are outliers due to receiver quality issues, and not because of the WAAS signal in space quality. Note that NSTB Grand Forks was not evaluated this quarter.

Parameter

CONUS Site/Maximum

CONUS Site/Minimum

Alaska Site/Maximum

Alaska Site/Minimum

95% Horizontal Accuracy (HPL


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TABLE OF CONTENTS 1.0 INTRODUCTION .......................................................................................................................... 1

1.1 Event Summary ........................................................................................................................... 4 1.2 Report Overview ......................................................................................................................... 7

2.0 WAAS POSITION ACCURACY ................................................................................................. 8 3.0 AVAILABILITY .......................................................................................................................... 23 4.0 COVERAGE ................................................................................................................................. 40 5.0 INTEGRITY ................................................................................................................................. 52

5.1 HMI Analysis ............................................................................................................................ 52 5.2 Broadcast Alerts ........................................................................................................................ 53 5.3 Availability of WAAS Messages (SM9, S15, and CRE) ........................................................... 54 5.4 Satellite Glitches ........................................................................................................................ 62

6.0 SV RANGE ACCURACY ........................................................................................................... 64 7.0 GEO RANGING PERFORMANCE .......................................................................................... 75 8.0 WAAS AIRPORT AVAILABILITY .......................................................................................... 77 9.0 WAAS CNMP BOUNDING ANALYSIS ................................................................................. 145 10.0 WRS ANTENNA SURVEY VALIDATION ............................................................................ 148 11.0 SQM ............................................................................................................................................. 163

11.1 Alpha Metrics .......................................................................................................................... 164 11.2 Type Bias ................................................................................................................................. 164 11.3 PRN Bias ................................................................................................................................. 165 11.4 SQM Trips ............................................................................................................................... 175

Appendix A: Glossary and Acronyms .................................................................................................... 176 Appendix B: Additional Coverage Plots ................................................................................................. 180


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LIST OF FIGURES Figure 2-1. LPV 95% Horizontal Accuracy ................................................................................................................ 12 Figure 2-2. LPV 95% Horizontal Accuracy ................................................................................................................ 13 Figure 2-3. LPV 95% Horizontal Accuracy ................................................................................................................ 14 Figure 2-4. LPV 95% Vertical Accuracy ..................................................................................................................... 15 Figure 2-5. LPV 95% Vertical Accuracy ..................................................................................................................... 16 Figure 2-6. LPV 95% Vertical Accuracy ..................................................................................................................... 17 Figure 2-7. NPA 95% Horizontal Accuracy ................................................................................................................ 18 Figure 2-8. NPA 95% Horizontal Accuracy ................................................................................................................ 19 Figure 2-9. LPV Horizontal Error Bounding Triangle Chart ....................................................................................... 20 Figure 2-10. LPV Vertical Error Bounding Triangle Chart ......................................................................................... 21 Figure 2-11. LPV 2-D Horizontal Error Distribution Histogram ................................................................................ 22 Figure 2-12. LPV 2-D Vertical Error Distribution Histogram ..................................................................................... 23 Figure 3-1. LPV Instantaneous Availability ................................................................................................................ 27 Figure 3-2. LPV Instantaneous Availability ................................................................................................................ 28 Figure 3-3. LPV Instantaneous Availability ................................................................................................................ 29 Figure 3-4. LPV200 Instantaneous Availability .......................................................................................................... 30 Figure 3-5. LPV200 Instantaneous Availability .......................................................................................................... 31 Figure 3-6. LPV200 Instantaneous Availability .......................................................................................................... 32 Figure 3-7. LPV Outages ............................................................................................................................................. 33 Figure 3-8. LPV Outages ............................................................................................................................................. 34 Figure 3-9. LPV Outages ............................................................................................................................................. 35 Figure 3-10. LPV200 Outages ..................................................................................................................................... 36 Figure 3-11. LPV200 Outages ..................................................................................................................................... 37 Figure 3-12. LPV200 Outages ..................................................................................................................................... 38 Figure 4-1. LP North America Coverage for the Quarter ............................................................................................ 42 Figure 4-2. LPV North America Coverage for the Quarter ......................................................................................... 43 Figure 4-3. LPV200 North America Coverage for the Quarter ................................................................................... 44 Figure 4-4. Daily LPV and LPV200 CONUS Coverage ............................................................................................. 45 Figure 4-5. Daily LPV and LPV200 Alaska Coverage ................................................................................................ 46 Figure 4-6. Daily LPV and LPV200 Canada Coverage ............................................................................................... 47 Figure 4-7. RNP 0.1 Coverage for the Quarter ............................................................................................................ 49 Figure 4-8. RNP 0.3 Coverage for the Quarter ............................................................................................................ 50 Figure 4-9. Daily RNP Coverage ................................................................................................................................. 51 Figure 5-1. SV Daily Alert Trend ................................................................................................................................ 54 Figure 5-2. SV Glitch Trend ........................................................................................................................................ 63 Figure 6-1. Range Error (PRN1–PRN16)–Washington D.C. ...................................................................................... 68 Figure 6-2. Range Error (PRN17–PRN32)–Washington D.C. .................................................................................... 69 Figure 6-3. Range Error (PRN131, PRN133, PRN138)–Washington D.C. ................................................................. 70 Figure 6-4. Ionospheric Error (PRN1–PRN16)–Washington D.C. .............................................................................. 73 Figure 6-5. Ionospheric Error (PRN17–PRN32)–Washington D.C. ............................................................................ 74 Figure 7-1. Daily PA SM9 GEO Ranging Availability Trend ..................................................................................... 75 Figure 7-2. Daily PA S15 GEO Ranging Availability Trend ...................................................................................... 76 Figure 7-3. Daily PA CRE GEO Ranging Availability Trend ..................................................................................... 76 Figure 8-1. WAAS LP Availability at Airports in the US and Canada with GPS RNAV IAPs ................................ 139 Figure 8-2. WAAS LP Outages at Airports in the US and Canada with GPS RNAV IAPs ...................................... 140 Figure 8-3. WAAS LPV Availability Airports in the US and Canada with GPS RNAV IAPs ................................. 141 Figure 8-4. WAAS LPV Outages at Airports in the US and Canada with GPS RNAV IAPs ................................... 142 Figure 8-5. WAAS LPV200 Availability at Airports in the US and Canada with GPS RNAV IAPs ....................... 143 Figure 8-6 WAAS LPV200 Outages at Airports in the US and Canada with GPS RNAV IAPs .............................. 144 Figure 9-1. CNMP Bounding Statistics ..................................................................................................................... 146 Figure 10-1. Release 53 Antenna Positions Deltas OPUS Survey ............................................................................. 152 Figure 10-2. Release 53 Antenna Positions Deltas OPUS Survey ............................................................................. 153 Figure 10-3. Release 53 Antenna Positions Deltas OPUS Survey ............................................................................. 154 Figure 10-4. OPUS Survey Overall RMS Qualities .................................................................................................. 155


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Figure 10-5. OPUS Survey Overall RMS Qualities .................................................................................................. 156 Figure 10-6. OPUS Survey Overall RMS Qualities .................................................................................................. 157 Figure 10-7. OPUS vs. CSRS RSS ECEF Deltas ...................................................................................................... 158 Figure 10-8. OPUS vs. CSRS RSS ECEF Deltas ...................................................................................................... 159 Figure 10-9. OPUS vs. CSRS RSS ECEF Deltas ...................................................................................................... 160 Figure 10-10. CSRS Survey Qualities ....................................................................................................................... 161 Figure 10-11. CSRS Survey Qualities ....................................................................................................................... 162 Figure 10-12. CSRS Survey Qualities ....................................................................................................................... 163 Figure 11-1. Type Bias Average Trend ..................................................................................................................... 165 Figure 11-2. PRN Bias Average for the Quarter ........................................................................................................ 167 Figure 11-3. PRN Bias Average Trend (PRN1 – PRN4) ........................................................................................... 168 Figure 11-4. PRN Bias Average Trend (PRN5 – PRN8) ........................................................................................... 169 Figure 11-5. PRN Bias Average Trend (PRN9 – PRN12) ......................................................................................... 170 Figure 11-6. PRN Bias Average Trend (PRN13 – PRN16) ....................................................................................... 171 Figure 11-7. PRN Bias Average Trend (PRN17 – PRN20) ....................................................................................... 172 Figure 11-8. PRN Bias Average Trend (PRN21 – PRN24) ....................................................................................... 173 Figure 11-9. PRN Bias Average Trend (PRN25 – PRN28) ....................................................................................... 174 Figure 11-10. PRN Bias Average Trend (PRN29 – PRN32) ..................................................................................... 175 Figure B-1. 98% CONUS LP Availability Contour .................................................................................................. 181 Figure B-2. 98% Alaska LP Availability Contour ..................................................................................................... 182 Figure B-3. 98% CONUS LPV Availability Contour................................................................................................ 183 Figure B-4. 98% Alaska LPV Availability Contour .................................................................................................. 184 Figure B-5. 98% CONUS LPV200 Availability Contour .......................................................................................... 185 Figure B-6. 98% Alaska LPV200 Availability Contour ............................................................................................ 186


