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Determining Requirements for Shipboard Display of Automatic Identification System Information

Displays fulfill different purposes depending on the operators who use them and the displays’ operational settings. The purposes are often identified by display designers and developers in requirements documents that define the functionality, services, and support that must be provided by a display. Requirements are derived from many sources—a display’s users, customers, designers, regulators, developers, and operating and technical environment. Each source may provide a different view of the functionality, services, and support required of a display. Requirements documents, thus, are the aggregate of those views, identified by source, and prioritized to reflect a composite view of what a display must do or provide.

Existing requirements for shipboard display of automatic identification system (AIS) information are described in this chapter, and an analysis of the requirements inventory with respect to three types of conceptual AIS is given. A catalog of existing requirements for shipboard display of AIS information is provided in Appendix C.

DETERMINING REQUIREMENTS FOR SHIPBOARD DISPLAY OF AIS INFORMATION

System design and development processes have evolved considerably over the past 50 years and generally follow the steps outlined in Figure 4-1. Problem and requirements analysis is a traditional first step in system design and development. Next, conceptual or logical models of the system are developed. The conceptual models are then compared with, or mapped to, the requirements to identify any needed changes. Improvements to the conceptual models are identified, and physical prototypes or designs are developed. The design is then developed into a system, implemented, maintained, and supported, as seen in Figure 4-1.

These steps are followed in the design and development of new displays, as well as in analysis, design, or review of existing displays such as AIS. Following such a process with an existing display can provide insights about



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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 4 Determining Requirements for Shipboard Display of Automatic Identification System Information Displays fulfill different purposes depending on the operators who use them and the displays’ operational settings. The purposes are often identified by display designers and developers in requirements documents that define the functionality, services, and support that must be provided by a display. Requirements are derived from many sources—a display’s users, customers, designers, regulators, developers, and operating and technical environment. Each source may provide a different view of the functionality, services, and support required of a display. Requirements documents, thus, are the aggregate of those views, identified by source, and prioritized to reflect a composite view of what a display must do or provide. Existing requirements for shipboard display of automatic identification system (AIS) information are described in this chapter, and an analysis of the requirements inventory with respect to three types of conceptual AIS is given. A catalog of existing requirements for shipboard display of AIS information is provided in Appendix C. DETERMINING REQUIREMENTS FOR SHIPBOARD DISPLAY OF AIS INFORMATION System design and development processes have evolved considerably over the past 50 years and generally follow the steps outlined in Figure 4-1. Problem and requirements analysis is a traditional first step in system design and development. Next, conceptual or logical models of the system are developed. The conceptual models are then compared with, or mapped to, the requirements to identify any needed changes. Improvements to the conceptual models are identified, and physical prototypes or designs are developed. The design is then developed into a system, implemented, maintained, and supported, as seen in Figure 4-1. These steps are followed in the design and development of new displays, as well as in analysis, design, or review of existing displays such as AIS. Following such a process with an existing display can provide insights about

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 FIGURE 4-1 System design and development process. missing, conflicting, or infeasible requirements, and can identify disconnects between requirements for the display and existing designs. Improvements or modifications of existing designs and requirements may result from these analyses. The core elements of the human factors design process—understand the user and the demands of the operational environment, design a system on the basis of human factors principles, and evaluate the system to ensure that it meets the needs of the user—are outlined in Chapter 5. These human factors design activities are integral elements of the overall system design and development process, as shown in Figure 4-1. Comprehensive system design and development processes incorporate system and human factors design activities to design and develop robust, effective, and useful systems. The committee performed an inventory of existing AIS display requirements (Step 1 in the design process). Requirements for high-level conceptual models for AIS display—Class A, Class B, and Class A derivative AIS—have been articulated by the International Electrotechnical Commission (IEC) (IEC 2001) and other standards bodies. These were the conceptual designs utilized in Step 2 of the design process. The inventoried AIS shipboard display requirements were then mapped to the AIS conceptual designs (Step 3),

