Work Package 1 - Progress Report€¦ · Document Id: ALL_WP1_1-2.0 File: F:\FT\NEAN\TRIALNET\WP1\T14\PRGRSS20.DOC Version: 2.0 Date: 1997-11-02 Status: Released Authored by: S.Penter/SLV,

$Page 1: Work Package 1 - Progress Report€¦ · Document Id: ALL_WP1_1-2.0 File: F:\FT\NEAN\TRIALNET\WP1\T14\PRGRSS20.DOC Version: 2.0 Date: 1997-11-02 Status: Released Authored by: S.Penter/SLV,$
Document Id: ALL_WP1_1-2.0File: F:\FT\NEAN\TRIALNET\WP1\T14\PRGRSS20.DOCVersion: 2.0Date: 1997-11-02Status: ReleasedAuthored by: S.Penter/SLV, P.Raffay/SLV, K.Werner/DLR, M.Poppe/DFS, P.Ericsson/LFV, M.Henriksson/LFVPrinted: 2000-10-13

Work Package 1 - Progress Report

Work Package 1 - Progress Report Page 2/48this report provides a detailed description of the nean work package 1 progress.

Document Id: ALL_WP1_1-2.0Version: 2.0Date: 1997-02-11

Distribution List

Name Authority

- NEAN TEAM MEMBERS

- NEAN STEERING COMMITTEE

- EUROCONTROL

- EUROPEAN COMMISSION



Control PageRevision Log.This version supersedes all previous versions of this document.

Version Date Author Pagesconcerned

Reason

1.0 1996-10-01 S.Penter (Editor) All First Release1.1 1996-12-11 S.Penter (Editor) p.16,32,37,38

p.32Minor misprints correctedUpdated status for EKEB, EKYT and Tyra.

2.0 1997-02-11 P.Raffay (Editor) p.15 - 18p.37p.47,48

Definitions rearanged.References to Appendicies added.Appendicies A and B added.



Table of Contents

0. GLOSSARY..................................................................................................................... 7

1. EXECUTIVE SUMMARY................................................................................................. 9

2. INTRODUCTION........................................................................................................... 102.1. DOCUMENT STATUS .................................................................................................. 102.2. SCOPE OF THE DOCUMENT......................................................................................... 10

3. REFERENCE DOCUMENTS ........................................................................................ 11

4. SYSTEM OVERVIEW ................................................................................................... 134.1. ARCHITECTURE AND DEFINITIONS............................................................................... 14

4.1.1. Network Definitions ......................................................................................... 154.1.2. Network Entity Definitions ............................................................................... 154.1.3. Protocol Definitions ......................................................................................... 18

4.2. GROUND STATION AND MONITOR STATION.................................................................. 194.3. TRANSMISSION PERMISSIONS..................................................................................... 21

5. GROUND STATION INSTALLATION ........................................................................... 225.1. PREREQUISITES AND STRATEGY ................................................................................. 225.2. SITE SURVEY............................................................................................................ 22

5.2.1. Geographical Location .................................................................................... 235.2.2. Ground Station Antennas................................................................................ 245.2.3. Remaining Ground Station Hardware ............................................................. 24

5.3. DIFFERENT SET-UPS FOR GROUND STATIONS ............................................................. 255.3.1. Set-up 1 - Stand alone Monitor Station ........................................................... 265.3.2. Set-up 2 - Stand alone Ground Station with multiple Display Systems........... 265.3.3. Set-up 3 - Connected Ground Station with multiple Display Stations ............. 275.3.4. Set-up 4 - Using a Regional Server as a Local Server Proxy.......................... 285.3.5. Set-up 5 - Connected Ground Station with attached Monitor Station.............. 285.3.6. Set-up 6 - Regional and National Server with multiple Display Stations ......... 29

5.4. DESCRIPTION OF GENERIC GROUND STATION SET-UP ................................................. 305.4.1. Generic Set-up................................................................................................ 305.4.2. Equipment List ................................................................................................ 31

5.5. STATUS.................................................................................................................... 336. MOBILE INSTALLATIONS............................................................................................ 35

6.1. MOBILE VEHICLE INSTALLATIONS................................................................................ 356.1.1. The Antennas.................................................................................................. 366.1.2. Equipment List For a Vehicle .......................................................................... 366.1.3. Status.............................................................................................................. 36

6.2. AIRCRAFT INSTALLATIONS.......................................................................................... 386.2.1. Certification ..................................................................................................... 386.2.2. Status.............................................................................................................. 39

7. PLANNING ACTIVITIES................................................................................................ 417.1. TRIALS PLANNING ..................................................................................................... 41

7.1.1. Trials Objective ............................................................................................... 41



7.1.2. Realisation ...................................................................................................... 427.1.3. Limitations....................................................................................................... 437.1.4. Test schedule.................................................................................................. 44

7.2. MAP GROUP............................................................................................................. 457.3. TRANSPONDER PROCUREMENT.................................................................................. 46

8. APPENDIX A................................................................................................................. 47

9. APPENDIX B................................................................................................................. 48



List of FiguresFigure 1 - NEAN System Architecture 14Figure 2 - Hierarchical structure of NEAN ground architecture 17Figure 3 - Remotely connected Display Stations without Local Server proxy 17Figure 4 - Remote connected Display Systems with a Regional Server as a Local Server Proxy 18Figure 5 - NEAN Ground Station, Monitor Station and Base Station 19Figure 7 - Theoretical NEAN coverage for FL 330 23Figure 8 - Stand alone monitor station 26Figure 9 - Stand alone ground station 27Figure 10 - Connected ground station 27Figure 11 - Regional Server as Local Server Proxy 28Figure 12 - Ground Station with attached Monitor Station 29Figure 13 - Regional and National Server LAN segments 29Figure 14 - Generic Ground Station set-up 30Figure 15 - Vehicle installation 35Figure 16 - Test schedule 44



0. GlossaryAC Alternating CurrentADS-B Automatic Dependent Surveillance BroadcastCAA Civil Aviation AdministrationCDTI Cockpit Display of Traffic InformationCPDLC Controller Pilot Data Link CommunicationDANT Danish NEAN Project TeamDC Direct CurrentDFS DFS - Deutsche Flugsicherung GmbHDGPS Differential Global Positioning SystemDLR Deutsche Forschungsanstalt für Luft- und RaumfahrtFMF Female-Male-FemaleGERT German NEAN Project Team.GNSS Global Navigation Satellite SystemGPS Global Positioning SystemILS Instrument Landing SystemITT Invitation To TenderLAN Local Area NetworkLFV LuftfartsverketLS Local ServerMAN Metropolitan Area NetworkMMI Man Machine InterfaceMS Management StationNEAN North European ADS-B NetworkNEAP North European Application ProjectNM Nautical MileNS National ServerOLT Ostfriesiche Lufttransport GmbHPSU Power Supply UnitRS Regional ServerSARPs Standards And Recommended PracticesSAS Scandinavian Airline SystemsSCAA Swedish CAASLV Statens LuftfartsvæsenSTDMA Self-organising Time Division Multiple AccessSVGA Super VGASWET Swedish NEAN Project TeamSWR Standing Wave RatioTCP Transmission Control ProtocolTCP/IP Transmission Control Protocol/Internet ProtocolTEN Trans European NetworkTO Technical OrderUTC Universal Time Co-ordinatedVDL VHF Data LinkVGA Video Graphics ArrayVHF Very High Frequency