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LIST OF TABLES Table 1-1. WAAS Service Levels.................................................................................................................................. 1 Table 1-2. PA Evaluation Sites ...................................................................................................................................... 2 Table 1-3. NPA Evaluation Site .................................................................................................................................... 2 Table 1-4. WAAS Performance Parameters .................................................................................................................. 4 Table 1-5. Events ........................................................................................................................................................... 4 Table 1-6. WAAS Upgrades .......................................................................................................................................... 6 Table 1-7. GUS Switchovers ......................................................................................................................................... 6 Table 2-1. PA 95% Horizontal and Vertical Accuracy .................................................................................................. 8 Table 2-2. NPA 95% and 99.999% Horizontal Accuracy ............................................................................................. 9 Table 2-3. Maximum LPV Error Statistics .................................................................................................................. 10 Table 3-1. 99% Protection Level ................................................................................................................................. 24 Table 3-2. PA Availability (15-minute window) ......................................................................................................... 25 Table 3-3. LPV and LPV200 Outage Rate (Per 150 sec approach) ............................................................................. 26 Table 3-4. NPA Availability (15-minute window) ...................................................................................................... 39 Table 3-5. NPA Outage Rates (Excluding FD/FDE) ................................................................................................... 39 Table 5-1. Minimum Safety Margin Index and HMI Statistics ................................................................................... 52 Table 5-2. WAAS SV Alert ......................................................................................................................................... 53 Table 5-3. Update Rates for WAAS Messages ............................................................................................................ 54 Table 5-4. WAAS Fast Correction and Degradation Message Rates–SM9 ................................................................. 55 Table 5-5. WAAS Long Correction Message Rates (Type 24 and 25)–SM9 .............................................................. 55 Table 5-6. WAAS Ephemeris Covariance Message Rates (Type 28)–SM9 ................................................................ 56 Table 5-7. WAAS Ionospheric Correction Message Rates (Type 26)–SM9 ............................................................... 57 Table 5-8. WAAS Ionospheric Mask Message Rates (Type 18)–SM9 ....................................................................... 57 Table 5-9. WAAS Fast Correction and Degradation Message Rates–S15 .................................................................. 57 Table 5-10. WAAS Long Correction Message Rates (Type 24 and 25)–S15 ............................................................. 58 Table 5-11. WAAS Ephemeris Covariance Message Rates (Type 28)–S15 ............................................................... 58 Table 5-12. WAAS Ionospheric Correction Message Rates (Type 26)–S15 ............................................................... 59 Table 5-13. WAAS Ionospheric Mask Message Rates (Type 18)–S15 ....................................................................... 60 Table 5-14. WAAS Fast Correction and Degradation Message Rates–CRE ............................................................... 60 Table 5-15. WAAS Long Correction Message Rates (Type 24 and 25)–CRE ............................................................ 60 Table 5-16. WAAS Ephemeris Covariance Message Rates (Type 28)–CRE .............................................................. 61 Table 5-17. WAAS Ionospheric Correction Message Rates (Type 26)–CRE ............................................................. 61 Table 5-18. WAAS Ionospheric Mask Message Rates (Type 18)–CRE ..................................................................... 62 Table 6-1. Range Error 95% Index and 3.29 Sigma Bounding ................................................................................... 65 Table 6-2. Range Error 95% Index and 99.9% Bounding ........................................................................................... 66 Table 6-3. Ionospheric Error 95% Index and 99.9% Sigma Bounding........................................................................ 71 Table 6-4. Ionospheric Error 95% Index and 99.9% Sigma Bounding........................................................................ 72 Table 7-1. GEO Ranging Availability ......................................................................................................................... 75 Table 8-1. WAAS LP, LPV, and LPV200 Outages and Availability .......................................................................... 78 Table 10-1. WAAS Antenna Positions (OPUS IGS08) as of 04/02/2017 ................................................................. 149 Table 11-1. Alpha Metrics ......................................................................................................................................... 164 Table 11-2. Type Bias Average for the Quarter ........................................................................................................ 164 Table 11-3. Type Bias Average since January 1, 2008 .............................................................................................. 164 Table 11-4. PRN Bias Average for the Quarter ......................................................................................................... 166


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1.0 INTRODUCTION

The FAA monitors the Wide Area Augmentation System (WAAS) and GPS Standard Positioning Service (SPS) performance to ensure the safe and effective use of the satellite navigation system in the National Airspace System (NAS). The WAAS augments timely integrity monitoring and improves GPS position accuracy and availability within the WAAS coverage area. The objectives of this report are:

1. To evaluate and monitor the WAAS ability to augment GPS by characterizing important performance parameters.

2. To analyze the effects of GPS satellite operation and maintenance as well as ionospheric activity on WAAS performance.

3. To investigate GPS and WAAS anomalies and determine potential user impact. 4. To archive GPS and WAAS performance for future evaluations.

The evaluation uses the WAAS data transmitted from geostationary satellites (GEOs) pseudo-random noise (PRN) 131 (SM9), 133 (S15), and 138 (CRE). SM9, S15 and CRE GEOs provide a precision approach (PA) ranging capability that supports all levels of WAAS service. In this report, the terms "PA" and "NPA" are used in reference of the two modes of user equipment operation. These terms were used in the original WAAS specification, FAA-E-2892. See Table 1-1 for a mapping of PA and NPA to the user service levels.

Table 1-1. WAAS Service Levels

User Service NPA or PA WAAS Protection Levels RNP 0.3 NPA HPL


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Table 1-2. PA Evaluation Sites

Location Number of Days Evaluated Number of

Samples NSTB: Arcata 82 7089474 Atlantic City 82 7103169 Oklahoma City 82 7056036 WAAS: Albuquerque 91 7861476 Anchorage 91 7857593 Atlanta 91 7861059 Barrow 91 7853765 Bethel 91 7853755 Billings 91 7861173 Boston 91 7861038 Chicago 91 7840820 Cleveland 91 7847473 Cold Bay 91 7849802 Dallas 91 7856461 Denver 91 7844008 Fairbanks 91 7860458 Gander 91 7859864 Goose Bay 91 7861351 Houston 91 7856056 Iqaluit 91 7860939 Jacksonville 91 7860135 Juneau 91 7855975 Kansas City 91 7857039 Kotzebue 91 7858652 Los Angeles 91 7825741 Memphis 91 7861023 Merida 91 7854595 Mexico City 91 7856038 Miami 91 7856527 Minneapolis 91 7861537 New York 91 7861027 Oakland 91 7855692 Puerto Vallarta 91 7846026 Salt Lake City 91 7860573 San Jose Del Cabo 89 7695348 Seattle 91 7856448 Washington DC 91 7860891 Winnipeg 91 7860682

Table 1-3. NPA Evaluation Site

Location Number of

Days Evaluated

Number of

Samples Albuquerque 91 7861987 Anchorage 91 7861982 Atlanta 91 7861985 Barrow 91 7858538 Bethel 91 7854212


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Location Number of

Days Evaluated

Number of

Samples Billings 91 7861860 Boston 91 7861987 Cleveland 91 7861987 Cold Bay 91 7859234 Fairbanks 91 7861686 Gander 91 7861869 Honolulu 91 7861987 Houston 91 7861978 Iqaluit 81 7023185 Juneau 91 7858101 Kansas City 91 7861884 Kotzebue 91 7858827 Los Angeles 91 7832596 Merida 91 7857365 Miami 91 7861984 Minneapolis 91 7861984 Oakland 91 7861985 Salt Lake City 91 7861983 San Jose Del Cabo 90 7769511 San Juan 91 7859970 Seattle 91 7861987 Tapachula 91 7857824 Washington DC 91 7858737

The report is divided by the performance category:

1. WAAS Position Accuracy 2. WAAS Operational Service Availability 3. WAAS Coverage 4. WAAS Integrity 5. WAAS Range Domain Accuracy 6. WAAS GEO Ranging Performance 7. WAAS Airport Availability 8. WAAS Code Noise and Multipath (CNMP) Analysis 9. WAAS Antenna Survey Validation 10. WAAS Signal Quality Monitor (SQM) Analysis

Table 1-4 lists the evaluated WAAS performance parameters for this report. Note that these are the performance parameters associated with the WAAS system, and that these requirements are extracted from FAA Specifications FAA-E-2892C and FAA-E-2976, as applicable.


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Table 1-4. WAAS Performance Parameters

Performance Parameter Expected WAAS Performance

LPV Accuracy Horizontal ≤ 1.5m error 95% of the time

LPV Accuracy Vertical ≤ 2m error 95% of the time LNAV Accuracy Horizontal ≤ 36m error 95% of the time

Availability LPV CONUS 99% availability of 100% of CONUS Availability LPV Alaska 95% availability of 75% of Alaska Availability LNAV CONUS 99.99% availability with HPL < 556m Availability LNAV Alaska 99.9% availability with HPL < 556m Availability En Route OCONUS 99.9% availability with HPL < 2nmi Probability of Hazardous Misleading Information


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Start Date End Date Location Satellite Service Affected Event Description

01/16/2020 01/17/2020 PRN28 LPV200_Alaska, LPV200_Canada

The reduction in LPV200 service in Alaska and Canada was due to a GPS NANU on PRN28 (see NANU2020005) which was unusable from 19:57 GMT on 01/16 to 1:47 GMT on 01/17. The NANU caused moderate degradation of: (1) LPV200 service coverage in Alaska from 01:36 GMT to 02:02 GMT; (2) LPV200 service coverage in Canada from 01:30 GMT to 02:02 GMT. Please see plot(s): LPV200_1/16/2020

02/04/2020 02/04/2020 GEO138,Woodbine (QWE) LPV200_Canada

The uplink for the CRE GEO, PRN138 switched from the Woodbine uplink site to the Brewster-B uplink site at 08:12:01 GMT. This caused a 4-second outage of the GEO 138 broadcast and also caused the WAAS carrier smoothing algorithm to reinitialize for PRN138. The elevated UDREs on PRN138 caused minor degradation of LPV200 service coverage in Canada from 08:12 GMT to 08:30 GMT.TOW 202338-202343 Please see plot(s): LPV200_2/4/2020

02/11/2020 04/07/2020 Washington D.C. (CnV), Atlanta (CnV)

None

Starting 02/11, WJHTC observed SV alerts unique to GEOS on specific C&Vs.