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 and insights resulting from the analysis provided input to committee deliberations about shipboard display of AIS information (Step 4). Following such a process offered a number of advantages: An aggregate view of existing AIS display requirements was developed. The process provided a mechanism for determining missing, conflicting, overlapping, or infeasible requirements, as well as patterns and similarities in requirements and conceptual designs. Because the steps and the outputs associated with the process are standardized, the process is replicable, which suggests that the reliability of the analysis and results may be enhanced. Finally, the process provides a mechanism to trace changes in requirements over time. This is particularly useful when system requirements are changing and when many parties provide input to the design of a system, as in the AIS development process. Performing an inventory of existing AIS display requirements provided an archive of articulated AIS display needs. Identifying sources for those requirements enhances auditability and accountability, so that changes in AIS display requirements and their sources can be tracked over time. Analysis of AIS display requirements with respect to AIS conceptual designs permits consideration of the importance of different requirements in different operational settings [e.g., International Convention for the Safety of Life at Sea (SOLAS) and non-SOLAS vessel use of AIS]. Missing, needed, infeasible, costly, or unresponsive requirements could thus be identified. The use of conceptual or logical AIS display models assists in identifying the adequacy of display requirements for different conceptual designs (e.g., Class A, Class B, and Class A derivative AIS) rather than the adequacy of a particular manufacturer’s display. The use of conceptual display models broadens the generality of the recommendations and allows those recommendations to extend beyond the current suite of AIS displays to future systems by considering interface, display, and control options independent of existing physical displays. The committee did not independently develop requirements for shipboard display of AIS information, but rather surveyed existing requirements to determine their adequacy. Although international standards bodies and

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 manufacturers, among others, have developed AIS displays and requirements for those displays, there is need to supplement, revise, and reconsider the existing requirements as well as to develop new requirements. Computer-aided software engineering (CASE) tools are useful in display design and development as electronic repositories for system requirements, as well as for logical and physical design models. The use of CASE tools promises to improve the quality of the designs and systems developed, increase the speed of design and development, improve the ease and integrity of analysis and modeling through automated checking, and improve the quality and completeness of system documentation (Hoffer et al. 2002). Moreover, CASE tools allow reuse of frequently utilized requirements, standards, and models. Thus, capturing system requirements and models electronically is a desirable goal, particularly for regulatory agencies with technology development and management responsibilities. The use of CASE tools can significantly reduce requirements, data, and model redundancy; permit requirements and model analysis across different vessel types, hardware, and software platforms; improve the economy of system models and requirements determination; and encourage component and system reuse. The U.S. Coast Guard (USCG) should utilize CASE tools in future requirements and standards specification activities. INVENTORY OF EXISTING AIS REQUIREMENTS The existing AIS display requirements, listed in Appendix C, are grouped into six categories: Information and task requirements—requirements that define the nature and type of information to be handled by the AIS display and the tasks to be supported by that information. Requirements in this category identify the nature, type, volume, and size of information to be displayed; minimum information requirements are included. The category also describes target discrimination and message requirements. Operational and organizational requirements—shipboard display requirements that result from the operating environment, culture, and expectations within which the AIS display will be used. Requirements for display of different port or waterway information, traffic management or vessel traffic service (VTS) information, and information to satisfy any re-

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 gulations or security requirements in effect are included. The category includes requirements to provide display support for different types of waterway users—for example, deep-sea ships and inland vessels. Another example in this category would be differing requirements for display of security, privacy, and safety information in different operational settings. The category includes organizational requirements—those requirements related to needs of the AIS host or parent environment and requirements related to local, state, national, or international policies and procedures. Technical display requirements—display requirements dictated by AIS display and control technologies: hardware, software, databases, networks, storage, and processing requirements. This category includes requirements for display performance, accuracy, reliability, maintainability, availability, integrity, loading, and clutter. The category also includes requirements for future AIS displays. Display format requirements—requirements for the appearance and configuration of AIS displays. Visual presentation, display options, symbology, display synchronization, presentation priority, and alarm requirements are included in this category. The category also includes requirements for display location (in X–Y space or superimposed), color, dimensionality (planar versus perspective, mono versus stereo), motion, intensity (display brightness), coding (color, size, and shape; analog and digital coding; analog and graphics versus text), modality (vision versus audition), contrast, and labeling (Wickens et al. 2003). The category covers requirements to support user expectations, user control, user help and error support, display customizability, and user interaction styles (e.g., menus, links, dialog boxes). Formats for navigation displays include requirements for route lists or command displays, chart legibility and clutter, position representation, chart orientation and scale, and support for planning and visualization (Wickens et al. 2003). Physical layout requirements—requirements for physical engineering and appearance of the display, including numbers and types of displays and display surfaces; display integration; display controls; and requirements for display lighting, sound and noise, thermal conditions, heating, and ventilation, for example. Environmental requirements—requirements for robustness of AIS display packaging with respect to environmental conditions. Requirements for

