1 zone a gnss/egnos trials icao afi gnss itf 1 st meeting dakar, 17-18 th november 2003 zone a...

Zone A GNSS/EGNOS Trials 1

ICAO AFI GNSS ITF 1ICAO AFI GNSS ITF 1stst MEETING MEETING

Dakar, 17-18Dakar, 17-18thth November 2003 November 2003

ZONE A TRIALSZONE A TRIALS

Joint presentation by . Hughes Secrétan (ESA) . Patrick LEFEVRE (ASECNA)


ICAO : GNSS AFI POLICYICAO : 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)


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


• 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

AFI Test Bed implementation in Zone AAFI Test Bed implementation in Zone A

N’Djamena

Douala

Brazzaville

Lomé

VPL Simulation ( ESA source)


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,


Zone A GNSS test bed architecture

Douala : RIMS and VSAT

Brazzaville : RIMS and VSAT

VSATASECNA

AFISNET

INMARSAT

GPS

INTELSAT

Thales Router

Ranging +GES

CPU

Thales RouterHonefoss

ESTB CPF

CPU

Lomé :Rims and VSAT

N’Djaména RIMS and VSAT

TOULOUSE HONEFOSS(NORVEGE)

RIMS data to CPF

GPS signals

EGNOS navigation Message(integrity and corrections


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


RIMS layoutRIMS layout

GPS/GEO antenna (Novatel)

RIMS

Receiver

CoreComputer

Atomic Clock

Local MaintenanceEquipment

RIMS DATA

SYNC

DATA

DAT

IP Router

NETWORK

Screen 15’’

Power Supply

PC Processor Unit

GPS/GEONovatel OEM3 L1/L2

Receiver

DAT Recording Unit

Rubidim Atomic Clock

Keyboard

IP Router


GNSS expected performances: vertical accuracy


GNSS expected performances : VPL Availability


ATR42 Avionics layoutATR42 Avionics layoutGPS/Glonass

AntennaGPS/Glonass

Antenna

RTKReceiver

Calibrationcomputer

TBUEReceiver

NovatelReceiver

Guidance computer *

Data collectioncomputer

Flight Management

System (FMS)

Tracking data (to Pegasus)

EGNOS data (to Pegasus)

GPSAntenna

HoneywellReceiver

Navigation sensors

CockpitElectronicDisplays

EGNOS

EFIS

EGNOS guidance sub-system

EGNOS raw data collection

sub-system

Airborne Calibrationsub-system

Aircraft Navigation

System

Existing equipment in the ATR42

equipment provided by ESA

New equipment acquired and installed by ASECNA


ATR42 GNSS Avionic layout (pictures)ATR42 GNSS Avionic layout (pictures)

EGNOS cockpit guidance display (EHSI)

ADAGIO cabin display


Final Approach proceduresFinal Approach procedures

Runway

Accuracy

Alarm Limit

HorizontalVertical

HorizontalVertical

CAT I APV2 APV1 NPA

16 m

4 à 6 m 8 m

40 m

10 à 15 m 20 m

16 m 220 m

20 m Not applicable

Not applicable 40 m

50 m

DH/MDH (mini)

Horiz. Visi. (mini)

Protection areas

Slope

200 ft 250 ft 250 ft

550 m 550 m T.B.D 1200 m

reduced (ILS)

near ILS

near ILS Important => Mimima if obstacles

5.2% (3°) Descent + stabilization => CFIT risk

APPROCH CATEGORIES

Vertical

5.2%(3°) 5.2% (3°)

200 ft

1000 m 1000 m T.B.D 1800 m

With Land. lights

Without Land. lights

Integrity/continuity of service yes yes yes not

Slope 5.2% (3°)

Horizontal plane MDH ( 250 ft)

220 m16 m

20m

16 m8 m

MAPT250 ft

200 ft


DOUALA RWY 30 DOUALA RWY 30 APV1 Instrument APV1 Instrument Approach ChartApproach Chart


APV1 benefits (1)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


APV1 benefits (2)

W

X XSurfa c e

Surfa c e

APV1 O AS surfa c e s

APV p ro te c tio ng a in

o b sta c le s within the se two a re a s a re no t ta ke n

into a c c o unt

C o m p a riso n b e twe e n APV1a nd G NSS NPA fina l a p p ro a c hp ro te c tio n a re a

Runwa y

NPA G NSS p rim a ry a re a s

1NM

1NM

0,5NM


GNSS ESTB Horizontal Guidance

0 1 2 3 4 5 6 7 8-50

-40

-30

-20

-10

0

10

20

30

40

50Erreur LOC ILS (uA) et Gabarit ILS Cat 1

0 1 2 3 4 5 6 7 8-50

-40

-30

-20

-10

0

10

20

30

40

50Erreur LOC EGNOS (uA) et Gabarit ILS Cat 1

Dakar ILS Localizer error (A)against distance to threshold (NM)

ILS Cat I Template

ESTB Lateral angular error (A)

Guidance signals provided by ESTB navigation system are

similar to actual ILS deviations.


GNSS/ESTB Vertical Guidance

0 2 4 6 8 10 12-50

-40

-30

-20

-10

0

10

20

30

40

50Conversion de l'écart métrique vertical moyen (-3.03e+000m) en déviation ang (en uA)

erreur angulaire verticale (uA)part due aux erreurs sur modèle

0 1 2 3 4 5 6 7 8-50

-40

-30

-20

-10

0

10

20

30

40

50Erreur GLIDE EGNOS (uA) et Gabarit ILS Cat 1

0 1 2 3 4 5 6 7 8-50

-40

-30

-20

-10

0

10

20

30

40

50Erreur GLIDE ILS (uA) et Gabarit ILS Cat 1

Dakar ILS Glide error (A)

against distance to threshold (NM)

and ILS Cat I Template

ESTB Vertical angular error (A)

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


Zone A preliminary results : accuracy (1)

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

18/09/03 120 Day 1.53 3.08 -0.08 4.25

18/09/03 120 Night 1.31 3.06 0.59 5.05

22/09/03 120 Day 2.37 3.99 -1.08 4.31

22/09/03 120 Night 1.93 4.71 -0.80 5.58

17/09/03 131 Day 1.31 2.74 -0.14 4.37

17/09/03 131 Day 1.43 3.66 1.24 4.97

19/09/03 131 Day 1.08 2.41 -0.93 4.59

20/09/03 131 Day 1.27 2.61 -0.93 4.59


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%)


Zone A preliminary results : availability (1)

Date PRN PeriodFull

corrections Hor. APV1 Vert. APV1

16/09/03 120 Day 77.34% 75.64% 75.82%

16/09/03 120 Night 85.99% 84.60% 83.81%

18/09/03 120 Day 93.96% 92.14% 91.41%18/09/03 120 Night 96.16% 94.93% 93.95%

22/09/03 120 Day 92.11% 88.71% 89.07%

22/09/03 120 Night 94.90% 93.23% 92.56%

17/09/03 131 Day 95.47% 93.85% 91.91%

17/09/03 131 Night 99.05% 97.97% 98.66%

19/09/03 131 Day 98.52% 97.37% 96.91%

20/09/03 131 Night 100% 100% 100%



Note : results obtained with the FAA tool : SISAT



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



• 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



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.


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


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


ZoneA preliminary results : integrity (3)

As shown in the previous diagrams, no misleading information (non integrity events) happened during all the static tests.


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).


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.


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.


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).


THANK YOU FOR YOUR ATTENTION

1 zone a gnss/egnos trials icao afi gnss itf 1 st meeting dakar, 17-18 th november 2003 zone a...

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