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ICAO AFI GNSS Trials Joint Presentation

Detailed overview of GNSS test-bed trials and implementation in Zone A, enhancing navigation in Africa. Collaboration between ESA, ASECNA, and partners to validate and prepare for operational systems.

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ICAO AFI GNSS Trials Joint Presentation

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  1. ICAO AFI GNSS ITF 1st MEETING Dakar, 17-18th November 2003ZONE A TRIALS Joint presentation by . Hughes Secrétan (ESA) . Patrick LEFEVRE (ASECNA)

  2. ICAO : GNSS AFI POLICY • The ICAO Africa and Indian Ocean (AFI) Regional Implementation Plan includes a GNSS strategy Plan • The Plan adopted by AFI States contains: • Phase 1(2002-2005): • use of GPS • implementation of an AFI GNSS test bed (extension of the EGNOS test bed) and preparation for the implementation of an operational system • Phase 2 (2005-2012): operation of SBAS (EGNOS extension) for en-route to APV-I (Approach with Vertical Guidance) capabilities • Phase 3 (2012-…) : operation of SBAS with CAT-1 capabilities (Precision Approach), relying upon the availability of a civil satellite constellation (e.g. GALILEO)

  3. GNSS test-bed trials objectives • To verify the navigation performances over selected areas and airports of western and Central Africa, • To analyze ionospheric impacts, • To evaluate critical issues (telecommunication network, expansion mode, airborne receivers performances,…) • To validate the EGNOS simulation model outside Europe, • To evaluate APV1 procedure design, constraints and operations • To sensitize potential services providers and users, • To develop expertise in the view of the implementation of the AFI test bed and an operational system

  4. AFI Test Bed implementation in Zone A • Implementation of a Test Bed in Central Africa (zone A), in line with the ICAO Strategy (Phase I) from December 2002 to september 2003. • Project with no exchange of funds • Links between the RIMS and ESTB based upon AFISNET satellite communication network • 4 RIMS installed by ASECNA at N’Djamena, Lomé, Douala and Brazzaville VPL Simulation ( ESA source) N’Djamena Lomé Douala Brazzaville

  5. ZONE A PROJECT PARTNERS • ESA (European Space Agency) : provided one ECUREV RIMS and CPF modification to manage the Dakar RIMS, • ASECNA : provided facilities for the RIMS, its EGNOS equipped calibration aircraft, APV1 design procedure • French DGAC : provided the airborne navigation software and data analysis support, • Eurocontrol : supplied the PEGASUS software for data acquisition and processing, • ENAV, the Italian Space Agency loaned 3 RIMS to ASECNA through ESA. • NAMA (Nigerian Airspace Management Agency) , which provided data for APV1 procedures design, support for the flights and organized demonstrations in Lagos, Kano and Port-Harcourt,

  6. Zone A GNSS test bed architecture INMARSAT INTELSAT GPS signals GPS RIMS data to CPF EGNOS navigation Message (integrity and corrections AFISNET HONEFOSS (NORVEGE) TOULOUSE VSAT ASECNA Ranging +GES ESTB CPF N’Djaména RIMS and VSAT Lomé :Rims and VSAT CPU CPU Douala : RIMS and VSAT Thales Router Thales Router Honefoss Brazzaville : RIMS and VSAT

  7. IMPLEMENTATION ISSUES • RIMS Antenna location • Interferences issues • Connexions to communication network • No spares • Lack of documentation • No central monitoring • No FTP server • Not an operational system • Management

  8. Screen 15’’ Keyboard PC Processor Unit GPS/GEO Novatel OEM3 L1/L2 Receiver DAT Recording Unit Rubidim Atomic Clock IP Router Power Supply RIMS layout GPS/GEO antenna (Novatel) Local Maintenance Equipment SYNC DAT Core RIMS Computer DATA Receiver RIMS DATA Atomic Clock NETWORK IP Router