WAN Wide Area NetworkWGS-84 World Geodetic System 84WP1 Work Package 1XPDR Transponder



1. Executive SummaryThis report provides a detailed description of the NEAN work package 1 progress. All envisagedobjectives have been met, i.e. the first installation phase is completed. There are four groundstations installed in Denmark, five in Germany and six in Sweden. Moreover, there are sevenaircraft equipped with GNSS transponder systems: four in Sweden (SAS), one in Denmark (SLVaircraft) and two in Germany (OLT). At least, one vehicle at every airport is equipped with theGNSS transponder.

All ground stations and mobile transponder installations have been locally tested to ensure properoperation. Except a minor problem with the power supply no serious hazards were detected.

Since the NEAN project mainly provides the infrastructure for other projects like NEAP andPETAL-II which embrace the applications the current planning activities comprise groundmovement and flight trials. The aim is to check the coverage at airports and en route, the reliabilityof the whole system, i.e. ground station, mobile installations and network operation, and the end-to-end performance of the data link and network. In the ground station software there are alreadyinterfaces present to access and store all data messages for off line assessment and statisticalanalysis.



2. IntroductionThis is the Progress Report of Work Package 1 on planning and installation of the EU funded TEN-T project "North European ADS-Broadcast Network (NEAN)". It comprises the reporting periodfrom January 1996 until September 1996.

All progress will be measured and reported against the NEAN Project Definition document [1]which provides a detailed description of all NEAN activities and milestones as agreed by the NEANSteering Committee. Project Definition document [1] represents the final report of Work Package 0,the project definition.

The overall objective of the NEAN project is to develop, evaluate and demonstrate newtechnologies for data links and networking, and thereby contribute to the implementation of anetwork for communication, navigation and surveillance in the provision of Air TrafficManagement in Europe. To achieve this objective, an experimental system, developed to prototypelevel, will be established comprising a network of ground stations in three countries and avionicsinstalled in aircraft from airlines and airport based vehicles.

Due to the structure of Work Package 1 this report is divided into three main chapters, i.e. thedescription of the NEAN base station installations, the equipment of the aircraft and the airport carsand the different planning activities in the field of digital maps in the WGS 84 co-ordinate system,procurement procedures and trials planning.

Since NEAN is an experimental system for carrying out field trials relying on a rather newtechnology it comprises some special features. The hardware components of the groundinfrastructure are off the shelf by different manufacturers while the software mainly has beendeveloped by the Swedish CAA for their national trials.

In the course of Work Package 3 the software will be adopted to the needs of NEAN. Although itcan be used for the trials there should be an upgrade and/or new development of parts of thesoftware in order to cope with the advanced NEAN requirements and to demonstrate the fullcapabilities of the underlying system concept and technology. This will be reflected in the WorkPackage 3 progress report.

2.1. Document Status

Document is released as the final deliverable of Work Package 1.

2.2. Scope of the document

The document aims at providing a technical overview over the progress of NEAN Work Package 1and describes the current status. Further details can be obtained from the reference list whichprovides a summary of the most relevant produced working papers during this period.



3. Reference Documents

[1] “North European ADS-B Project Definition”, Version 3.0LFV_WP0_02-3.0, K.Bech/LFV, August 1996.

[2] “The GNSS transponder”, v 8.5, H.Lans.

[3] “Configuration Control Document NEAN Installations Germany”DFS_WP1_01-2.0, M.Poppe, September 11, 1996

[4] “Ground Station Setup Control Document”DFS_WP1_02-1.1, M.Poppe, September 20, 1996

[5] “Software Maintainability Test Report NEANSERV”DFS_WP1_03-1.0, M. Poppe, September 2, 1996

[6] “NEAN Naming Convention”DLR_WP1_01-1.1,, K. Werner, September 30, 1996

[7] “NEAN Problem and Change Report”SLV_WP1_01-1.1, S.Penter, September 9, 1996

[8] “Selection of NEAN software for the Danish sites”SLV_WP1_02-1.0, S.Penter, May 21, 1996

[9] “Selection of NEAN hardware for the Danish sites and network segment”SLV_WP1_03-1.0, S.Penter, September 2, 1996

[10] “Test Specification for Equipment LAB-Test”SLV_WP1_06-1.1, S.Penter, September 9, 1996

[11] “Lab-test of old and new transponders with old and new DGPS stations in Copenhagen”SLV_WP1_07-1.1, S.Penter, September 30, 1996

[12] “Quality Standards Document”SLV_WP1_09-1.0, P.Raffay, In preparation

[13] “Base Station Installation Verification”LFV_WP1_02-1.0, J.Carlsson, September 30, 1996

[14] “Standards and Recommended Practices for the Application and use of self-organizing timedivision multiple access (STDMA) for VHF air-ground communication” (Appendix Av/3.3, Appendix B v/3.3)AMCP WG-D/3, Prepared by Stephen B. Heppe, K.Prasad Nair, May 8, 1995

[15] “RTCA/DO 178, Software Considerations in Airborne Systems and EquipmentCertification”



[16] “ARINC specification 429-3”, December 15, 1979

[17] “Requirements specification of a ground based GNSS Transponder platform for the NEANproject”LFV_WP5_03-5.0, N.Gustavsson, June, 1996

[18] “Requirements specification of an Airborne GNSS Transponder platform for the NEANproject”LFV_WP5_02-5.0, N.Gustavsson, June, 1996

[19] “Report from the GNSS Transponder tender evaluation group”LFV_WP5_04-1.0, N.Gustavsson, November 1996

[20] “GNSS Transponder Procurement Proposal”LFV_WP5_05-2.0, N.Gustavsson, November 1996

[21] “Ground Station Set-up by using STRANCS Configuration program”LFV_WP1_01-2.0, P.Ericsson, August 1996

[22] “Reference Station Connection and Configuration”LFV_WP1_03-1.0, J.Carlsson, September 1996

[23] “NEAN Server Software Documentation”LFV_WP5_06-1.0, M.Henriksson, November 1996

Note: The NEAN produced documents listed reflects only most relevant working documents andthe dates shows the latest internal release



4. System OverviewThe North European ADS-B Network (NEAN) is a proto-type system capable of networkingground-based GNSS transponders into a cellular VDL/STDMA net with national and internationalcoverage. The VHF coverage around a ground-based GNSS transponder is referred to as a ‘cell’.

