GIT-2 Australia GRAS.pdf

7/28/2019 GIT-2 Australia GRAS.pdf

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Update on

Ground based RegionalAugmentation System (GRAS)

Keith McPherson, Manager GNSS


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GRAS Definition

A system providing GNSS augmentation service by which the

user receives information directly from ground-based

transmitters, allowing continuous reception of the service over alarge geographical are(200Nm+). The ground components may

be interconnected in a network


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Rationale behind GRAS Availability of (D)GNSS is paramount for Air Traffic Management(ATM) development

Impact on both Navigation, Surveillance and Communications

Availability must be from gate-to-gate

Minimum of new systems for CNS cost efficiency

Value added service to CNS/ATM improved business cases

Available for all user groups at reasonable costs

High latitudes

National and/or Regional sovereign control of the service delivery is vital


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Aircraft GNSS integrity feed

GNSS Receiver

GPS/GLONASS/GALILEO

Navigation datalink Communications datalink

GRAS ADS-B Service


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Alternative Augmentation

Ground based Regional Augmentation System

Key BenefitsEnroute navigation over entire continent

Non-Precision Approaches, Approaches with vertical guidance

No single point of failure for whole system

Relatively inexpensive compared to US and Europeanaugmentation systems

Expected potential to further reduce current navigation aids


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GRAS usage En-route

APV I/II CAT I

A-SMGCS/ Surface movement

ADS-B Surveillance


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GRAS Concept

GPS Constellation

GRS GMSSatcom orTerrestrial

Links

Satcom orTerrestrial

LinksGVS

L

L

L

VHF

Users

GRAS Master Station processes GRS data

determines GPScorrections & integritystatus

generates SBASmessages

GRAS Ref. Stn

collects GPSmeas. & data

formats/sendsdata to GMS

GRAS VHF StnReceives &

verifies SBAS

messages

converts to GBAS

..format

broadcasts GRAS

messages at VHF

User Equip.

receives GPS

& GRAS datacomputes

SARPs-based

nav solution

GPS Constellation

GRS GMSSatcom orTerrestrial

Links


Links


Links


LinksGVS

L

L

L

VHF

Users

GRAS Master Station processes GRS data

determines GPScorrections & integritystatus

generates SBASmessages

GRAS Ref. Stn

collects GPSmeas. & data

formats/sendsdata to GMS

GRAS VHF StnReceives &

verifies SBAS

messages

converts to GBAS

..format

broadcasts GRAS

messages at VHF

User Equip.

receives GPS

& GRAS datacomputes

SARPs-based

nav solution


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Technical concept

GRASData Link

Automatic Ground

Station selection

GBAS

Format

VHF Data Links

Terrestrial Data Link

Large

AirportSmall

Airport


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Ground Reference Stations Broome

Carnavon

Perth Darwin

Alice Springs

GRAS Schematic

Master Control Stations Brisbane & Melbourne

Data Lines

(Operational Concept)

Not to Scale

VHF Transmitters Using current VHF voice transmission

sites

Connected by data-line to MasterControl Station

Ceduna

Thursday I

Mackay Canberra

Hobart


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VHF Sites Across Australia


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GRAS Architecture

Ground network

GRAS Broadcast

Interface to other

systems, e.g. other

GRAS stations or

SBAS/EGNOS

(external GRAS)

Remote service

monitoring etc.


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GRAS LATERAL ERROR

POINT COOK APPROACH RWY 35

RUN 35

-30

-20

-10

0

10

20

30

10

9.

69

9.

37

9.

03

8.

68

8.

34 8

7.

65

7.

3

6.

95

6.

59

6.

24

5.

89

5.

54

5.

18

4.

82

4.

46

4.

09

3.

72

3.

36 3

2.

65

2.

3

1.

94

1.

6

1.

26

0.

93

0.

6

0.

28

NM TO THRESHOLD

METRES

LATERAL ERROR

CAT 1 NSE LIMIT


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GRAS VERTICAL ERROR

POINT COOK APPROACH RWY 35

RUN 35

-20

-15

-10

-5

0

5

10

15

20

10

9.

69

9.

37

9.

03

8.

68

8.

34 8

7.

65

7.

3

6.

95

6.

59

6.

24

5.

89

5.

54

5.

18

4.

82

4.

46

4.

09

3.

72

3.

36 3

2.

65

2.

3

1.

94

1.

6

1.

26

0.

93

0.

6

0.

28

NM TO THRESHOLD

METRES

VERTICAL ERROR

CAT 1 NSE LIMIT


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VHF Cross-over Tests

elbourne

Cooma

Sydney

HobartTasmania

New South Wales

Albury


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VHF Cross-over Interference (None so far)

Slots A & H Equal Power Level Slots A & B Equal Power Level

Slots A & B Closer to Cooma


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20 August 2001

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10014074 10015074 10016074 10017074 10018074 10019074 10020074 10021074 10022074 10023074 10024074 10025074

dBm Melbourne

Cooma


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CNS/ATM Toolbox

Communications Navigation

Broadcast GRAS ADS-B

ATN

non-ATN

ADS-CPoint-to-point

ATC

Aircraft

Surface

ATC

Surveillance

FIS

TIS GNSS

RAIM Prediction


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GRAS

Navigat ion Survei l lance

En-route through APV to

Surface navigat ion

GNSS AUGMENTATION

ATC, aircr aft

and su rface vehicles


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GRAS in perspective

SBAS+ Wide Coverage

- Complexity

Institutional

GBAS

+ Local(23Nm)

- Dedicated landingSystem

Expensive

ABAS

+ Autonomous

- High End A/C

GRAS

+ Regional service

Step wise implementation

Added value service- Line of sight


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GRAS today

Sent to ICAO for standardisation (GNSSP) uses GBASmessage format with one change

Solid manufacturing support

Still a chance to control the development process

Service identical to GBAS standard.

GRAS supports PVT and is compatible to GNSSP PVT

Need for broader understanding and inclusion in regionalprograms as an alternative, regional solution


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ICAO Approval Status GRAS

Concept presented to ICAO

Air Navigation Commission tasked GNSS Panel to developSARPs 1999

Australia (Airservices) selected to develop SARPs

Standards and Recommended Practices (SARPs)

November 2000 - Concept of Operations developed

March 2001 - first draft of SARPs distributed

November 2001 - text mostly accepted by ICAO

October 2002 - final text

2002-2003 - validation process

March 2003 - approval expected by GNSS Panel


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ANY QUESTIONS ??

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