MARITIME POLICY
FOR A FUTURE GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS)
(Adopted on 27 November 1997)
THE ASSEMBLY,
RECALLING Article 15(j) of the Convention on the International
Maritime Organization concerning the functions of the Assembly in relation to
regulations and guidelines concerning maritime safety,
RECALLING ALSO resolutions A.529(13) on Accuracy Standards for
Navigation and A.815(19) on the World-Wide Radionavigation System,
RECOGNIZING the need for a future civil - and internationally -
controlled global navigation satellite system (GNSS) to provide ships with
navigational position-fixing throughout the world for general navigation,
including navigation in harbour entrances and approaches and other waters in
which navigation is restricted,
BEING AWARE of the current work of the
International Civil Aviation Organization (ICAO) on the aviation requirements
for a future GNSS,
RECOGNIZING FURTHER the need to identify early the maritime user
requirements for a future GNSS to ensure that such requirements are taken into
account in the development of such a system,
HAVING CONSIDERED the recommendation made by the Maritime Safety
Committee at its sixty-seventh session,
1. ADOPTS the Maritime Requirements for a Future Global Navigation
Satellite System (GNSS), set out in the annex to the present resolution, as the
IMO policy for a future GNSS;
2.
INVITES Governments and international organizations providing or intending to
provide services for the future GNSS to take account of the annexed Maritime
Requirements in the development of their plans and to inform the Organization
accordingly;
3. REQUESTS the Maritime Safety Committee to keep this policy
under review and to report, as necessary, to the Assembly.
MARITIME REQUIREMENTS FOR A
FUTURE GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS)
1.1 A Global Navigation Satellite System (GNSS) is a satellite
system which provides a world-wide position determination, time and velocity
capability for multi-modal use. It includes user receivers, one or more
satellite constellations, ground segments and a control organization with
facilities to monitor and control the world-wide conformity of the signals
processed by the user receivers to pre-determined operational performance
standards. The relevant definitions are included in appendix 1 to this annex.
1.2 For maritime users IMO is the international organization which
will recognize a GNSS as a system which meets the carriage requirements for
position-fixing equipment for a world-wide radionavigation system (WWRNS). The
formal procedures and responsibilities for the recognition of a GNSS should be
in accordance with paragraph 2 of the annex to resolution A.815(19) on WWRNS,
as far as applicable.
1.3 The present GNSSs (see paragraph 2) are expected to be fully
operational until at least the year 2010. A future GNSS will improve, replace
or supplement the present GNSSs, which have shortcomings in regard to
integrity, availability, control and system life expectancy.
1.4 Maritime users are expected to be only a small part of the
very large group of users of a future GNSS. Land mobile users are potentially
the largest group. Maritime users may not have the highest operational
requirements.
1.5 Early identification of the maritime user requirements is
intended to ensure that these requirements are considered in the development of
a future GNSS.
1.6 There are
rapid technological developments in the field of dionavigation and
radiocommunica-tions. Developments in shipping and maritime navigation in the
next 15 to 20 years have to be taken into account, but are not fully
predictable.
1.7 The long period required to develop and implement a future
GNSS has led the Organization to determine the maritime requirements for a
future GNSS at an early stage.
1.8 However, as development of a future GNSS is presently only in
a design stage, these requirements have been limited only to basic user
requirements, without specifying the organizational structure, system
architecture or parameters. These maritime requirements, as well as the
Organization's recognition procedures, may need to be revised as a result of
any subsequent developments.
1.9 When proposals for a specific future GNSS are presented to IMO
for recognition, these proposals will be assessed on the basis of any revised
requirements.
1.10 Early co-operation with air and land users and providers of
services is essential to ensure that a multi-modal system is provided in the
time expected.
2.1 Presently two State-owned military-controlled positioning
satellite systems are offered for civilian use. These systems are mainly used
in shipping and in aviation, and land mobile transport survey. For maritime use
the following aspects of each system are most relevant:
.1.1 The Global Positioning
System (GPS) Standard Positioning Service (SPS) is a space-based
three-dimensional positioning, three-dimensional velocity and time system which
is operated for the Government of the United States by the United States Air
Force. GPS met full operational capability in 1995.