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 displays to pass packaging, emission, vibration, humidity, temperature, ruggedability, pollution, and contamination tests are included. Four types of information about the requirements are contained in Appendix C: A categorization of the type of requirement (information and task, operational and organizational, etc.); A description of the requirement; An operationalization or definition of the requirement in the form, “The AIS display shall …”; and An indication of the source of the requirement. Each display requirement described in Appendix C is numbered sequentially and is identified by source, which provides identification, traceability, and auditability for the requirements (Wiegers 1999). Traceability is helpful because the AIS display requirements were inventoried from several sources. A bibliography of sources is provided in the references to the requirements table in Appendix C. The AIS display requirements describe the functionality and information to be provided by different types of AIS displays, as well as the context and constraints within which the displays will operate. The following section contains an analysis of those requirements. REQUIREMENTS ANALYSIS The inventory of requirements for shipboard display of AIS information was analyzed with respect to three AIS conceptual designs: Class A SOLAS vessel displays, Class A derivative displays [e.g., personal pilot units (PPUs)], and Class B (non-SOLAS vessel) displays. The purpose of the analysis was to assess the adequacy of existing requirements for shipboard display of AIS information, which is discussed in the following sections.

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Information and Task Requirements Information and task requirements define the nature and type of information to be handled by the AIS display and the tasks to be supported by that information. Requirements in this category identify the nature, type, volume, and size of information to be displayed; minimum information requirements are included. The category also describes target discrimination and message requirements. Some of the information to be transmitted by AIS may be available in existing navigational equipment aboard the bridges of ships. Thus, determining the information requirements for AIS displays is an important first step in developing effective displays. Future activities for the determination of AIS information should consider the overlap in available information among existing and future navigational equipment and appropriate integration or information allocation strategies. Functional Requirements Displays of AIS information are to be used to assist in collision avoidance, to provide information about the vessel and its cargo, and to assist in vessel traffic management. As described previously, at a minimum, three types of core, representative information are to be displayed by AIS: static information, dynamic information, and voyage-related information. Static information is the relatively permanent information that pertains to a particular vessel—its name, call sign, merchant marine station identifier (MMSI) number, type of ship, and so forth. Static information can be used for identification [vessel name, call sign, MMSI number, type of ship, International Maritime Organization (IMO) number, etc.], for collision avoidance (length, beam, antenna location), and for vessel traffic management (length, beam, antenna location) (see Figure 4-2). The AIS information transmitted can support several functions; for instance, vessel length and beam information can be used for identification as well as for collision avoidance. Moreover, static, dynamic, and voyage-related information may be categorized differently in different operational settings. For instance, in inland waters, “static” information such as vessel length, beam, or cargo may change by port call, thus becoming “dynamic” information. As a result, assumptions about the nature and type of static,

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 FIGURE 4-2 Representative AIS data elements, functions, and information. dynamic, and voyage-related information may be different in different operational settings. Dynamic information provides the vessel and waterway context that permits the mariner to maintain orientation in the harbor, accurately fix and track the vessel’s position, understand other vessels’ movements and tracks, appreciate how other vessels’ characteristics can affect maneuvering or a transit, and understand and anticipate the dynamic characteristics of the environment. Dynamic information can be used for vessel identification (cargo), collision avoidance (course, heading, speed, position, length/beam, rate of turn), and vessel traffic management (navigational status, weather) (see Figure 4-2). Voyage-related information is acquired before and during a particular transit. It includes data on the vessel, the environment, the waterway, and their interactions under the conditions of a specific transit. Voyage-related information can be used for identification (cargo), collision avoidance (draft), and vessel traffic management [hazardous cargo, draft, estimated time of arrival (ETA), and route plan]. The use of these three types of informa-

