PROPOSAL FOR A COUNCIL DECISION ON THE LORAN-C RADIONAVIGATION SYSTEM
Date: 1991-01-21
Institutions: European Commission
Subjects: communications systems, environmental protection, maritime shipping, maritime surveillance, traffic signs

COMMISSION  OF THE  EUROPEAN  COMMUNITIES 

C0MC91) 1 final 

Brussels, 21 January 1991 

Proposal for a 

COUNCIL DECISION 

on  the  LORAN-C  radionavigation  system 

$ÈM 

m 

(presented by the Commission) 

-  2 -

l . Introduct ion 

The  enhancement  of  the  standard  of  maritime  safety  in  general  and  in 
Europe  in  particular  is  one  of  the  concerns  of  the  Community.  While 
recognising  the  important  role of  international  organisations,  such  as 
the  International  Maritime  Organisation,  for  the  establishment  of 
worldwide  safety  rules  it  is nevertheless  in the field of operations of 
the  maritime  industry  that  the  European  Community  can  best  develop 
specific  actions.  With  the  objective  of  ensuring  the  safety  of 
navigation  in  Europe  and  neighbouring  areas,  the  development  and 
improvement  of  aids  to  navigation  is one  of  the  actions  which  we  are 
currently  concerned with. 

Although  the Commission  intends  to outline  its view on maritime  safety 
at  a  later  date,  recent  developments  have  made  It  a  necessity  to 
consider  the matter  of  radionavigation aids at  this stage. 

-  3  -

Il.  Radionavigation  Aids 

Under  the  Safety  of  life  at  Sea  Convention  (SOLAS  1974),  as  amended, 
especially  regulation  14  of  Chapter  V  "Safety  of  Navigation",  dealing 
with  aids  to  navigation,  each  contracting  government  has  the  obligation 
to  arrange  the  establishment  and  maintenance  of  such  aids  to  navigation 
as  in  their  opinion  the  volume  of  traffic  justifies  and  the  degree  of 
risk  requires.  In  European  waters,  and  especially  in  coastal  areas, 
radionavigation  aids  have  long  been  recognised  as  an  Important  element 
of  the  provisions  made  to  meet  the  above  mentioned  international 
obligation  to  maintain  maritime  safety. 

Radionavigation  aids  are  complemented  by  the  visual  aids  of  lights  and 
buoys,  of  which  a  basic  system  will  continue  to  be  necessary  to  mark 
hazards  and  navigable  channels  and  give  visual  confirmation  of  a  ship's 
position.  With  the  advance  of  technology,  however,  there  is  a  growing 
wealth  of  choice  of  electronic  aids  to  navigation. 

radiopositioning  systems  can  be  divided 
hand 
systems  on 

into  two 
The  existing 
categories, 
the 
and 
terrestrial-based  systems  on  the  other.  The  systems  can  be  further 
classified  on  the  basis  of  the  extent  of  their  coverage  extending  from 
purely  local  to  worldwide  coverage. 

the  space-based 

the  one 

Two  satellite  systems  offering  worldwide  cover  to  an  intended  accuracy 
of  100 metres  for  civil  users  are  expected  to  be  operational  in  the  mid 
1990's.These  are  the  U.S.  Global  Positioning  System  (GPS)  and  the  USSR 
Global  Navigation  Satellite  System  (GLONASS). 

both 

Unfortunately 

are  military 

Due  to  similarities  between  the  two  systems  it  might  theoretically  be 
possible  for  users  to  have  receivers  that  could  work  with  either 
system. 
Many 
systems 
organisations  within  the  International  Maritime  Organisation  have 
expressed  reservations  about  adopting  either  system  as  a  worldwide 
civil  navigation  system.  As  stated  in  the  U.S.  Federal  Radionavigation 
Plan,  GPS  signals  will  be  available  to  serve  the  safety  of  navigation 
at  all  times  except  during  a  time  of  national  emergency  when  only  those 
radionavigation  signals  that  serve  the  national 
interest  will  be 
available.  The  recent  past  has  proved  that  despite  the  policy  detente 
regional  conflict  cannot  be  ruled  out.  Thus  total  reliance  on  any 
single 
no 
users 
radionavigation  aid.  In  addition  there  is  uncertainty  concerning  the 
possible  future  introduction  of  user  dues  on  the  satellite  systems. 

systems. 

to  the 

expose 

system 

having 

would 

risk 

of 

On  the  European  level,  GRANAS  (Global  Radionavigation  System)  and 
N A V S AT , developed  by  the  European  industries,  funded  by  the  European 
Space  Agency,  are  global  civil  navigation  satellite  systems  which  have 
similar  operational  objectives  to  GPS.  These  are  still  in  the  planning 
phase. 

Technical  specifications  of  these  systems  are  given  in  annex  B  1. 

-  4  -

systems 

satellite 

position 
provide 
The 
determination.  Satellite  systems  have  an  achievable  accuracy  of  between 
2.4  and  24 metres  according  to  whether  the  user  is  stationary  or  moving 
but  for  the  civilian  user  the  accuracy  offered  is  in  the  order  of  100 
metres. 

dimensional 

three 

will 

As  terrestrial-based  radionavigation  systems  suitable  for  general 
navigational  .purposes  the  OMEGA,  the  DECCA  Navigator  System  and  the 
LORAN-C  system  can  be  identified. 

The  OMEGA  system  provides  position  fixing  of  limited  accuracy,  it  Is 
only  usable  for  general  navigation  on  routes  followed  by  ships  in  the 
ocean  phase  and  for  aircraft.  It  Is  likely  to  be  replaced  by  GPS  but 
may  be  retained  for  marine  use  until  the  turn  of  the  century. 

The  technical  specifications  of  the  DECCA  system  are  given  In  annex 
B  1.  Coverage  by  DECCA  is  adequate  around  the  British  Isles,  extensive 
in  western  Europe  from  Norway  to  the  English  Channel  including  part  of 
the  Baltic,  it  is  also  provided  in  certain  other  sea  areas  around  the 
Iberian  Peninsula,  Australia,  Japan,  South  Africa,  India  and  the 
Arabian  Gulf,  it  has  been  estimated  there  are  about  140.000  users 
worldwide;  most  are  in  Europe.  In  total  about  80.000,  rising  to  90.000 
by  the  end  of  1989,  are  fitted  to  vessels  which  use  three  UK  chains. 

The  Loran-C  system 
is  also  a  terrestrial-based  radio  hyperbolic 
position-fixing  system.  The  system  is  based  upon  measurements  In  the 
difference  in  time  of  arrival  of  pulses  of  radio  frequency  energy 
radiated  by  a  chain  of  synchronised  transmitters  which  are  separated  by 
hundreds  of  miles.  More  technical  information  is  given  In  annexes  B 1 
and  B  2. 
Although  initially  established  to  meet  US  defense  requirements  LORAN-C 
is  widely  available  for  civil  use  in  the  Northern  Hemisphere  to  all 
using  a  commercially  available  receiver.  In  addition  to  the  fourteen 
LORAN-C  chains  managed  by  the  US  Coastguard  worldwide  LORAN-C  chains 
have  been  established  in  France,  Egypt,  Saudi  Arabia,  China,  India  and 
Korea.  The  Soviet  Union  operates  a  similar  radionavigation  system 
caI led  Chayka. 