The cellular network capability is currently achieved through the use of a TCP/IP ‘ground-based’network which can utilise any standard WAN/MAN or LAN technology as long as a TCP layer isprovided as transport mechanism. Therefore it is important to distinguish between the VHF (sub-)network, based on the STDMA access and control mechanism, and the ground (sub-) networkwhich interconnects all ground stations to ensure message exchange and routing.

In principle the system provides only a basic network infrastructure enhanced with certain NEANnetwork services. Currently two services exist:

1. A real-time data-acquisition service for collecting ADS-B position report from mobile entities inthe VDL/STDMA sub-network and producing a ‘global’ situation picture.

2. A connectionless (i.e. unconfirmed end-to-end) message service.

On the international level the NEAN network consist of one or more interconnected NationalDomains which together form an International Domain. For the trials the National Domains areGermany, Sweden and Denmark and the International Domain is Northern Europe, i.e. thegeographical area covered by the above mentioned National Domains.

A National Operator will have the overall administrative control of a National Domain and aNational Domain is conceptually kept within national borders. However, neighbouring NationalDomains will in practical terms ‘overlap’ across national borders since they are based on a cellularVDL/STDMA sub-net.

The NEAN project participants are the National Operators for the trials.

National Domain National OperatorDenmark SLV - Statens LuftfartsvæsenGermany DFS - Deutsche Flugsicherung GmbH, jointly with

DLR - Deutsche Forschungsanstalt für Luft- und RaumfahrtSweden LFV - Luftfartsverket

There is no single administrative International Operator for the International Domain.Administration of the International Domain are undertaken jointly by the participating nationalauthorities.



4.1. Architecture and Definitions

This section defines the NEAN System Architecture and the special terminology for theinfrastructure which will be used in the frame of the whole project to unanimously identify thereferred components and to ease the understanding of the overall installation concept

figure a below shows the logical NEAN system architecture for a single National Domain.

P2

P2

P3

Ground Network

Regional Level

National Level

P2

Other NationalDomains

National Server

Workpackage 1

P0

Mobile

VDL/STDMA Network

P0

Local Level P1Base Station

Local ServerDisplay Station

Regional Server

SNMP

National Domain

Display Station

Display Station

ManagementStation

Mobile

Figure A - NEAN System Architecture

As indicated in the figure above Work Package 1 is only concerned with setting up Ground Stations(i.e. building the individual ‘cells’) in the cellular network and equipping mobiles with GNSStransponders (the dark shaded area), whereas Work Package 3 deals with issues concerning thenetworking aspects.



The figures shows that a National Domain (the dotted line) is divided into two (sub-) networks: TheGround Network and the VDL/STDMA Network. The Ground Network is further hierarchicallydivided into three levels: A National Level, A Regional Level and a Local Level. To understand theconcept all relevant entities are described in the following sections.

4.1.1. Network Definitions

Ground Network The NEAN Ground Network consists of the Base Stations, theLocal/Regional and National Server and the Display Stations.In principle also the Management Station is part of the GroundNetwork, but for clarity it is show ‘outside’ the network (figurea).

VDL/STDMA Network This describes the VDL/STDMA sub-network containingmobile units (Mobile) - airborne or ground-based.

4.1.2. Network Entity Definitions

Mobile

Mobile

A mobile unit in the VDL/STDMA Network. All mobile unitsmust be equipped with the GNSS (STDMA) transponder.Mobile units can both be aircraft and ground vehicles.(Refer to chapter ‘4.2 ground station and monitor station’ for adetailed description and definition of the GNSS transponder).

Base Station

Base

A Base Station is on the boundary between the Ground Networkand the VDL/STDMA Network. It comprises the GNSStransponder and a differential GPS reference receiver (DGPSreceiver) which may be external to or internally integrated inthe transponder.(For a more detailed picture of a base station and definitions ofthe GNSS transponder and the DGPS reference reciver refer to‘4.2 ground station and monitor station‘ figure e.)

Display Station

DS

Display Station or

A Display Station visualises the current air traffic situationeither in real time or off-line. It is not related to a Base Stationor to any type of server. A Display Station may independentlybe integrated into a Ground Station or may be directlyconnected to a WAN with access to the NEAN exchanged datamessages, e.g. the ADS-B reports. If a Display Station isoperated separately sometimes it is referred to as En-RouteStation.A Display Station is currently a PC running the AIRSYSsoftware. Due to some constraints another display system maybe selected in the future.



Management Station

MS

Display Station or

A Management Station monitors and supervises (the national)parts of the whole NEAN network. It is up to the NationalOperator and the underlying transport mechanisms of thenetwork which configuration and protocols will be supported bythe Management Station. A typical example is a SimpleNetwork Management Protocol (SNMP) stack integrated in awork station.As a Display Station, a Management Station is independent ofany other system elements.

Local Server

LS

Local Server or

A Local Server processes all uplink and downlink messages andprovides the interface between the VDL/STDMA-network andthe Ground network.Currently, the hardware platform is a PC which contains theNEANSERV software. The Local Server is connected to a BaseStation or a Monitor Station and via a router to any WAN andother NEAN Servers.

Regional Server

RS

Regional Server or

A Regional Server can be regarded as a Local Server but with adifferent configuration. In principle, it is the same hardwareinterfaces and it is the same NEANSERV software running.The Ground Network concept allows a hierarchical structure ofall NEAN Ground Stations as indicated in figure a. TheRegional Server is the next level in the hierarchy and mayembrace several Local Server. In some circumstances RegionalServers can be used as proxies for Local Servers. See later inthis section or section ‘5.3.4. set-up 4 - using a regional serveras a local server proxy’

National Server

NS

National Server or

A National Server is in the top of the hierarchy in a NationalDomain and forms the reference point for other internationalconnections (please refer to figure b).This entity provides the overall situation picture of all traffic inthe National Domain.There is only one National Server in each National Domain



M Regional Server(s)

N Local Server(s)

NationalServer

National NEANGround Network

National NEAN mobilesub-network One or more

Base/Monitor Station(s)

N >M

Figure B - Hierarchical structure of NEAN ground architecture

The NEAN servers are primarily used by the National Operator as building blocks in thehierarchical structure but they also have another purpose. They can operate as proxies for oneanother to counter real-world problems of low-bandwidth WAN connections.