Date PRN GEO C&V 02/11–02/14 13 138 ZTL 03/07 13 138 ZTL 03/10–03/11 13 138 ZTL 04/04, 04/06–04/07

13 133, 138

ZDC, ZTL

32 138 ZTL The elevated UDREs caused no impact on coverage at these times. This issue has been described in WPR WAAS00127329.

02/13/2020 02/13/2020 PRN21 LPV200_CONUS

There was a UDRE spike on PRN21 at 07:13 GMT. During this time there was an LPV200 service outage in CONUS from the Gulf of Mexico stretching to Michigan. The outage lasted for 30 seconds. Please see plot(s): LPV200_2/13/2020

02/14/2020 02/14/2020 None

WJHTC observed SQM jumps on all IIF satellites starting on 02/14. Further analysis reveals jumps in L2 C/No around the same time each day on the affected satellites. Neither the SQM jumps nor the increase in L2 C/No caused an impact on WAAS coverage.

02/17/2020 02/17/2020 Santa Paula (SZ1) None

There was an SV alert on PRN131 at 10:18:13 GMT. The UDRE stayed at 14 for 7-minutes then dropped to 11 until 18:00 GMT. This event is similar to an event on 01/06. At the time of both events there was a doppler spike visible on L1 omni and downlink (L1, L5).

ftp://ftp.nstb.tc.faa.gov/pub/NSTB_data/24HOURPLOTS/W2088D4/LPV200_W2088D4.pngftp://ftp.nstb.tc.faa.gov/pub/NSTB_data/24HOURPLOTS/W2091D2/LPV200_W2091D2.pngftp://ftp.nstb.tc.faa.gov/pub/NSTB_data/24HOURPLOTS/W2092D4/LPV200_W2092D4.png


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Start Date End Date Location Satellite Service Affected Event Description

02/19/2020 04/01/2020 PRN11 None

Starting 02/19, WJHTC observed high horizontal position errors at Cold Bay. The high error corresponds to high range errors on PRN11. These elevated errors last approximately 30-50 minutes and occur at an elevation of about 8-10 degrees. This was due to an L2 signal tracking anomaly on PRN11 due to high power. (See DR 144)

02/20/2020 02/21/2020 PRN11 LPV200_Canada

The reduction in LPV200 service in Canada was due to a GPS NANU on PRN11 (see NANU2020009) which was unusable from 19:46 GMT on 02/20 to 02:12 GMT on 02/21. The NANU caused moderate degradation of LPV200 service coverage in Canada from 23:50 GMT on 2/20 to 00:12 GMT on 02/21. Please see plot(s): LPV200_2/21/2020

02/25/2020 02/25/2020 PRN21 LPV200_CONUS

There was a UDRE spike on PRN21 at 06:23 GMT. During this time there was an LPV200 service outage in CONUS from the Gulf of Mexico stretching to Michigan. The outage lasted for 30-60 seconds. Please see plot(s): LPV200_2/25/2020

03/09/2020 03/09/2020 PRN23 None SVN60 (PRN23) was decommissioned (see NANU 2020012). This change in constellation had no impact on WAAS coverage.

Table 1-6. WAAS Upgrades

Start Date End Date Location Satellite Event Description None None None No Upgrades This Quarter

Table 1-7. GUS Switchovers

Start Date End Date GUS Switch Location Satellite

Service Affected Event Description

01/02/2020 01/02/2020 Faulted GEO131, Southbury (DX1)

None The uplink for the SM9 GEO, PRN131 switched from the Southbury uplink site to the Santa Paula uplink site at 07:32:34 GMT. This caused a 19-second outage of the GEO 131 broadcast and also caused the WAAS carrier smoothing algorithm to reinitialize for PRN131. There was no impact on coverage. TOW 372771-372791

01/30/2020 01/30/2020 Missed Navigation Message

GEO138, Woodbine (QWE), Atlanta (CnV)

None Woodbine had CnV Source Select from Atlanta to Los Angeles. TOW 389095-389097

ftp://ftp.nstb.tc.faa.gov/pub/NSTB_data/24HOURPLOTS/W2093D5/LPV200_W2093D5.pngftp://ftp.nstb.tc.faa.gov/pub/NSTB_data/24HOURPLOTS/W2094D2/LPV200_W2094D2.png


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Start Date End Date GUS Switch Location Satellite

Service Affected Event Description

02/04/2020 02/04/2020 Manual GEO138, Woodbine (QWE)

LPV200_Canada The uplink for the CRE GEO, PRN138 switched from the Woodbine uplink site to the Brewster-B uplink site at 08:12:01 GMT. This caused a 4-second outage of the GEO 138 broadcast and also caused the WAAS carrier smoothing algorithm to reinitialize for PRN138. The elevated UDREs on PRN138 caused minor degradation of LPV200 service coverage in Canada from 08:12 GMT to 08:30 GMT.TOW 202338-202343

02/05/2020 02/05/2020 Manual GEO131, Santa Paula (SZ1)

None The uplink for the SM9 GEO, PRN131 switched from the Santa Paula uplink site to the Southbury uplink site at 08:01:28 GMT. This caused a 4-second outage of the GEO 131 broadcast and also caused the WAAS carrier smoothing algorithm to reinitialize for PRN131. There was no impact on coverage. TOW 288105-288110

03/09/2020 03/09/2020 Manual GEO133, South Mountain (CM1)

None The uplink for the S15 GEO, PRN133 switched from the South Mountain uplink site to the Brewster uplink site at 08:24:26 GMT. This caused an 4-second outage of the GEO 133 broadcast and also caused the WAAS carrier smoothing algorithm to reinitialize for PRN133. There was no impact on coverage. TOW 116678-116683

03/10/2020 03/10/2020 Manual GEO138, Brewster-B (BRE-B)

None The uplink for the CRE GEO, PRN138 switched from the Brewster-B uplink site to the Woodbine uplink site at 08:01:41 GMT. This caused a 4-second outage of the GEO 138 broadcast and also caused the WAAS carrier smoothing algorithm to reinitialize for PRN138. There was no impact on coverage. TOW 201718-201723

1.2 Report Overview

Section 2.0 provides the observed Localizer Performance with Vertical Guidance (LPV) and NPA performance for the evaluated receiver locations (see Table 1-2 and Table 1-3). This section also shows tabulated data for the 95% accuracy and the maximum inaccuracy. In addition, the daily 95% accuracy for each receiver and the histograms of vertical and horizontal error are shown. Section 3.0 provides the summary of the WAAS instantaneous availability performance at each receiver for three operational service levels. In addition, the daily availability, number of outages, and outage rate for each evaluated receiver are also reported.


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Section 4.0 provides geographic plots of the WAAS service availability. Also shown in this section are plots of the percentage of the Continental United States (CONUS) and Alaska service areas covered by various levels of service availability. Section 5.0 provides the summary of the Hazardous Misleading Information (HMI) analysis as well as a safety margin index for each receiver. This section also shows update rates of WAAS messages transmitted from CRE, SM9, and S15. Section 6.0 provides the UDRE and GIVE bounding percentages and the 95% index of the range and ionospheric accuracy for each satellite tracked by the WAAS receiver at 12 locations. Section 7.0 provides the GEO ranging performance for CRE, SM9 and S15. Section 8.0 provides the WAAS LPV availability and outages at selected airports. Section 9.0 provides the assessment of WAAS CNMP bounding for 114 WAAS receivers. Section 10.0 provides surveyed positions of all Wide-Area Reference Equipment (WRE) and the difference between the WRE survey positions and the survey positions using both the National Geodetic Survey (NGS) Online Positioning Use Server (OPUS) and the Canadian Spatial Reference System (CSRS) Precise Point Positioning (PPP) service. Section 11.0 provides the daily and quarterly average of SQM PRN-type biases and PRN biases. 2.0 WAAS POSITION ACCURACY

Navigation error data, collected from WAAS and NSTB reference stations, was processed to determine position accuracy at each location. This was accomplished by using the GPS/WAAS position solution tool to compute a RTCA DO-229D-weighted least squares user navigation solution and WAAS horizontal protection level (HPL) and vertical protection level (VPL) once every second. The user position calculated for each receiver was compared to the surveyed position of the antenna to assess position error associated with the WAAS signal in space (SIS) over time. The position errors were analyzed and statistics were generated for the operational service levels shown in Table 1-1. Table 2-1 shows PA horizontal and vertical position accuracy maintained for 95% of the time at LP, LPV and lateral navigation (LNAV)/vertical navigation (VNAV) operational service levels as well as 95% SPS accuracy for certain locations. Note that WAAS accuracy statistics presented are compiled only when all WAAS corrections (i.e., fast, long term, and ionospheric corrections) for at least four satellites are available; this is referred to as PA navigation mode. Table 2-1 also shows the percentage of time PA navigation mode was supported by WAAS at each receiver. The maximum and minimum LPV errors for this reporting period are:

• The maximum 95% CONUS horizontal LPV error was 1.569 meters observed at Arcata. • The maximum 95% CONUS vertical LPV error was 1.649 meters observed at Miami. • The minimum 95% CONUS horizontal LPV errors was 0.537 meters observed at Memphis. • The minimum 95% CONUS vertical LPV error was 0.692 meters observed at Salt Lake City.