___________________________
* When GPS and GLONASS are
mentioned in this annex the Standard Position Services (SPS) provided by these
systems are being referred to.
.1.2 The GPS is expected to be
available for the foreseeable future, on a continuous, world-wide basis and
free of direct user fees. The United States expects to be able to provide at
least six years notice prior to termination of GPS operation or elimination of
the GPS. This service, which will be available on a non-discriminatory basis to
all users, meets the requirements for general navigation with a horizontal
position accuracy of 100 metres (95%).
.1.3 Accordingly, GPS has been
offered and recognized as a component of the world-wide
radionavigation system (WWRNS) for navigation use in other waters.
.1.4 Without augmentation
GPS accuracy is not suitable for navigation in harbour entrances and approaches
or restricted waters. GPS does not provide instantaneous warning of system malfunction.
However, differential corrections using maritime radiobeacons can enhance
accuracy (in limited geographic areas) to 10 metres (95%) and also offer
integrity monitoring. Integrity provision may be possible by receiver
autonomous integrity monitoring (RAIM).
_______________________
* When GPS and GLONASS are
mentioned in this annex the Standard Position Services (SPS) provided by these
systems are being referred to.
.2.1 GLONASS (Global
Navigation Satellite System) is a space-based three-dimensional positioning,
three-dimensional velocity and time system, which is managed for the Government
of the Russian Federation by the Russian Space Agency.
.2.2 GLONASS has been
offered and recognized as a component of WWRNS. GLONASS has been fully
operational since 1996 and is expected to be operational at least until 2010
for unlimited civilian use on a long-term basis and to be free of direct user
fees.
.2.3 GLONASS is meant to
provide long-term service for national and foreign civil users in accordance
with existing commitments. The service will meet the requirements for general
navigation with a horizontal position accuracy of 45 metres (95%). Without
augmentation, GLONASS accuracy is not suitable for navigation in harbour
entrances and approaches.
.2.4 GLONASS does not
provide instantaneous warning of system malfunction. However, augmentation can
greatly enhance both accuracy and integrity. Differential corrections can
enhance accuracy to 10 metres (95%) and offer integrity monitoring. Integrity
provision may be possible by RAIM.
2.2 There are several initiatives to improve the accuracy and/or
integrity of GPS and GLONASS by augmentation. The use of different differential
correction signals for local augmentation of accuracy and integrity and RAIM
may be mentioned as example of such initiatives. In addition, integrated
receivers are being developed, combining signals from GPS, GLONASS, LORAN-C
and/or Chayka. Wide area augmentation systems are also being developed using
differential correction signals from geostationary satellites, in particular
Inmarsat III satellites, for instance by the United States and Europe.
2.3 Within the overall context of radionavigation the developments
concerning terrestrial systems must also be taken into consideration. DECCA
will be phased out in many countries by the year 2000. OMEGA was also phased
out in 1997. The United States-controlled LORAN-C networks are under
consideration for phasing out by the year 2000. However, the Russian
Federation-controlled Chayka networks will not be considered for phasing out
until at least the year 2010. Civil-controlled LORAN-C and LORAN-C/Chayka
networks are being set up in the Far East, north-west Europe and other parts of
the world with plans for extension in some areas.
3. MARITIME
REQUIREMENTS FOR A FUTURE GNSS
3.1 The maritime requirements for a future GNSS can be subdivided
into the following general, operational, institutional and transitional
requirements:
.1 The future GNSS should
primarily serve the operational user requirements for navixgation. For maritime
use this includes navigation in harbour entrances and approaches, and other
waters in which navigation is restricted.
.2 The future GNSS should
have the operational and institutional capability to meet additional
area-specific requirements through local augmentation, if this capability is
not otherwise provided. Augmentation provisions should be harmonized world-wide
to avoid the necessity of carrying more than one shipborne receiver or other
devices.
.3 The future GNSS should
have the operational and institutional capability to be used by an unlimited
number of multi-modal users at sea, in the air and on land.