-  5 -

III.  INTERNATIONAL  DEVELOPMENTS 

The  US  Coastguard  has  stated  its  intention  to  cease  funding  and 
manning  all  Loran-C  stations  outside  of  the  US  at  the  end  of  1994.  The 
US  Coastguard  has  also  offered  to  transfer  all  or  part  of  Loran-C 
station  equipment  to  interested  host  nations  when  these  are  no  longer 
needed  by  the  U.S. 

A  working  group  comprising  representatives  from  Canada,  Denmark,  the 
Federal  Republic  of  Germany,  France,  Iceland,  Ireland,  Norway  the  USA 
and  IALA  (the  International  Association  of  Lighthouse  Authorities) 
started  discussions  about  the  future  of  Loran-C  In  1983. 

In  1985  France  introduced  a  Loran-C  chain  at  Its  own  expense  which  is 
operated  with  two  stations. 

From  1  January  1987  the  RACAL  DECCA  Company  ceased  to  be  responsible 
for  the  management  of  the  DECCA  navigator  chains  around  Great  Britain 
and  Ireland  and  the  responsibility  for  them  has  been  assumed  by  the 
Lighthouse  Authorities. 

in  March  1987  a  special  radionavigation  Conference  of  IALA  presented 
seven  conclusions  on  Loran-C.  The  most  important  conclusion  undoubtedly 
was  that  whereby  Denmark,  France,  the  Federal  Republic  of  Germany, 
Ireland,  the  Netherlands,  Norway  and  the  United  Kingdom  agreed  to  enter 
into direct  negotiations  with  each  other  to  consider  the  possibility  of 
extending  Loran-C  coverage  in  N.W.  Europe.  The  conference  concluded 
that 
terrestrial 
radionaviagtion  systems  should  be  maintained  after  the  introduction  of 
new  satellite  navigation  systems  for  the  foreseeable  future. 

appropriate 

national 

Regional 

areas 

and 

in 

Another  conclusion  reached  by  the  conference  was  that  the  IALA  will 
continue  to  pursue  the  possibility  of  extending  Loran-C  coverage  along 
the  Iberian  Peninsula  and  in  the  Mediterranean  until  such  time  as  the 
into  direct 
governments  concerned  are 
negotiations  with  each  other. 

in  a  position  to  enter 

Discussions  between  the Mediterranean  countries  started  In  1989  in  IALA 
with  the  participation  of  the  Commission  of  the  European  Communities  to 
examine 
in  the 
the  need  to  maintain  or  even  extend  Loran-C 
Mediterranean  area. 

in  1989  the  USA  and  the  USSR  signed  an  agreement  for  a  Joint  Loran-
C/CHAYKA  radionavigation  system  to  facilitate  improved  marine  and  air 
navigation  in  the  North  Pacific  Ocean  and  the  Bering  Sea  areas. 

in  April  1990,the  UK  decided  in  principle,  on  technical  and  cost 
grounds,  to  join  the  international  civil  Loran  C  system  currently 
proposed  for  N  w  Europe  and  the  North  Atlantic.  Implementation  of  this 
decision  is dependent  upon  a  satisfactory  International  agreement  being 
achieved  by  early/mid  1991  with  the  other  interested  states,  with  the 
new  Loran  c  system  in  place  and  operational  before  the  end  of  1993.The 
existing  contractual  arrangements  for  the  UK  Decca  Navigation  system 
extend  to  February  1997. 

-  6  -

in May  1990  the  French,  Portuguese  and  Spanish  governments  begun  expert 
level  discussions  on  the  establishment  of  a  Loran-C  chain  for  the 
Atlantic  with  sufficient  coverage  to  link  the  Mediterranean  and  North 
Atlant ic cha ins. 

in  September  1990  IALA  chaired  a  first  meeting,  In  Tokyo,  between 
Japan, USSR, China  and  Republic  of  Korea  with  a view  to seeking  the  co 
operative operation of  the Loran-C  in these  countries. 

-  7  -

IV. ADVANTAGES  AND  POSSIBILITIES  POSED  BY  THE  LORAN-C 

Loran-C  satisfies  the  mariners  needs  for  accuracy.  It  meets  the 
requirements  of  IMO  Resolution  A  529  (13)  and  provides  an  accuracy 
level  at  least  equal  to,  and  in many  cases  better  than,  the  existing 
DECCA  system. 

The  existence, of  operational  Loran-C  stations,  and  others  coming  into 
operation,  facilitates  the  development  of  a  European  Network  In  the 
short  term. 

The  handover  of  existing  facilities  without  charge  has  an  obvious  cost 
advantage  and  Loran-C  is  considered  to  be  markedly  less  costly  than 
the  existing  DECCA  system. 

Loran-C  is  capable  of  being  extended  to  provide  coverage  of  all 
European  and  neighbouring  waters  without  major  difficulty.  Existing 
projects  will  offer  coverage  of  blind  radionavigation  areas  which  is 
not  possible  with  existing  DECCA  (especially  in  Irish  waters,  and  the 
Bay  of  Biscay).  Furthermore  the  co-operation  with  the  USSR  Chayka 
Chains  will  oe  possible. 

The  existing  Loran-C  charts  would  continue  to  apply  thus  minimising 
inconvenience  and  costs  to mariners. 

The  Loran-C  system  has  proved  to  have  an  acceptable  level  of 
reliability  of  operation  which  is vital  for  the  mariner. 

Loran-C  technology  is  already  developed  and  transmitters/receivers  are 
commercially  available.  A  large  number  of  receiver  types  are  available 
without  restrictive  systems  patents.  This  provides  considerable  scope 
for  lower  unit  costs  and  hence  lower  selling  prices  of  receivers  as  the 
system  is  extended. 

Confidence  is  lacking  in  the  continuing  availability  of  essentially 
military  satellite  systems  and  Loran-C  would  be  a  terrestrial-based 
alternative  civil  system  under  the  control  of  contracting  governments. 

The  chain  configuration  of  Loran-C  facilitates  phased  implementation 
for  programmed  growth  and  utility  in  the  coverage  area. 

As  there  is  no  limit  to  the  number  of  receivers  that  can  use  Loran-C 
simultaneously  future  capacity  considerations  are  accommodated. 

Applications  of  Loran-C  are  not  confined  to  maritime  use.  It  can  also 
be  extended  for  land  and  air  use.  There  has  been  a  significant  Increase 
in  the  number  of  users  in  the  US  civil  aviation  community  in  recent 
years.  The  US  has  established  new  stations  to  complete  coverage  of  the 
entire  continental  US. 

Combined  Sate I Iite/Loran-C  coverage  will  offer  the  highest  degree  of 
system  verification  and  continuity  of  radionavigation  coverage  for  the 
benefit  of  maritime  safety  and  environmental  protection. 

