CELEX: 51991PC0001
Language: en
Date: 1991-01-21
Title: PROPOSAL FOR A COUNCIL DECISION ON THE LORAN-C RADIONAVIGATION SYSTEM

COMMISSION OF THE EUROPEAN COMMUNITIES
                                          C0MC91) 1 final
                                          Brussels, 21 January 1991
                           Proposal for a
                         COUNCIL DECISION
              on the LORAN-C radionavigation system
                   (presented by the Commission)
$ÈM
 m
 ---pagebreak---                                  - 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.
 ---pagebreak---                                     - 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.
The existing      radiopositioning systems     can be divided        into  two
categories,    the   space-based   systems on     the one     hand    and  the
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.
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).
Due to similarities between the two systems it might theoretically be
possible for users to have receivers that could work with either
system.    Unfortunately    both  systems   are   military     systems.   Many
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    system   would   expose  users   to   the   risk    of   having   no
radionavigation aid. In addition there is uncertainty concerning the
possible future introduction of user dues on the satellite systems.
On   the European level, GRANAS (Global Radionavigation System) and
NAVSAT  , 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.
 ---pagebreak---                                   - 4 -
The    satellite systems   will  provide  three   dimensional  position
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.
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.
 ---pagebreak---                                     - 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    in   appropriate   national    and Regional  areas   terrestrial
radionaviagtion systems should be maintained after the introduction of
new satellite navigation systems for the foreseeable future.
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
governments    concerned  are   in a position    to enter   into direct
negotiations with each other.
Discussions between the Mediterranean countries started In 1989 in IALA
with the participation of the Commission of the European Communities to
examine    the need    to maintain or even extend      Loran-C   in the
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.
 ---pagebreak---                                  - 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.
 ---pagebreak---                                   - 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.
 ---pagebreak---                                    - 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   coverage     area.  The  UK  emphasised   that  an   acceptable
international agreement on Loran-C is a prerequisite for the UK for
changing from its DECCA system to the Loran-C.
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.
 ---pagebreak---                                  - 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.
 ---pagebreak---                                        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
Mediterranean      and   Iberian  chains,   the Commission    supports  the
<.k:ve lopment of  regional chains with the largest coverage  area.
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.
 ---pagebreak---                                  - 11
As soon as the European interest in the Loran-C chains is recognised it
w i n 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.
 ---pagebreak---                                    - 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;
 ---pagebreak---                                      - 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,
 ---pagebreak---                                    - 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
 ---pagebreak---                                     - 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.
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                                                          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).
 ---pagebreak---                                     - 17 -
                                                         AiJNJEJLBl/
                            2. GRANAS/NAYSAT
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.
 ---pagebreak---                                    - 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.
 ---pagebreak---                                      - 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).
 ---pagebreak---                                     - 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.
 ---pagebreak---                                    - 21 -
                                                          AHO-fil/-.
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.
 ---pagebreak---                                     - 22 -
                                                         AifiEJL_Bl/
                               5. LORAlh£
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.
 ---pagebreak---                                   - 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.
 ---pagebreak---                         - 24 -
                                              ANNEX B2
Proposed configuration NW-Europe and Atlantic
 ---pagebreak---                                    - 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.
 ---pagebreak---                                    - 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.
 ---pagebreak---          - 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
 ---pagebreak---                                   - 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.
 ---pagebreak---                                      - 29 -
6. What la the. M Ko I Y effect on ;
   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.
 ---pagebreak---  ---pagebreak---                                                                                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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