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 tion is essential to ship navigation (Huffner 1978; Farnsworth and Young 1988; Hutchins 1995; Grabowski and Wallace 1993; Grabowski and Sanborn 2001). Other information may also be transmitted as required by a port or waterway or by prevailing circumstances that require transmission of important information to the mariner, in addition to the static, dynamic, and voyage-related information just described. Other AIS information, such as real-time weather, environmental, and surface data, as well as local port security notices, is currently ill defined. This information may be particular to a port, waterway, environmental condition, or a port state, and further definition is needed. Table 4-1 summarizes the inventory of AIS requirements. As indicated in Table 4-1, eight functional requirements for Class A AIS information were identified: a Class A AIS is intended to provide identification, navigation information, and vessel’s current intentions to other ships and to shore. As such, the AIS must autonomously and continuously provide ship-to-ship collision avoidance information, as well as positional and maneuvering information at a data rate adequate to facilitate accurate track-keeping. Class A AIS units must be capable of sending ship information such as identification, position, course, speed, ship length, draft, ship type, and cargo information to other ships and aircraft and to the shore. They must also be able to receive and process information from other sources, including information from a competent authority and from other ships. Class A AIS units must respond to high-priority and safety-related calls with a minimum of delay. No functional requirements for Class B were identified by the committee. Two functional requirements for Class A derivative AIS were identified, but the requirements are lacking: Class A derivatives are not clearly defined in any of the AIS-related documents. Class A derivatives may be the result of any local or international development of AIS for particular uses—for example, in inland and coastal navigation, in PPUs, and in harbors for service vessels such as tugs, buoy tenders, hydrographic ships, and pilot vessels. Class A derivatives are intended to use the same functionality and reporting rate as the Class A stations on the VHF data link (VDL) message level. The main difference between Class A and Class A derivative AIS is that not all mandatory components of Class A AIS stations must be included. However, these

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 TABLE 4-1 Requirements by AIS Class Requirement Type Class A Class B Class A Derivative 1.0 Information and Task Requirements 1.1 Functional X (8)   X (2) 1.2–1.4 Minimum keyboard and display X (27) X (2) X (3) 1.5 Target discrimination X (3)     1.6 Additional information X (5)     1.7 Messages   X (2)   1.7.1 Short safety-related X (7)     1.7.2 Aids to navigation X (3)     1.7.3 Advice to VTS/route plan X (3)     1.7.4 Class B       2.0 Operational and Organizational Requirements 2.1 Operational X (8)     2.2 Security       2.3 Privacy       2.4 Port/waterway       2.5 Organizational       2.6 Regulatory       3.0 Technical Display Requirements 3.1 Display performance       3.2 Display accuracy       3.3 Display reliability       3.4 Display maintainability       3.5 Display availability       3.6 Display integrity       3.7 Display loading       3.8 Display hardware, software, networks, etc.       3.9 Future displays—growth      

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Requirement Type Class A Class B Class A Derivative 4.0 Display Format 4.1–4.3 Visual presentation X (15) X (1) X (2) 4.4 Display options X (18)     4.5 Symbology X (5)     4.6 Display synchronization X (1)     4.7 Presentation priority X (6)     4.8 Display alarms X (3)     4.9 Display location       4.10 Use of sound and color       4.11 Display dimensionality       4.12 Display motion       4.13 Display intensity       4.14 Display coding       4.15 Display modality       4.16 Display contrast       4.17 User interaction style       4.18 User help and error support       4.19 Display labeling       4.20 User control       4.21 User expectations       4.22 Display customizability       4.23 Chart legibility       4.24 Chart decluttering       4.25 Position representation       4.26 Chart orientation       4.27 Chart scale       4.28 Visualization support       4.29 Planning support      

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 symbology, display synchronization, presentation priority, and alarms, as well as requirements to meet user expectations, user control, user help and error support, display customization, and user interaction styles (e.g., menus, links, dialog boxes). They also include requirements for display location (in X–Y space or superimposed), color, dimensionality (planar versus perspective, mono versus stereo), motion, intensity (display brightness), coding (color, size, and shape; analog and digital coding; analog and graphics versus text), modality (visual, auditory, haptic, etc.), contrast, and labeling (Wickens et al. 2003). Display formats for navigation displays include requirements for route lists or command displays, chart legibility and clutter, position representation, chart orientation and scale, and support for planning and visualization. Forty-eight Class A display format requirements, 1 Class B display format requirement, and 2 Class A derivative display format requirements were identified. Most (36) were visual presentation and display option requirements. Additional display format requirements are needed, especially those that reference or follow existing international standards and guidelines for visual display terminals (ANSI 2002). No international standards or guidelines were referenced by existing AIS documentation and standards. As can be seen in Table 4-1, display format requirements for all classes of AIS displays are needed. USCG should develop display format requirements for shipboard display of AIS information after its assessment of mariner information needs, referencing existing international human factors and display format standards where applicable. Visual Presentation Requirements Fifteen Class A visual presentation requirements were identified. They state that if Class A AIS information is presented graphically, at least the following information shall be provided: Vessel position, Course over ground, Speed over ground, Heading, and Rate of turn (or direction of turn).

