AI 1.8 Maritime GMDSS

Agenda item 1.8

1.8              to consider possible regulatory actions to support Global Maritime Distress Safety System (GMDSS) modernization and to support the introduction of additional satellite systems into the GMDSS, in accordance with Resolution 359 (Rev.WRC-15);

 

Resolution 359 (Rev.WRC‑15) – Consideration of regulatory provisions for updating and modernisation of the Global Maritime Distress and Safety System

Executive summary

WRC-19 agenda item 1.8 encompasses two separate items. The first is global maritime distress and safety system (GMDSS) modernization, referred to as "Issue A." The second is the introduction of additional satellite systems into the GMDSS, referred to as "Issue B."

To satisfy Issue A three methods are presented to be reflected in the Radio Regulations. The first method is no change; the second method includes frequencies to be used for medium frequency (MF) and high frequency (HF) navigational data (NAVDAT) systems, in support of GMDSS modernisation.

The third method is similar to the second one with the following conditions:

•             NAVDAT transmits only from coastal stations

•             Their usage is subject to agreement to be obtained with affected administrations.

CEPT proposes some regulatory changes similar to the second method. This is in order to prepare for the continuation of the modernisation of the GMDSS which will be addressed at WRC-23.

 

To satisfy Issue B several methods are presented to reflect in the Radio Regulations the frequencies used by a non-GSO GMDSS satellite system, noting the activities of International Maritime Organization (IMO).

CEPT proposes some regulatory  actions to introduce an additional satellite system into the GMDSS at 1621.35-1626.5MHz with a primary allocation to the maritime mobile satellite service. CEPT proposes the strengthening of regulatory provisions in order to protect services in that frequency band and adjacent bands.

 

                Background

Issue A: Global maritime distress and safety system modernisation

Governments adopted the GMDSS as part of the 1988 amendments to the International Convention for the Safety of Life at Sea, 1974 (SOLAS). It was fully implemented in 1999. It has served the mariner and the maritime industry well since its inception. Some of the GMDSS technologies used have not reached their full potential. More modern technologies could performed some GMDSS functions .

The International Maritime Organisation (IMO) has adopted a modernisation plan for the GMDSS containing a high-level review and a detailed review. The detailed review and the plan show that the use of some existing services is declining. The sector is considering some new technologies for  possible introduction in the modernised GMDSS. VHF data exchange system (VDES) and the NAVDAT system are two examples of such potential new technologies. WRC-15 addressed the terrestrial component of VDES. Another Agenda Item (1.9.2) covers the satellite component.

Navigational text (NAVTEX) is already incorporated into the regulations for the GMDSS for disseminating maritime safety information. NAVDAT is counted as an enhancement of existing NAVTEX and could be considered as a potential entity in next generation of GMDSS. WRC-12 addressed the allocation of the 495-505 kHz frequency band for the maritime mobile service. The IMO regard this band as the most suitable for MF NAVDAT application. However, regulatory provisions are still needed for both MF and HF NAVDAT applications.

 

Issue B: Introduction of additional satellite systems into the Global Maritime Distress and Safety System

To date, only one satellite system has been incorporated by the IMO in the GMDSS "system of systems". Observers expert that further systems will become operational and incorporated into the GMDSS "system of systems".  WRC-19 is invited to consider the ITU-R studies undertaken as part of this agenda item.

 

The IMO is currently considering one operating non-GSO MSS system which could provide worldwide operation of GMDSS within MSS allocations in the frequency range 1 616-1 626.5 MHz, including to Arctic and Antarctic areas. The satellite system under consideration by IMO operates using the same frequency for both uplink and downlink, to each mobile earth station

MSS satellite systems in the band 1 610-1 626.5 MHz are subject to frequency coordination between geostationary and non-geostationary satellite networks alike. They must also undergo frequency co-ordination with other services having equal rights. The above-mentioned system's service links within this band (both uplink and downlink) have been coordinated with those services with equal status. The notifying administration has notified them and recorded them in the Master International Frequency Register (MIFR). However the MSS downlinks are recorded as having secondary status.

The notifying administration has authorised the space stations of the satellite system to operate in the 1 618.725-1 626.5 MHz band. It has authorised the space stations of the satellite system in the 1 617.775-1 618.725 MHz band on a shared basis with another non-GSO network under the responsibility of the same notifying administration .

There are two views in respect of the downlinks having secondary status, given the Safety of Life aspect of GMDSS:

–             View 1: These assignments are operated using time division duplex (TDD), in which the subscriber units and satellites transmit and receive in the same frequency band. Therefore the primary uplink communication links effectively protect the secondary downlinks. Thus in practice both uplink and downlink benefit from the same rights in the 1 618.725-1 626.5 MHz band. There is no other operational MSS system which is co-frequency with the Non-GSO MSS system. From the practical perspective of the assignments and their protection, there is suitable protection for use of the frequencies in both directions.  The following points are important to this view;

  • the unique operation of the satellite uplink and downlink in the same frequency band ("time division duplex"),
  • the date priority enjoyed by the particular MSS filing, and
  • the primary allocation status of the uplink.

–             View 2: The synchronization and the channel assignments of the uplink are managed by the satellite. It is vital for the function of this system that the downlink can be received without interruption.  That cannot be ensured with a secondary allocation. The operation of this satellite system downlink has a status of "non-interference, non-protection" vis-à-vis any primary service within the same band and in adjacent bands. Because there are no reliable coordination criteria, the allocation should not be a candidate to provide a safety-of-life aspect as required by the GMDSS.

 

 

Methods to satisfy the agenda item

The ITU_R preparatory work proposes three methods to satisfy Issue A, while it proposes four methods to satisfy Issue B.

