SBAS/EGNOSINTRODUCTION
GIANLUCA MARUCCO, GABRIELLA POVEROGabriella Povero | Navigation Technologies
GNSS Training
AIT, Bangkok | 14-18 January 2019©2019 LINKS

1OUTLINE❖ INTRODUCTION TO AUGMENTATIONSYSTEMS❖ EGNOS AND ITS SERVICES❖ EGNOS ARCHITECTURE❖ EGNOS PERFORMANCE

Gabriella Povero | Navigation Technologies
GNSS Training
AIT, Bangkok | 14-18 January 2019©2019 LINKS

2OUTLINE❖ INTRODUCTION TO AUGMENTATIONSYSTEMS❖ EGNOS AND ITS SERVICES❖ EGNOS ARCHITECTURE❖ EGNOS PERFORMANCEGabriella Povero | Navigation Technologies
GNSS TrainingAIT, Bangkok | 14-18 January 2019©2019 LINKS

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WHAT’S UP IN THE SKY?
RNSSIRNSS-NAVIC

GNSS©2019 LINKS

SBAS
4SATELLITE BASED AUGMENTATION SYSTEMSUSAWAAS - Wide Area Augmentation
SystemEuropeanUnion

EGNOS - European GeostationaryNavigation Overlay ServiceJapan

MSAS - Multifunctional Satellite
Augmentation SystemIndia

GAGAN - GPS Aided Geo
Augmentation Navigation

RussiaSDCM - System of Differential
Correction and Monitoring

China

BeiDou Wide Area Differential service

Korea

KASS - Korea Augmentation Satellite
SystemLatin
America

SACCSA - Soluciόn de Aumentaciόnpara Caribe,Centro y Sudamérica

AfricaAFI (Africa-Indian Ocean)

BeiDouUsed to improve the performance of global
navigation satellite systems (GNSS)

Thailand, Malaysia©2019 LINKS

5AUGMENTATION: PURPOSES
An augmentation system has the general objective of improving the use of GNSS, through theprovision of additional information (differential corrections or measurements).

• Systems that keep the focus on accuracy.
They are intended for:oLBS in general including leisureoMapping

oCadastral

oSurveyingo Air navigationo Water navigationo Transports in general

SBASs arestandardized at ICAO
level to ensureinteroperability©2019 LINKS• Systems for Safety of Life applications withfocus on integrity:• Systems for other services with legal orliability implications:o Road Tollingo Exclusive Economic Zone control

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SAFETY AND ACCURACY➢ Safety is guaranteed through the satisfaction of requirements provided byinternationals bodies as International Civil Aviation Organization (ICAO) andInternational Maritime Organization (IMO).
o Such requirements take also into account accuracy but the human life protection isthe main driver.
o Integrity:▪ Timely alarms in case of GNSS signal failure▪ Information to users to compute the level of trust (confidence bounds) of the received GNSS signals➢ In non-SoL systems accuracy is the focus. Different levels of performance can beachieved to satisfy different needs including economic aspects.

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COVERAGE➢ A different categorization can be done on the basis of the system coverage:o Local area (LAAS or GBAS)
oo

Range corrections
Common SVs viewo Wide Area (SBAS)
oo©2019 LINKS

Separate corrections for each error
Large network of reference stations needed©Navipedia

8ERRORS
Errors affecting GNSS performance depend on
several factors:➢ At system (space-control) level:o Clock errorso Ephemeris errorso [ Selective Availability (S/A) ]➢ During the path from satellite to receiver(propagation):o Ionosphere effectso Troposphere effects➢ At receiver level:o Receiver noiseo Multipaths, interfering signals, etc.

©2019 LINKS➢ Error sources can be divided in two main groups:
o errors with strong spatial correlationo errors with weak spatial correlation
Spatial correlation refers to the variation of theerror magnitude with respect to the change ofthe receiver position.
➢ Different GNSS receivers will experience theeffect of the same error source depending on:o the error spatial correlationo the distance among the receivers➢ Two receivers with a certain degree of proximity
will be affected by common errors and by errors
with a strong spatial correlation that can bemitigated.