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Moreover, Class A AIS visual presentation requirements state that if Class A AIS information is presented graphically on a radar display, radar signals should not be masked, obscured, or degraded. The graphical properties of other target vectors must be equivalent to those of the AIS target symbols, and the type of vector presentation (radar plotting symbols or AIS symbols) should be selectable by the operator. Active display modes on Class A AIS units should be indicated on graphical displays, and a common reference point for superimposition of AIS symbols with other information on the same display and for calculation of target properties [i.e., closest point of approach (CPA), time to CPA (TCPA)] should be utilized. Class A AIS positional information must be displayed relative to the observing vessel, and indications should be provided if own AIS is out of service or switched off. More capable Class A displays are encouraged in the requirements because of the greater functionality provided by such displays, but selection of display types is dependent on the user requirements and options offered by manufacturers. Visual overloading of AIS display screens is to be avoided. Other visual presentation requirements for Class A shipboard AIS displays are needed. For instance, although requirements exist for the transmission of waypoint data from shore stations to ships, there are as yet no requirements for the visual presentation of that information. Visual presentation requirements for Class A AIS units should be defined following completion of USCG’s assessment of mariners’ information needs for shipboard display of AIS information. Two Class A derivative requirements for visual presentation exist. First, there is no requirement for Class A derivative AIS units to carry the same presentation interfaces as Class A stations. Second, the position information for Class A derivative stations may be derived from the internal (D)GNSS receiver. These are clearly inadequate requirements for visual presentation of Class A derivative AIS information. Similarly, a single Class B AIS visual presentation requirement was identified: there may be other equipment on board non-SOLAS vessels with interfaces that are noncompliant with IEC 61162-1 standard (i.e., RS-232). Thus, there is also a need to develop visual presentation requirements for shipboard display of AIS information for Class B and Class A derivative AIS. These requirements should be defined after completion of USCG’s assessment of mariners’ information needs for shipboard display of AIS information.

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Display Option Requirements Eighteen Class A display option requirements but no Class B or Class A derivative display option requirements were identified. On Class A AIS units, operators may choose to display all or any AIS targets for graphical presentation. When they do so, the mode of presentation should be indicated. If color fill is used in display of AIS target symbols, no other information should be masked or obscured. On Class A units, AIS symbols for activated targets may be replaced by a scaled ship symbol on a large scale/small range display. Furthermore, means should be provided to select a target or own ship for display of its AIS information on request, and if more than one target is selected, the relevant symbols, corresponding data, and source of the data (e.g., AIS, radar) should be clearly identified. If zones or limits for automatic target acquisition for Class A AIS are set, the requirements state that they should be the same for automatically activating and presenting any targets, regardless of their source. In addition, the vector time set should be adjustable and valid for presentation of any target, regardless of its source. If radar plotting aids are used for display of AIS information on Class A units, they should be capable of calculating and displaying collision parameters equivalent to the available radar plotting functions. Class A AIS display option requirements also state that if the calculated CPA and TCPA values of an AIS target are less than the set limits, a target of concern symbol should be displayed. Means to recover data for a number of last acknowledged lost targets may be provided; preferably, the ability to recover data for targets may be applied to any AIS target within a certain distance. Class A AIS units should permit operators to make reasonable changes to the default parameters of automatic selection criteria, and means should be provided to display alarm messages from own AIS stations. Further display option requirements are needed. Display option requirements for Class A, Class B, and Class A derivative AIS should be defined after completion of USCG’s assessment of mariners’ information needs for shipboard display of AIS information. Symbology Requirements Class A AIS symbology requirements are simply stated: if AIS information is graphically presented, the symbols described in the appendix to IMO SN/ Circular 217 (IMO 2001) and repeated in the Appendix 4-1 of the International Association of Aids to Navigation and Lighthouse Authorities (IALA)

