ICGOct APPSG ICG APPSG 2014 Meeting Slide Jeju

ICGOct. APP-SG ICG APP-SG 2014 Meeting - Slide Jeju, South Korea Oct. 22, 2014 East Asia – The Region with the Densest SBAS Augmentation Takeyasu Sakai Electronic Navigation Research Institute, Japan

ICG APP-SG Oct. 2014 - Slide 1 Introduction • We are going to have more SBAS services: – Japan and India are operating MSAS and GAGAN, respectively. – Russian SDCM, Chinese SNAS (COMPASS-SBAS), and Korean K-SBAS are planned and being developed; SDCM is already broadcasting test signal. – We will have 5 SBAS in East Asia Region soon; Their service areas are overlapping. • Basically good news, but maybe some issues: – – Increased opportunity of SBAS signal; But degraded C/N 0 due to interference. Users can choose the best SBAS; But how should users choose the best? Need to equip many channels in user receivers. Interoperability and legal issues might also arise. • Coordination and communications: – Interoperability between SBAS services is important from user’s perspective. – Users should be informed the situation and should make feedbacks.

ICG APP-SG Oct. 2014 - Slide 2 MSAS Service by Japan • Japanese MSAS (MTSAT Satellite Based Augmentation System) has been operational since 2007 with two GEO satellites at 140 E and 145 E. • The global beam of MTSAT GEO widely covers the East Asia Region. • Basically serves for users within Japanese FIR; Used for Enroute flights and horizontal navigation on the ground.

ICG APP-SG Oct. 2014 - Slide 3 Architecture of MSAS MTSAT-1 R GPS Satellites Ranging Signals Users Augmentation Signals Kobe MCS (and GMS) Sapporo GMS Fukuoka GMS Ground Network Naha GMS • • • MTSAT-2 Tokyo GMS Hitachi-Ota MCS (and GMS) Hawaii MRS Australia MRS 6 GMS in Japan Hawaii MRS Canberra MRS MSAS Monitor Stations 2 GEO, 2 MCS (Master Control Station), 4 GMS (Ground Monitor Station), and 2 MRS; MCS also has GMS function; MSAS has 6 domestic monitor stations. 2 MRS (Monitor and Ranging Station) for GEO positioning for GEO ranging function.

ICG APP-SG Oct. 2014 - Slide 4 Performance of MSAS GPS only w/ MSAS Horizontal 0. 425 m RMS GPS only w/ MSAS Vertical 0. 607 m RMS N-S U-D E-W GEONET 940058 (Takayama) 08/1/17 -19 PRN 129 (MTSAT-1 R) Broadcast Signal

ICG APP-SG Oct. 2014 - Slide 5 SBAS in the World (1) • US WAAS (Wide Area Augmentation System): – The first SBAS operational since July 10, 2003. – Currently serving Enroute to LPV-200 flight modes with 3 GEO, after stepwise performance improvements. – Now Phase-IV: Developing dual frequency operation system. • Japanese MSAS (MTSAT Satellite Based Augmentation System): – Operational since Sept. 27, 2007 with 2 GEO. – Currently serving Enroute to NPA (Non-Precision Approach) flight modes; Available only for horizontal navigation. • European EGNOS (European Geostationary Navigation Overlay Service): – Operational since March 2011 after broadcasting test signal in 2005. – Currently EGNOS v 2 serving Enroute to LPV flight modes with 2 GEO. – Ongoing performance improvement for LPV-200 operation. – EGNOS v 3 is planned for dual frequency operation with Galileo.

ICG APP-SG Oct. 2014 - Slide 6 SBAS in the World (2) • Indian GAGAN (GPS-Aided Geo-Augmented Navigation): – Operational since Feb. 14, 2014 with 2 GEO. – Currently serving Enroute to NPA; Certification for LPV operation is ongoing. • Russian SDCM (System for Differential Corrections and Monitoring): – Already broadcasting test signal from their geostationary satellites. – Consists of 3 geostationary satellites: 2 already on orbit and 1 more in 2014. – In Japan, signals from Luch-5 A and Luch-5 V are possibly received • We have already received PRN 140 signal from Luch-5 A. • Chinese SNAS (COMPASS-SBAS): – Served as a part of Bei. Dou/COMPASS Satellite Navigation System. – Consists at least 3 Geostationary satellites at 80 E, 110 E, and 140 E; All signals can be received in Japan. • Korean K-SBAS: – Planned with 1 or 2 GEO to be operational by around 2020.

ICG APP-SG Oct. 2014 - Slide 7 SBAS in the World (3) SDCM SNAS K-SBAS Operational Since 2003 Since 2011 Since 2014 Since 2007 SACCSA • • • Already Operational: WAAS, MSAS, EGNOS, and GAGAN. Planned and Being Developed: SDCM, SNAS, K-SBAS, and SACCSA, … We will have 5 SBAS in East Asia Region: The Densest Region in the World !

ICG APP-SG Oct. 2014 - Slide 8 Good News? • We will have 5 SBAS in East Asia Region soon: – Operational: Japanese MSAS and Indian GAGAN. – Upcoming: Russian SDCM, Chinese SNAS, and Korean K-SBAS by 2020. – Other systems? • Possible advantages: – Increased opportunity of SBAS augmentation signal. • Expect 10 or more GEO satellites broadcasting SBAS signals. • Possibility to receive some of SBAS signals which survives in urban canyon. – Users can choose the best SBAS available. • Criteria: Highest elevation angle, lowest HPL, the largest number of SV, … – Also mixed use of multiple SBAS is possible. • Increased number of GPS satellites with augmentation. • Russian SDCM would augment GLONASS as well as GPS. – Increased ranging signals from SBAS GEO. • Some SBAS provide ranging function: currently only MSAS.