-  8  -

V.  State  of  the  discussion  on  international  level 

1.  North  West  European  chain  : 

The  governmental  representatives  of  Denmark,  The  Federal  republic  of 
Germany,  France,  Ireland,  the  United  Kingdom,  Canada,  Iceland  and 
Norway,  members  of  the  Loran-C  Policy  Group,  will  finalise  an 
agreement  bas,ed  upon  the  Policy-Group  report  before  the  end  of  this 
year.  Since  July  1990  the  E.C.  Commission  has  attended  the  meetings  of 
the  Group  as  an  observer. 

The  governments  participating  in  the  Loran-C  Policy  Group  will  be 
invited  to  establish  a  Loran-  C  system  for  North  West  Europe  and  the 
North  Atlantic.  An  agreement  has  and  already  been  reached  on  the 
configuration  (Annex  B  2)  and  on  the  technical  requirements  of  the 
System  (Annex  B 3 ). 

it  will  be  noted  that  in  the  current  stage  of  the  discussions  the 
Benelux  countries  are  not  envisaged  to  be  involved  in  the  foreseen 
agreement. 

The  Netherlands  initially  participated  in  the  policy  group  but  decided 
not  to  participate  in  the  agreement.  Their  reasons  are  that  the  two 
DECCA  navigator  chains  controlled  by  the  Dutch  authorities  still  meet 
the  requirements  regarding  maritime  traffic  In  their  coastal  waters. 

Despite  the  opinion  of  all  other  Member  States 
involved,  the 
Netherlands  considers  that  putting  Loran-C  into  operation  in  Dutch 
coastal  waters  would  be  a  superfluous  interim  step  in  the  global 
changeover  from  terrestrial  navigation  systems  to  satellite  based 
systems. 

Denmark  has  already  agreed  to maintain  the  Loran-C  stations  in Ejde  and 
Angissoq  but  will  not  be  able  to  take  a  final  decision  regarding  Its 
participation  in  the  final  agreement  before  the  end  of  this  year.  It  is 
the  intention  of  the  Policy  Group  to  finalise  the  agreement  before  the 
end  of  the  year  even  if  the  Netherlands  or  Denmark  will  not  participate 
in an  agreement. 

Germany  supports  the  NWE  chain.  That  results  from  the  inclusion  of  the 
Sylt  station  in  the  chain.  Germany 
is  prepared  to  support  an 
enhancement  of  the  Loran-C  system  in  the  Baltic  with  possible  new 
stations  in  the  eastern  part  of  Germany  or  the  Polish  area.  The 
International  Telecommunications  Unions  has  already  been  asked  to 
allocate  frequencies  for  an  East  European  Chain.  The  Soviet  Union  is 
prepared  to  co-operate  In  this  respect. 

The  United  Kingdom,  Ireland  and  Iceland  support  the  agreement  with  the 
largest 
acceptable 
international  agreement  on  Loran-C  is  a  prerequisite  for  the  UK  for 
changing  from  its  DECCA  system  to  the  Loran-C. 

area.  The  UK  emphasised 

coverage 

that 

an 

France  is  prepared  to  bring  its  two  stations  built  on  its  own  account 
into  the  system.  France  is  supporting  the  chain  with  the  largest 
coverage  to ensure  the  link  with  the  foreseen  Atlantic  chain.  Therefore 
France  is prepared  to make  signals  from  its  two  stations  available  for 
hyperbolic  use  of  the  system  with  other  stations. 

-  9  -

Canada  is  participating  in  the  chain  because  of  its  interest  In  the 
Loran-C  station  at  Angissoq  which  is dualrated  as  part  of  the  Labrador 
Sea  chain. 

it  is  important  to  emphasise  that  the  decision  of  the  Netherlands  or 
Denmark  not  tp  participate  in an  agreement  will  probably  not  affect  the 
configuration  and  coverage  of  the  foreseen  N.W.  European  Chain. 
Although  a  revision  of  the  costsharing  agreement  could  have  an 
influence on  some  technical  aspects  such  as  the  power  of  the  stations. 

The  agreement  will  be  finalised  in  the  January  meeting  of  the  Policy 
group. 

The  Mediterranean  chain 

The  IALA  took  the  initiative  to  bring  the  interested  parties  of  the 
Mediterranean  area  together  with  the  aim  of  setting  up  a  similar 
agreement  to  the  NWE  agreement.  Representatives  of  Italy,  Greece, 
France,  Spain,  Portugal,  Algeria,  Egypt,  the  US  Coast  Guard  and  the 
Commission  of  the  E.C.  have  met  each  other  since  January  1989. 

There  is  a  general  consensus  in  the  Mediterranean  working  group  in 
favour  of  maintaining  the  existing  Loran-C  stations  In  Italy  and  Spain 
and  maintaining  the  existing  coverage  In  the  Mediterranean  for  the 
benefit  of  merchant  ships,  fishing  vessels,  pleasure  craft  and 
hydrographie  surveys  after  the  US  Coastguard  cease  to  operate  the 
stations  in  1994. The  latest  meeting  in Paris  confirmed  the  need  for  a 
terrestrial  navigation  system  in  the  Mediterranean  Sea  and  that  the 
Loran-c  was  the  only  feasible  system  meeting  the  maximum  service 
requirements  of  coverage  in  the  most  cost-effective  way. 

A  subcommittee,  coordinated  by  Italy,  will  study  the  technical  and 
administrative matters  concerning  the  existing  Loran-C  stations. 

To  ensure  a  coverage  equivalent  to or  even  better  than  the  actual  chain 
it  is  vital  that  a  solution  for  the  re-sltlng  of  the  Turkish  Station 
of  Kargaburun  be  found  if  the  Turkish  government  maintains  its  decision 
not  to  take  over  the  US  Coastguard  station  on  its  territory.  One 
solution  could  be  to  site  a  new  station  on  Greek  territory.  The  final 
objective  of  the  group  is to  facilitate  as  soon  as  possible  the  setting 
up  of  a  Mediterranean  MOU  for  the  Mediterranean  Loran-C  with  1994  as 
the  operational  target  date. 

Iberian  (Atlantic)  chain 

The  French, Spanish  and  Portuguese  representatives  participating  In  the 
Mediterranean  Loran-C  group, confirmed  their  intention  to extend  Loran-
C  coverage  into  the  Atlantic  Ocean,  including  the Azores  and  the  Canary 
islands  and  improve  coverage  in SW Mediterranean  area. 

As  a  result,  preliminary  discussions  started  in  Madrid  in  May  1990 
between  experts  of  those  countries.  It  Is  the  Intention  to  find  an 
agreement  on  the  configuration  and  the  technical  requirements  of  the 
chain  thus  ensuring  a  link  with  the  NW  European  and  Mediterranean 
cha ins. 

10 -

VI.  Community  interests  in  the  Loran-C  chain 

The  countries  participating  in  the  N.W.  European  Loran-C  Policy  group 
and  in  the  Mediterranean  Loran-C  group  consider  It  advisable  that  the 
goal  should  be  to  have  a  single  terrestrial  based  radionavigation 
system,  stretching  from  North  Europe  to  the  Mediterranean  and  through 
the  Atlant ic. 