  9. GNSS expected performances: vertical accuracy

  10. GNSS expected performances : VPL Availability

  11. ATR42 Avionics layout GPS/Glonass Antenna GPS/Glonass Antenna GPS Antenna TBUE Receiver Novatel Receiver Honeywell Receiver RTK Receiver Flight Management System (FMS) Navigation sensors Guidance computer * Data collection computer Calibration computer EGNOS data (to Pegasus) Tracking data (to Pegasus) EGNOS EFIS Cockpit Electronic Displays EGNOS raw data collection sub-system Aircraft Navigation System EGNOS guidance sub-system Airborne Calibration sub-system Existing equipment in the ATR42 equipment provided by ESA New equipment acquired and installed by ASECNA

  12. ATR42 GNSS Avionic layout (pictures) ADAGIO cabin display EGNOS cockpit guidance display (EHSI)

  13. Final Approach procedures 16 m 220 m 20m Horizontal plane MDH ( 250 ft) 16 m MAPT 250 ft 8 m 200 ft Slope 5.2% (3°) Runway APPROCH CATEGORIES NPA APV1 CAT I APV2 16 m 220 m Horizontal 16 m Accuracy Vertical Not applicable 8 m 20 m 4 à 6 m Horizontal 40 m 40 m Alarm Limit 50 m Vertical Not applicable 10 à 15 m 20 m 250 ft Vertical 250 ft DH/MDH (mini) 200 ft 200 ft 1200 m T.B.D With Land. lights 550 m 550 m Horiz. Visi. (mini) Without Land. lights 1800 m 1000 m T.B.D 1000 m Important => Mimima if obstacles reduced (ILS) near ILS near ILS Protection areas Descent + stabilization => CFIT risk 5.2% (3°) Slope 5.2% (3°) 5.2%(3°) yes yes not Integrity/continuity of service yes

  14. DOUALA RWY 30 APV1 Instrument Approach Chart

  15. APV1 benefits (1) • Control of the vertical position thanks to the EGNOS signal and added descent fixes • No more flat step before the miss approach point (see point V) reducing CFIT (Controlled Flight Into Terrain) risk • Reduced operational minima • Ease of flyability

  16. APV1 benefits (2)

  17. GNSS ESTB Horizontal Guidance Guidance signals provided by ESTB navigation system are similar to actual ILS deviations. Dakar ILS Localizer error (mA) against distance to threshold (NM) ILS Cat I Template ESTB Lateral angular error (mA)

  18. GNSS/ESTB Vertical Guidance Dakar ILS Glide error (mA) against distance to threshold (NM) and ILS Cat I Template ESTB Vertical angular error (mA) Conversion of the constant linear Vertical ESTB error into angular Error (blue line) Impact of trajectography Path model (red line) Vertical guidance signals provided by ESTB are close to ILS Glide deviations and available on all Runways

  19. Horizontal error (HPE) Vertical error (VPE) Date GEO Period Mean 95% Mean 95% 16/09/03 120 Day 1.67 3.30 -0.43 4.21 16/09/03 120 Night 1.33 3.23 0.69 4.49 18/09/03 17/09/03 17/09/03 131 120 131 Day Day Day 1.31 1.43 1.53 3.66 3.08 2.74 1.24 -0.14 -0.08 4.97 4.37 4.25 18/09/03 120 Night 1.31 3.06 0.59 5.05 20/09/03 19/09/03 22/09/03 131 120 131 Day Day Day 1.27 2.37 1.08 2.61 3.99 2.41 -0.93 -0.93 -1.08 4.31 4.59 4.59 22/09/03 120 Night 1.93 4.71 -0.80 5.58 Zone A preliminary results : accuracy (1)

  20. Zone A preliminary results : accuracy (2) Accuracy performance, when full corrections are broadcast, is complying with the APV1 SARPS requirements with HPE around 3m (95%) and VPE around 4.5 m (95%)

  21. 95.47% 93.85% 91.91% 17/09/03 131 Day 99.05% 97.97% 98.66% 17/09/03 131 Night Full corrections Hor. APV1 Vert. APV1 Date PRN Period 98.52% 97.37% 96.91% 19/09/03 131 Day 77.34% 75.64% 75.82% 16/09/03 120 Day 100% 100% 100% 20/09/03 131 Night 85.99% 84.60% 83.81% 16/09/03 120 Night 93.96% 92.14% 91.41% 18/09/03 120 Day 96.16% 94.93% 93.95% 18/09/03 120 Night 92.11% 88.71% 89.07% 22/09/03 120 Day 94.90% 93.23% 92.56% 22/09/03 120 Night Zone A preliminary results : availability (1)