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 AIS guidelines (IALA 2001) should be applied. However, no Class A derivative or Class B AIS symbology requirements were defined. If the intent is to extend Class A AIS symbology requirements to Class A derivative or Class B AIS units, or both, that extension should be made explicit. If exceptions to the Class A AIS symbology requirements are to be made for Class A derivative and Class B AIS units, those exceptions should also be so noted. In any event, further work is required to define symbology requirements for all classes of AIS. The committee identified symbology requirements for ship targets during its inventory, but not symbology requirements for other types of AIS information—vessel tracklines, for instance. IEC Technical Committee 80 Working Group 13 (IEC 2001), among others, is working on the development of additional AIS symbology, and much work in chart and map symbology has been done in other domains. AIS symbology requirements should leverage this earlier and ongoing work as requirements for shipboard display of Class A, Class B, and Class A derivative AIS information are developed. USCG should participate in international discussions on developing standards for AIS symbology. USCG should integrate standards as guides to developing symbology requirements for shipboard display of AIS information in different operational environments. These symbology requirements should conform to international and other standards for symbology. USCG should leverage earlier work in symbology development and follow international procedures [i.e., ISO TR 7239 (ISO 1984)] in developing symbology requirements. Display Synchronization, Presentation Priority, and Alarm Requirements One display synchronization, six presentation priority, and three alarm requirements were identified for Class A AIS, but no such requirements were identified for Class B or Class A derivative AIS units. The single Class A AIS display synchronization requirement states that if AIS information is graphically displayed on a radar, the equipment should be capable of appropriately stabilizing the radar image and the AIS information. Six Class A presentation priority requirements were identified. The presentation of AIS target symbols, except for sleeping or lost targets, should have priority over other target presentations within the display area. Automatic display selection functions may be provided to avoid presentation of

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 two target symbols for the same physical target. If target data from AIS and radar plotting functions are available and the automatic selection criteria are fulfilled, then the activated AIS target symbol should be presented. In contrast, if target data from AIS and radar plotting functions are available and the automatic selection criteria are not fulfilled, the respective symbols should be displayed separately. The Class A AIS requirements further specify that mariners should be able to select additional parts of information from AIS targets, such as ship’s identification (at least the MMSI); those additional parts of information should be presented in the data area of display. An indication should be given if the additional information from AIS targets is incomplete. The three Class A AIS alarm requirements identified indicate that alarms should be provided if the calculated CPA and TCPA values of an AIS target are less than the set limits, as well as when the signal of an AIS target of concern is not received for a set time. Means should be provided to acknowledge alarm messages from own Class A AIS. No Class B or Class A derivative requirements for display synchronization, presentation priority, or alarms were identified. Thus, such requirements must be developed. In addition, alarm requirements for all classes of AIS displays should be reviewed, because existing requirements for AIS display alarms focus on the visual and auditory senses. USCG should consider alternative modes for alarms and consider alarm design in the context of existing alarms and ambient noise on the bridges of ships in different operational settings. Target discrimination, display synchronization, presentation priority, and alarm requirements for all classes of AIS should be developed by USCG. The committee did not find any requirements for configuration of AIS displays, including display location, color, dimensionality, motion, intensity, coding, modality, contrast, user expectations, user control, user help and error support, user interaction style, or display customizability. Furthermore, display format requirements for navigation displays, such as chart legibility or decluttering, position representation, and chart orientation and scale, and for support for visualization and planning were not found. These requirements are well-known needs for display format and need to be developed for all classes of AIS displays (Wickens et al. 2003; ANSI 2002). Thus, USCG should develop requirements for all of these display format items for all classes of shipboard AIS.

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Physical Layout Requirements General Physical layout requirements include requirements for physical engineering and appearance of the display, including numbers and types of displays and display surfaces; display integration; display controls; and requirements for display sound and noise, lighting, thermal conditions, heating, and ventilation, for example. Only six display integration requirements for Class A AIS and one Class A derivative display integration requirement were found. No other physical layout requirements for shipboard display of AIS information were identified. Thus, USCG should develop physical layout requirements, including display integration requirements, for all classes of AIS. Display Integration Requirements The Class A AIS integration requirements stipulate that AIS displays should be integrated with one of the existing graphical displays on the bridge or presented on a dedicated graphical display. Ideally, AIS would be displayed on the ship’s radar, ECDIS, or a dedicated display. Per existing integration requirements, Class A AIS display integration options may include connections to external GNSS/DGNSS equipment and sources of navigational information from ship’s equipment. The shipboard AIS is required to be connected to a power source, an antenna, and a variety of shipboard equipment, or to the integrated navigation system. Class A derivative AIS units are described in the IALA AIS guidelines as a pilot workstation combined with portable AIS that is used primarily to provide marine pilots with the capability to carry on board an AIS station when they are piloting vessels not fitted with an AIS. Such a pilot pack contains GNSS/DGNSS, AIS (optional), heading sensor, and a workstation. Class A derivatives were considered to be portable AIS units carried aboard a vessel for the purpose of meeting the vessel’s AIS carriage requirements, while PPUs brought aboard vessels for a pilot’s personal use, not to satisfy an AIS carriage requirement, were not considered to be covered by requirements for Class A derivatives. There is a proliferation of stand-alone electronic navigation equipment aboard the bridges of modern vessels. Under such conditions, operators must integrate information from different sources, scales, and sensors, and they must make decisions on the basis of that information in time-critical