.4 The future GNSS should be
reliable and of low user cost. With regard to the allocation and recovery of
costs, a distinction should be made between maritime users that rely on the
system for reasons of safety and other users that primarily profit from the
system in commercial or economic terms. Also the interests of both shipping and
the coastal States should be taken into consideration when dealing with
allocation and recovery of costs.
.5 Three possible
cost-recovery options are identified as follows:
- through funding by
international organizations concerned (IMO, ICAO, etc.);
- through cost-sharing
between Governments or commercial entities (e.g. satellite communication
providers); or
- through private
investments and direct user charges or licensing fees.
.6 The future GNSS should
meet the maritime user's operational requirements for general navigation,
including navigation in harbour entrances and approaches and other waters where
navigation is restricted. These requirements for general navigation are given
in appendix 2 to this annex.
.7 The service provider
would not be held responsible for the performance of the shipborne equipment.
This equipment should meet performance standards developed simultaneously with
the service provider and adopted by IMO.
.8 The future GNSS should
enable shipborne equipment to provide the user with information on position,
course and speed over the ground, have a data-link capability and meet the
requirements for interoperability with the shipborne GMDSS equipment.
.9 The following are
examples of additional applications which should be taken into consideration in
the future GNSS:
- Shipborne applications:
ECDIS interface, automatic
position reporting interface, GMDSS interface, high-speed craft requirements,
track control, docking/mooring, ship motion monitoring, voyage data recorder,
ship heading and attitude indication.
- External applications:
SAR, hydrographic survey,
buoy positioning, fairway design and dredging.
.10 No user requirements
have been included for non-general navigation purposes (e.g. fishing,
hydrographic surveys, offshore-resource mining, mine-sweeping, etc.), as these
relate to specific areas of activities, each with specific user requirements.
These requirements may be addressed by individual Administrations or relevant
organizations.
.11 The future GNSS should
have institutional structures and arrangements for control by an international
civil organization in particular representing the contributing Governments and
users.
.12 The international civil
organization should have institutional structures and arrangements to enable it
to provide, operate, monitor and control the system to the predetermined
requirements at minimum cost.
.13 These requirements can
be achieved either by the use of an existing organization or by the
establishment of a new organization. The organization can provide and operate
the system by itself or monitor and control the service provider.
.14 IMO itself is not in a
position to provide and operate a GNSS. However, IMO has to be in a position to
maintain control over the following aspects of a GNSS:
- the continued provision of
the service to the maritime users;
- the operation of the GNSS
in respect of its ability to meet maritime user requirements;
- the application of
internationally established cost-sharing and cost-recovery principles; and
- the application of
internationally established principles on liability issues.
.15 The future GNSS should
be developed in parallel to the present GNSS, or could evolve, in part or in
whole, from the present GNSS.
.16 In advance of full
system implementation, a regional system that is fully operational and which
has the potential to be a component of a global system may be recognized as a
component of a future GNSS.
.17 The terrestrial
infrastructure (surveillance stations and monitoring centre) forming the ground
segments of the future GNSS should, as far as possible, be compatible with the
infrastructure used for the present GNSS.
.18 The shipborne receivers
or other devices required for a future GNSS should, where practicable, be
compatible with the shipborne receiver or other devices required for the
present GNSS.
4. REQUIRED ACTIONS
AND TIME-SCALE
4.1 A continuing involvement of IMO will be necessary. The maritime
requirements given in this annex should be continually reassessed and updated
on the basis of new developments and specific proposals.
4.2. The involvement of IMO should be positive and interactive and
the Organization should consider establishing a forum whereby meaningful
discussions can take place with air and land users, to resolve difficult mutual
institutional matters and consider a joint way forward.
4.3 Recognizing that ICAO is also studying the aviation
requirements for a GNSS and that there are prospects of a Joint IMO/ICAO
Planning Group for the development of the GNSS, close contacts between IMO and
ICAO are necessary.
4.4 International, regional and national organizations, as well as
individual companies, involved in the development of a future GNSS should be
informed of the requirements set by IMO for acceptance of a future GNSS. These
IMO requirements should be incorporated in their GNSS plans to be accepted for
maritime use.