Without  prejudice  to  the  development  of  satellite  navigational  systems, 
the  Commission  supports  the  development  of  a  European  Loran-C  coverage 
composed  of  three  regional  chains.  A  possible  configuration  of  the 
Furopean  chain  is given  in annex  B  4) 

Taking  account  of  the  achievements  of  the  discussions  on  a  NW  European 
chain  and  the  intention  of  the  Mediterranean  countries  regarding  the 
the 
Mediterranean  and 
<.k:ve lopment  of  regional  chains  with  the  largest  coverage  area. 

Iberian  chains,  the  Commission 

supports 

As  safety  is  an  integral  part  of  the  Common  Transport  Policy  it  is  the 
role  of  the  Community  to  develop  initiatives  in  the  field  of  maritime 
safety  with  special  regard  to  the maintenance  of  high  safety  standards. 
Having  regard  to  the  achievement  of  the  objectives  of  the  Treaty  it  Is 
the  role  of  the  Commission  to  base  its  proposals  to  the  Council  upon  a 
high  level  of  protection. 

Radionavigation  systems  are  part  of  the  safety  environment  of  ships. 
The  withdrawal  of  existing  systems  without  any  replacement  by  another 
reliable  and  accurate  system  will  affect  the  level  of  safety  of  ship 
operations  in  Community  waters.  The  development  of  regional  Loran-C 
chains  is,  for  the  immediate  future  only,  a  suitable  alternative  for 
existing  terrestrial  systems  which  are  being  phased  out,  It will  result 
m  an  improvement  of  the  actual  accuracy  of  radioposit Ioning.  In  the 
future  Loran-C,  as  an  essential  and  economical  verification  system  for 
satellite  navigational  aids  will  contribute  to  the  enhancement  of 
maritime  safety  in Europe  on  a  large  scale. 
Recognising  that  Loran-C  is  an  accurate  radiopositioning  system  that 
can  be  developed  on  the  European  level  in  the  very  near  future,  the 
Commission,  with  the  purpose  of  maintaining  and  developing  the  high 
standard  of  safety  for  ship  operations  In  European  waters,  proposes 
to  the  Council  that  it  supports  the  achievement  of  regional  Loran-C 
chains  in  the  European  area.  This  will,  through  its  operation, 
contribute  significantly  to  the  preservation  and  protection  of  the 
marine  envirionment. 

Considering  the  need  for  the  compatibility  of  the  aids  to  navigation 
systems  introduced  or  foreseen  on  the  regional  level  in  Europe  it  Is 
important  that  the  Commission  acts  so  as  to ensure  such  compatibility. 

it  must  be  noted  that  the  withdrawal  of  any  involved  party  from  the 
envisaged  agreement  will  seriously  jeopardise  the  development  of  the 
European  network. 

Following  an  agreement  between  the  USA  and  the  USSR  on  Loran-C  the 
development  of  a  European  Loran-C  chain  will  extend  Loran-C  coverage  to 
the  entire  northern  hemisphere. 

- 11 

As soon as the European  interest  in the Loran-C chains  is recognised  it 
w in  be  necessary  to  improve the accuracy  of  the system  and  to develop 
the  most  suitable  receivers,  with  regard  to  future  developments 
espec ialy by satelIi te. 

Taking account  of  the decision of some Member  States  to cease operating 
the  DECCA  system  appropriate  measures  have  to  be  found  to  ensure  the 
transition  frpm  one  radionavigation  system  to  another  is  achieved  at 
the  lowest  cost  for  the users. 
The Commission  is prepared  to start  investigation  In this field. 

For  all  the  above  mentioned  reasons  there  now  exists  a  unique 
opportunity  to  provide  a  low-cost  radionavigation  system  to  cover 
European  waters  thus  enhancing  maritime  safety  and  protection  of  the 
maritime  environment.  It  is vital  that  this opportunity  is seized. The 
Commission  proposes  to  the Council  the adoption,  as soon  as possible, 
of a Decision, based upon  the proposal  in Annex  A. 

-  12 - 

ANNEX A 

Proposal  for a 
COUNCIL  DECISION 

on the LORAN-C  radionavigation  system 

THE COUNCIL OF THE EUROPEAN  COMMUNITIES, 

Having  regard  to  the  Treaty  establishing  the  European  Economic 
Community,  and  in particular  Article 84 paragraph  2 thereof, 

Having  regard  to the proposal  from  the Commission, 

Having  regard  to the opinion of  the European  Parliament, 

Having  regard  to the opinion of  the Economic and Social  Committee, 

Whereas  the  international  Maritime Organisation  (IMO) requires  the 

contracting governments  to the SOLAS Convention  to undertake  to arrange 

for  the establishment  and maintenance of  such aids to navigation as the 

volume of  traffic  Justifies and  the degree of  risk requires; 

Whereas  it  is a concern of  the Community  to ensure  the highest  degree 

of safety of navigation and protection of  the marine environment; 

Whereas  the United States Coastguard  has decided  to terminate  its 

LORAN-C  commitments outside  the USA before  1994 and  has  the  intention 

to offer  the LORAN-C  facilities to the relevant  host  nations; 

Whereas  the  international  Association of Lighthouse Authorities  (IALA) 

supports  the need  for a terrestrial  radionavigation system  to meet  the 

needs of maritime navigation; 

Whereas certain Member  States  intend  to participate  in one or more 

regional  agreements on  the establishment  of LORAN-C  chains covering 

North West  Europe and  the North Atlantic, the Mediterranean, the 

Iberian Peninsula and  the Baltic; 

-  13 -

Whereas  the LORAN-C  system  satisfies the  international  requirements  and 

the more general  utilisation  of  the LORAN-C  system  does not  prejudice 

the development  of  satellite aids  to navigation; whereas, furthermore, 

combined  coverage  by  satellite and LORAN-C  will  offer  the  highest 

degree of  system  verification and  continuity of  radionavigation 

coverage  for  the benefit  of maritime safety  and  environmental 

protection; 

Whereas  the establishment  of  regional  LORAN-C  systems must  ensure, a 

coherent  and  complete  coverage of  the European maritime  area,  avoiding 

as much  as possible  the  imposition of  additional  costs upon  the  users 

of existing  terrestrial  radionavigation systems; 

HAS ADOPTED THIS DECISION : 

Article 1 

1.  The Member  States shall  participate  in or  Join  regional  agreements 

on  LORAN-C  as  far  as necessary  to realise  the  international 

objectives. 

2.  With  regard  to their  participation  in regional  agreements  the 

Member  States shall  seek  to achieve  the LORAN-C  configurations 

which  cover  the widest  possible geographical  area  in Europe and  in 

neighbouring waters. 

Article  2 

The  Commission: 

shall  ensure  coordination  between  the Member  States 

participating  in regional  agreements with  a view  to 

ensuring  compatabiIity  between  the LORAN-C  chains 

introduced  on  the  regional  level, 

-  14 -

shall  encourage  the development  of  LORAN-C  receivers, 

taking  account  of  the ongoing  development  of  satellite 

systems and  the enhancement  of  the present  LORAN-C 

system, 

and shall  propose, where necessary,  to the Council  the  necessary 

measures. 