Consider the following example with a low bandwidth WAN and three Display Systems (DS) on aremote LAN segment all requesting a ‘traffic situation picture’ from the Local Server (LS).

LAN

LAN

Lowbandwidth

WAN

DS DS DS

R

R

DS LS

Figure C - Remotely connected Display Stations without Local Server proxy

All Display Systems (DS’s) have to make a logical connection (the dotted lines) through the lowbandwidth WAN and have the same data fed, meaning that exactly the same data will be sent overthe WAN three times ( figure c).

In this case - due to the flexible nature of the NEAN servers - a Regional Server (RS) can be placedon the remote LAN together with the Display Stations and configured to operate as a proxy forLocal Server (LS). The Display Systems can now obtain their feed from the Regional Server (RS)on the LAN and the data traverses only the WAN once ( figure d).



LAN

LAN

DS DS DS

R

R

DS LS

RS

Lowbandwidth

WAN

Figure D - Remote connected Display Systems with a Regional Server as a Local Server Proxy

4.1.3. Protocol Definitions

P0 P0 is the protocol used between mobiles and between mobilesand base stations. P0 is the STDMA link-layer protocol whichforms the basis of the NEAN concept. A detailed descriptioncan be found in [2].

P1 P1 is the protocol used between Base Stations andLocal/Regional or National Servers. It is a serial line protocol.A detailed description can be found in [2].

P2 P2 is a protocol used within the NEAN Ground Networkbetween NEAN Servers. It is an application layer protocolbased on TCP/IP. For details see [2].

P3 P3 is a protocol used within the NEAN Ground Networkbetween NEAN Servers and Display Stations. This is also aTCP/IP based application layer protocol. For details see [2].



4.2. Ground Station and Monitor Station

In addition to the entities mentioned in the previous chapter ’architecture and definitions’ GroundStation, Base Station and Monitor Station are used in the NEAN concept describing compositeentities.

figure e below shows a more detailed example of the relationship between a Ground Station,Monitor Station and a Base station.

Router/Bridge

Ground Station

Monitor Station

Base Station

WAN

LAN

XPDR DGPS

LS DS

R

Display Station

GNSSTransponder

DGPSReceiver

Local/Regional orNational Server

RS NS

Figure E - NEAN Ground Station, Monitor Station and Base Station



Ground Station A NEAN Ground Station comprises as minimum either a BaseStation or a Monitor Station, thus providing VHF transceiver.Usually, a server is part of the Ground Station and optionally, aDisplay Station or Management Station may be connected.

Base Station A Base Station comprises the GNSS transponder and adifferential GPS reference receiver (DGPS receiver) which maybe external to or internally integrated in the transponder.(Sometimes a Base Station also is referred to as ReferenceStation because it transmits the differential corrections.)

Monitor Station A Monitor Station is a Base Station without differential GPSreceiver. The aim is monitoring the VHF signals in space.Usually, the Monitor Station is connected to a NEAN server(Though not required).

GNSS Transponder

XPDR

The GNSS Transponder consists of an internal GPS receiver(switched off if external GPS receiver is connected), acommunication processor and a VHF transceiver. Currently atransponder from the Swedish Space Corporation is used.

See [2] and [3] for transponder details and user changeableparameters.

DGPS Receiver

DGPS

The GPS receiver operates as a differential GPS referencestation and provides the GNSS transponder with the correctiondata at an update rate of 1/second. In the NEAN ground stationsthe 12 channel Leica MX 9112 engine is used. The connectionfrom the GPS equipment port to the GNSS transponder is aserial RS232 interface, using the NMEA-0183 data interfaceformat.

The detailed configuration of the MX 9112 is described in [3]

The system concept shown in figure e indicates that a Ground Station consists of a Base Station, anytype of Server and the connection to a WAN via a router. If a National Server is connected, theremay be more than one access line to the WAN. The Display Station is directly connected to theLAN. This allows easy extension and integration of other system elements by adding them to theLAN. It is independent of a specialised hardware platform. In principle, every element can bedifferent as long as the interface formats (message formats etc.) are the same.



4.3. Transmission permissions

The GNSS transponder is transmitting on a frequency of 136,950 MHz in a range of approximately200 NM (nautical miles) at sea level. As all transmission activities requires permission from theauthorities, the project had to obtain transmission permissions for the transponders.



5. Ground Station InstallationThis chapter gives the rationale and the strategy for the chosen ground sites of the NEAN network.

Setting up a NEAN Ground Station is equivalent to building one or more ‘cells’ in the cellularNEAN Ground Network. The chapter outlines the considerations which must be made whenchoosing a location for a Ground Station and setting up the hardware. The activity is referred to as a‘Site Survey’.

The chapter also contains an overview of possible Ground Station configurations due to the highdegree of flexibility offered by the system and a practical ‘Generic Equipment List’ for an actualGround Station.

5.1. Prerequisites and strategy

In the NEAN EU Project Application a number of ground stations were proposed which togetherform the NEAN (Ground) Network. In the course of Work Package 1 an investigation took placewhether the proposed sites fulfil the requirements with respect to the envisaged applications.Overall, the following priorities were taken into account:

1. Optimum en-route coverage for the National Domains: Sweden, Denmark and Germany2. Provision of differential corrections and coverage of the surface of all major airports in order to

support approaching aircraft and ground vehicles, e.g. Marshall cars3. Network access possibilities to Wide Area Networks (WAN) for national and international

connection of ground stations4. Easy extension of the network and connection of additional ground stations, also in different

countries

As a matter of fact, the investigation showed that all proposed sites fulfil the describedrequirements.It was decided that which national network connections to use were left to the National Operator. InSweden the currently used private TCP network was chosen, in Denmark a backbone network ofleased lines is currently under construction and in Germany the CAA’s private X.25 packet networkwas selected. The latter was mainly done for security and administrative reasons because inprinciple every underlying "transport network" could be used as long as it copes with the NEANrequirements.

5.2. Site Survey

Site surveys were carried out by the each National Operator participating in NEAN

The objectives of the Site Survey activities are three-fold:

• Finding a suitable geographical location for the Ground Station within a National Domain.



• Finding a suitable placement for the antennas (VHF and GPS)• Finding suitable placement for the rest of the Ground Station hardware.

5.2.1. Geographical Location

The geographical location of a NEAN Ground Station must be such that coverage of the domain isas complete as possible.

It is estimated that the coverage of the VDL is 200 NM so - taking the earth’s curvature into account- you can calculate theoretical coverage for different flight levels.

