Report on SBAS Ionospheric Working Group Todd Walter Stanford University Todd Walter Stanford University

2 SBAS Ionospheric Working Group  Chartered under the IWG to investigate ionospheric issues that jointly affect SBAS providers  Led by Bertram Arbesser-Rastburg (ESA) and Patricia Doherty (Boston College)  First meeting in Canada in 1999  Attendees from Europe, U.S., and Canada  Later meetings also included representatives from Japan, India, and Brazil  19 meetings held to date (one to two a year)  Most recent meeting – April 2012 at ITCP in Trieste in conjunction with African Outreach Workshop  Next meeting in two weeks in Bath, England

Ionospheric Working Group Major Activities  Facilitate interaction of ionospheric scientists supporting SBAS  Exchange of data and ideas  Coordinate research and data collection  Harmonize threats and threat models  Produced two major White Papers  “Ionospheric Research Issues for SBAS”  Released Feb 2003 on ionospheric effects  “Effect of Ionospheric Scintillation on GNSS”  Released Nov on scintillation  Available at: 3

4 Current Topics of Discussion  Monitoring networks  Identification of ionospheric events  Effects of recent storms  Ionosphere modeling  Correlation of scintillation fading on L1, L2, and L5  Proposed MOPS change for scintillation  Progression of solar cycle 24

5 Solar Cycle 24

Next Meeting Agenda (1 of 2) 6  Friday,  09:00 Opening, Welcome, Approval of Agenda  SBAS Status Reports  09:05 WAAS Status (Todd Walter)  09:25 EGNOS status (Stefan Schlueter)  09:45 GAGAN Status (P.V. Rama Rao)  Plans for new Augmentation systems  10:00 Activities with ASECNA in Africa (Stefan Schlueter)  10:15 GBAS possibilities for Brazil (Ivan Kantor)  Operational experience  10:50 Scintillation on GPS L1, L2 & L5 signals (Charles Carrano)  11:10 Impact of Ionosphere on EGNOS (Angeline Billot)  11:30 Scintillation effects on WAAS at solar max (Eric Altshuler)  11:50 EGNOS open service iono model (Roberto Prieto Cerdeira)  12:10 Comparison of EGNOS, global maps & experimental data at position domain (Claudia Paparini)  12:20 Ongoing SBAS / Ionospheric training at ICTP (Sandro Radicella)  Scintillation Observations and Modeling  14:00 Scintillation results from MONITOR Project (Yannick Beniguel)  14:20 Latest developments in GISM Scintillation model (Yannick Beniguel)  14:40 Scintillation observations in India (P.V. Rama Rao)  Reports on Experimental Campaigns  15:00 Ionospheric scintillation and TEC studies over Brazil using GNSS [Eurico de Paula)  15:20 ESA Ionospheric activities at low latitudes (Roberto Prieto Cerdeira)

Next Meeting Agenda (2 of 2)  Saturday,  Experiments Continued  09:00 LISN Status (Pat Doherty)  09:20 LISN Processing and prelim results (Eric Altshuler)  09:40 IGS MGEX campaign (Richard Langley)  10:00 Comparison of modern scint-mon receivers (Keith Groves)  Ionospheric Storms  10:15 New indicator for definition of iono storm conditions (Jaume Sanz)  10:50 Discussion on way forward  Next Meeting  A.o.B.  12:00 Close of meeting 7

8 Summary  SBAS Ionospheric Working group continues to meet once to twice a year  Current focus on:  addressing recommendations of Scintillation White Paper  collecting (and making available) data sets for sharing  planning updates of white paper as results provide new information  Next meeting in 2 weeks:  University of Bath, after the Beacon Satellite Symposium

Recent Ionospheric Effects on WAAS Todd Walter Stanford University Todd Walter Stanford University

Summary of Effects  Since January 2013 there has been one minor ionospheric storm that impacted WAAS service over CONUS  June 1, 2013  A few minor storms have had some impact over Alaska and/or Canada  March 17 & 27, May 16, 19, 25, & 26, & June 7,

Kp 11

Coverage (Storms) 12 NominalMar. 17 Mar. 27June 1

Coverage 13 Apr. 4June 7 Loss due to PRN 18 being out of service, not to the ionosphere Largest Kp day of the quarter (Kp = 7)

Presented to: Distribution By: Bill Wanner Date: June 3, 2013 Federal Aviation Administration Effect on WAAS from Iono Activity on June 1, 2013

Federal Aviation Administration Kp Index Chart

Federal Aviation Administration Coverage vs. Time Charts This event affected WAAS early in the day (GMT time) on June 1 For a comparison of a ‘good’ day and the coverage on June 1 the following two slides shows CONUS and Alaska coverage for June 1 and June 2

Federal Aviation Administration Coverage vs. Time Charts – CONUS – May 31 vs June 1 May 31, 2013June 1, 2013 Iono activity from about 03:00 – 09:00 GMT

Federal Aviation Administration Coverage vs. Time Charts – Alaska – May 31 vs June 1 May 31, 2013June 1, 2013 Iono activity from about 03:00 – 09:00 GMT

Federal Aviation Administration LPV-200 Coverage – June 1, 2013

Federal Aviation Administration RNP 0.1 Coverage – June 1, 2013

Federal Aviation Administration Accuracy – WAAS User Accuracy was higher on June 1 than other days –Both horizontal and vertical position errors were higher Next two charts show the HPE and VPE, respectively, at the Seattle WAAS reference station on June 1 and June 2 –Seattle is used as an example The maximum HPE at Seattle is normally less than 1.5 meters –The maximum HPE was about 2.9 meters on June 1 –HPL was 22.5 meters at the time of the maximum error HPE/HPL ratio =.13 The maximum VPE at Seattle is normally less than 3 meters –The maximum VPE was about 6.8 meters on June 1 –VPL was 25.3 meters at the time of the maximum error VPE/VPL ratio =.27, the highest of all WAAS sites on June 1 but VPE was still very well bounded by VPL

Federal Aviation Administration

Federal Aviation Administration

Federal Aviation Administration Accuracy – GPS User The following table shows a comparison of the calculated accuracy for a single frequency L1 SPS user and a position solution using dual frequency (L1 and L2) for several sites: Site Name Dual Frequency Horizontal Position Error (m) Dual Frequency Vertical Position Error (m) SPS Horizontal Position Error (m) SPS Vertical Position Error (m) Cold Bay San Jose del Cabo Los Angeles Oakland

Federal Aviation Administration EGNOS Coverage Since EGNOS is publishing LPV procedures we took a look at the 24 hour coverage plot The plot is based on data collected from the Atlantic City and Bangor NSTB reference receivers –Data from ENGOS GEO PRN 120 On the next slide the top plot is WAAS and EGNOS LPV coverage on June 1 and the bottom plot is June 2 –Little impact to EGNOS LPV coverage due to the iono activity on June 1 when compared to June 2 MSAS is included in the plot but there is no LPV approved procedures that use MSAS

Federal Aviation Administration WAAS/EGNOS Coverage June 1-2

Federal Aviation Administration Conclusion Iono activity on June 1 caused a loss of LP, LPV, and LPV-200 coverage in the WAAS service volume Accuracy for a WAAS and single frequency GPS user was increased on June 1 compared to June 2 EGNOS coverage was minimally impacted due to this iono event