Article  3 

In their  role as member  or observer  within  the  International 

Association  of  Lighthouse Authorities  the Member  States and  the 

Commission  shall  strive  to obtain  the participation of  the greatest 

possible number  of  countries  in the European  regional  LORAN-C  chains 

with  the purpose of enlarging  the coverage of LORAN-C worldwide  in 

order  to  improve  safety of navigation and protection of  the marine 

env i ronment. 

Article  4 

This Decision  is addressed  to the Member  States, 

Done at Brussels, 

For  the Council 

The  President 

- 15 -

AJUiEJL-ai/... 

TECHNICAL  SPECIFICATION OF AIDS TO NAVIGATION  SYSTEMS 

1. GLOBAL  POSITIONING  SYSTEM  (GPS) 

GENERAL 

The  Global  Positioning  System  (GPS)  Is  a  space-based,  radio 
positioning,  navigation  and  time-transfer  system  having  free  major 
segments:  space,  control  and  user.  The  GPS  space  segment,  when  fully 
operational, will  be  composed of  21 satellites, plus  three  operational 
spares  In six  orbital  planes. The  satellites  will  operate  In circular 
20,200  km  orbits  at  an  inclination  angle  of  55'  and  with  a  12-hour 
period.  The  spacing  of  satellites  in orbit  will  be  precisely  arranged 
so  that  a  minimum  of  four  satellites  will  be  in  view  to  any  user, 
thereby  ensuring  world-wide  coverage.  Each  satellite  will  transmit  L1 
and  L2  signals.  L1  will  carry  a  precise  (P)  signal  and  a 
coarse/acquisition  (C/A)  signal.  L2  will  carry  a  P  signal  only. 
Superimposed  on  these  signals  will  be  navigation  and  atmospheric-
propagation correction data, and satellite clock-bias  information. 

The  control  segment  will  Include  a  number  of  monitor  stations  and 
ground  antennas  located  throughout  the world. The monitor  stations will 
use  GPS  receivers  to  track  passively  all  satellites  In  view,  and 
thereby  accumulate  ranging  data  from  the  satellite  signals.  The 
information  from  the monitor  stations  will  be  processed  at  the master 
control  station  (MCS) to determine  the satellite orbits, and  to update 
the navigation message of each satellite. This updated  information will 
be  transmitted  to  the  satellites  via  the  ground  antennas,  which  will 
also  be  used  for  transmitting  and  receiving  satellite  control 
Informat Ion. 

The  user  segment  will  consist  of  antennas  and  recel verprocessors  that 
will  provide positioning and navigation data to the user. 

PURPOSE 

GPS  is  a  position-fixing  system  which  will  be  used  for  general 
navigation  on  land, sea  and  air.  It will  also  have  survey  and  timing 
appiicat ions. 

-  16  -

A2fiiEjL_Bl/ 

SIGNAL CHARACTERISTICS 

The GPS concept  depends upon having accurate and contlnous knowledge of 
the  spatial  position  of  any  satellite  in  the  system,  In  terms  of  the 
time  and  distance  of  the  satellite  from  the  user.  Each  satellite 
transmits  its own  ephemeris data. This data  Is periodically  updated  by 
the  control  station,  and  is based  upon  information  obtained  from  five 
widely dispersed monitor  stations. 

The  GPS  receiver  automatically  selects  appropriate  signals  from  three 
or  four  of  the  satellites  that  give  the  best  view  as  based  on  the 
optimum  satellite-to-user  geometry.  It  then  solves  tlme-of-arrI va I 
difference  quantities  to obtain  the distances between  the user  and  the 
satellites.  This  information  establishes  the  user's  position  with 
respect  to  the  satellite  system.  A  timecorrection  factor  then  relates 
the satellite system  to earth co-ordinates. Each satellite  continuously 
transmits  a  composite  spread-spectrum  signal  at  12227.6  (L2)  and 
1575.42(H) MHz  that  contains  a  precise  navigational  signal,  a  coarse 
navigational  signal, satellite  ephemeris  data,  atmospheric-propagation 
correction data and clock-bias  Information. The user  equipment  measures 
four  Independent  pseudo-ranges and  range rates, and  translates  these to 
a  three-dimensional  position, a velocity  and a system  time. 

ACCURACY 

Reference System. The geodetic reference system  selected  for use by the 
Global  Positioning System  (GPS)  is the World Geodetic System  (WGS). The 
GPS  currently  uses  the  1984  version, which  Is  designated  as  WGS  84. 
Datum  transformation will  permit  coordinates  to be  transformed  between 
WGS 84 and most of  the major  and  local datums  in the world. 

The GPS provides  two services for position determination. 

The  Precise  Positioning  Service  (PPS)  will  provide  predictable 
positioning  accuracy  of  17.8  m  (2dRMS)  horizontally  and  27.7  m  (2 
sigma) vertically, velocity  accuracy  of  0.2 m/sec  (2 slgma)  In each of 
the  three  dimensions, and  timing  accuracy.  The  PPS will  be  limited  to 
the US and  allied military  and  federal  government  users. Limited civil 
use  may  be  authorised  to  those  who  can  demonstrate  a  need  for  the 
accuracy  that  cannot  be obtained  by other  means,  Is  in the US national 
interest  and can satisfy US national  security  requirements. 

The  Standard  Positioning  Service  (SPS) will  provide  a  lower  level  of 
accuracy  than  the  PPS.  The  SPS  will  be  made  available  to  civil, 
commercial  and  other  users  at  the  highest  level  of  accuracy  that  Is 
consistent  with  the  national  Interests of  the  USA.  The  current  policy 
of  the American Department of Defense  (DOD)  Is to provide  the SPS at an 
accuracy  of  100 m  (2 dRMS). 

- 17 -

2. GRANAS/NAYSAT 

AiJNJEJLBl/ 

GENERAL 

The  GRANAS  (Global  Radio  Navigation  System)  Is  a  planned  civil, 
satellite-based  radio  navigation  system  with  the  capability  of 
additional  communication  services.  NAVSAT  is  a  planned  global  civil 
navigation satellite system which  has similar operational  objectives to 
the GPS. 

GRANAS  has been  investigated  by  Standard  Elektrlk  Lorenz,  (SEL) funded 
by  the  German  Ministry  of  Research  and  Technology.  NAVSAT  has  been 
developed  by  European  industries, funded  by  the  European  Space  Agency 
(ESA). 

Both  systems  reveal  more  similarities  than  differences.  In  order  to 
enhance  the  prospect  of  a  future  system  realization,  ESA  decided  to 
release  a  study  which  aims  at  the  harmonization  of  the  GRANAS  and 
NAVSAT  systems.  It was  the objective of  the study  to  Identify  the best 
features  of  the  original  concepts  and  to  merge  them  Into  a  single 
consolidated  system. 

For  the  method  of  satellite  position  determination  the  principles  of 
GRANAS  and  NAVSAT  are  taken  as  two parallel  options. One of  these will 
be  selected  at  a  later  stage,  when  some  realization  aspects  are 
considered  in more detail, e. g. by means of an experimental  validation 
system. 

