AIS ASM

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Overview

AIS Application-Specific Messages are transmitted and received by shipborne mobile AIS devices and AIS base stations. Shore-based stations can receive ASMs and distribute them to shore-based users.

The display capability of ASMs is not part of the mandatory functions of the Minimum Keyboard and Display (MKD). The display of the information transmitted by AIS Application-Specific Messages requires external hardware and dedicated software in addition to the AIS equipment. The generation and transmission of AIS Application-Specific Messages also requires dedicated software and suitable equipment for entering the information.

AIS may use binary messages for transmission of ASMs as a means for certain types of limited communications. ASMs may be either addressed or broadcasted. The technical characteristic and the structure of the ASMs are specified in Recommendation ITU-R M.1371. The content and format of the AIS Application-Specific Messages were tailored to different applications and were defined by IMO.

Rules/Requirements

• SN.1/Circ.289 Guidance on the use of AIS Application-Specific Messages - provides an overview of the purpose and scope of AIS Application-Specific Messages, and provides guidance on their use
• ITU-R M.1371 Technical characteristics for an automatic identification system using time-division multiple access in the VHF maritime mobile band - technical characteristics and structure of ASMs
• IEC 62288:2014 - addresses portrayal of ASMs

Manufacturer support

There is no mandatory regulatory requirement for navigation equipment such as ECDIS or Radar to display ASMs. The most recent edition of display standard IEC 62288:2014 (edition 2) addresses portrayal of ASMs by standardising symbolisation, but this standard was published in 2014 and will take time to be implemented on board (through new/replacement equipment), and furthermore it does not address operational implementation nor provide detail on display of the associated data. Ultimately it is still down to the equipment provider whether or not to implement display of ASMs in their equipment.

In the absence of mandatory requirements, adoption of ASM display requirements by ECDIS providers must be customer-driven. General consensus amongst the CIRM members who have commented on this matter in the past is that their customers are not demanding this functionality, and so they have not implemented these requirements. However some members have been developing this functionality, noting that carry-on ‘portable pilot units’ (PPUs) are being used as a platform for testing at present, mainly because PPUs are not subject to the same SOLAS regulatory processes that control navigation products like ECDIS and Radar.

Lack of global implementation of ASMs

While the met-hydro ASM has been defined, only recently have sources been providing data on other than testbed basis. Members have reported that the US (through the NOAA PORTS system), Canada (through the CCG), UK (through the PLA) and Sweden are some of the only countries currently providing met/hydro data. There is no IMO-mandated global implementation plan. Furthermore there is an impression that the shore infrastructure may not be ready for transmitting the met/hydro data as a complete package. One company reported that they had software supporting display of message FI 31 (Hydro/Meteo) in accordance with SN.1/Circ.289 for a couple of years, but when the data was received and displayed, many fields were blank.