Issue A: Modernisation of the global maritime distress and safety system (resolves to invite ITU-R 1)

Method A1

No change to the Radio Regulations.

Method A2

MF NAVDAT

The frequency band 495-505 kHz is intended to be used for international MF NAVDAT.

This method includes the removal of the limitation on the use of the bands 415-495 kHz and 505-526.5 kHz (505-510 kHz in Region 2) by radiotelegraphy only in the maritime mobile service.  It would also be possible to use these bands for national MF NAVDAT.

HF NAVDAT

This method includes WRC19 modifying RR Appendix 17. The modification would allow the frequency bands described in the most recent version of Recommendation ITU-R M.2058 to be used for the HF NAVDAT system. This method proposes that WRC19 would also develop proper regulatory provisions. These provisions would ensure compatibility of HF NAVDAT systems with digital maritime mobile systems operating in the frequency bands concerned subject to relevant existing allocations.

Method A3

MF NAVDAT

Method A3 is identical to Method A2 except that only coastal stations would be permitted to transmit MF NAVDAT. This use would be subject to obtaining agreement with affected administration using the aeronautical radionavigation service.

HF NAVDAT

Method A3 is identical to Method A2 except that only coastal stations would be permitted to transmit HF NAVDAT. This use would be subject to obtaining agreement with affected administrations.

Proponents of Method A3 consider that the transmitting power of MF NAVDAT and HF NAVDAT systems is much higher compared with that of existing systems in the maritime mobile service in the frequency bands considered. The proposed Method A3 provisions are suggested to provide for compatibility of NAVDAT systems with existing systems and services.

WRC-23 will consider the modernisation of the GMDSS after IMO has concluded its work on this topic. At that time it will be possible to consider a possible revision of RR Appendix 15.

 

Issue B: Introduction of additional satellite systems into global maritime distress and safety systems (resolves to invite ITU-R 2)

The methods are presented in the following order hereafter; B3, B1, B4, B2.

Method B3

With Method B3 No Change is proposed.

 

Method B1

Method B1 proposes that regulatory modifications would be necessary to the Radio Regulations, in order to implement the "recognition" by IMO of the system for the GMDSS. These include:

a)            A footnote in the MSS allocations to identify their use in the GMDSS;

b)            Modification of provisions RR Nos. 5.364 and 5.368 in order to avoid any inconsistency and ambiguity about the regulatory status of the maritime mobile-satellite service in the band 1 616-1 626.5 MHz when used for GMDSS.

 Method B1 proposes that a note could be associated with this band in RR Appendix 15 in order not to create a precedent.

 

Method B4

 

Proponents of Method B4 consider that a secondary allocation is not compatible with a safety service like the GMDSS. They proposed to upgrade the status from secondary to primary but solely for the frequency band 1 621.35-1 626.5 MHz. This 5.15 MHz is fully sufficient to operate the GMDSS.

Furthermore under Method B4 modifications might refer only to MMSS (space-to-Earth). This is because modifications in MSS (space-to-Earth) would be beyond the scope of WRC-19 AI 1.8. Any upgrade of the allocation for MMSS (space-to-Earth) should not be interpreted as a relaxation of the obligation to protect the radio astronomy.

The regulatory proposal for this method is as follows:

–             Upgrade the status of the band 1 621.35-1 626.5 MHz from a secondary to a primary allocation to the MMSS (space-to-Earth).

–             Identify this band 1 621.35-1 626.5 MHz in RR Appendix 15 for GMDSS purpose. Add a note as follows;

 "In addition to its availability for routine non-safety purposes, the band 1 621.35-1 626.5 MHz is used for distress and safety purposes in the Earth-to-space and space-to-Earth directions in the maritime mobile-satellite service. GMDSS distress, urgency and safety communications have priority in this band."

–             Modification of RR Nos. 5.364 and 5.368 in order to remove any ambiguity due to the upgrade of the status for the downlink segment.

–             The band 1 613.8 1 621.35 MHz will remain secondary for MSS (space-to-Earth).

–             Steps to make mandatory and quantify the protection of the radio astronomy.

 

Method B2

This method addresses the regulatory status of the band 1 616-1 626.5 MHz with respect to MSS operations in the adjacent frequency band 1 626.5-1 660.5 MHz. The adjacent band is used by transmitting MESs in GSO MSS networks, including ship earth stations used in the GMDSS.

The current allocation to MSS (space-to-Earth) in the band 1 616-1 626.5 MHz is secondary, while the MSS (Earth-to-space) allocation in the band 1 626.5-1 660.5 MHz is primary.

Method B2 supplements methods B1 and B4 with additional regulatory text. This additional text would maintain the current regulatory status with respect to GSO MSS operations in the adjacent band.

Method B2 proposes to apply an additional regulatory provision in a footnote in Article 5 of the Radio Regulations. This would state that mobile earth stations receiving in the band 1 616-1 626.5 MHz shall not claim protection from mobile earth stations transmitting in the adjacent band 1 626.5-1 660.5 MHz.

Method B2 is divided into two sub-methods: Method B2(a) and Method B2(b). These will supplement methods B1 and B4 respectively with additional regulatory text. This would maintain the current regulatory status of non-GSO MSS with respect to GSO MSS operations in the adjacent band.

Method B2(a)

This method is the same as B1 (i.e. retain the secondary status of the allocation to the MSS (space-to-Earth) in the band 1 613.8-1 626.5 MHz) except with no change to RR No. 5.364. Furthermore it adds a footnote to prevent constraints on the MSS services in the adjacent band.

Method B2(b)

Same method as B4 (i.e. upgrade the status of the allocation to the MSS (space-to-Earth) in the band 1 621.35-1 626.5 MHz to primary) and add a footnote to prevent constraints on the MSS services on adjacent band.