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Geo-localisation in CERN’s underground facilities CERN has recently deployed a digital radio network, based on TETRA technology, to be used by the Fire Brigade and other services, both on the surface and in CERN’s underground facilities. As a key TETRA feature for the Fire Brigade is the integrated GPS localisation system, we faced the challenge of providing an Indoor Localisation System to cover the underground facilities. The solution chosen is based on autonomous beacons placed in strategic locations, each broadcasting a specific identification number. TETRA handsets compare signal strengths from beacons within range and transmit the ID of the closest beacon to the Fire Brigade Control Center where, by making use of CERN’s Geographic Information System (GIS), the localisation system highlights the position of TETRA handsets on a detailed map. IT CERN TETRA network architecture Localisation System concept TETRA (TErrestrial Trunked RAdio) E.T.S.I. standard digital radio technology working in the 410-430MHz frequency band based on TDMA (Time Division Multiple Access) multiplexing and phase modulation uses up to 2 Control Channels for signalling and SDS (Short Data Messages) This technology provides voice services (individual and group calls), message services (SDS), pre-emptive prioritisation, busy queuing and many other services. Its main purpose is to enhance radio communication services for professional users in their safety and security daily operations. Conceptual view of CERN’s TETRA network Challenges Faced—and Overcome! Indoor Localisation System (ILS) components Beacons integrating a transmitter in ISM 868MHz band and an antenna. They are identified by an ID stored in internal memories A receiver module in the TETRA handsets An Indoor Localisation and Dispatcher Add-on (ILDA) application integrated in the TETRA dispatcher workstation A GIS server recording beacon locations System configuration Application With beacons deployed, TETRA handsets transmit, encapsulated into an SDS, the beacon IDs they detect to the ILDA. Then the position (ID) of the beacon is displayed, indicating the information on the last known location of the handset. The application also allows to display the direction of radio moving in CERN indoor infrastructure. Combined with ManDown (lose of verticality) and Emergency alarming features, the ILS brings crucial additional information in case of rescue intervention. 1 2 3 1. Beacons located in the tunnel each broadcast their ID through an integrated antenna 2. Handsets forward the ID of the nearest beacon to the Indoor Geolocalisation Display at the Fire Brigade (via a "leaky feeder " which provides GSM and radio coverage in the tunnel) 3. In case of incident (loss of verticality or emergency button pressed) an emergency SDS and an alarm are sent to the Fire Brigade Dispatcher Firebrigade Operator A High Radiation Environment (up to 600Gy/yr!) Problem : spontaneous beacon ID changes due to radiation. Solution: ID is stored in triplicate; beacon firmware ensures recovery from single corruption, only halting ID transmission if all stored IDs are inconsistent. CERN’s TETRA architecture 3 TBS (TETRA Base Stations) ensure outdoor radio coverage 5 TMO (Trunked Mode Operation) frequencies enable up to 17 simultaneous calls 2 redundant TETRA Switches handle handover between TBS 2 PABX gateways link TETRA to GSM and fixed telephones OMUs (Optical Master Units), Optical/RF repeaters and 50km of radiating cable allow deliver radio coverage to underground sites a dedicated, fibre-based, IP network a backup microwave link between the two main TBS SDS overload Problem: Transmission of beacon IDs presents heavy load due to number of SDS messages---from handsets to TBS and from TBS to ILDA Solution: Enable direct IP connection from TBS to ILDA reducing SDS messages by factor of two Frequency planning: very complicated! Multiple frequencies needed! How to deal with both Swiss and French regulatory authorities? How to ensure failover for redundancy? Providing Power Problem : Beacon placement must ensure full coverage of the underground areas; external electrical power is not available in all selected locations. Solution: Beacons are powered by a high-capacity battery; the normal 10-year duration is reduced to 5-years in the LHC environment, but this is sufficient to cover the time between major By configuring specific settings on the beacons (output power, sensibility threshold, ID corresponding to beacon’s location, ID sending period) a precise mapping of the area can be established. Beacon icons can then be placed on a dedicated layer into a GIS server. A simple request from ILDA to this server enables the display of the expected map. Geo-localisation in CERN’s underground facilities Aurélie PASCAL – IT-CS CERN IT Departmen t UTP cabling : ~100m Beam Line Concrete Wall Beacons Antennas USB cables Ethernet/USB converters Electrical boxes enabling remote reboot ~ AC 230V Laptop running beacons configuration tool Ethernet/USB converters ~ AC 230V USB Hub Terminal Server LHC2 LHC3 LHC4 LHC5 LHC6 LHC7 LHC8 SPS1 OMU 7 OMU 5 OMU 6 TBS 3 TRX E Indoor Repeate r Indoor Repeat er Indoor Repeat er Indoor Repeater Indoor Repeate r Indoor Repeate r Outdoor Repeate r Outdoo r Repeat er Outdoor Repeate r Indoor Repeate r Fq C+D to Core SPS2 Indoor Repeat er SPS3 Indoor Repeate r SPS4 Indoor Repeate r SPS5 Indoor Repeate r SPS7 Indoor Repeate r Fq A+B to Core B a c ku p Mi cro wav e l in k Indoor Repeate r Indoor Repeate r Indoor Repeat er SDI2 PS/Booster LINAC4 OMU 2 OMU 1 OMU 4 Repeate r Repeate r OMU 3 LHC1 Indoor Repeate r BA80 Core Indoor Repeate r Outdoo r Repeat er Indoor Repeate r Fq C+D from TBS2/OMU 6 Fq A+B from TBS1/OMU 5 Fq A+B and Fq C+D to repeaters Fq E to outdoor repeaters Legend: Optical fiber link RF link Radiating cable TBS 2 TRX C TRX D TBS 1 TRX A TRX B