The  new  system  Is  characterized  by  the  composition  of  the  following 
features : 

SPACE SEGMENT 

The  configuration  of  the  space  segment  Is characterized  by  6  equally 
spaced  geostationary  satellites  (GEO)  supplied  by  12  satellites  in 6 
inclined  highly-elliptic  orbits  (HEO)  with  12-hour  periods.  These 
orbits are arranged within 3 orbital  planes mutually  separated  by  120 X 
in right  ascension  of  ascending  nodes  and  incline by  63.4 with  regard 
to the equator. Each  plane  Includes  two orbits, one with  its apogee  in 
the  Northern,  the  other  with  its  apogee  In  the  Southern  hemisphere. 
During  5/6  of  a  HEO  period  the  ground  track  is  concentrated  on  a 
relative  small  area  providing  good  visibility  conditions  and  making 
this type of orbit  comparable  to GEO satellites. Only  the altitude of a 
HEO  satellite  is changing  considerably  increasing up  to 39,000 km.  To 
avoid  problems  of  high  Doppler  frequencies  each  HEO  satellite  becomes 
operational  only  above  an  altitude  of  about  10,000  km.  Nevertheless, 
this constellation guarantees, that  during 96,2 X of  the  time at  least 
4 satellites  (GEO as well  as HEO) are visible. 

The communication  function  (e.g. for  the purpose of  position  reporting 
in case of SAR) may be realized according  to  INMARSAT  standards. 

- 18 -

ANttHLfii/... 

GROUND SEGMENT 

in  the  case  of  autonomous  satellite  position  determination  16  ground 
stations  are  proposed  which  are  equipped  with  simple  transponders  to 
respond  to  the  interrogation signal. The monitor  function  is performed 
simultaneously. 

For  the  ground  based  position  determination  6  Regional  Centres  are 
needed,  one  of  which  provides  the  service  of  the  Mission  Centre. 
However,  about  10  additional  monitor  and  tracking  stations  are 
required. For  these the same  locations as above can be used. 

USER  SEGMENT 

The  harmonized  navigation  system  offers  two  navigation  modes  : dual 
frequency  and  single  frequency.  The  dual  frequency  mode  permits 
correction  for  Ionospheric delays  to be made  and  hence  provides  higher 
accuracy  than the single frequency mode of operation. 

PURPOSE 

GRANAS/NAVSAT  would  be a general  navigation  system  for  position-fixing 
by air,  land and sea users. 

SIGNAL CHARACTERISTICS 

The  determination  of  the  user  position  is similar  to  that  of  GPS  In 
making  pseudorange  measurements  to at  least  4 satellites. However,  the 
new  system  bases on a  time-devlsion multiplex  (TDMA) approach  using  15 
time  slots  within  a  frame  length  of  2.4  s.  Each  navigation  burst 
consists  of  a  synchronization  preamble  (24  ms),  5  data  words  (100 ms 
and  a postamble  16 ms). The  latter  Is transmitted  at  another  frequency 
(1228 MHz  compared  to  1575 MHz)  in order  to compensate  for  Ionospheric 
delays. 

The  data  part  of  the  burst  includes  system  time,  satellite  position 
coordinates  as well  as an additional  word  Indicating  the  health  status 
of  the system. 

ACCURACY 

Due  to  the  chip  rate  of  4  MHz  and  the  dual-frequency  method,  the 
accuracy  of user  position  is comparable  to that of  the GPS P-code. 

According  to whether  a user  is stationary  or moving  an accuracy of  2.4 
or  24 m  (2dRMS) respectively  Is achievable. 

- 19 -

AitiEJL_ûl/... 

3. GLOBAL  NAVIGATION  SATELLITE 

SYSTEM  (GLONASS) 

GENERAL 

The  Global  Navigation  Satellite  System  (GLONASS)  Is  a  space-based, 
radio  positioning  system  that  is  being  Introduced  In  the  USSR  for 
world-wide use by aircraft, but  it could also be used at sea  level. The 
system will  start operation with between 10 and  12 satellites, of which 
5  or  6  will  be  positioned  in  each  of  two  orbital  planes  having  an 
inclination  of  65*.  The  satellites  will  operate  In  nearly  circular 
orbits  at  an  approximate  height  of  19,100  km,  and  with  a  period  of 
11.25  hours. The  system  is finally  intended  to contain  24 satellites, 
of  which  3 will  normally  serve  in a  standby  mode,  three  orbit  planes 
120'  apart will each contain seven  to eight satellites. 

The  user  will  establish  his  position  by  receiving  signals  from  three 
satellites  and  thereby  calculating  the  distances  to  the  satellites. A 
signal  that  will  give  a  very  precise  fix of  position  will  be  provided 
to  users  who  are  allowed  the  means  to  decode  It,  while  a  different 
signal  that will  give a  less accurate  fix will  be generally  available. 
The  former  signal  will  be carried  by  two frequencies  in the L band  (L1 
and  L2),  while  the  latter  will  be  carried  by  only  one  of  these 
frequencies.  This  arrangement  is similar  to  the  P  and  C/A  signals  of 
the  GPS.  it  might  be  possible,  because  of  similarities  between  the 
GLONASS  and  GPS,  for  users  to  have  receivers  that  could  work  with 
either  system. 

PURPOSE 

Glonass  is  a  position-fixing  system  which  will  be  used  for  general 
navigation by aircraft  and ships. 

SIGNAL CHARACTERISTICS 

A  master  station  monitors  the  satellites  In  order  to  keep  the 
ephemeris, or  positional, data  of  each  one  up  to date. The  satellites 
transmit  their  data  over  separate  channels  using  a  spread-spectrum 
technique. The L1 and L2 frequencies are respectively  1597-1617 MHz and 
1240-1260 MHz. 

ACCURACY 

100  m  horizontal,  150  m  vertical  and  15  cm/s  velocity  (all  95  X 
probability). 

- 20 -

A2JN£L_B1/ 

4.  DECCA 

GENERAL 

The  Decca  Navigator  System, generally  known  as  Decca,  Is a  hyperbolic 
radio  navigation  system,  operating  in  the  70-130  kHz  frequency  band, 
using  groups of  at  least  three ground  transmitter  stations, each  group 
making  a  system  unit  known  as  a  chain.  A  Decca  chain  consists  of  one 
Master,  and  two  or  three  Slave  stations,  80-110  km  from  the  Master, 
designated  as  Red,  Green  and  Purple.  The  signals  can  be  received  by 
surface  craft  and  by aircraft  at  all  altitudes down  to ground  level at 
distances  of  several  hundred  kilometres  from  the  transmitters.  The 
characteristic  high  accuracy  of  Decca  results  from  Its combination  of 
hyperbolic geometry, and  the phase comparison method of  time-difference 
measurement. 

PURPOSE 

The  Decca  Navigator  System  Is used  for  position-fixing  principally  by 
maritime and aviation users. 

SIGNAL CHARACTERISTICS 

Transmitter  signals  are  continuous  unmodulated  radio  waves,  the  Slave 
signal  is  phase-locked  to  the  Master.  The  frequencies  of  the 
unmodulated  continuous  radio  waves  transmitted  from  the  Master  and 
Slaves are harmonically  related  to a fundamental  value  "f" which  is not 
transmitted  but  which  is roughly  14 kHz, the exact  value  varying  from 
chain  to chain. 