Table 2-1. PA 95% Horizontal and Vertical Accuracy

Location Horizontal

(HAL=40m) (Meters)

Horizontal (HAL=556m)

(Meters)

Vertical (VAL=50m)

(Meters)

Percentage in PA

mode (%)

SPS Accuracy

95% Horizontal

95% Vertical

Arcata 1.569 1.569 1.309 100 * * Atlantic City 1.144 1.144 1.412 100 * * Oklahoma City 0.951 0.951 1.191 100 * * Albuquerque 0.719 0.719 0.792 100 1.67 4.22 Anchorage 0.555 0.555 1.213 100 1.5 3.96 Atlanta 0.929 0.929 1.071 100 2.04 4.22


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Location Horizontal

(HAL=40m) (Meters)

Horizontal (HAL=556m)

(Meters)

Vertical (VAL=50m)

(Meters)

Percentage in PA

mode (%)

SPS Accuracy

95% Horizontal

95% Vertical

Barrow 0.609 0.609 1.203 100 1.36 4.22 Bethel 0.517 0.517 1.030 100 1.47 4.06 Billings 0.735 0.735 0.908 100 1.85 3.91 Boston 0.896 0.896 0.870 100 2.33 3.93 Chicago 1.047 1.047 0.866 100 * * Cleveland 0.793 0.793 0.954 100 2.31 4.28 Cold Bay 0.605 0.605 1.187 100 1.48 4 Dallas 0.647 0.647 1.175 100 * * Denver 0.622 0.622 0.745 100 * * Fairbanks 0.509 0.509 1.105 100 1.48 3.87 Gander 0.859 0.859 0.989 100 2.21 3.18 Goose Bay 0.739 0.739 0.873 100 * * Houston 0.676 0.676 1.331 100 1.75 4.4 Iqaluit 0.877 0.877 1.326 100 1.49 3.75 Jacksonville 0.727 0.727 1.222 100 * * Juneau 0.643 0.643 1.081 100 1.46 3.5 Kansas City 0.575 0.575 0.853 100 2.04 4.13 Kotzebue 0.483 0.483 0.999 100 1.53 3.98 Los Angeles 0.902 0.902 1.113 100 1.75 4.51 Memphis 0.537 0.537 1.042 100 * * Merida 0.641 0.641 1.755 100 1.65 4.85 Mexico City 0.573 0.573 1.536 100 * * Miami 0.953 0.953 1.649 100 1.79 4.62 Minneapolis 0.856 0.856 0.818 100 2.16 4.01 New York 0.795 0.795 0.845 100 * * Oakland 0.805 0.805 1.016 100 1.77 4.54 Puerto Vallarta 0.601 0.601 1.651 100 * * Salt Lake City 0.655 0.655 0.692 100 1.7 4.08 San Jose Del Cabo 0.620 0.620 1.836 100 2.03 4.63 Seattle 0.697 0.697 0.843 100 1.63 3.9 Washington DC 1.004 1.004 0.827 100 2.32 4.19 Winnipeg 0.745 0.745 0.914 100 * *

NPA navigation mode is when only WAAS fast and long term corrections are available to a user (i.e., no ionospheric corrections). Table 2-2 shows the 95%, 99.999%, and maximum NPA horizontal position accuracy. The maximum and minimum NPA errors for this reporting period are as below:

• The maximum 95% horizontal error was 2.370 meters observed at Honolulu. • The maximum 99.999% horizontal error was 6.197 meters observed at Honolulu. • The minimum 95% horizontal error was 0.994 meters observed at Iqaluit. • The minimum 99.999% horizontal error was 1.983 meters observed at Barrow.

Table 2-2. NPA 95% and 99.999% Horizontal Accuracy

Location 95%

Horizontal (Meters)

99.999% Horizontal (Meters)

Percentage in NPA Mode

(%)

Maximum Horizontal

Error (Meters)

Albuquerque 1.062 3.107 100 3.289 Anchorage 1.143 2.426 100 2.563 Atlanta 1.354 3.521 100 3.753 Barrow 1.010 1.983 100 2.260 Bethel 1.145 2.226 100 2.609


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Location 95%

Horizontal (Meters)

99.999% Horizontal (Meters)

Percentage in NPA Mode

(%)

Maximum Horizontal

Error (Meters)

Billings 1.378 2.431 100 2.601 Boston 1.885 3.276 100 3.496 Cleveland 1.671 3.784 100 4.015 Cold Bay 1.118 3.131 100 3.743 Fairbanks 1.445 2.691 100 2.812 Gander 1.747 3.030 100 3.817 Honolulu 2.370 6.197 100 6.474 Houston 1.382 3.522 100 3.705 Iqaluit 0.994 2.380 100 4.349 Juneau 1.113 2.363 100 2.490 Kansas City 1.145 2.453 100 2.589 Kotzebue 1.244 2.396 100 2.489 Los Angeles 1.514 2.854 100 3.032 Merida 1.161 2.778 100 3.020 Miami 1.333 2.833 100 2.970 Minneapolis 1.739 3.249 100 3.467 Oakland 1.455 3.187 100 3.419 Salt Lake City 1.210 2.239 100 2.392 San Jose Del Cabo 1.348 3.442 100 3.655 San Juan 1.096 6.025 100 6.316 Seattle 1.187 2.046 100 2.924 Tapachula 1.278 5.075 100 5.315 Washington DC 1.925 3.991 100 4.108

Table 2-3 shows the quarterly maximum LPV error statistics: (1) the column Horizontal Error column shows the maximum position errors while the calculated HPL meets the LPV service level defined in Table 1-1, (2) the Vertical Error column shows the maximum position errors while the calculated VPL meets the LPV service level, (3) the Horizontal Error/HPL column and the Vertical Error/VPL column show the ratio of position error to protection level at the time the maximum error occurred, (4) the Horizontal Maximum Ratio column and the Vertical Maximum Ratio column show the maximum position error to protection level ratio for the quarter. During this reporting period, the maximum LPV horizontal error was 3.505 meters occurred at Arcata and maximum vertical LPV error was 5.292 meters occurred at Merida. Note that Grand Forks was not evaluated for this quarter.

Table 2-3. Maximum LPV Error Statistics

Location Horizontal

Error (m)

Horizontal Error HPL

Horizontal Maximum

Ratio

Vertical Error (m)

Vertical Error VPL

Vertical Maximum

Ratio Arcata 3.505 0.258 0.260 3.160 0.147 0.173 Atlantic City-a 2.303 0.147 0.216 3.467 0.179 0.179 Oklahoma City 2.273 0.208 0.242 2.891 0.188 0.194 Albuquerque 1.721 0.134 0.158 2.553 0.123 0.126 Anchorage 1.379 0.115 0.123 2.914 0.136 0.143 Atlanta 1.984 0.201 0.206 2.510 0.140 0.140 Barrow 3.039 0.114 0.189 5.114 0.186 0.202 Bethel 1.301 0.086 0.100 2.297 0.106 0.116 Billings 1.551 0.171 0.181 2.635 0.115 0.137 Boston 1.924 0.157 0.157 2.498 0.135 0.136 Chicago 2.116 0.210 0.214 2.440 0.135 0.139 Cleveland 2.141 0.142 0.182 2.727 0.111 0.150 Cold Bay 1.884 0.082 0.128 2.455 0.101 0.118 Dallas 1.663 0.174 0.174 2.768 0.135 0.190


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Location Horizontal

Error (m)

Horizontal Error HPL

Horizontal Maximum

Ratio

Vertical Error (m)

Vertical Error VPL

Vertical Maximum

Ratio Denver 1.504 0.155 0.155 2.297 0.128 0.128 Fairbanks 1.449 0.147 0.147 3.153 0.153 0.171 Gander 2.047 0.118 0.126 2.768 0.098 0.114 Goose Bay 1.664 0.091 0.116 2.162 0.104 0.110 Houston 1.748 0.161 0.170 3.203 0.159 0.208 Iqaluit 3.072 0.121 0.176 3.966 0.131 0.171 Jacksonville 1.787 0.145 0.175 3.166 0.153 0.163 Juneau 1.342 0.105 0.126 2.431 0.114 0.146 Kansas City 1.601 0.178 0.178 2.347 0.109 0.140 Kotzebue 1.959 0.127 0.134 2.654 0.101 0.133 Los Angeles 2.134 0.139 0.160 2.642 0.124 0.141 Memphis 1.599 0.165 0.165 2.527 0.135 0.163 Merida 1.871 0.080 0.125 5.292 0.148 0.169 Mexico City 1.584 0.069 0.127 3.982 0.080 0.152 Miami 2.041 0.178 0.178 4.233 0.149 0.192 Minneapolis 1.663 0.144 0.172 2.122 0.115 0.123 New York 1.875 0.125 0.160 2.050 0.100 0.129 Oakland 2.083 0.142 0.154 2.252 0.131 0.132 Puerto Vallarta 1.468 0.080 0.122 4.187 0.142 0.177 Salt Lake City 1.700 0.157 0.161 1.834 0.108 0.124 San Jose Del Cabo 1.594 0.046 0.117 4.450 0.157 0.181 Seattle 1.533 0.133 0.148 2.195 0.122 0.122 Washington DC 2.193 0.197 0.209 2.439 0.096 0.115 Winnipeg 1.627 0.148 0.149 2.650 0.117 0.162

Figure 2-1 through Figure 2-3 show the daily LPV 95% horizontal accuracy at the PA evaluation sites, and Figure 2-4 through Figure 2-6 show the daily LPV 95% vertical accuracy. Noteworthy increases in the 95% PA position errors over multiple evaluation sites due to geomagnetic activity in Figure 2-1 through Figure 2-6 are listed below.

• January 5, 2020—Position errors in CONUS, Canada, and Mexico were elevated. The maximum 95% horizontal and vertical LPV errors were 1.877 meters and 2.924 meters at Arcata and Puerto Vallarta, respectively. The Kp index was 4.

• January 31, 2020—Position errors in CONUS were elevated. The maximum 95% horizontal and vertical LPV errors were 1.437 meters and 1.502 meters at Los Angeles and Miami, respectively. The Kp index was 4.

• February 19, 2020—Position errors in CONUS, Alaska, Canada, and Mexico were elevated. The maximum 95% horizontal and vertical LPV errors were 1.357 meters and 2.323 meters at Chicago and Merida, respectively. The Kp index was 5.