Geo-localisation in CERN’s underground facilities

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Fq C+D from TBS2/OMU 6. IT. Beam Line. LHC4. Geo- localisation in CERN’s underground facilities. CERN. TBS 2 TRX C TRX D. Indoor Repeater. Indoor Repeater. OMU 2. IT. Repeater. Geo-localisation in CERN’s underground facilities. Outdoor Repeater. Concrete Wall. OMU 4. - PowerPoint PPT Presentation

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Page 1: Geo-localisation  in CERN’s underground facilities

Geo-localisation in CERN’s underground facilities

CERN has recently deployed a digital radio network, based on TETRA technology, to be used by the Fire Brigade and other services, both on the surface and in CERN’s underground facilities. As a key TETRA feature for the Fire Brigade is the integrated GPS localisation system, we faced the challenge of providing an Indoor Localisation System to cover the underground facilities.The solution chosen is based on autonomous beacons placed in strategic locations, each broadcasting a specific identification number. TETRA handsets compare signal strengths from beacons within range and transmit the ID of the closest beacon to the Fire Brigade Control Center where, by making use of CERN’s Geographic Information System (GIS), the localisation system highlights the position of TETRA handsets on a detailed map.

IT

CERN TETRA network architecture

Localisation System concept

TETRA (TErrestrial Trunked RAdio)

E.T.S.I. standard digital radio technology working in the 410-430MHz frequency band based on TDMA (Time Division Multiple Access) multiplexing and phase modulation uses up to 2 Control Channels for signalling and SDS (Short Data Messages)

This technology provides voice services (individual and group calls), message services (SDS), pre-emptive prioritisation, busy queuing and many other services. Its main purpose is to enhance radio communication services for professional users in their safety and security daily operations.

Conceptual view of CERN’s TETRA network

Challenges Faced—and Overcome!

Indoor Localisation System (ILS) components

Beacons integrating a transmitter in ISM 868MHz band and an antenna. They are identified by an ID stored in internal memories

A receiver module in the TETRA handsets An Indoor Localisation and Dispatcher Add-on (ILDA) application integrated in the TETRA dispatcher

workstation A GIS server recording beacon locations

System configuration

Application

With beacons deployed, TETRA handsets transmit, encapsulated into an SDS, the beacon IDs they detect to the ILDA. Then the position (ID) of the beacon is displayed, indicating the information on the last known location of the handset. The application also allows to display the direction of radio moving in CERN indoor infrastructure.Combined with ManDown (lose of verticality) and Emergency alarming features, the ILS brings crucial additional information in case of rescue intervention.

