Resolution A.915(22)

 

REVISED MARITIME POLICY AND REQUIREMENTS FOR A FUTURE GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS)

(adopted on 29 November 2001)

 

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,

 

RECOGNIZING the need for a future civil and internationally-controlled global navigation satellite system (GNSS) To contribute to the provision of navigational position-fixing for maritime purposes throughout the world for general navigation,) including navigation in harbour entrances and approaches and other waters in which navigation is restricted,

 

RECOGNIZING ALSO that the maritime needs for a future GNSS are not restricted to general navigation only. Recommendations for requirements for other maritime applications should also be considered as the strict separation between general navigation and other navigation and positioning applications can not always be made, and the intermodal use of GNSS is expected to increase in the future.

 

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,

 

BEING AWARE of the current work of the International Civil Aviation Organization (ICAO) on the aviation requirements for a future GNSS,

 

HAVING CONSIDERED the recommendation made by the Maritime Safety Committee at its seventy-third session,

 

1. ADOPTS the Revised Maritime Policy and Requirements for a Future Global Navigation Satellite System (GNSS), set out in the Annex to the present resolution, as the IMO policy for future GNSS(s);

 

2. INVITES Governments and international organizations providing or intending to provide services for the future GNSS to take account of the annexed Maritime Policy and Requirements in the development of their plans and to inform the Organization accordingly;

 

3. REQUESTS the Maritime Safety Committee to keep this policy and requirements under review and to adopt amendments thereto, as necessary.

 

4. REVOKES resolution A.860(20).

 

Annex

REVISED MARITIME POLICY AND REQUIREMENTS FOR A FUTURE GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS)

 

1. INTRODUCTION

 

1.1 A Global Navigation Satellite System (GNSS) is a satellite system that provides world-wide position, velocity and time determination 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. A set of relevant definitions and a glossary are included in Appendix 1 to this Annex.

 

1.2 For maritime users IMO is the international organization that will recognise 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 satellite navigation systems (see paragraph 2) are expected to be fully operational until at least the year 2010. Future GNSS(s) will improve, replace or supplement the present satellite navigation systems, which have shortcomings in regard to integrity, availability, control and system life expectancy (see paragraph 2).

 

1.4 Maritime users arc expected to be only a small pan 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 most demanding requirements.

 

1.5 Early identification of the maritime user requirements is intended to ensure that these requirements are considered in the development of future GNSS(s).

 

1.6 There are rapid developments in the field of radionavigation, radiocommunication and information technology. Developments in these technologies for maritime use have to be taken into consideration.

 

1.7 The long period required to develop and implement a GNSS has led the Organization to determine the maritime requirements for future GNSS(s) at an early stage.

 

1.8 However, as development of future GNSS(s) is presently only in a design stage, these requirements have been limited only to basic user requirements, without specifying the organizational structure and system architecture. The 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. PRESENT SITUATION

 

2.1 Currently two State-owned military-controlled satellite navigation systems are available for civilian use. These systems are mainly used in shipping, in aviation, and in land mobile transport; the systems are also used for hydrography, survey, timing, agricultural, construction and scientific purposes. For maritime use the following aspects of each system are most relevant:

 

.1 GPS*

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* When GPS and GLONASS arc mentioned in this Annex the Standard Position Services (SPS) provided by these systems are being referred to.

 

.1.1 The Global Positioning System (GPS) 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 achieved full operational capability (FOC) in 1995. The system will undergo a modernisation programme between 2002 and 2010, when the performance of the system will be improved.

 

.1.2 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 or elimination of GPS. This service, which is available on a non-discriminatory basis to all users has, since FOC, met accuracy requirements for general navigation with a horizontal position accuracy of 100 metres (95%).

 

.1.3 Accordingly, GPS has been recognized as a component of the World-Wide Radionavigation System (WWRNS)for navigation use in waters other than harbour entrances and approaches and restricted waters.

 

.1.4 Without augmentation, GPS accuracy does not meet the requirements for navigation in harbour entrances and approaches or restricted waters. GPS does not provide instantaneous warning of system malfunction. However, differential corrections can enhance accuracy (in limited geographic areas) to 10 m or less (95%) and also offer external integrity monitoring. Internal integrity provision is possible by autonomous integrity monitoring using redundant observations from either GNSS or other (radio) navigation systems or both.

 

.2 GLONASS*

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* When GPS and GLONASS arc 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 recognized as a component of the WWRNS. GLONASS was declared fully operational in 1996, and was declared to be operational at least until 2010 for unlimited civilian use on a long-term basis and to be free of direct-user fees. Early in 2000, the intended space segment was not fully available.

 

.2.3 GLONASS is meant to provide long-term service for national and foreign civil users in accordance with existing commitments. When fully operational, the service will meet the requirements for general navigation with a horizontal position accuracy of 45 m (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 m or less (95%) and offer external integrity monitoring. Internal integrity provision may be possible by using redundant observations from either GNSS or other (radio) navigation systems or both.

 

2.2 There are several techniques that can improve the accuracy and/or integrity of GPS and GLONASS by augmentation. The widespread use of differential correction signals from stations using the appropriate maritime radionavigation frequency band between 283.5 and 325 kHz for local augmentation and craft or receiver autonomous integrity monitoring may be mentioned as examples. In addition, integrated receivers are already developed and in development, 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 such as EGNOS for Europe, WAAS for the United States and MSAS for Japan. Receivers for these augmentation systems are being developed.