• March 1, 2020—Position errors in CONUS were elevated. The maximum 95% horizontal and vertical LPV errors were 1.846 meters and 1.684 meters at Arcata and Miami. The Kp index was 4.


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Figure 2-1. LPV 95% Horizontal Accuracy


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Figure 2-4. LPV 95% Vertical Accuracy


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Figure 2-7 and Figure 2-8 show the daily NPA 95% horizontal accuracy at the NPA evaluation sites for the reporting period. The increases in 95% NPA position errors due to geomagnetic activity occurred on January 5, 2020 and February 18–19, 2020.


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Figure 2-7. NPA 95% Horizontal Accuracy


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Figure 2-8. NPA 95% Horizontal Accuracy

Figure 2-9 through Figure 2-12 show the distributions of the vertical and horizontal errors at all 38 WAAS receiver for the quarter. Figure 2-9 and Figure 2-10 show the triangular distributions of vertical position error (VPE) versus VPL and horizontal position error (HPE) versus HPL: (1) the horizontal axis is the position error, (2) the vertical axis is the WAAS protection level where lower protection levels equate to better availability, (3) the diagonal line shows the point where error equals protection level, (4) above and to the left of the diagonal line show where errors are bounded (WAAS is providing integrity in the position domain), and (5) below and to the right show where errors are not bounded (HMI could be present). Figure 2-11 and Figure 2-12 show the 2-D histograms of HPE, VPE, and normalized position errors: (1) the blue trace shows the distributions of the actual HPE and VPE; (2) the horizontal axis is the position errors and the vertical axis is the total count of data samples (log scale) in each 0.1-meter bin; (3)


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the magenta trace shows the distributions of the actual horizontal and vertical errors normalized by one-sigma value of the protection level: horizontal protection level (HPL/6.0) and vertical protection level (VPL/5.33); (4) the horizontal axis is the standard units and vertical axis is the observed distribution of normalized errors data samples in each 0.1-sigma bin. The narrowness of the normalized error distributions indicates good safety performance.

Figure 2-9. LPV Horizontal Error Bounding Triangle Chart


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Figure 2-10. LPV Vertical Error Bounding Triangle Chart


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Figure 2-11. LPV 2-D Horizontal Error Distribution Histogram


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Figure 2-12. LPV 2-D Vertical Error Distribution Histogram

3.0 AVAILABILITY

The WAAS availability evaluation documents the percentage of time the WAAS provided service for the operational service levels defined in Table 1-1. The RTCA DO-229D VPL and HPL were computed for each evaluated receiver. Table 3-1 shows the evaluated receivers, the 99% maintained protection levels, and the percentage in PA mode (described in Section 2.0). The maximum and minimum VPL and HPL for this reporting period are listed as:

• The maximum 99% CONUS HPL was 15.911 meters observed at Miami • The maximum 99% CONUS VPL was 30.704 meters observed at Oakland • The minimum 99% CONUS HPL was 10.775 meters observed at Denver • The minimum 99% CONUS VPL was 20.240 meters observed at Kansas City • The maximum 99% Alaska HPL was 18.981 meters observed at Cold Bay • The maximum 99% Alaska VPL was 29.119 meters observed at Barrow • The minimum 99% Alaska HPL was 13.032 meters observed at Juneau • The minimum 99% Alaska VPL was 21.154 meters observed at Anchorage


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Table 3-1. 99% Protection Level

Location 99% HPL

(Meters)

99% VPL

(Meters)

Percentage in PA mode

Arcata 14.519 30.138 100 Atlantic City 15.551 24.296 100 Oklahoma City 11.733 22.297 100 Albuquerque 12.030 22.156 100 Anchorage 13.425 21.154 100 Atlanta 12.589 22.871 100 Barrow 16.412 29.119 100 Bethel 15.127 23.005 100 Billings 11.945 20.590 100 Boston 15.607 21.440 100 Chicago 12.007 20.352 100 Cleveland 15.581 24.262 100 Cold Bay 18.981 25.966 100 Dallas 10.980 22.361 100 Denver 10.775 25.003 100 Fairbanks 13.534 21.963 100 Gander 21.379 29.427 100 Goose Bay 19.718 26.358 100 Houston 11.213 23.337 100 Iqaluit 18.070 28.677 100 Jacksonville 13.496 25.475 100 Juneau 13.032 22.540 100 Kansas City 11.282 20.240 100 Kotzebue 15.219 26.013 100 Los Angeles 14.503 29.698 100 Memphis 11.612 22.898 100 Merida 17.436 33.112 100 Mexico City 22.147 34.819 100 Miami 15.911 27.398 100 Minneapolis 12.122 20.313 100 New York 15.122 22.517 100 Oakland 14.253 30.704 100 Puerto Vallarta 25.556 38.123 100 Salt Lake City 10.962 21.942 100 San Jose Del Cabo 23.282 38.910 100 Seattle 12.967 22.439 100 Washington DC 14.384 23.485 100 Winnipeg 13.402 21.772 100

Availability of LP, LPV, and LPV200 services are evaluated by monitoring the WAAS protection levels at receiver locations. Service is available when the VPL is less than the vertical alert limit (VAL) and the HPL is less than the horizontal alert limit (HAL). When the protection level exceeds the alert limit, the service is unavailable and an outage in service is recorded along with its duration. The operational service is not available again until both protection levels are within the alert limits for at least 15 minutes. Although this will cause minimal reduction in operational service availability, it will substantially reduce the number of service outages and prevent excessive switching in/out of service availability. Table 3-2 shows the percentage of time LP, LPV, and LPV200 service is available using the 15-minute window criteria. Table 3-3 shows LP, LPV, and LPV200 service outages and associated outage rates. The outage rate is the percentage of theoretically interrupted approaches through a loss of operational service once the approach had started.


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Figure 3-1 through Figure 3-6 show the daily availability of LPV and LPV200 service levels. Figure 3-7 through Figure 3-12 show the daily interruptions of LPV and LPV200 service levels.

Table 3-2. PA Availability (15-minute window)

Location LP WAAS

With 15 Minute Window (%)

LPV WAAS With 15 Minute Window

(%)

LPV200 WAAS With 15 Minute Window

(%) Arcata 100 100 100 Atlantic City-GA 100 100 100 Atlantic City-GB 100 100 100 Atlantic City-a 100 100 100 Oklahoma City 100 100 100 Albuquerque 100 100 100 Anchorage 100 100 100 Atlanta 100 100 100 Barrow 100 100 99.76 Bethel 100 100 100 Billings 100 100 100 Boston 100 100 100 Chicago 100 100 100 Cleveland 100 100 100 Cold Bay 100 100 99.99 Dallas 100 100 100 Denver 100 100 100 Fairbanks 100 100 100 Gander 100 100 99.87 Goose Bay 100 100 100 Houston 100 100 100 Iqaluit 99.99 99.98 99.97 Jacksonville 100 100 100 Juneau 100 100 100 Kansas City 100 100 100 Kotzebue 100 100 99.99 Los Angeles 100 100 100 Memphis 100 100 100 Merida 100 99.7 99.33 Mexico City 100 99.92 98.52 Miami 100 100 100 Minneapolis 100 100 100 New York 100 100 100 Oakland 100 100 100 Puerto Vallarta 100 99.71 96.53 Salt Lake City 100 100 100 San Jose Del Cabo 100 99.42 98.35 Seattle 100 100 100 Washington DC 100 100 100 Winnipeg 100 100 100


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Table 3-3. LPV and LPV200 Outage Rate (Per 150 sec approach)

Location LP

Outages (Number)

LP Outage Rates

LPV Outages

(Number)

LPV Outage Rates

LPV200 Outages

(Number)

LPV200 Outage Rates

Arcata 0 0.000000 0 0.000000 0 0.000000 Atlantic City-GA 0 0.000000 0 0.000000 0 0.000000 Atlantic City-GB 0 0.000000 0 0.000000 0 0.000000 Atlantic City-a 0 0.000000 0 0.000000 0 0.000000 Oklahoma City 0 0.000000 0 0.000000 0 0.000000 Albuquerque 0 0.000000 0 0.000000 0 0.000000 Anchorage 0 0.000000 0 0.000000 0 0.000000 Atlanta 0 0.000000 0 0.000000 0 0.000000 Barrow 2 0.000038 7 0.000134 92 0.001761 Bethel 0 0.000000 0 0.000000 0 0.000000 Billings 0 0.000000 0 0.000000 0 0.000000 Boston 0 0.000000 0 0.000000 0 0.000000 Chicago 0 0.000000 0 0.000000 0 0.000000 Cleveland 0 0.000000 0 0.000000 0 0.000000 Cold Bay 0 0.000000 0 0.000000 2 0.000038 Dallas 0 0.000000 0 0.000000 0 0.000000 Denver 0 0.000000 0 0.000000 0 0.000000 Fairbanks 0 0.000000 0 0.000000 0 0.000000 Gander 0 0.000000 0 0.000000 20 0.000382 Goose Bay 0 0.000000 0 0.000000 0 0.000000 Houston 0 0.000000 0 0.000000 0 0.000000 Iqaluit 2 0.000038 5 0.000095 14 0.000267 Jacksonville 0 0.000000 0 0.000000 0 0.000000 Juneau 0 0.000000 0 0.000000 0 0.000000 Kansas City 0 0.000000 0 0.000000 0 0.000000 Kotzebue 0 0.000000 1 0.000019 3 0.000057 Los Angeles 0 0.000000 0 0.000000 0 0.000000 Memphis 0 0.000000 0 0.000000 3 0.000057 Merida 0 0.000000 55 0.001053 83 0.001596 Mexico City 0 0.000000 32 0.000611 293 0.005679 Miami 0 0.000000 0 0.000000 0 0.000000 Minneapolis 0 0.000000 0 0.000000 0 0.000000 New York 0 0.000000 0 0.000000 0 0.000000 Oakland 0 0.000000 0 0.000000 0 0.000000 Puerto Vallarta 0 0.000000 92 0.001764 509 0.010081 Salt Lake City 0 0.000000 0 0.000000 0 0.000000 San Jose Del Cabo 0 0.000000 69 0.001353 208 0.004122 Seattle 0 0.000000 0 0.000000 0 0.000000 Washington DC 0 0.000000 0 0.000000 0 0.000000 Winnipeg 0 0.000000 0 0.000000 0 0.000000


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Figure 3-1. LPV Instantaneous Availability


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Figure 3-4. LPV200 Instantaneous Availability


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Figure 3-7. LPV Outages


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Figure 3-10. LPV200 Outages


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Availability of NPA service is evaluated by monitoring the WAAS HPL at receiver locations. Service is available when the HPL is less than a HAL of 556 meters. The service is unavailable when HPL exceeds the HAL or when a WAAS navigation message is not received, and the service outage and its duration are recorded. NPA service is not available again until the HPL is within the HAL for at least 15 minutes. Table 3-4 shows the percentage of time that NPA service is available using the 15-minute window criteria. Table 3-5 shows the NPA service outages and associated outage rates. The outage rate is the percentage of theoretically interrupted NPA approaches through a loss of operational service once the approach had started.