1

2

3

1. Beacons located in the tunnel each broadcast their ID through an integrated antenna

2. Handsets forward the ID of the nearest beacon to the Indoor Geolocalisation Display at the Fire Brigade (via a "leaky feeder " which provides GSM and radio coverage in the tunnel)

3. In case of incident (loss of verticality or emergency button pressed) an emergency SDS and an alarm are sent to the Fire Brigade Dispatcher

Firebrigade Operator

A High Radiation Environment (up to 600Gy/yr!)

Problem: spontaneous beacon ID changes due to radiation.

Solution: ID is stored in triplicate; beaconfirmware ensures recovery from single corruption, only halting ID transmission if all stored IDs are inconsistent.

CERN’s TETRA architecture

3 TBS (TETRA Base Stations) ensure outdoor radio coverage 5 TMO (Trunked Mode Operation) frequencies enable up to 17 simultaneous calls 2 redundant TETRA Switches handle handover between TBS 2 PABX gateways link TETRA to GSM and fixed telephones OMUs (Optical Master Units), Optical/RF repeaters and 50km of radiating cable allow deliver radio coverage to underground sites a dedicated, fibre-based, IP network a backup microwave link between the two main TBS

SDS overload

Problem: Transmission of beacon IDs presents heavy load due to number of SDS messages---from handsets to TBS and from TBS to ILDA

Solution: Enable direct IP connection from TBS to ILDA reducing SDS messages by factor of two

Frequency planning: very complicated!

Multiple frequencies needed!

How to deal with both Swiss and French regulatory authorities?

How to ensure failover for redundancy?

Providing Power

Problem: Beacon placement must ensure full coverage of the underground areas; external electrical power is not available in all selected locations.

Solution: Beacons are powered by a high-capacity battery; the normal 10-year duration is reduced to 5-years in the LHC environment, but this is sufficient to cover the time between major maintenance periods.

By configuring specific settings on the beacons (output power, sensibility threshold, ID corresponding to beacon’s location, ID sending period) a precise mapping of the area can be established. Beacon icons can then be placed on a dedicated layer into a GIS server. A simple request from ILDA to this server enables the display of the expected map.

Geo-localisation in CERN’s underground facilities

Aurélie PASCAL – IT-CS

CERNITDepartment

UTP cabling : ~100m

Beam Line

Concrete Wall

Beacons Antennas

USB cables

Ethernet/USB converters

Electrical boxes enabling remote reboot

~ AC 230V

Laptop running beacons

configuration tool

Ethernet/USB converters

~ AC 230V

USB Hub

TerminalServer

LHC2

LHC3

LHC4

LHC5

LHC6

LHC7

LHC8

SPS1

OMU 7

OMU 5

OMU 6

TBS 3TRX E

IndoorRepeater Indoor

Repeater

IndoorRepeater

IndoorRepeater

IndoorRepeater

IndoorRepeater

Outdoor Repeater

Outdoor Repeater

OutdoorRepeater

IndoorRepeater

Fq C+D to Core

SPS2

IndoorRepeater

SPS3 IndoorRepeater

SPS4 IndoorRepeater

SPS5

IndoorRepeater

SPS7IndoorRepeater

Fq A+B to Core

Bac

kup

Mic

row

ave

link

IndoorRepeater

IndoorRepeater

IndoorRepeater

SDI2

PS/Booster

LINAC4

OMU 2

OMU 1

OMU 4Repe

ater

Repe

ater

OMU 3

LHC1

IndoorRepeater

BA80Core

IndoorRepeater

Outdoor Repeater

IndoorRepeater

Fq C+D from TBS2/OMU 6

Fq A+B from TBS1/OMU 5

Fq

A+

B a

nd

Fq

C+

D t

o r

epea

ters

Fq E to outdoor repeaters

Legend:

Optical fiber link

RF link

Radiating cable

TBS 2TRX CTRX D

TBS 1TRX ATRX B