Performed by ASECNA with the support from PILDO Labs Dakar - May, 30-31, 2013

1. International Conference On Global Navigation Satellite Systems ( GNSS) Technologies and Applications for the development of Sub-Saharan African Countries First Feasibility Study of The GBAS on the African Continent Performed by ASECNA with the support from PILDO Labs Dakar - May, 30-31, 2013

2. Summary • Introduction • Results • Conclusions

3. Introduction The research of innovative solutions that contribute to the improvement of air navigation safety, is defined within the ASECNA Strategic Orientation Plan (POS) as first strategic objective of the Agency.The Engineering and Prospects Department of the Agency, applying the guidelines of this POS plan, and in accordance with the Africa and the Indian Ocean (AFI) strategy regarding NAV means implementation, has included in its action plan, and in particular in its R&D activities, the operational evaluation and implementation of Ground Based Augmentation System(GBAS), based on satellite technology, as in replacement of actual Instrument Landing Systems (ILS). First feasibility study of GBAS in Africa has served to: • Develop a good competence within ASECNA in the field of GNSS and in particular GBAS; • Create a technical and operational team necessary to support any potential future GBAS Programme; • Assess the feasibility (opportunities, constraints, financial impact, etc ...) of the implementation of GBAS within ASECNA Airspace, and in particular Dakar International Airport; • Reinforce Agency’s position as leader in the supply and implementation of new navigation systems in the region. • The study was made possible thanks to a partnership agreement signed in 2011 within PILDO and ASECNA to share experiences and engage R&D activities to explore sources of innovation. Fig 1. Ground Based Augmentation System

4. Pildo Labs • Engineering company founded in 2001 • Specialized in delivering top of the edge technology within the aeronautics and space sectors • PildoLabs is recognized as one of the main players for the development of advanced Air Navigation products and services enhanced by Satellite Navigation or GNSS (basic GPS or EGNOS, GBAS augmentations).

5. Regional GNSS: SBAS • SBAS: Satellite Based Augmentation System • Systems today available for Aviation: • EGNOS: European SBAS • WAAS: USA and CANADA SBAS • MSAS: Japanese SBAS • Systems under development/analysis: • GAGAN: Indian SBAS (2014) • SACSA: South American SBAS • SDCM: Russian and Chinese SBAS

6. What is EGNOS? EGNOS (the European SBAS) allow the implementation of RNAV instrument approach procedures down to LPV minima (up to 250 ft above airport elevation) Main Advantages of RNAV instrument approach procedures with vertical guidance are: • Vertical and lateral guidance is provided • ILS-alike approaches • Use of more flexible route and procedure designs • Limited need for ground infrastructure • Engine-idle descents • Improved track keeping • Can provide approaches to more runways without additional infrastructure costs • Reduced delays, diversion and cancellations due to bad weather • Reduced controller and pilot workload

7. Summary • Introduction • Results • Conclusions

8. Leopold Sedar Senghor International Airport Airport Siting activities for the installation of three GNSS receivers were performed with the support from ASECNA local maintenance team: • Identify suitable locations for the installation of three GNSS receivers • Antenna and receiver installation; • Geo-Position three selected positions based on 24 hours data collected; • Validate the installation based on data analysis (multipath, shadowing effects…); Fig 2. Three reference receivers location

9. Data Collection Campaign • Data set • 15 days of GPS data (31/Oct 2012– 14/Nov 2012) • More than 11 Gb of GPS data Fig 6: Collected data set validity

10. GBAS Ground Station Performance Results (1/2) Two main tasks have been performed for performance assessment at GBAS station level: 1) Assess technical feasibility for the installation of a GBAS station at Dakar Airport (satellite visibility , signal to noise ratio C/No, number of satellites monitored by the station); Fig 3: Nominal number of GPS monitored satellites (>10 most of the time) Fig 4: Excellent Signal to Noise ratio around 45dB

11. GBAS Ground Station Performance Results (2/2) 2) Simulate GBAS messages with appropriate GAD parameter configuration computed based on measured data statistics ; Fig 5. Ground Accuracy Designator (GAD) characterizes the contribution of the ground station to the GPS measurements error. Measured values for Dakar receivers, depicted in red in the graphic, indicates excellent accuracy up to [C] level ground station type.