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Table 3-4. NPA Availability (15-minute window)

Location

NPA Availability (Excluding RAIM/FDE)

(%) Arcata 99.9838 Atlantic City-GA 99.9566 Atlantic City-GB 99.9566 Oklahoma City 99.9616 Albuquerque 100 Anchorage 100 Atlanta 100 Barrow 100 Bethel 100 Billings 100 Boston 100 Cleveland 100 Cold Bay 100 Fairbanks 100 Gander 100 Honolulu 100 Houston 100 Iqaluit 100 Juneau 100 Kansas City 100 Kotzebue 100 Los Angeles 100 Merida 100 Miami 100 Minneapolis 100 Oakland 100 Salt Lake City 100 San Jose Del Cabo 100 San Juan 100 Seattle 100 Tapachula 100 Washington DC 100

Table 3-5. NPA Outage Rates (Excluding FD/FDE)

Location NPA

Outages (Number)

NPA Outage Rates

Albuquerque 0 0 Anchorage 0 0 Atlanta 0 0 Barrow 0 0 Bethel 0 0 Billings 0 0 Boston 0 0 Cleveland 0 0 Cold Bay 0 0 Fairbanks 0 0 Gander 0 0 Honolulu 0 0


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Location NPA

Outages (Number)

NPA Outage Rates

Houston 0 0 Iqaluit 0 0 Juneau 0 0 Kansas City 1 0.000019 Kotzebue 0 0 Los Angeles 0 0 Merida 0 0 Miami 0 0 Minneapolis 0 0 Oakland 0 0 Salt Lake City 0 0 San Jose Del Cabo 2 0.000039 San Juan 0 0 Seattle 0 0 Tapachula 0 0 Washington DC 0 0

The availability decreases for this quarter were due to satellite outages, geomagnetic activity, communication outages, radio frequency interference (RFI), and elevated UDRE and GIVE values. Noteworthy events that affected availability are:

• January 8–Local RFI at Denver caused a reduction and eventual loss of SV tracking. The outage occurred at 18:35 GMT.

• January 9–Satellite maintenance elevated UDREs on PRN9 and reduced LPV200 availability in Canada and Alaska.

• January 16–Satellite maintenance elevated UDREs on PRN28 and reduced LPV200 availability in Alaska and Canada.

• January 22–Local RFI at Denver caused a reduction and eventual loss of SV tracking. The outage occurred at 18:59 GMT.

• February 4–A GUS switchover on CRE caused a reduction of LPV200 availability in Canada. • February 13–A UDRE spike on PRN21 caused a reduction of LPV200 availability in CONUS. • February 19–Local RFI at Denver caused a reduction and eventual loss of SV tracking. The outage

occurred at 15:55 GMT. • February 20–Satellite maintenance elevated UDREs on PRN11 and reduced LPV200 availability in

Canada. • February 25–A UDRE spike on PRN21 caused a reduction of LPV200 availability in CONUS. • March 13–Local RFI at Kansas City caused a reduction and eventual loss of SV tracking. The outage

occurred at 22:02 GMT.

4.0 COVERAGE

The WAAS coverage area evaluation estimates the percent of service volume where WAAS provided service for the operational service levels defined in Table 1-1. The WAAS message and GPS/GEO satellite status are used to determine WAAS availability across North America. For PA coverage, protection levels were calculated at 30-second intervals at 1-degree spacing over the PA service volume, whereas for NPA coverage, the protection levels were calculated at 30-second intervals at 5-degree spacing over the NPA service volume. Daily PA analysis was conducted for LP, LPV, and LPV200 service levels. The PA coverage plots provide 100%, 99.9%, 99%, 98%, and 95% availability contours. Figure 4-1 shows the rollup LP North America coverage, Figure 4-2 shows the rollup LPV North America coverage, Figure 4-3 shows the rollup LPV200 North America coverage, Figure 4-4 shows the daily LPV and LPV200 CONUS coverage, Figure 4-5 shows the daily LPV Alaska coverage at 99% availability and ionosphere Kp index values, and Figure 4-6 shows the daily LPV and LPV200 Canada coverage


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at 99% availability and ionosphere Kp index values. See Appendix B for coverage plots of 98% LP and LPV availability contour and 99% LPV200 availability contour. Kp quantifies the disturbance in the Earth's magnetic field and is an indicator of solar storms causing geomagnetic disturbances, which can cause an unpredictable ionosphere. When the WAAS detects a disturbed ionosphere, it increases GIVE values that may result in unavailable PA service.


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Figure 4-1. LP North America Coverage for the Quarter


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Figure 4-2. LPV North America Coverage for the Quarter


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Figure 4-3. LPV200 North America Coverage for the Quarter


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Figure 4-4. Daily LPV and LPV200 CONUS Coverage


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Figure 4-5. Daily LPV and LPV200 Alaska Coverage


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Figure 4-6. Daily LPV and LPV200 Canada Coverage


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Daily analysis for NPA was conducted for the Required Navigation Performance (RNP) 0.1 and RNP 0.3 service levels based on a 100% availability requirement. The NPA coverage plots provide 100%, 99.9%, and 99% availability contours. Figure 4-7 shows the rollup RNP 0.1 coverage and Figure 4-8 shows the rollup RNP 0.3 coverage for the quarter. Figure 4-9 shows the daily RNP coverage at 100% availability and ionosphere Kp index values for this quarter.


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Figure 4-7. RNP 0.1 Coverage for the Quarter


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Figure 4-8. RNP 0.3 Coverage for the Quarter


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Figure 4-9. Daily RNP Coverage


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The coverage decreases for this quarter were due to satellite outages, geomagnetic activity, communication outages, and elevated UDRE and GIVE values. Noteworthy events that affected coverage are:

• January 9–Satellite maintenance elevated UDREs on PRN9 and reduced LPV200 coverage in Canada and Alaska.

• January 16–Satellite maintenance elevated UDREs on PRN28 and reduced LPV200 coverage in Alaska and Canada.

• February 4–A GUS switchover on CRE caused a reduction of LPV200 coverage in Canada. • February 13–A UDRE spike on PRN21 caused a reduction of LPV200 coverage in CONUS. • February 20–Satellite maintenance elevated UDREs on PRN11 and reduced LPV200 coverage in Canada. • February 25–A UDRE spike on PRN21 caused a reduction of LPV200 coverage in CONUS.

5.0 INTEGRITY

5.1 HMI Analysis

Integrity analysis includes the identification and evaluation of HMI as well as the generation of the safety index to illustrate the safety margin provided by WAAS protection levels. The safety index is a metric that shows how well the protection levels are bounding the maximum observed error when LPV service is available. The horizontal and vertical safety margin index is the ratio of HPL/HPE and VPL/VPE, respectively, at the time the maximum position error occurred. Section 2.0 provides a detailed description of the methodology for computing HPL, VPL, and position errors. A computed safety margin index of greater than one indicates safe bounding of the greatest observed error, less than one indicates that the maximum error was not bounded, and a result equal to one means that the maximum position error was equal to the protection level. An HMI event occurs if the position error exceeds the protection level in the vertical or horizontal dimensions at any time and coupled with the passage of 6.2 seconds before this event is corrected by WAAS. Table 5-1 lists the safety margin index and the number of HMI events. For this reporting period, the lowest safety margin index is 4.203 at Arcata and there were no HMI events. There has not been an HMI event since WAAS was made available to the public in August 2000. In July 2003, WAAS was commissioned by the FAA for safety of life services.