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 situations. Equipment randomly placed in available space on the bridge can increase mariners’ difficulty in accessing needed information and can add to operator distraction. International committees are currently exploring standards and guidelines for integrated bridge systems. These trends highlight the need to identify and consider mariners’ information needs in different operational settings when display integration requirements are developed. Such requirements are needed; USCG should develop them. Environmental Requirements Environmental requirements include requirements for robustness of AIS display packaging with respect to environmental conditions. Requirements for displays to pass packaging, emission, vibration, humidity, temperature, ruggedability (i.e., robustness), pollution, and contamination tests are included. No such requirements exist; thus, USCG should develop them for all classes of shipboard display of AIS information. SUMMARY Table 4-1 summarizes the inventory of existing requirements for shipboard display of AIS information by class of AIS. The table indicates that some information and display format requirements have been developed for Class A AIS, but much work remains to be done. The committee did not independently develop requirements for shipboard display of AIS information. Instead, it surveyed existing requirements, standards, and guidelines to determine whether they are adequate to cover all aspects of design and meet the needs of a display user. Although international standards bodies and manufacturers, among others, have been developing AIS displays and requirements for them, most need to be supplemented, revised, or reconsidered. In addition, new requirements for shipboard display of AIS information are needed for different vessel classes and operating environments. In the analysis, CASE tools that are useful in display design and development were identified. CASE tools provide an electronic repository for system requirements, as well as for logical and physical design models. The use of CASE tools can significantly reduce requirements, data, and model redundancy; permit requirements and model analysis across different vessel types, hardware, and software platforms; improve the economy of system models

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 and requirements determination; and encourage component and system reuse. USCG could also use CASE and other electronic requirements and modeling tools in its requirements and standards specification activities. Some of the information to be transmitted by AIS may be available in other existing navigational equipment aboard the bridges of ships. Thus, determining the information requirements for AIS displays is an important first step in developing effective displays. This indicates that USCG can also consider the overlap in available information among existing and future navigational equipment and develop appropriate integration or information assignment strategies in its standards-setting process. The MKD requirements, by definition, contain a limited amount of information. However, the committee believes that the size and limited nature of the text-only display, coupled with the operator manipulation and information transposition required (e.g., the requirement for operators to transpose text information from the MKD into spatial information for decision making), render the MKD inadequate to meet the needs of mariners in different operational settings. These limitations, and others, suggest that USCG should determine such needs and revise or reevaluate the minimum display requirements accordingly. There is also a need to develop visual presentation requirements for all classes of shipboard AIS displays. For example, although requirements exist for the transmission of waypoint data from shore stations to ships, there are no requirements for how that information is to be presented visually. In the same manner, there is a need to develop display option requirements for shipboard displays. International bodies have been working on the development of additional AIS display symbology. In addition, much work in chart and map symbology has been done in other domains. However, symbology requirements for shipboard display of Class A, Class B, and Class A derivative AIS information are not now completed, and much more work is needed. USCG could participate in international discussions on developing standards for AIS symbology. It could also integrate standards as guides to developing symbology requirements. Symbology requirements should conform to international and other standards. USCG could leverage earlier work in symbology development and follow international procedures in developing symbology requirements.