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SBAS STRUCTURE➢ Space Segmento geostationary satellites➢ Ground Segmento Control and Monitoring Centres
o Network of Monitoring Stationso Stations to upload messages➢ User Segmento All receivers enabled to elaborate the SBAS
signal to improve performanceo Applications based on provided services➢ Services enabled by broadcast signals© GSA©2019 LINKS

10OUTLINE❖ INTRODUCTION TO AUGMENTATIONSYSTEMS❖ EGNOS AND ITS SERVICES❖ EGNOS ARCHITECTURE❖ EGNOS PERFOMANCE©2019 LINKS

11EGNOS➢ EGNOS - European Geostationary Navigation Overlay
Service - is Europe regional SBAS

➢ EGNOS was promoted by the European Tripartite Group
formed by Eurocontrol, the European Commission and theEuropean Space Agency.
➢ It was initially designed for aviation to enable aircrafts to use
GPS for all phases of flight, from en route down to precision
approaches to any airport within its coverage area.
➢ EGNOS provides safety of life navigation services also tomaritime and land-based users Its main features are theprovision of:oWide Area Differential corrections

oIntegrity information©2019 LINKS➢ Currently it augments GPS L1
C/A signal➢ Galileo augmentation plannedin future system versions

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EGNOS➢ EGNOS is operational since 2009
➢ EGNOS meets stringent International Civil Aviation Organisation (ICAO)
requirements for all phases of flight➢ It is compliant with relevant ICAO Standards And Recommended Practices for
SBAS (SARPS) and Minimum Operational Performance Standard (MOPS)➢ EGNOS is fully interoperable with all other SBAS worldwide➢ EGNOS is managed by:oEuropean GNSS Agency (GSA): exploitation phase, overall operational programmemanagementoEuropean Satellite Service Provider (ESSP): is the EGNOS Services Provider within Europe,
certified according to the Single European Sky (SES) regulation as an Air Navigation ServiceProvider (ANSP) (under GSA contract).

oEuropean Commission (EC): owner of the EGNOS system.

oEuropean Space Agency (ESA): led EGNOS technical development; mandated by EC as agent
for design and procurement for system evolutions.

©2019 LINKS

13EGNOS SERVICESEGNOS provides 3 services➢ Open Service (OS)➢ Safety of Life (SoL) Service➢ EGNOS Data Access Service (EDAS)©2019 LINKS

14EGNOS OS➢ EGNOS Open Service: available since 1st October 2009➢

OS is freely accessible with a GPS/SBAS compatible receiver within
the EGNOS OS area without any specific authorisation requirements.

➢ EGNOS OS can only be used for non-safety critical purposes.
➢ The EGNOS OS service improves positioning accuracy by correctingerror sources affecting GNSS signals.
➢ The corrections transmitted by EGNOS help mitigate ranging error
sources related to satellite clocks, satellite position andionospheric effects.
➢ EGNOS can also detect distortions affecting the signals transmittedby GNSS, preventing users from tracking unhealthy or misleading
signals that could lead to inaccurate positioning.
OS minimum accuracy©2019 LINKS

15EGNOS SOL SERVICE➢ EGNOS SoL Service is available since 2nd March 2011
➢ It provides the most stringent level of signal-in-space (SIS) performance for all
SoL users➢ It supports civil aviation operations down to LPV (Localiser Performance withVertical Guidance) minima (performance characterisation conducted).
➢ SoL may be used in maritime, railways and road domains whenever citizens’ life
can be endangered by performance of the navigation system below specified
accuracy or by no alert notice given within a specified time interval.
➢ SoL SIS was designed to comply with ICAO SARPS.
➢ Sol SIS provides integrity information, it is open and freely accessible.
➢ Sol SIS:
oaugmentation signal to GPS SPS for positioning

oadditional timing signal©2019 LINKS16

EGNOS EDAS
➢ The EGNOS Data Access Service (EDAS) offers ground-based access to EGNOS
data through the Internet on a controlled access basis.
➢ EDAS is the access point to data collected and generated by the EGNOS groundinfrastructure distributed over Europe and North Africa.
➢ EDAS provides the same data that is broadcast by the EGNOS satellites (EGNOSMessage) in near real-time.
➢ EDAS delivers EGNOS data to users who cannot always view the EGNOS
satellites (such as those in urban canyons).
➢ EDAS primarily provides the following types of data:oraw GPS, GLONASS and EGNOS geostationary satellite observations

onavigation data collected by the entire network of EGNOS stations;oEGNOS augmentation messages, as normally received by users via the EGNOSgeostationary satellites.

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OUTLINE❖ INTRODUCTION TO AUGMENTATIONSYSTEMS❖ EGNOS AND ITS SERVICES❖ EGNOS ARCHITECTURE❖ EGNOS PERFOMANCE©2019 LINKS

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SYSTEM ARCHITECTURE©2019 LINKS

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SPACE SEGMENT➢ EGNOS data transmission primarily relies on three telecommunication geostationary satellites
centred over Europe:oPRN 120 Test Mode
Inmarsat-3F2 AOR-E(Atlantic Ocean Region East)stationed at 15.5° W.

oPRN 123 Safety of Life Mode
Astra 5B
stationed at 31.5° E.

oPRN 136 Safety of Life Mode
Astra SES-5
stationed at 5.0°E.