Table 5-1. Minimum Safety Margin Index and HMI Statistics

Location Horizontal

Safety Index (meters)

Vertical Safety Index

(meters)

Number of

HMIs

Arcata 4.203 6.818 0 Atlantic City 6.788 5.722 0 Oklahoma City 4.807 5.307 0 Albuquerque 7.471 8.097 0 Anchorage 8.698 7.339 0 Atlanta 4.984 7.164 0 Barrow 8.763 5.387 0 Bethel 11.635 9.434 0 Billings 5.842 8.674 0 Boston 6.384 7.429 0 Chicago 4.751 7.385 0 Cleveland 7.022 9.034 0 Cold Bay 12.159 9.877 0 Dallas 5.752 7.416 0 Denver 6.440 7.793 0


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Location Horizontal

Safety Index (meters)

Vertical Safety Index

(meters)

Number of

HMIs

Fairbanks 6.802 6.555 0 Gander 8.457 10.166 0 Goose Bay 10.993 9.605 0 Houston 6.205 6.275 0 Iqaluit 8.267 7.648 0 Jacksonville 6.909 6.546 0 Juneau 9.534 8.756 0 Kansas City 5.605 9.211 0 Kotzebue 7.889 9.856 0 Los Angeles 7.198 8.045 0 Memphis 6.059 7.386 0 Merida 12.562 6.776 0 Mexico City 14.388 12.503 0 Miami 5.617 6.714 0 Minneapolis 6.948 8.695 0 New York 8.016 9.978 0 Oakland 7.042 7.655 0 Puerto Vallarta 12.567 7.032 0 Salt Lake City 6.375 9.270 0 San Jose Del Cabo 21.954 6.361 0 Seattle 7.527 8.192 0 Washington DC 5.072 10.446 0 Winnipeg 6.766 8.552 0

5.2 Broadcast Alerts

The WAAS transmits alert messages for user protection when the active WAAS corrections are no longer bound by the UDREs. Alerts increase the UDRE for one or more PRNs, which can reduce the weighting of the satellite or exclude the satellite from the navigation solution. An increase in UDREs after an alert effectively increases the user protection levels (HPL and VPL), which affects the availability. Additionally, if an alert message sequence lasts for more than 12 seconds, the WAAS fast corrections can time out and cause a loss of continuity. Table 5-2 shows the total number of alerts and the average number of alerts per day.

Table 5-2. WAAS SV Alert

Number of Alerts Average Alerts Per Day Message Type SM9 S15 CRE SM9 S15 CRE

T2 38 38 50 0.4176 0.4176 0.5495 T3 284 284 287 3.1209 3.1209 3.1538 T4 12 13 12 0.1319 0.1429 0.1319 T5 0 0 0 0 0 0 T6 0 1 0 0 0.0110 0 T24 0 0 0 0 0 0 T26 0 0 0 0 0 0

Total SV Alerts : 334 336 349 3.6703 3.6923 3.8351 Days in Service 91 91 91

Figure 5-1 provides the daily SV alerts. The number of alerts on one GEO is often the same as the number of alerts on the other GEO, therefore, lines tend to overlap in most points on this plot.


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Figure 5-1. SV Daily Alert Trend

5.3 Availability of WAAS Messages (SM9, S15, and CRE)

Accurate and current calculations of user position are dependent on the broadcast and receipt of the WAAS message within precise time specifications. This aspect of the WAAS is critical to maintaining continuity requirements. Each message type in the WAAS SIS has a specific timeout interval and expected worst-case broadcast interval. Table 5-3 lists the maximum intervals at which each message must broadcast to meet system requirements.

Table 5-3. Update Rates for WAAS Messages

Data Associated Message Types

Maximum Update Interval

(seconds)

En Route, Terminal,

NPA Timeout (seconds)

Precision Approach Timeout

(seconds)

WAAS in Test Mode 0 6 N/A N/A PRN Mask 1 60 None None UDREI 2-6, 24 6 18 12

Fast Corrections 2-5, 24 See Table A-8 in RTCA DO-229C See Table A-8 in RTCA DO-229C

See Table A-8 in RTCA DO-229C

Long Term Corrections 24, 25 120 360 240

GEO Nav. Data 9 120 360 240 Fast Correction Degradation 7 120 360 240

Weighting Factors 8 120 240 240 Degradation Parameters 10 120 360 240

Ionospheric Grid Mask 18 300 None None Ionospheric Corrections 26 300 600 600


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Data Associated Message Types

Maximum Update Interval

(seconds)

En Route, Terminal,

NPA Timeout (seconds)

Precision Approach Timeout

(seconds)

UTC Timing Data 12 300 None None Almanac Data 17 300 None None

GUS switchovers and broadcast WAAS alerts can interrupt the normal broadcast message stream. If these events occur when the maximum interval of a specific message is approaching, that message may be delayed, resulting in its late transmittal. For this quarter, statistics reported for late messages were mainly caused by GEO SIS outages, GUS switchovers, and SV alerts; excluding message type 7 and 10. Furthermore, the delay of message types 7 and 10 had little or no impact on user performance and safety, and were not caused by GEO SIS outages, GUS switchovers, or SV alerts. Table 5-4 through Table 5-8 show statistics for fast correction, long correction, ephemeris covariance, ionosphere correction, and ionospheric mask message rates broadcasted on SM9 GEO. Table 5-9 through Table 5-13 show statistics for message rates broadcasted on S15 GEO. Table 5-14 through Table 5-18 show statistics for message rates broadcasted on CRE GEO.

Table 5-4. WAAS Fast Correction and Degradation Message Rates–SM9

Message Type

On Time (number received)

Late (number received)

Max Late Length (seconds)

1 103024 0 0 2 1310440 54 25 3 1311181 48 25 4 1310379 36 22 7 96412 11 128 9 92132 1 185 10 96461 10 195 17 31131 0 0

Table 5-5. WAAS Long Correction Message Rates (Type 24 and 25)–SM9

PRN On Time (number received) Late

(number received) Max Late Length

(seconds) 1 48926 0 0 2 47472 0 0 3 47967 0 0 4 40371 0 0 5 47375 0 0 6 47452 0 0 7 46979 0 0 8 48346 0 0 9 46477 0 0 10 47082 0 0 11 48658 0 0 12 46821 0 0 13 48944 0 0 14 46511 0 0 15 47585 0 0 16 47309 0 0 17 47439 0 0 19 46161 0 0 20 45838 0 0 21 47636 0 0


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(seconds) 22 48064 0 0 23 35712 0 0 24 49192 0 0 25 48407 1 180 26 47630 0 0 27 48543 0 0 28 47352 0 0 29 46878 0 0 30 46733 0 0 31 47091 0 0 32 46188 0 0

Table 5-6. WAAS Ephemeris Covariance Message Rates (Type 28)–SM9



(seconds) 1 40200 2 152 2 39000 0 0 3 39381 1 208 4 33152 0 0 5 38848 0 0 6 38923 2 208 7 38547 0 0 8 39698 0 0 9 38130 0 0 10 38602 0 0 11 40034 2 203 12 38460 0 0 13 40220 1 144 14 38159 1 210 15 39070 0 0 16 38825 0 0 17 38968 0 0 19 37907 0 0 20 37605 0 0 21 39145 0 0 22 39514 0 0 23 29316 0 0 24 40410 0 0 25 39734 1 210 26 39075 0 0 27 39899 0 0 28 38890 1 138 29 38499 1 208 30 38424 0 0 31 38613 0 0 32 37901 0 0

131 75550 0 0 133 75518 0 0 138 75568 0 0


Report 72 57

Table 5-7. WAAS Ionospheric Correction Message Rates (Type 26)–SM9

Band Block On Time (number received) Late


(seconds) 0 0 27295 1 301 0 1 27296 7 579 0 2 27283 4 583 1 0 27298 2 302 1 1 27294 2 301 1 2 27296 0 0 1 3 27303 5 306 1 4 27293 3 304 2 0 27295 5 306 2 1 27306 2 305 2 2 27291 5 305 2 3 27295 5 304 2 4 27300 0 0 3 0 27299 5 304 3 1 27294 2 301 3 2 27297 3 302 9 0 27297 3 301 9 1 27305 2 306 9 2 27290 1 305 9 3 27282 5 304 9 4 27293 6 306 9 5 27295 5 304 9 6 27310 6 306

Table 5-8. WAAS Ionospheric Mask Message Rates (Type 18)–SM9

Band On Time (number received) Late


(seconds) 0 35345 0 0 1 35396 0 0 2 35318 0 0 3 35384 0 0 9 35367 0 0

Table 5-9. WAAS Fast Correction and Degradation Message Rates–S15

Message Type On Time (number received)



1 103406 1 124 2 1310435 54 14 3 1311177 48 10 4 1310379 34 10 7 96910 15 194 9 92127 0 0

10 96739 5 126 17 31152 0 0


Report 72 58

Table 5-10. WAAS Long Correction Message Rates (Type 24 and 25)–S15



(seconds) 1 48917 0 0 2 47479 0 0 3 47957 0 0 4 40368 0 0 5 47371 0 0 6 47443 0 0 7 46961 0 0 8 48337 0 0 9 46476 0 0 10 47061 1 171 11 48650 0 0 12 46816 0 0 13 48930 0 0 14 46503 0 0 15 47574 0 0 16 47316 0 0 17 47442 0 0 19 46145 0 0 20 45828 0 0 21 47633 0 0 22 48056 0 0 23 35705 0 0 24 49185 0 0 25 48406 0 0 26 47624 0 0 27 48539 0 0 28 47346 0 0 29 46878 0 0 30 46724 0 0 31 47091 0 0 32 46182 0 0

Table 5-11. WAAS Ephemeris Covariance Message Rates (Type 28)–S15

PRN On Time (number received) Late (number

received) Max Late Length

(seconds) 1 40175 1 182 2 38992 0 0 3 39364 0 0 4 33141 0 0 5 38841 0 0 6 38924 0 0 7 38552 0 0 8 39667 1 184 9 38119 0 0 10 38622 0 0 11 40030 0 0 12 38468 0 0 13 40226 0 0 14 38158 0 0 15 39050 0 0 16 38838 0 0


Report 72 59

PRN On Time (number received) Late (number

received) Max Late Length

(seconds) 17 38958 0 0 19 37911 0 0 20 37597 0 0 21 39141 0 0 22 39495 0 0 23 29315 0 0 24 40405 0 0 25 39737 0 0 26 39082 0 0 27 39884 0 0 28 38880 1 166 29 38500 0 0 30 38399 0 0 31 38613 0 0 32 37909 0 0

131 75525 0 0 133 75522 0 0 138 75527 0 0

Table 5-12. WAAS Ionospheric Correction Message Rates (Type 26)–S15

Band Block On Time (number received)