The figure below ( figure f) illustrates this for FL 330

Figure F - Theoretical NEAN coverage for FL 330



5.2.2. Ground Station Antennas

Choosing the locations of the antennas are of the highest importance in setting up a Ground Station,since the placement of the VHF antenna will determine the VDL coverage and the placement of theGPS antenna will determine the accuracy of the ADS-B position reports within that cell.

VHF Antenna

The VHF antenna should be placed such that the following requirement is fulfilled:

1. Line of sight to Final Approach Segment, Runways, Taxiways and Apron.

This is normally fulfilled with a placement in the Airport tower. However, since a multitude of VHFfrequencies are normally used in the tower area it is recommended that a ‘band-pass filter’ isinserted between the Transponder and the Antenna to minimise interference with other frequencies

GPS Antenna

The GPS antenna must be placed such that the following requirements are fulfilled:

1. Uninterrupted views 360° azimuth and above 4° elevation2. The exact position of the antenna must be measured by a land surveyor3. The antenna cable between the transponder and the GPS antenna should not exceed 15 meters.

The quality of the differential GPS corrections depends on the accuracy of the surveyed positionbecause the receiver computes the differences. In order to achieve an overall accuracy of 3 m orbetter (95% value) it was decided to determine the positions of the GPS antenna within 10 cm in theWGS 84 reference co-ordinate system.

The worst problem surrounding the placement of the GPS antenna is that of ‘multipath’, where theantenna receives reflections from the satellites and as a result provides incorrect differentialcorrections to the Ground Station transponder. A test procedure [13] was developed to detect theseproblems, but it is based on measurements after the antenna is in place.

5.2.3. Remaining Ground Station Hardware

The remaining Ground Station hardware, except the Display Stations/Management Stations or En-Route Stations, should be placed together for ease of maintenance.

Local or Regional Server

Consider the following when selecting the physical placement of a Regional/Local NEAN server:

• A NEAN Server is a standard PC (desktop or tower) with it’s own built-in power supply. Accessto 220-250V AC must be available

• The interface between the Local or Regional Server and the Transponder is a standard RS232serial link. If you intend to place the server more than 15 m from the transponder (e.g. if it is



located in another building) you should use a pair of base-band modems to prolong the seriallink.

• The Server should have LAN access.

Display Station/En-Route Station

Consider the following when selecting the physical placement of a Display :

• Currently the chosen Display Station is a standard PC (desktop or tower) with it’s own built-inpower supply. Access to 220-250V AC must be available

• A Display Station takes it’s ‘primary data feed’ from either a Local Server, Regional Server orNational Server on a logical connection over the physical network. Therefore the DS shouldpreferably be on the same LAN as the station feeding it. This is especially true when connectinga cluster of Display Stations to a NEAN Server. However, a DS on any LAN can also take it’sdata feed from any other NEAN server.

Routers

Placing a NEAN router is no different from placing a router for other purposes. Consider thefollowing:

• The Router must have access to the LAN where the NEAN server is located• The router must be near the WAN access point• A Router must be near an amble power supply

The configuration should be done in accordance with the router configuration manuals.

5.3. Different Set-ups for Ground Stations

The NEAN architecture is highly flexible in terms of how the various components can interact withone another, thus it is possible to set up Ground Stations to fulfil many needs. From an unconnectedexperimental monitor station to a fully connected Ground Station with bridged LAN segments it ispossible to adapt the configuration to the specific user requirements.

This section illustrates different set-ups for Ground Stations.



Legend for the illustrations

R

DGPSNSRS

MSRouter MS=Mgmt. Station

NS=National Server

RS=Regional Server

LS=Local Server

DS=Display Station

LS

GNSS transp.

DGSP station.

GPS Antenna.

VHF Antenna.

BridgeB

XPDR

Modem

Band-pass filter DS

PSU Power Supply

5.3.1. Set-up 1 - Stand alone Monitor Station

This scenario shows the simplest set-up for a Ground Station. Only the transponder and a DisplaySystem is required. The transponder is connected directly to a Display System via a serial Link. Nonetwork (LAN) is required (figure g).

If the station is located near another Ground Station with a Reference Receiver it can receiveDifferential Corrections over the VDL.

XPDR

DS

Figure G - Stand alone monitor station

This set-up is used for testing purposes only.

5.3.2. Set-up 2 - Stand alone Ground Station with multiple Display Systems

The second example also shows a stand alone Ground Station not connected to the NEAN GroundNetwork but with multiple Display Stations (DS) attached on a LAN segment (figure h).



DS

XPDR DGPS

LS

DS DS

Figure H - Stand alone ground station

The Display Stations (DS’s) can also be connected directly to the Local Server (LS) on serial links ifthe LS has sufficient serial ports. However, it is easier to expand the LAN segment solution into aproper networked Ground Station by adding a router.This set-up can be used for regional trials without interfering with other installations.

5.3.3. Set-up 3 - Connected Ground Station with multiple Display Stations

This scenario has the Local Server (LS) on a LAN segment together with a single Display System(DS) and the Router (R) for interconnection to the NEAN Ground Network. A band-pass filter hasbeen inserted on the VHF antenna to avoid interfering with other adjacent frequencies (figure i).

R DS

XPDR DGPS

LS

DSB B

Remote Office

Figure I - Connected ground station

An additional Display System (DS) has been placed in a remote office on a bridged (B) LANsegment. There is full flexibility as to how the LAN segment with the LS is organised. However, ifthere is a low bandwidth connection between LAN segments avoid placing many Display Stationson the remote segment, since all Display Stations will make a logical connection to the LocalServer. (See next set-up example on how to use a Regional Server as a proxy for the Local Server).

This Ground Station set-up is the most common due to the router interface (R) to the global groundnetwork.



5.3.4. Set-up 4 - Using a Regional Server as a Local Server Proxy

If you have several Display Stations (Dss) on a remote office LAN segment and a low bandwidthsconnection between this and your main LAN segment you can use a Regional Server (RS) as aLocal Server Proxy (figure j).

R DS

XPDR DGPS

LS

DSB B

Remote OfficeLAN

RS DS DS DS

Display System Cluster

Figure J - Regional Server as Local Server Proxy

By inserting a Regional Server (RS) - configured to receive data from the Local Server (LS) - on theremote LAN segment the Display System Cluster can connect to the Regional Server (RS) and thusavoid each making a connection to the Local Server (LS) over the low bandwidth link between thetwo LAN segments.

5.3.5. Set-up 5 - Connected Ground Station with attached Monitor Station

In this example a standard Ground Station with Local Server (LS), LAN, Router and a singleDisplay Station is expanded with a remote Monitoring Station over a serial link and a pair of base-band modems (figure k).