➢ High level of redundancy over the wholeservice area in the event of a failure in thegeostationary satellite link.
➢ Any time, EGNOS operations ensure at least
two GEOs broadcast an operational signal.

➢ Real time information about status:
https://egnos-user-support.essp-sas.eu/new_ egnos_ ops/egnos_ system_ realtime©2019 LINKS20

EGNOS GROUND SEGMENT
The EGNOS Ground Segment consists of:➢ 40 Ranging Integrity Monitoring Stations (RIMS)(extensions foreseen)➢ 2 Mission Control Centres (MCC): these receive the information from the RIMS and generatecorrection messages to improve satellite signal accuracy and information messages on thestatus of the satellites (integrity). The MCC act as the EGNOS system’s 'brain'.
➢ 6 Navigation Land Earth Stations (NLES) (2 for each GEO)➢ The EGNOS Wide Area Network (EWAN) which provides the communication network for all thecomponents of the ground segment.
➢ 2 additional facilities are also deployed as part of the ground segment to support system
operations and service provision:o the Performance Assessment and Checkout Facility (PACF) - performance analysis,troubleshooting, and operational procedures as well upgrading specifications andvalidations and providing maintenance support.
o the Application Specific Qualification Facility (ASQF) - provides civil aviation andaeronautical certification authorities with the tools to qualify, validate and certify thedifferent EGNOS applications.
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RIMS
➢ The main function of the 40 RIMS is to collect measurements from GNSS satellites and to transmit
these raw data (GPS L1 and L2 + GEO/GLO L1) every second to the Central Processing Facilities(CPF) of each MCC.
➢ Additional RIMS in La Palma, (Spain), Athens (Greece) and Alexandria (Egypt) have been deployed.
➢ A further extension is also planned inorder to improve the EGNOS
performance in the southernparts of the service area.

©2019 LINKS22RIMS SITES➢ Each RIMS site is surveyed w.r.t.:oElectromagnetic Interferenceo

Multipath environment

Trondheim

Reykjavik©2019 LINKS

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NLES BLOCK DIAGRAM
2 Navigation Land EarthServices per GEO satellite:
the NLES transmit the EGNOS
message received from theCentral Procesing Facility tothe GEO satellites forbroadcasting to users and toensure synchronisation withthe GPS signal.

FDN

GEO L1P

L1/L2

GEO L1

FDN

L1

FUP-R

Integrity
Box

L1

CAL

CALDN

FUP

ON/OFF

GroundCommunication
NetworkEWAN
FEE

L1

FDNL1

FUP-RL1
L1

Long
Loop

Core
Receiver

1PPS

Rx message

Time
OffsetGEO
messageFrequency
Standard

CAL

10 MHz Distribution

70.42
MHz

Monitoring & Control©2019 LINKSGPSRFRF Adapter

CPF
CCFGEOFUCoreComputer

1PPS
Tx message

1PPS

GPS / GEOs / GLONASS phase and code
raw measurements

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USER SEGMENT - EGNOS ADOPTION••

301 airports with EGNOS landing procedures
557 EGNOS approaches•••~60% EU tolled roads take advantage of Galileo/EGNOSFirst cars in the market with eCall using Galileo/EGNOS (Volvo and Honda)
Main car makers are testing Galileo in view of the first highly autonomouscars•••

IMO recognised Galileo for merchant shipping
10% Galileo OS penetration in receiver models
80% EGNOS OS penetration in receivers models• Around 80% of tractors in Europe using GNSS are equipped with EGNOS• 55% of all new 'GNSS tractors' in the EU are Galileo enabled• Over 50% of surveying and mapping receivers are Galileo-capable• Around 80% of mapping and GIS receivers are EGNOS compatible• The main PPP providers support Galileo corrections (Fugro, Veripos, NovAteland Trimble)©2019 LINKS

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OUTLINE❖ INTRODUCTION TO AUGMENTATIONSYSTEMS❖ EGNOS AND ITS SERVICES❖ EGNOS ARCHITECTURE❖ EGNOS PERFOMANCE©2019 LINKS

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EGNOS PERFORMANCE• SoL APV-1 SDD Availability

Current SDD©2019 LINKS

Publication
Issue 3.2

New SDD
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EGNOS PERFORMANCEEGNOS Portal:
www.egnos-portal.gsa.europa.eu©2019 LINKS

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CONTACTGABRIELLA POVERO
gabriella.povero@linksfoundation.com
www.navsas.eu
www.ismb.it

LINKS FOUNDATION
Via Pier Carlo Boggio 61 | 10138 Torino+(039) 011 2276 150©2019 LINKS@linksfoundation

linksfoundation@linksfoundation

linksfoundation.com
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