ICG APP-SG Oct. 2014 - Slide 9 Potential Issues • Lower C/N 0 due to other SBAS signals: – SBAS signals interfere each other. – ITU frequency coordination might limit the bandwidth of some SBAS signals. • Induces degradation of ranging accuracy. • How should user choose the best SBAS? – Criteria: Highest elevation angle, lowest HPL, the largest number of SV, … – Need to be standardized? • If not, we cannot predict the actual performance of user receivers. • User receivers need to equip many channels to track SBAS satellites: – Need additional channels to choose the best SBAS and for transition of augmentation source. – Also need to decode and process SBAS signals being tracked: Increased computational loads. • Interoperability between SBAS. • Legal issues between States: – Problems to use SBAS provided by another State. – Could an SBAS provider assure to continue its service for other States?

ICG APP-SG Oct. 2014 - Slide 10 Example: MSAS and GAGAN Geostationary Satellites: MSAS GSAT-8 GSAT-10 MTSAT-1 R @140 E MTSAT-2 @145 E MTSAT-2 GAGAN GSAT-8 @55 E GSAT-10 @83 E • India began the operation of GAGAN in Feb. 2014. • In Japan, we can receive GAGAN signals in addition to MSAS signals. • Which SBAS does the SBAS-receiver use for augmentation? Ø Likely MSAS, but using GAGAN is allowed and possible. Ø There is some reports on observation of some receivers using GAGAN.

ICG APP-SG Oct. 2014 - Slide 11 Interference between SBAS Estimated C/N 0 with Interference Degradation of C/N 0 • Degradation of C/N 0 of MSAS signals due to interference from other SBAS. • Assume 12 GEO: 2 GAGAN GEO, 3 SDCM GEO, 5 COMPASS GEO, and 2 K -SBAS (120 E and 130 E); All broadcast SBAS L 1 C/A signals. • Max degradation: 0. 46 d. B/Hz at 116 E.

ICG APP-SG Oct. 2014 - Slide 12 SBAS Satellite Selection (1) MSAS Availability (1 Critical GPS Out) • • • GAGAN Availability (1 Critical GPS Out) Example case: Availability of navigation using either MSAS or GAGAN. NPA mode (RNP 0. 3 for Enroute) availability for 3 days of May 25 to 27, 2014. The service area is limited to each region.

ICG APP-SG Oct. 2014 - Slide 13 SBAS Satellite Selection (2) Selection by Elevation Angle (1 Critical GPS Out) Selection by HPL (1 Critical GPS Out) • Availability of navigation for receivers which select MSAS or GAGAN as an augmentation source. • Selection criteria: (Left) Higher elevation angle; or (Right) Lower HPL. • Selecting SBAS extends the service area as expected.

ICG APP-SG Oct. 2014 - Slide 14 Interoperability • Interoperability between SBAS: – Important from user’s perspective. – Property that user receivers can receive and process any SBAS signals broadcast by different service providers in the completely same manner. – Information broadcast on different SBAS signals has the same property. • Same definition of the contents. • Must be certified for the same level of integrity. • Interoperability is not assured automatically: – SBAS is the international standard system defined by the ICAO SARPS. • However, there are some ambiguities: MT 9 for non-ranging GEO (recently clarified), LTC for broadcasting/non-broadcasting GEO, GPS/GLONASS offset, … • Also there are some options: MT 27 or MT 28, usage of MT 6, … – Need communications between SBAS providers: • ICAO meetings twice a year. • SBAS IWG (Interoperability Working Group) Meeting twice a year. – Feedback from users is welcome.

ICG APP-SG Oct. 2014 - Slide 15 Legal Issue: Monitoring SBAS • Monitoring SBAS: – Another issue might be the necessity of monitoring the performance of the system operated by other States. – SBAS is used as a primary means of navigation. • Question: Is it allowable to fly in the airspace of a State dependently upon a primary means of navigation provided by another State? – A possible way to relax such legal issues caused by using SBAS operated by another State is to monitor the performance of the SBAS. • If necessary, warn to users in the airspace in case that the SBAS should not be used. • Actually, in Spring 2014, MSAS has broadcast messages with anomalous preambles. • GNSS Monitor System: – In order to monitor an SBAS, one also needs to monitor GPS satellites augmented by the SBAS to check correctness of augmentation information. – Japan Civil Aviation Bureau intends to implement monitor systems for GNSS including GPS and SBAS whose signal can be received in Japanese territory.

ICG APP-SG Oct. 2014 - Slide 16 GAGAN Integrity in Tokyo All-in-View Mode All Possible Combinations • Triangle chart comparing HPL and the associated position error provided by GAGAN GSAT-10 in Tokyo, Japan. • The availability of NPA mode is 97. 8% for all-in-view receivers. • In terms of safety assurance, all possible combinations should be tested like the chart at the right; Unsafe condition that the error exceeds HPL did not occur for this period. • Furthermore, all possible combinations of active SBAS messages should be tested.

ICG APP-SG Oct. 2014 - Slide 17 Conclusion • Situation in East Asia Region: – We will have 5 SBAS in East Asia Region soon: MSAS, GAGAN, SDCM, SNAS (COMPASS-SBAS), and K-SBAS. – Their service areas are overlapping each other. • Basically good news, but maybe some issues: – Need analysis and consideration in detail from user’s viewpoints. • Coordination and communications: – Interoperability between SBAS services is important from user’s perspective. – Users should be informed the situation and should make feedbacks.