R DS

XPDR DGPS

LS

Monitor Station

XPDR

Figure K - Ground Station with attached Monitor Station

The remote monitor station could be installed to provide better VDL coverage and differentialcorrections from the base station could be forwarded through this.

5.3.6. Set-up 6 - Regional and National Server with multiple Display Stations

Below is shown two set-ups (figure l). One for a standalone Regional Server (RS) with multipleDisplay Stations (DSs) attached and one for a National Server (NS) with multiple Display Stations(DSs) and a Network Management Station (MS).

DS

NS

DSDSDS

RS

DSDS MSRR

Figure L - Regional and National Server LAN segments

A Base Station (transponder and Reference Station) can be attached to both the Regional Server andthe National Server. However, it is not recommended for the National Server, since the load on thismachine can be quite high.

The Management Station (MS) can be any Network Management Station. It is used to monitor andmanage the standard network components in the NEAN Ground Network. Since TCP/IP is currentlyused within NEAN the management system must be SNMP compliant.



5.4. Description of Generic Ground Station Set-up

This section describes a generic NEAN ground station set-up in practical terms of neededequipment.

5.4.1. Generic Set-up

The chosen set-up is a ‘normal’ Ground Station with only one transponder (working as a BaseTtation) and two Display Stations (figure m).

Router

Display Stations

Local Server

2xbasebandmodems

LAN

Transponder & Reference Station

VHF Antenna GPS Antenna

PSUPSU

PSU

Transceiver (AUI-BNC) BNC T-Connector +Terminator

WAN

Figure M - Generic Ground Station set-up



For this scenario the following is assumed:

• The LAN - used to interconnect the PC’s is a Thinwire (10Base2) Ethernet, but since the NEANarchitecture is independent of the physical network any LAN technology could be used as long asthe transport protocol is TCP.

• All PC’s are equipped with a Ethernet card with a BNC connection.• The router only has an AUI connection wherefore a Transceiver is needed to connect the router

to the 10Base2 Ethernet. However, some router can be delivered with a BNC interface.• The Transponder and the Local Server PC are so far apart that a pair of baseband modems are

needed to interconnect the two.

5.4.2. Equipment List

Most of the NEAN hardware components - except the DGPS receiver and the GNSS Transponder -are standard off-the-shelf equipment.

Hardware

# Items Item1 VHF antenna. Omni-directional base station antenna for 118-136 MHz civil aircraft

band. SWR optimised at 137 MHz.1 KATHREIN 2 cavities band-pass filter. Type no. K64 1231 (Tuned for 136.95

MHz with 2 dB insertion loss)1 VHF antenna cable. 10 m RG 231/U1 GPS antenna (Included with the Leica Reference Station)1 GPS antenna cable (15 m RG 59 B/U included with the Leica)1 GNSS Transponder (Cable for connecting the MX9112 is included)1 DGPS Reference Station 12 Channel. Leica MX9112.1 Transponder-DGPS serial cable (Included with the transponder)2 5 m, Transponder-PC serial cable (Straight through)2 Baseband modems and PSU. (Any type).1 50 m 4 wire serial cable (between baseband modems)1 Any PC: Pentium 100 MHz or faster, 1 GB Disk, 32 MB RAM, w/ BNC Ethernet

Card and 14” VGA (for the Local Server)2 Any PC’s: Pentium 100 MHz or faster, 1 GB Disk, 32 MB RAM w/ BNC Ethernet

card and 17” SVGA (For the Display Systems). A low-cost 14” screen can be usedfor the servers.

2 50 Ohms 10Base2 BNC Terminators3 BNC FMF T-connectors3 10m segments of 10Base2 Cables (RG58)1 IP-Router. (Cisco 2500 (or other) with 1xLAN-port, (min.) 1xWAN-port)



Software

# Items Item1 MS-DOS v/6.20 for the Local Server.1 PCTCP from FTP Software, inc. v/4.1. For the Local Server1 NEAN Server software v/960710 (or higher) for the servers. (Delivered by the

NEAN Consortium)1 Set-up program for the Leica Reference Station: CDU406.EXE v/4.06 (included

with the Leica) for DOS. (See [23] for configuration details)1 Set-up program for the Transponder: STRANCS v/1.1 for windows (Delivered by

the NEAN Consortium. See [21] for details)1 Terminal Emulation Program: E.g. ProComm for DOS any version.2 MS WindowsNT v/3.51 or higher2 Airsys 95 beta v/0.4 or higher. (Delivered by the NEAN Consortium)

In addition to this it is useful to have a Windows based lab-top PC with a serial cable and thefollowing software tools installed for maintenance of the components:

Component Software Tool Short DescriptionGNSS Transponder STRANCS software [21],

GPCLoad

Terminal Emulator(e.g. ProComm)

Change of transponder name, change ofused time slots

Change of internal transponderparameters, e.g. transmit power,frequency etc.

GPS receiver CDU406 configuration tool Change of internal GPS parametersRouters Terminal Emulator Configuration of parameters

If a lap-top is not available a Local Server can also be used. However, MS Windows (3.1x) shouldbe installed on your Server PC, since STRANCS is a windows program.



5.5. Status

There are 15 Base Stations installed and put into operation, i.e. 6 stations in Sweden, 3 in Denmark(1 more under construction) and 5 in Germany. Due to the participation of EUROCONTROL in theframe of PETAL-II trials an additional Base Station is planned for Maastricht which will go intooperation in March 1997.

The table below shows the actual progress made in the project

Country Geographic Location StatusSweden Stockholm - Arlanda

(ESSA)Site survey completed and location selected.Base Station installed and operating

Stockholm - Bromma(ESSB)

Site survey completed and location selectedBase Station installed and operating

Norrköping(ESSP)


Jönköping(ESGJ)


Göteborg - Landvetter(ESGG)


Malmö - Sturup(ESMS)


Denmark Copenhagen - Kastrup(EKCH)


Aalborg(EKYT)


Esbjerg(EKEB)


Tyra - Northsea Oilrig(EKGF)

Under Construction

SLV - Main office atEllebjergvej

Site survey completed and location selectedMonitor Station installed and operating

Germany Berlin - Tempelhof(EDDI)


Bremen(EDDW)




Country Geographic Location Status

Braunschweig(EDVE)


Frankfurt(EDDF)


Köln/Bonn(EDDK)

Site survey completed and location selectedBase Station installed but not fully tested

Netherlands EUROCONTROLMaastricht

Planned - This base station will be part of the PETAL-IItrials



6. Mobile InstallationsThe mobile GNSS transponder installations differentiates from the ground based stations by the factthat the mobile transponder units are always equipped with a built-in GPS receiver. As the mobiletransponder units primarily receive their error vitiated satellite positions and secondarily receivecorrection data from the nearest Base Station in order to be able to broadcast the corrected positionreports, the mobile transponder units also need to be equipped with a GPS- and a VHF antenna.Together with a power supply of 12 to 32 V DC these are the parts constituting a mobiletransponder unit.