Phase  synchronisation  of  Master  and  Slave  transmissions  creates  a 
pattern  of  hyperbolic  position  lines  along  which  the  phase  difference 
between  Master  and  Slave  is  constant.  Position  fixing  carried  out  by 
the Decca  receiver  consists basically  of  identifying  position  lines by 
phase comparison carried out with a multiple  frequency. 

in  receivers,  the  transmitted  frequencies  are  multiplied  in  order  to 
produce  comparison  frequencies  of  24f  (Red),  18f  (Green)  and  30f 
(Purple). 

Taking  the  Red  comparison  frequency  as  an  example,  24f  equals 
approximately  340  kHz  corresponding  to  a  wavelength  of  about  880 
metres. By  travelling  440 metres  (half  a wavelength) along  the Master-
to-Slave baseline a phase change of  360*  is produced, and  this distance 
is designated  as  a  lane  and  Indicated  by  a complete  revolution  of  the 
phasemeter  pointer  of  Deccometer  receivers  and  by  counting  up  or  down 
100 divisions of one  lane, at  the displays of  receivers with a digital 
performance. 

However, on  the  latest  receivers  the  position  is usually  displayed  In 
geographical  coordinates. 

-  21  -

A H O - f i l / -. 

Off  the  inter-statIon  baseline,  the  lane  widths  expand  In  accordance 
with  the  hyperbolic  geometry  but  the  Instrinslc  accuracy  of  the  system 
is  indicated  by  the  fact  that  phase  Is measured  to  within  one  or  two 
hundredths  of  a  lane, corresponding  to a few metres  In distance. 

Lanes  and  zones  (groups  of  24  Red,  18  Green  and  30  Purple  lanes)  are 
counted  by  either  a  geared  pointer  on  the  Deccometer  or  on  a  digital 
display  of  a modern  microprocessor  based  receiver. 

Once  every  20  seconds  lane  identification  signals  known  as  multipulse, 
are  transmitted  from  each  station  in  turn.  Their  prime  purpose  Is  to 
provide  a  check  on  the  lane  settings,  however,  because  these  signals 
are  formed  from  a  1  f  pulse  syntheslsed  from  all  four  radiated 
frequencies,  they  are  much  less  susceptible  to  skywave  errors  at  night 
than  those  that  may  be experienced  using  the normal  patterns,  it can  be 
shown  that  variable  errors,  particularly  at  longer  ranges  from  the 
chain,  are  significantly  smaller  at  night  using multipulse  -  and  can  be 
up  to  2:1  better.  In  the  current  generation  of  Decca  receivers,  the 
multipulse  signals  can  provide  the  primary  fixing  information,  being 
rate-aided  between  transmissions by  the normal  or  continuous  patterns. 

ACCURACY 

The  accuracy  of  Decca  is  specified  in  some  metres  at  positions  on  or 
near  the  baselines  between  two stations, but  this accuracy  decreases  as 
the  distance  from  the  baseline  Increases. Due  to  sky-wave  Interference 
Decca  is  susceptible  to  night  effect  which  generally  reduces  the 
accuracy  by  a  factor  of  6  to 8. 

In  daylight  at  a  distance  of  240  km  the  accuracy  will  be  better  than 
440 metres;  this  figure  deteriorates  to  approximately  2.4  km  at  night. 
Within  80  km  of  the  Master  station  the  accuracy  Is  approximately  25 
metres  by  day  and  190 metres  at  night. 

All  accuracies  quoted  are  at  2 dRMS. 

In areas  of  fringe  cover,  a  single  line  is used  for  homing  purposes  by 
mariners.  The  high  order  of  repeatability  of  the  Decca  system  Is  also 
particularly  significant.  For  example,  if  the  Decca  co-ordinates  of  a 
particularly  good  fishing  area  are  known,  a  vessel  can  subsequently 
return  to  the  position  by  referring  solely  to  the  Decca  readings. 
Similarly,  any  user  can  be  directed  to  a  precise  location  by  using 
Decca  coordinates. 

In certain  areas  the  hyperbolic  patterns  are distorted,  mainly  owing  to 
the  signals  passing  over  ground  of  low  electrical  conductivity.  These 
distortions,  known  as  fixed  errors,  should  be  taken  Into  consideration 
when  fixing  the  ship's  position.  This  Information  is published  In  the 
form of  Pattern  Correction  Charts  in the Chain  Data  Sheets. 

-  22  -

5. LORAlh£ 

AifiEJL_Bl/ 

PURPOSE 

LORAN-C  is a general  navigation  system  for air,  land and sea users. In 
addition  to  its position  fixing  capability  It can be used  for  timing 
purposes. 

SIGNAL  CHARACTERISTICS 

LORAN-C  is a  hyperbolic  system  operating  In the 90-110  kHz  frequency 
band.  Each  station  of  a  chain  is separated  by  several  hundred  miles 
with each  transmitting a series of eight  precisely  timed RF pulses. 

Chain  differentiation  Is provided  by Group  Repetition  Interval  (GRI). 
Selection of specific GRI may be coordinated  with the US Coast  Guard to 
avoid  Interference. 

The  system  is based  on the measurement  of the differences  In the time 
of  arrival  of signals  from the stations  In a chain. The measurements of 
the  Time  Difference  (TD) are made  in a  receiver  which  achieves  high 
accuracy  by  comparing  a  specified  cycle  zero-crossing  within  the 
transmitted  pulses of the master  and secondary  stations of a chain. The 
comparison  is  made  at  the  30  us  zero  crossing  to  avoid  sky-wave 
interference.  Additionally, the phase of the pulses  is alternated  In a 
predetermined  pattern  over  two groups  of  eight  pulses  to  limit  the 
effects of  long delayed sky waves. Precise control  over  the pulse  shape 
ensures  the proper  comparison at the 30 us zerocrosslng. 

ACCURACY 

Within  the defined  coverage  area,  Loran-C  provides  the user  using an 
adequate  receiver  with  a  predictable  accuracy  of  0.25 m  (2dRMS) or 
better. The repeatable  and relative  accuracies  range  between  18 and 90 
m.  Accuracy  Is  dependent  upon  the  Geometric  Dilution  of  Precision 
(GD0P) at the user's  location,  the measurement  error  (slgnal-to-nolse 
ratio) and chart or  local  area  calibration. The Loran-C  ground  wave Is 
primarily  used  for  navigation;  precise  time  measurement  and  time 
Interval  dissemination are also derived  from the Loran-C signal. 

Sky-wave  navigation  is  feasible,  but  with  a  significant  loss  In 
accuracy.  Like ground  waves,  sky-waves  to some  extent  may also be used 
for  time dissemination. Loran-C was originally designed  to be primarily 
a  hyperbolic  navigation  system.  However, with  the advent of the highly 
stable  frequency  standards, Loran-C can also be used  In the range-range 
(rho-rho) mode of navigation.  This  is accomplished  by a comparison of 
the  received  signal  phase  with  a  known  time  reference  to  determine 
propagation  time  and, therefore,  range  from  the stations.  It can be 
used  In  situations  where  the  user  is  within  reception  range  of 
individual  stations, but beyond  the hyperbolic coverage  area. The rho-
rho method  using  Loran-C  requires  that  the user  has a very  precise and 
stable  time  reference.  The high  cost  of  equipment  limits  the use of 
this mode. 