4.5 The anticipated time-scale for introduction of the future GNSS
is given in appendix 3 to this annex. Though radionavigation systems are under
the responsibility and/or control of individual States or groups of States, the
time-scales for the expected introduction and phasing out of these systems,
such as the present GNSS, the augmentation facilities and terrestrial systems,
are also included in appendix 3. The time-scales of these systems determine the
time-scale for the decision-making process within IMO.
4.6 For the early and orderly participation of IMO in the
introduction of the future GNSS the following anticipated time-scale for the
IMO process of decision-making is envisaged:
- Autumn 1999 (A.21):
Reassessment of this
resolution, if necessary as a result of unforeseen developments on specific
proposed future GNSSs.
- Autumn 2001 (A.22):
Consideration of the
proposed future GNSS, including the related agreements between interested
Governments, other international organizations and/or system providers.
- 2008:
Completion of the
implementation (system and organization) of the proposed GNSS with final
acceptance by IMO of this future GNSS as a WWRNS for maritime use.
Accuracy. The degree of conformance between the estimated or
measured parameter of a craft at a given time and its true parameter at that
time. (Parameters in this context may be position co-ordinates, velocity, time,
angle, etc.)
- Absolute accuracy
(Geodetic or Geographic accuracy). The accuracy of a position with respect to
the geographic or geodetic co-ordinates of the Earth.
- Geodetic or Geographic
accuracy. See Absolute accuracy.
- Operational technical
accuracy (OTA). The accuracy with which the craft is controlled as measured by
the indicated craft position with respect to the indicated command or desired
position. It does not include operator errors.
- Relative accuracy. The
accuracy with which a user can determine position relative to that of another
user of the same navigation system at the same time.
- Repeatable accuracy. The
accuracy with which a user can return to a position whose co-ordinates have
been measured at a previous time with the same navigation system.
Along-track error. A position error in the direction of the
intended track.
Ambiguity. The condition obtained when one set of measurements
derived from a navigation system defines more than one point, direction, line
of position or surface of position.
Augmentation. Any technique of providing enhancement to the GNSS
in order to provide improved navigation performance to the user.
- Satellite-based
augmentation system (SBAS). A system providing additional satellite signals
over a wide area in order to enhance the performance of the GNSS service.
- Ground-based augmentation
system (CBAS). A system providing additional signals from a ground-based
station for a limited geographical area in order to enhance the performance of
the GNSS service.
Availability. The percentage of time that an aid, or system of
aids, is performing a required function under stated conditions.
- Signal availability. The
availability of a radio signal in a specified coverage area.
- System availability. The
availability of a system to a user, including signal availability and the
performance of the user's receiver.
Circular error probable (CEP). The radius of a circle, centred on
the measured position, inside which the true position lies with 50%
probability.
Confidence interval. The numerical range within which an unknown
is estimated to be with a given probability.
Confidence level. The probability that a given statement is
correct, or the probability that a stated confidence interval (numerical range)
includes an unknown.
Confidence limits. The extremes of a confidence interval.
Continuity. The ability of a system to function within specified
performance limits without interruption during a specified period.
Correction. The numerical value of a correction is the best
estimate which can be made of the difference between the true and the measured
value of a parameter. The sign is such that a correction which is to be added
to an observed reading is taken as positive.
Coverage. The coverage provided by a radionavigation system is
that surface area or space volume in which the signals are adequate to permit
the user to determine position to a specified level of performance.
Cross-track error. A position error perpendicular to the intended
track.
Craft autonomous integrity monitoring (CAIM). This is a technique
whereby all navigation sensor information available on the craft is
autonomously processed to monitor the integrity of the navigation signals. (See
also Receiver autonomous integrity monitoring.)
Differential system. An augmentation system whereby
radionavigation signals are monitored at a known position and the corrections
so determined are transmitted to users in the coverage area.
Dilution of precision. The factor by which the accuracy of the
GNSS position and time co-ordinates are degraded by geometrical