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Existing requirements for alarms and alerts for shipboard display of AIS information focus on the visual and auditory senses only. A body of work outside the marine field has investigated and applied alternative human interface modes (e.g., by utilizing senses other than, or in addition to, the visual and auditory senses). USCG could consider alternative modes for alarms and consider alarm design in the context of existing alarms and ambient noise on the bridges of ships in different operational settings. Another important topic is display integration requirements. Stand-alone units of electronic navigation equipment are proliferating aboard the bridges of modern vessels. Under such circumstances, operators must integrate information from different sources, scales, and sensors, and they must make decisions on the basis of that information in time-critical situations. Equipment randomly placed in available space on the bridge can increase the difficulty in accessing needed information and can add to operator distraction. International committees are currently exploring standards and guidelines for integrated bridge systems. These trends highlight the need to identify and consider mariners’ information needs in different operational settings when integration requirements for shipboard display of AIS information are developed. There is a need to define requirements for safety-related messages more carefully to avoid overload of AIS with messages that might better be sent through other media. USCG should consider the appropriateness of different modes and media for transmission of such information. USCG’s standards-setting process should consider the importance of local information in safety-related messages in a particular port or waterway. Short safety-related messages have the potential to distract operators from their primary duties, and therefore USCG should consider appropriate message traffic types, levels, loading, and communication requirements. Information may be categorized differently in different operational settings. For instance, in inland waters, “static” information such as vessel length, beam, or cargo may change by port call. Thus, assumptions about the nature and type of static, dynamic, and voyage-related information may be different in different operational settings. Some of the information to be transmitted by AIS may be available in other existing navigational equipment aboard the bridges of ships. Thus, determining the information requirements for AIS displays is an important first step in developing effective displays.

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Given these factors, USCG activities for the determination of requirements for AIS information should consider the overlap in available information among existing and future navigational equipment and appropriate integration or information assignment strategies. No current or future technical display requirements were found for any class of AIS. AIS technical display requirements also include requirements to accommodate future interfaces, displays, and technology. AIS technical display requirements are needed for all classes of AIS and for different operational settings. Thus, USCG should develop technical display requirements as part of its standards-setting process. USCG should investigate future display requirements as part of its research program. USCG standards-setting and requirements processes should be flexible in order to accommodate and adjust to future capabilities, displays, controls, and technology. Finally, no display format, physical layout, or environmental display requirements for shipboard display of AIS information for any type of vessel or class of AIS exist. Therefore, such requirements are needed. REFERENCES Abbreviations ANSI American National Standards Institute IALA International Association of Aids to Navigation and Lighthouse Authorities IEC International Electrotechnical Commission IMO International Maritime Organization ISO International Standards Organization MIT Massachusetts Institute of Technology ANSI. 2002. Human Factors Engineering of Computer Workstations. BSR/HFES 100. Human Factors and Ergonomics Society, Santa Monica, Calif. Farnsworth, B. A., and L. C. Young. 1988. Nautical Rules of the Road: The International and Unified Inland Rules, 3rd ed. Cornell Maritime Press, Centreville, Md. Grabowski, M. R., and S. D. Sanborn. 2001. Evaluation of Embedded Intelligent Real-Time Systems. Decision Sciences, Vol. 32, No. 1, pp. 95–123. Grabowski, M. R., and W. A. Wallace. 1993. An Expert System for Maritime Pilots: Its Design and Assessment Using Gaming. Management Science, Vol. 39, No. 12, pp. 1506–1520. Hoffer, J. A., J. F. George, and J. S. Valacich. 2002. Modern Systems Analysis and Design, 3rd ed. Prentice Hall, Inc., Upper Saddle River, N.J. Huffner, J. R. 1978. Pilotage in the Port of New York. Report CG-D-81-78. Office of Research and Development, U.S. Coast Guard, Washington, D.C.

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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Hutchins, E. 1995. Cognition in the Wild. MIT Press, Cambridge, Mass. IALA. 2001. Draft Interim Guidelines on Universal Shipborne Automatic Identification System (AIS). AIS10/5/3. Oct. 31. www.uscg.mil/hq/g-a/avt/documents/PDF/AIS%20Guidelines,%2010-31-01.pdf. IEC. 2001. IEC 61993 Part 2: Universal Shipborne Automatic Identification System (AIS). Operational and Performance Requirements, Methods of Testing and Required Test Results. IEC/TC80/WG8. Geneva, Switzerland, June. IMO. 2001. Interim Guidelines for the Presentation and Display of AIS Target Information. SN/Circular 217. London, July 11. ISO. 1984. Development and Principles for Application of Public Information Symbols. Geneva, Switzerland. MIT. 2002. Wearable Computing Project. www.media.mit.edu/wearable. Rifkin, J. 2002. The Hydrogen Economy. Basic Books, New York. Wickens, C. D., S. E. Gordon, and Y. Liu. 2003. An Introduction to Human Factors Engineering. Longman/Addison-Wesley, New York. Wiegers, K. 1999. Writing Quality Requirements. Software Development, May, pp. 45–48. www.sdmagazine.com.