-  23 -

AlHEJL_ai/... 

The  accuracy  of  the  Loran-C  system  makes  It  a  suitable  candidate  for 
many  land  radiolocation  applications.  Loran-C  can  be  received  In 
mountainous  areas  where  VHF  and  UHF  systems  are  terrain  limited.  Some 
distortion  of  the  hyperbolic  grid  Is to be  expected  since  the  100  kHz 
signal's  time  of  arrival  and  strength  are  affected  by  the  soil 
conductivity  and  terrain.  Propagation  anomalies  may  be  encountered  In 
urban areas where  the proximity of  large man-made  structures affect  the 
signal.  The  existence  of  these  anomalies  Is  predictable  and  can  be 
compensated  for, usually  by  surveying  the  area.  The  long  range  of  the 
Loran-C  system  makes  it  particularly  desirable  for  application  to 
remote  areas,  or  where  the  user  population  Is  too  low  to  Justify  the 
cost of  a  large number  of  short-range  facilities. 

Proposed  configuration NW-Europe  and  Atlantic 

-  24 -

ANNEX  B2 

-  25  -

AHJBLB2/ 

SYSTEM  DESCRIPTION 

Genera 

1.  The  North  West  European  Loran  C  system  shall  comprise  the  eight 
existing  stations  of  the  Icelandic, Norwegian  and  French  chains, with 
the addition of  two new stations  In Norway  and one each  In  Ireland and 
the Uni ted Kingdom. 

2.The coverage  of  the new system  Is shown  In annex  2. The  area  shaded 
is  limited  either  by  accuracy  (maximum  error  .25 n. mile  2drms) or  by 
signal  strength  (minimum SNR - 10db noise 6ldB above  luV/m). 

Transmitted  Signal 

3.  The  signal  from  all  the  transmitters  shall  conform  to  the 
requirements  of  the  "Specification of  the  transmitted  Loran  C  signal" 
(USCG-USDOT COMDTINST M  16562. 4 July  1981). 

Transmitting Equipment 

4.The  transmitters  shall  be of  modular  construction  and  shall  consist 
of  a  prime  power  unit,  timing  and  control  units,  pulse  generating 
assemblies,  a  coupling  network,  output  cabinets,  switch  network  and 
antenna fenders. 

5.New  transmitting  equipment  shall  be  required  at  all  sites  except 
those  In France. Gamvlk, FedJe, South West  Ireland and North East 
England  are  new  sites.  The  existing  stations  In  Norway  (Boe  and  Jan 
Mayen)  shall  be  dual-rated  In  the  new  system,  but  the  existing 
transmitting equipment  is unsuitable. The present  valve transmitters on 
the  other  four  sites  (Anglssoq,  Sandur,  EJde  and  Sylt)  shall  be 
replaced with solid-state equipment. 

6.  Power  reqlrements vary depending on the ranges and  types of  terrain 
to  be  covered.  Transmitters  of  different  peak  radiated  power  (p.r.p.) 
can be provided  using  the same components  but  increasing  the number  of 
pulse generating assemblies. 

Antenna 

7.  The  antenna  is  a  top-loaded,  guyed,  steel  lattice  tower,  fully 
Insulated  from  the guys  and  foundation with  the exception  of  the  feed 
from the antenna coupler. The antenna may be 200 m to 400 m high. 

- 26 -

AUUBLfia 

Monitoring  and  control 

8.  Time  of  transmission  (TOT)  control  will  probably  be  used  for  the 
complete  system  eventually,  although  existing  USCG  stations  will  be 
controlled  via  System  Area  Monitors  at  least  until  the  proposed 
handover  date  (1994). 

9.  Under  TOT,  times of  transmission  are  fixed  relative  to  an  external 
standard  such  as  Universal  Co-ordinated  Time  (UTC).  Propagation  time 
along  the baselines  Is measured  by monitor  receivers  located  at or  near 
the  transmitter  sites.  Data  from  these  monitors  is  automatically  sent 
to  a control  centre  from  which  commands  such  as  timing  adjustments  are 
sent,  again  by  data  link. 

10. The  standard  deviation  of  TOT,  with  respect  to  UTC,  for  each 
transmitter  shall  be kept  below  a pre-determined  value, probably  50-100 
nanosec. The  standard  deviation of  time differences  between  masters  and 
secondary  shall  be  less  than  30 nanosec. 

11. The  system  shall  be controlled  from  two centres  : Boe  In Norway  for 
the  Iceland  and  Norwegian  Sea  chains  and  Brest  in France  for  the North 
Sea  and  Biscay  chains. 

12. The principal  maintenance  centres  and  stores shall  also be at  these 
control  centre  locations,  together  with  a maintenance  centre  at  Sandur. 

-  27 -

ANNEX  B 4 

EXISTING  LORAN  C  COVERAGE 

PROPOSED  COVERAGE 

N-W  EUROPEAN  LORAN  C 

-5 

o 

5 

'O 

^3 

ENVISAGED  LORAN  C 

COVERAGE  IBERIAN  PENINSULA 

AND  MEDITERRANEAN  SEA 

-  28 -

COMPETITIVENESS AND EMPLOYMENT  IMPACT STATEMENT 

1.  What  Is the main reason for  introducing the measure ? 

The simultaneous withdrawal  of the DECCA RACAL company and the US 

Coastguard  from the provision of radionavigation signals  In Europe 

and the on-going development of new radionavigation systems  In the 

Iberian Peninsula and the Mediterranean poses the potential major 

problem of piecemeal, uncoordinated, and hence uneconomic 

development of radionavigation signal  systems  In Europe. The 

proposal  alms to secure the commitment of the Member  States and 

Inter alia third countries to the introduction of  the LORAN-c 

radionavigation system as the European standard  for the medium 

term. 

2.  Faaturea of the business  In question 

All enterprises which use radionavigation signal systems. 

3.  What obligations does this measure  Impose directly on business ? 

No additional obligations. 

4.  What  Indirect obligations are national, regional  or  local 

authorities  likely to Impose on business ? 

Authorities are  likely  In-due course to require vessel owners to 

adapt or replace existing receiving equipment  to ensure the 

maintenance of high safety standards. 

5.  Are there any special  provisions  In respect of SME's ? 

None. 

6.  What  la the. M Ko I Y effect on ; 

- 29 -

a)  The, competitiveness of the business 

The  competitiveness of  Community  vessel  operators  will  be 

enhanced  through  the  avoidance  of  the  necessity  to  equip 

vessels  with  multiple  receivers  to  Interface  with  different 

radionavigation  signal  systems. 

b)  Employment 

PosItive. 

ISSN 0254-1475 

COM(91) 1  final 

DOCUMENTS 

EN 

15 

Catalogue number : CB-CO-91-022-EN-C 
ISBN 92-77-68909-9 

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