12. GBAS Airborne Performance Accuracy Results Fig 5: Horizontal and Vertical Accuracy results with 95%-ile values in green As required for CAT-I operations (ICAO Annex 10): HPL 95% < 16 m VPL 95% < 4 m

13. GBAS Airborne Performance Integrity Results Fig 6: Integrity Stanford Plot, position error XPE (horizontal axis) versus protection level XPL (vertical axis) To be in compliance with the Integrity Requirement the XPL/XPE values depicted in the graph shall be in the white area limited by the GBAS Alert Limits for the final part of the approach segment As required for CAT-I operations (ICAO Annex 10): HPL 95% < 40 m (HPL95 = 2.568 m) VPL 95% < 10 m (VPL95 = 3.593 m)

14. GBAS Airborne Performance Summary Table below summarizes the measured performance against CAT-I requirements: Fig 7: Table comparing RNP CAT-I measured perfomance at Dakar Airport with SARPS Requirements CAT-I Requirements taken from ICAO Annex 10 – Table 3.7.2.4-1

15. GBAS Approach Design and Simulation • GBAS approach on Dakar Airport RWY 36 was designed using PRODAN (in-house Pildo Labs tool) and verified with GeoTitan used by ASECNA, based on actual ICAO General Criteria from Doc.8168. Initial segments are equal to actual RNAV GNSS procedure, while a new Final Approach Point so-called PILDO is included. Missed approach segment is proposed towards the IAF/IF because of the holding pattern. Obtained minima is equivalent to 200 ft for all aircraft categories. • Procedure’s flyability was validated throughout PLATERO (*) coupled with the ESP Microsoft Flight Simulator. • (*)PLATERO is developed by Pildo Labs to support flight validation activities either on simulated or in-flight tests environment Fig 8 & 9: Flight Procedure chart and validation environment

16. Cost Benefit Analysis (1/2) A Cost Benefit Analysis (CBA) was performed evaluating the total anticipated cost in a period of 15 years, for the provision of precision approach services by installing a GBAS station, in comparison with conventional precision approach procedures enhanced by ILS. • At operational level and just for the purpose of the CBA exercise, most pessimistic scenario vis-a-vis of ILS is defined by assuming: • Equal Concept of Operations for GBAS and ILS without taking into account additional benefits offered by GBAS like for example increased capacity, optimal interference for initial fix, curved approaches, among others. Therefore Costs are just quoted, assuming benefits from GBAS and ILS are equal; • Actual IFR Runway at Dakar Airport is considered only, keeping secondary Runway for VFR operations; • Safety levels are maintained for GBAS as per ILS. Other financial costs or benefits from airlines perspective are not considered, like for example potential reduced fuel consumption, optimal flight profiles, and costs per avionics retrofit or equipage. Such assessment would require a dedicated Airline oriented CBA complementary to the present one. Nevertheless an initial assessment has been performed on the actual fleet avionics equipment flying to Dakar Airport, which indicates that a GBAS service would be potentially rapidly adopted by users, based on the type of aircraft operated. Fig 10: Aircraft type operating Dakar International Airport (source ASECNA)

17. Cost Benefit Analysis (2/2) • The Net Present Costs are computed for a set of scenarios mixing actual precision approach service with future additional GBAS or ILS ones. • B1- Dual ILS on RWY36/18 • B2- GBAS by keeping ILS RWY36 • B3- GBAS by decommissioning ILS RWY36 Fig 11: Set of scenarios assessed in the CBA for different ILS and GBAS configurations providing precision approach service Fig 12: GBAS initial investment is higher than for ILS (red line versus grey line in NPC graphic). However due to lower OPEX for the GBAS procedures, Net Present Cost is similar. Hypothetical ILS decommission would report economic benefits for GBAS exploitation after 5-6 years (grey line versus blue line in NPC graphic)

18. GBAS Activities in the World

19. Summary • Introduction • Results • Conclusions

20. Conclusions The GBAS Inception Phase provided very promising results which invites ASECNA to build up a more consistent Research & Development Programme towards the final implementation of GBAS services in the Agency’s Airspace. Such statement is endorsed by the following elements: • Technical and Operational competence created in support not only to future GBAS implementation, but GNSS operations in a wider Performance Based Navigation (PBN) concept perspective; • Dakar International Airport is confirmed to be a very suitable scenario for the future operational implementation of GBAS services, initially in combination with actual ILS service and ultimately with its decommissioning; • Excellent measured performance indicates the suitability of the GBAS concept for the provision of precision approach services at African regional level , although due to the limited time data collected final conclusions cannot be derived;

21. ThankYouforYourAttention Performed by ASECNA with the support from PILDO Labs