There are two different implementations of the mobile units: A mobile unit installed in a groundbased vehicle and a mobile unit installed in an aircraft.

6.1. Mobile Vehicle Installations

The actual transponder installed in a vehicle is the GNSS Transponder. The transponder box couldbe physically mounted under a seat or in the locker of the vehicle, with the power cable connecteddirectly to the starter mechanism in order to have the transponder up and running as soon as thestarting key of the vehicle has been turned on. There is an additional device available to detect ‘engine-off’ status. This device will maintain the power to the transponder for a pre-determinedperiod of time - after the engine has been turned off - to ensure continued operation (figure n).

Usually the mobile vehicle broadcasts their accurate position once per second. To reduce thechannel load there is a programmable trigger speed limit which means that below a chosen velocity(5 km/h) the update rate will be reduced accordingly.

VHF Antenna GPS Antenna

Battery Engine OffDevice

Figure N - Vehicle installation



6.1.1. The Antennas

The GPS antenna used in vehicles is normally of a rather inexpensive and small type with nobackplane. It is mounted on the roof of the vehicle, preferably in the middle thus making the roofitself serve as the backplane.The VHF antenna is likewise normally of a rather inexpensive and small type mounted somewhereon the sides or the roof of the vehicle.

The cabling of the antennas and the power supply shall be secured in such a way, that luggage andother remedies accidentally can not disrupt the installation.

6.1.2. Equipment List For a Vehicle

# Items Item1 VHF antenna1 GPS antenna1 GNSS Mobile Transponder1 (optionally). Engine-off device

6.1.3. Status

At the end of Work Package 1, 14 GNSS transponders have been installed in mobile vehicles. Atleast one vehicle at every airport site has been equipped in order to carry out local tests and toensure and verify correct operation of the NEAN Ground Station. Furthermore, the localenvironment can be used to correct possible map errors. In detail, mobile transponder units havebeen installed in the following vehicles in the following airports:

Country Location Vehicle and StatusSweden Stockholm - Arlanda

(ESSA)2 vehiclesInstalled and operating

Stockholm - Bromma(ESSB)

1 vehicleInstalled and operating

Göteborg - Landvetter(ESGG)

2 vehiclesInstalled and operating

Malmö - Sturup(ESMS)

2 vehiclesInstalled and operating

Denmark Copenhagen - Kastrup 1 Marshall vehicle (Airport Authorities)



Country Location Vehicle and Status(EKCH) Under installation

Aalborg(EKYT)

1 Technician’s Car (SLV)Under installation

Esbjerg(EKEB)

1 Technician’s Car (SLV)Under installation

Germany Berlin - Tempelhof(EDDI)

1 Marshall vehicle (Airport Authorities)Installed and operating

Bremen(EDDW)

1 Maintenance car (Airport Authorities)Installed and operating.

Braunschweig(EDVE)

1 Maintenance car (DLR)Installed and operating

Frankfurt(EDDF)

1 Marshall vehicle (Airport Authorities)Installed and operating.

Moreover, the Frankfurt Airport Authorities decided toequip on their own expense 3 more cars with GNSStransponders to evaluate the potential benefit. It is amutual co-operation with NEAN because they use thedifferential corrections provided by the Frankfurt GroundStation, and on the other hand they will provide NEANwith the ADS-B reports from their vehicles. This increasesthe database and statistics evaluation in the later phases ofthe project.

Köln/Bonn(EDDK)

1 Marshall vehicle (Airport Authorities)Installed and operating.

During Work Package 2 3-4 additional vehicles will beequipped depending on the availability of transponders.



6.2. Aircraft Installations

The GNSS transponder and the connected GPS- and VHF antennas are physically installed by theAirline Companies Technical departments in accordance with the issued Technical Order (TO) andis therefore solely the responsibility of the Airline Company. Thus the Airline Companies are free tochoose suitable GPS- and VHF antennas. For an example of a specific Technocal Order for atransponder installation in a SAS F-28 please refer to Appendix A.

It is possible to enhance the current installations - now providing ADS-B - with cockpit display andinterfaces to other avionics. However, issues concerning this is part of the “North EuropeanApplications Project” (NEAP) which runs in parallel with NEAN. For an example of a specificPilots Operational Manual please refer to Appendix B, describing the MMI 5000 Cockpit Interface.

The PETAL-II project will use the NEAN data link mainly for CPDLC.

6.2.1. Certification

Normally it is not permitted to install any equipment within an aircraft unless it has been thoroughlycertified and a JAA Formular ONE has been issued for the particular piece of equipment to beinstalled. The existing GNSS Transponders are not certified and can therefore not be equipped witha JAA Formular ONE.

Overcoming this problem has caused the project a great effort in negotiations with the AviationAuthorities involved. The result of these negotiations is that the transponders can be installed inaircraft on a dispensary basis if the following demands are fulfilled:

1. Each transponder to be installed must be equipped with a Manufacturer Declarationstating that the transponder is compliant to requirements defined by the respectiveNational Flight Safety Departments.

2. The Manufacturer Declaration must at all times be kept in the aircraft together with thetransponder.

3. The technicians who physically is installing the transponder in the aircraft must besidesthe normal Technical Order (TO) also provide a document stating that the weight andbalance of the aircraft etc. is not disturbed by the installation. Both the Technical Orderand the ‘weight and balance’ document shall be forwarded to the Aviation Authoritieswho then will grant a dispensation.

4. The dispensation will be limited in time and given only on the presumption that theinstallation is purely experimental.

5. The installation must be of a purely isolated nature and must not interfere with otherinstruments within the aircraft.



6.2.2. Status

At the end of Work Package 1, 6 GNSS transponders have been installed in aircraft grouped inaccordance with the following table:

Country Airline StatusSweden SAS 2 Fokker F28. Installed and operating.

Call Sign: SE-DGFSE-DGL

Both aircraft are primarily flying domestic routes and areboth equipped with cockpit displays.

1 King Air 200

Call Sign: SE-KDK

1 PA 31 Chieftain

Call Sign: SE-GNI

GoldenAir 1 Saab 340

Call Sign: SE-ISG

Denmark MAERSK 1 Helicopters planned.

The helicopter will commute to and from the NorthseaOilrig Tyra.

(SLV Owned andoperated)

1 Nord 262. Installed and operating.

Call sign: OY-IVA

The aircraft is used for testing ILS equipment in Danishairports among other things. No cockpit display isinstalled.