  22. Zone A preliminary results : availability (2) Note : results obtained with the FAA tool : SISAT

  23. Zone A preliminary results : availability (3) Numerous causes of unavailability : • Telecommunications outages or malfunctions, (N’Djaména, Brazzaville, Toulouse), • interferences issues (N’Djaména and Douala ?), • RIMS mains failure (N’Djaména), • RIMS malfunctions • destruction of GNSS antenna at Douala from lightning, • Erroneous RIMS re-configurations after re-starts (Brazzaville, N’Djaména and Douala), • Ionospheric effects • RIMS HMI ( human machine Interface ) miss designed for local maintenance purpose

  24. Zone A preliminary results : availability (4) • When the ESTB signal is providing full corrections (fast corrections + iono corrections), the HPL/VPL availability for APV1 is roughly 98.5% (between 97% and 100%). • APV1 service availability is better during night then day, most probably due to ionosphere effects, in particular the GIVE that is smaller during night. • The improvement of the quality of the RIMS and communications lines, which are generating some gaps and time-delay may improve significantly the ESTB performances

  25. Zone A preliminary results : availability (5) The service availability on AFI-A area is mainly affected by 2 phenomena: • Don’t use IGP’s events (GIVE set to “don’t use”). Such GIVE status may be explained by a high ionosphere activity. More static tests would be very useful to monitor the ESTB iono corrections, understand and optimize the CPF configuration regarding such iono activity. A dedicated iono receiver is under installation at Douala, • UDRE set to “not monitored by the CPF. Most of the satellites located in the South part of the region have an UDREI of 14 (not monitored) and are therefore not used in the navigation solution. It needs to be investigated in more details as it prevents quite a significant amount of satellites from being used.

  26. ZoneA preliminary results: S.I.S (Hor.) Integrity (1)

  27. ZoneA preliminary results: S.I.S (vert.) Integrity (2)

  28. ZoneA preliminary results : integrity (3) As shown in the previous diagrams, no misleading information (non integrity events) happened during all the static tests.

  29. Flight tests and demonstrations (1) • Extensive flight tests and demonstrations were performed in; • Lomé (Togo) • Lagos, Kano and Port-Harcourt (Nigeria) • Malabo (Equatorial Guinea) • Libreville (Gabon) • Douala and Yaoundé (Cameroon) • More than 100 persons including pilots, African Civil Aviation Authorities and Air Forces representatives flew aboard the ATR42. • GNSS presentations were carried at every airport (except Malabo).

  30. Flight tests and demonstrations (2) • All the FAS data (Final Approach Segment) prepared for the APV1 procedures were right • On all the flown approaches, the runway axis alignments were well within the CAT1 tolerances (and APV1). • Regarding the descent path it was found on two airports a difference of about 50 ft at the threshold. Investigations are on-going to determine the cause.

  31. RIMS installation recommendations • Training of technical staff is necessary to handle maintenance operations • Site survey in compulsory in order to minimise installation delays ( interference effects, length of cable between antenna and Rims, etc…) • RIMS alimentation must be on unbreakable power supply • Connection to ground network ( réseau de terre) must be necessary done with appropriate cable • Access to telecommunications network must be done either by V24 link or by IP link using frame relay multipliers equipments.

  32. Conclusions • Preliminary results show EGNOS may satisfy AFI navigation requirements contained in the GNSS AFI Strategy, • Hardware, software and operation procedures constituting the test-bed have to be improved to significantly increase the ESTB performances, • Training and expertise of AFI staff about GNSS evaluation is mandatory, • Complementary evaluations have to be made in equatorial region ( either by extension of zone A trials or through extensive zone C evaluation).

  33. THANK YOU FOR YOUR ATTENTION

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