 

2.3 Within the overall context of radionavigation the developments concerning terrestrial systems must also be taken into consideration. DECCA is phased out in many countries, OMEGA was phased out in 1997. The future of the United States controlled LORAN-C networks is under consideration. 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 in operation in the Far East, North-West Europe and other parts of the world, with plans for extension in some areas. A number of Loran-C and Chayka stations are transmitting on an experimental basis differential GPS correction.

 

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:

 

General requirements

 

.1 A future GNSS should primarily serve the operational user requirements for general navigation. This includes navigation in harbour entrances and approaches, and other waters in which navigation is restricted.

 

.2 A future GNSS should also serve other operational navigation and positioning purposes where applicable.

 

.3 A 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 harmonised world-wide to avoid the necessity of carrying more than one shipborne receiver or other devices.

 

.4 A 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.

 

.5 A 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 those that additionally benefit 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.

 

.6 Some 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.

 

Operational requirements

 

.7 Future GNSS(s) 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. The minimum maritime user requirements for general navigation are given in Appendix 2 to this Annex.

 

.8 Future GNSS(s) should meet the maritime operational requirements for positioning applications. The minimum maritime user requirements for positioning are given in Appendix 3 of this Annex.

 

.9 Future GNSS(s) should operate with the geodetic and time reference systems compatible with present satellite navigation systems.

 

.10 Service provider(s) are not responsible for the performance of the shipborne equipment. This equipment should meet performance standards adopted by IMO.

 

.11 The development and use of integrated receivers using future GNSS(s) and terrestrial systems is recommended.

 

.12 Future GNSS(s) should enable shipborne equipment to provide the user with information on position, time, course and speed over the ground.

 

.13 Shipborne equipment for GNSS(s), including integrated receivers mentioned in 3.11, should have a data interface capability with other shipborne equipment to provide and/or use information for navigation and positioning such as: ECDIS, AIS, the GMDSS, track control, VDR, ship heading and attitude indication and ship motion monitoring.

 

.14 Users should all be timely informed of degradations in performance of individual satellite signals and/or of the total service, by the provision of integrity messages.

 

Institutional requirements

 

.15 GNSS(s) should have institutional structures and arrangements for control by an international civil organization in particular representing the contributing Governments and users.

 

.16 International civil organizations should have institutional structures and arrangements to enable (supervision of) the provision, operation, monitoring and control of the system(s) and/or service(s) to the predetermined requirements at minimum cost.

 

.17 These requirements can be achieved either by the use of existing organizations) or by the establishment of new organization(s). An organization can provide and operate the system by itself or monitor and control the service provider.

 

.18 IMO itself is not in a position to provide and operate a GNSS. However, IMO has to be in a position to assess and recognise the following aspects of a GNSS:

 

— provision of the service to maritime users on a non-discriminatory basis;

 

— operation of the GNSS in respect of its ability to meet maritime user requirements;

 

— application of internationally established cost-sharing and cost-recovery principles; and

 

— application of internationally established principles on liability issues.

 

Transitional requirements

 

.19 Future GNSS(s) should be developed in parallel to, or could evolve in part or in whole from the present satellite navigation systems.

 

.20 A regional satellite navigation system that is fully operational may be recognised as a component of the WWRNS*.

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* See resolution A.815(19).

 

.21 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 satellite navigation systems.

 

4. REQUIRED ACTIONS AND TIME-SCALE

 

4.1 The 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 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 future GNSSs, 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 future GNSSs is given in Appendix 4 to this Annex. The time-scales for the expected introduction and phasing out of radionavigation systems, such as the present satellite navigation systems, the augmentation facilities and terrestrial systems, are also included in Appendix 4. 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 future GNSS(s), the process of decision-making should include means to:

 

— review this resolution periodically;

 

— consider proposals urgently when submitted; and,

 

— recognise new systems when submitted.

 

Appendix 1

TERMS USED IN GNSS

 

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 coordinates, velocity, time, angle, etc.)

 

— Absolute accuracy (Geodetic or Geographic accuracy). The accuracy of a position estimate with respect to the geographic or geodetic co-ordinates of the Earth.

 

— Geodetic or Geographic accuracy. See Absolute accuracy.

 

— Predictable accuracy. The accuracy of the estimated position solution with respect to the charted solution.

 

— 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 coordinates have been measured at a previous time using uncorrelated measurements from the same navigation system.

 

Alert limit (or threshold value). The maximum allowable error in the measured position — during integrity monitoring — before an alarm is triggered.

 

Along-track error. The component of the Vessel Technical 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 in order to enhance the performance of the GNSS service.

 

— Ground-based augmentation system (GBAS). A system providing additional signals from a ground-based station 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. The non-availability can be caused by scheduled and/or unscheduled interruptions.

 

— 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.

 

Chart error. Position errors in the chart caused by inaccuracies m surveying and by errors in the reference geodetic system.

 

Circular error probable (CEP). The radius of a circle, centered on the measured position, inside which the true position lies with 50% confidence.

 

Confidence interval. The numerical range within which an unknown is estimated to be with a given (probability).

 

Confidence level. The percentage of confidence that a given statement is correct, or the percentage of confidence that a stated interval (numerical range) includes an unknown.