Germany OLT 2 Fairchild Metroliner from the German regional AirlineCompany “Ostfriesische Lufttransport GmbH (OLT)” .Installed and operating.

Call Sign: D-COLBD-COLT

Both aircraft operates mainly on a scheduled base in the



northern part of Germany. Neither have cockpit displaysinstalled.



7. Planning Activities

7.1. Trials Planning

The main objective of the trials is to verify the functionality and performance of the infrastructurethat will be established. This infrastructure, the VHF STDMA data link and the ground network,will be used for other trials and project, e.g. the proposed NEAP (NEAN Applications), and musttherefore be well documented.

7.1.1. Trials Objective

Coverage

The VHF coverage of the STDMA data-link during all phases of flight shall be examined. Thefollowing deliverables shall be produced:

• Coverage diagram over Denmark, Germany and Sweden (en-route). The diagrams will showareas where success rate >95% and >67% on a given altitude. See definition of success ratebelow.

• Coverage diagram over airports equipped with ground stations. The diagrams will show areaswhere throughput >95% and >67%.

• Analysis report

Success rate= Received ADS-B reports per UTC-minute/expected per UTC-minute

Reliability

The reliability of all used equipment shall be documented. The following deliverables shall beproduced:

• Report on reliability for transponders installed in aircraft.• Report on reliability for transponders installed in ground vehicles.• Report on reliability for ground station installations.• Report on network component reliability.

Performance

The following performance parameters shall be measured:

• Ground network delays.• Ground network throughput.• System delays (STDMA data link and Ground network).• System throughput (STDMA data link and Ground network).



The following deliverable shall be produced:

• Report on system performance.

7.1.2. Realisation

Coverage

Transmitted ADS-B reports received in any ground station, can be recorded anywhere in the groundnetwork, as long as no filtering is done between national servers. To get a consistent picture of the”en-route” coverage, the recording and analysis of this data preferably is done at the same node forall three countries. Recording of data and analysis of airport coverage are handled by each country.

A special recording and analysis software has been developed. The output from the analysis tool arepossible to plot on maps to create a graphic picture of the coverage.

Each team is responsible for the data collection for airport coverage diagrams.The Swedish Team is responsible for the en-route data collection and the en-route coveragediagram. The German Team is responsible for the Analysis Report.

Reliability

The data for the reliability study, consist of ”Problem and Change” reports. Any recognised failureshall be reported to a responsible person in each country by using the report template [7]. Thereports will be categorised and stored.

The German Team is responsible for the Equipment Reliability Reports.

Performance

To measure delay between two points in the ground network, the time reference from GPS-receiverswill be used. This means that the delay in the ground network will be measured between two serversconnected to GNSS-transponders. When the transponder puts out the GPS-time, the time-base in theserver will be adjusted. The principle to measure system delays is the same. In this case theMMI5000 CDTI in the cockpit will be used. This CDTI is also connected to a GNSS-transponderand has therefore UTC time-base. Special test messages will be used for this purpose and they willbe transmitted continuously during the test period.

Network and system throughput is calculated from the number of test messages transmittedsuccessfully. Due to the Central Limit Theorem it is assumed that the delay times will follow aGaussian Distribution. Appropriate tools will be used for statistical analysis.

The Danish Team is responsible for the network performance testThe Swedish Team is responsible for the system performance test.



7.1.3. Limitations

Coverage

The ADS-B reports collected from transponder equipped SAS and OLT aircraft, is the basicinformation for the verification of the VHF coverage. There is no budget within NEAN for anytypes of test flights. This means that the covered area is limited to the routes for these aircraft. Formore detailed ground coverage diagrams, additional data collecting activities can be done atairports, by using transponder equipped ground vehicles.

There will not be any recording on-board the aircraft to verify when ADS-B reports has beentransmitted. The coverage study will be based on the knowledge a priori of the report rate.

Reliability

Reliability in this case is referring to the operational reliability of hardware and software for thespecific piece of equipment. The questions to be answered are how often and for what reason theequipment is not working as expected. The quality of the output data (e.g. accuracy of own position)from the equipment will not be measured in this case.

The reliability study will only comprise equipment installed exclusively for the NEAN project.

Performance

The delays in the ground network will be affected by the priority for the traffic in different segmentof the infrastructure. NEAN related traffic is non priority data traffic in most of the segments. Thismeans that the performance will vary during the day.

It will not be possible to measure system delays (STDMA delay + network delay) and systemthroughput between all nodes in the ground network. Two or three nodes will be selected for thispurpose.



7.1.4. Test schedule

The test period is from January 1997 to August 1997 (figure o).

ID Aktivitet1 Data Recording, en-route coverage

2 Coverage Diagram en-route

3 Data Recording, airport coverage

4 Coverage Diagram airports

5 Data Collection, equipment reliability

6 Reliability Report, AC transponders

7 Reliability Report, GV transponders

8 Reliability Report, Ground stations

9 Reliability Report, Network componen

10 Data Recording, Performance

11 Performance Report

��

��

��

��

��

��

12 01 02 03 04 05 06 07 08 091997

Figure O - Test schedule



7.2. Map Group

In all systems used for surveillance, geographical maps are essential as references for presentedpositions of aircraft. Different display-systems will be used in NEAN which requires geographicalmaps over land-, lake- and sea-areas as well as detailed airport maps.

To achieve a common NEAN map standard, a special working group was established during WP1.



7.3. Transponder Procurement

The so-called SARP:s [14] transponder shall be installed in aircraft and vehicles during WP 2. Tobe able to meet the time table a procurement process was started up in April 1996.The key elements of a SARP transponder are:

• Two receivers, 1 transmitter (dual-frequency operation)• Software Development according to RTCA DO/178 [15]• ARINC 429 interface [16]• Certifiable Equipment

During the transition period, existing transponders from the Swedish Space Corporation will beused.

The procurement of the NEAN transponders are handled by the Group Purchasing at SCAA.The planned purchasing of SARP:s transponders was announced in The Official Journal in April1996. Nine companies applied for the Invitation To Tender (ITT). Two different requirementspecifications were produced and included in the ITT, one for the ground station transponder [17]and one for the airborne transponder [18]. Two of these nine companies made offers that were sendto SCAA in June.

An offer evaluation group, consisting of representatives from the different NEAN parties, wasestablished in August. The instructions from the steering committee to the evaluation group are toprepare a proposal for the committee to decide upon. The proposal shall include the number oftransponders to be purchased, and from which company. (See [19], [20] for details)

The evaluation process is expected to end in November 1996.



8. Appendix ATechinical Orderfor the installation of the transponder in a F-28 from SAS.



9. Appendix BPilots Operational Manual from SASfor the MMI 5000 Cockpit Display Interface.