0 0 27285 5 302 0 1 27288 2 306 0 2 27301 5 306 1 0 27285 4 305 1 1 27279 6 304 1 2 27286 3 306 1 3 27299 6 312 1 4 27281 4 306 2 0 27295 2 301 2 1 27293 4 306 2 2 27291 6 305 2 3 27281 4 307 2 4 27282 7 310 3 0 27290 3 301 3 1 27281 0 0 3 2 27306 3 301 9 0 27294 7 306 9 1 27286 3 304 9 2 27292 1 301 9 3 27281 4 305 9 4 27288 1 301 9 5 27287 6 304 9 6 27293 4 301


Report 72 60

Table 5-13. WAAS Ionospheric Mask Message Rates (Type 18)–S15



(seconds) 0 35360 0 0 1 35402 0 0 2 35422 0 0 3 35409 0 0 9 35377 0 0

Table 5-14. WAAS Fast Correction and Degradation Message Rates–CRE

Message Type

On Time (number received)



1 105022 0 0 2 1310450 65 13 3 1311169 56 14 4 1310336 58 18 7 98300 4 125 9 92124 0 0 10 98285 9 131 17 31280 0 0

Table 5-15. WAAS Long Correction Message Rates (Type 24 and 25)–CRE



(seconds) 1 48909 0 0 2 47472 0 0 3 47949 0 0 4 40372 0 0 5 47370 0 0 6 47452 0 0 7 46968 0 0 8 48329 0 0 9 46474 0 0 10 47066 0 0 11 48650 0 0 12 46818 0 0 13 48865 0 0 14 46509 0 0 15 47568 0 0 16 47309 0 0 17 47434 0 0 19 46143 0 0 20 45825 0 0 21 47629 1 161 22 48052 0 0 23 35695 0 0 24 49178 0 0 25 48414 0 0 26 47617 0 0 27 48541 0 0 28 47351 0 0 29 46884 0 0 30 46725 0 0


Report 72 61



(seconds) 31 47087 0 0 32 46179 0 0

Table 5-16. WAAS Ephemeris Covariance Message Rates (Type 28)–CRE



(seconds) 1 40190 0 0 2 38993 0 0 3 39380 0 0 4 33135 0 0 5 38846 0 0 6 38919 0 0 7 38541 0 0 8 39675 0 0 9 38128 0 0 10 38613 2 183 11 40031 0 0 12 38478 1 187 13 40164 1 136 14 38172 0 0 15 39036 0 0 16 38812 1 204 17 38948 0 0 19 37912 0 0 20 37583 0 0 21 39144 0 0 22 39491 1 193 23 29298 0 0 24 40396 1 135 25 39758 0 0 26 39083 0 0 27 39872 1 142 28 38882 0 0 29 38506 0 0 30 38393 0 0 31 38608 0 0 32 37892 0 0

131 75483 2 5488 133 75575 0 0 138 75554 0 0

Table 5-17. WAAS Ionospheric Correction Message Rates (Type 26)–CRE



(seconds) 0 0 27294 0 0 0 1 27281 5 305 0 2 27285 1 304 1 0 27282 10 339 1 1 27289 6 550 1 2 27277 7 352 1 3 27289 4 374 1 4 27278 7 383


Report 72 62



(seconds) 2 0 27281 4 388 2 1 27295 2 352 2 2 27285 4 383 2 3 27279 2 394 2 4 27276 5 370 3 0 27287 6 377 3 1 27287 6 392 3 2 27280 5 370 9 0 27284 5 369 9 1 27280 5 374 9 2 27288 5 352 9 3 27289 4 350 9 4 27279 6 328 9 5 27282 4 303 9 6 27285 5 306

Table 5-18. WAAS Ionospheric Mask Message Rates (Type 18)–CRE



(seconds) 0 35594 1 322 1 35562 0 0 2 35618 0 0 3 35629 1 305 9 35620 0 0

5.4 Satellite Glitches

The GPS satellites will occasionally experience periods of signal carrier stability glitches of varying magnitude. These glitches are short degradations in the signal, which in severe cases may cause WAAS to lose track or cycle slip for some or all of the WAAS receivers. The more severe glitches will cause the WAAS-reported UDRE to increase to “Not Monitored” and result in an alert. Figure 5-2 shows satellite glitches visible to WAAS for the quarter. Glitches are categorized into four severity levels. Severity zero glitches occur when a WAAS reference station receiver tracks more than 14 satellites. The WAAS reference station software is limited to sending data for no more than 14 satellites. Severity one glitches cause a significant number of the receivers to report bad subframe parity data, cycle slips, or when the receivers lose track of L1 and/or L2. Severity two glitches cause all of the receivers to report bad subframe parity data and no SQM data. Severity three glitches cause all of the receivers to lose track of both L1 and L2. For this reporting period, severity zero glitches were observed for a short period of time daily on PRN9 and PRN26 when more than 14 GPS satellites were visible to the Alaska region.


Report 72 63

Figure 5-2. SV Glitch Trend


Report 72 64

6.0 SV RANGE ACCURACY

Range accuracy evaluation computes the probability that the WAAS UDRE and GIVE statistically bound 99.9% of the range residuals for each satellite tracked by the receiver. A UDRE is broadcasted by the WAAS for each monitored satellite and the 99.9% bound (3.29 sigma) of the pseudorange residual error after application of fast and long-term corrections is checked. The pseudorange residual error is determined by taking the difference between the raw pseudorange and a calculated reference range. The reference range is equal to the true range between the corrected satellite position and surveyed user antenna plus all corrections (i.e., WAAS fast clock, WAAS long-term clock, WAAS ionospheric delay, tropospheric delay, receiver clock bias, and multipath). Because the true ionospheric delay and multipath error are not precisely known, the estimated variance in these error sources are added to the UDRE before comparing it to the residual error. The GPS satellite range residual errors were calculated for 12 WAAS receivers during the quarter. Table 6-1 and Table 6-2 show the range error 95% index and 99.9% bounding statistics for each SV at the selected locations. Figure 6-1 through Figure 6-3 show the 95% range error for each SV measured by the WAAS receivers at the Chicago reference station.


Report 72 65

Table 6-1. Range Error 95% Index and 3.29 Sigma Bounding

Site Minneapolis Chicago Boston Juneau Honolulu Salt Lake City

PRN ↓

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

1* 0.982 100 1.169 100 1.397 100 1.052 100 1.562 100 1.170 100 2 0.894 100 0.858 100 0.814 100 1.237 100 1.348 100 1.268 100

3* 0.770 100 1.571 100 1.825 100 0.862 100 1.390 100 1.829 100 4 0.876 100 0.798 100 0.907 100 0.805 100 1.089 100 0.915 100 5 0.851 100 1.014 100 1.096 100 0.990 100 1.228 100 0.783 100

6* 0.858 100 0.960 100 1.088 100 0.816 100 1.260 100 1.167 100 7 0.963 100 1.292 100 0.811 100 0.944 100 1.513 100 0.740 100

8* 1.318 100 0.959 100 0.967 100 1.340 100 1.035 100 0.857 100 9* 0.769 100 0.759 100 0.865 100 0.763 100 1.568 100 0.819 100 10 1.052 100 1.137 100 0.976 100 1.597 100 1.023 100 1.186 100 11 0.978 100 1.030 100 1.218 100 1.240 100 2.652 100 1.371 100 12 1.042 100 0.959 100 1.397 100 1.227 100 1.196 100 1.038 100 13 0.986 100 0.980 100 1.052 100 1.220 100 1.139 100 0.781 100 14 1.013 100 1.680 100 0.796 100 1.256 100 1.088 100 1.210 100 15 1.158 100 0.923 100 1.131 100 1.031 100 1.241 100 0.788 100 16 0.899 100 0.780 100 0.924 100 1.343 100 1.017 100 0.761 100 17 1.038 100 0.688 100 0.712 100 0.997 100 1.178 100 1.176 100 18 - - - - - - - - - - - - 19 0.704 100 0.726 100 0.726 100 1.039 100 2.180 100 1.295 100 20 1.069 100 1.284 100 0.980 100 1.586 100 1.143 100 0.958 100 21 0.825 100 1.185 100 1.158 100 1.369 100 1.477 100 0.783 100 22 0.991 100 0.992 100 1.053 100 1.212 100 1.593 100 1.179 100 23 0.894 100 1.029 100 1.116 100 0.948 100 1.767 100 0.750 100

24* 1.286 100 0.973 100 0.864 100 1.183 100 1.603 100 1.084 100 25* 1.131 100 0.870 100 1.093 100 1.283 100 1.289 100 0.983 100 26* 0.992 100 1.059 100 0.743 100 1.023 100 1.071 100 0.916 100 27* 1.305 100 1.263 100 1.539 100 1.132 100 0.881 100 0.837 100 28 1.397 100 1.418 100 1.063 100 1.460 100 0.947 100 1.347 100 29 1.058 100 0.900 100 0.974 100 1.361 100 1.761 100 1.316 100

30* 0.789 100 1.455 100 1.165 100 1.137 100 1.788 100 0.660 100 31 0.759 100 0.903 100 0.770 100 1.233 100 1.204 100 0.918 100 32 1.150 100 0.800 100 0.803 100 1.335 100 2.074 100 0.894 100

131 1.860 100 1.822 100 1.927 100 1.521 100 1.617 100 1.465 100


Report 72 66

Site Minneapolis Chicago Boston Juneau Honolulu Salt Lake City

PRN ↓

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

0.95 Range Error

(Meters)

3.29 Sigma

Bounding (%)

133 1.920 100 2.033 100 1.492 100 1.332 100 1.427 100 1.235 100 138 1.51

WIDE AREA AUGMENTATION SYSTEM PERFORMANCE ...and Multipath analysis, WAAS reference station survey...

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