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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Executive Summary Over the next several years, commercial vessels worldwide, operating on the high seas and in coastal and inland waterways, will begin to carry new technology, known as automatic identification systems (AIS), that promises to enhance the safety of navigation and allow traffic managers to do their jobs more safely and effectively. AIS is essentially a communications medium that automatically provides vessel position and other data to other vessels and shore stations and facilitates the communication of vessel traffic management and navigational safety data from designated shore stations to vessels. The onboard “AIS unit” (which consists of a VHF-FM transceiver, an assembly unit, and a communications transceiver) continuously and automatically broadcasts identification, location, and other vessel voyage data, and receives messages from other ships and shore stations. Three functions have been identified by the International Maritime Organization (IMO) for AIS: (a) to serve as a collision-avoidance tool while the system is operating in the vessel-to-vessel mode, (b) to provide information about a vessel and its cargo to local authorities who oversee waterborne trade, and (c) to assist those authorities engaged in vessel traffic management. As AIS technology and its applications evolve, additional useful and beneficial functions of AIS will most likely also evolve. Over the past few years, IMO, working through the International Telecommunication Union and other organizations, has published technical and operational standards for AIS; however, these standards do not address shipboard displays, except for a minimum alphanumeric presentation. For international shipping, AIS equipment requirements, including an implementation schedule, have been established through an amendment to the International Convention for the Safety of Life at Sea (SOLAS). In the United States, where AIS technology is in the early stages of implementation and just beginning to become available within certain port and waterway regions, the U.S. Coast Guard (USCG) has the responsibility for establishing carriage requirements for AIS equipment aboard vessels in U.S. waters and aboard U.S.-flag vessels. USCG is in the process of developing rulemaking to ensure compliance of
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 SOLAS vessels in U.S. waters and concurrently developing carriage requirements for non-SOLAS vessels operating in U.S. waters. The initial SOLAS carriage requirements for oceangoing vessels do not specify any shipboard display for use by the mariner except for minimal basic numerical data. Because USCG has the responsibility in the United States for determining whether and what requirements should be established for shipboard AIS displays, it asked the Transportation Research Board (TRB)/Marine Board to undertake an investigation and analysis of the key issues affecting the design, development, and implementation of shipboard AIS displays. TRB convened a committee to address USCG’s request for guidance. Specifically, USCG asked the committee to assess the state of the art in AIS display technologies, evaluate current system designs and their capabilities, and review the relevant human factors aspects associated with operating these systems. The challenges associated with shipboard display of AIS information are addressed in this report. However, this does not cover the full spectrum of AIS challenges. For example, AIS complements traditional navigational aids; it does not replace them, nor does it substitute for good judgment or replace the need to use all available means appropriate to the prevailing circumstances and conditions to establish vessel position. Therefore, government and industry need to address the challenge of integrating existing navigation aids and, in the process, encourage the appropriate use of technology. The introduction of onboard displays of AIS information represents an opportunity for significant improvements in available knowledge and awareness of waterway and vessel traffic situations for all mariners. It is intended to result in safety and efficiency benefits. If AIS displays are thoughtfully introduced aboard ships so that mariners’ needs are met and they are not overburdened with unnecessary information, the benefits may be considerable. However, there are dangers and limitations associated with this technology that could overshadow such benefits. The committee is both encouraged at the prospects for major improvements for vessel operations with the proper display of AIS information and cautious about problems that could result from poor display of AIS information. ESTABLISHING A SYSTEMATIC IMPLEMENTATION PLAN It is important to have a plan and schedule for any process as complex and multifaceted as that for implementing AIS and their displays aboard vessels—
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 especially when there is some urgency to put needed improvements into effect. In the past, USCG has sponsored and conducted pilot tests of AIS in selected regions and has supported the introduction of AIS technology to enhance vessel traffic management and safety. However, USCG does not have a systematic plan for implementation of AIS shipboard displays in U.S. waterways or aboard U.S. vessels. A systematic implementation plan is needed, for example, because assumptions are being made about particular types of equipment that are on board and with which the AIS will need to be integrated. While this is somewhat true for SOLAS vessels, it is not true for inland and coastal vessels. In turn, requirements for integrating AIS information with information from other onboard electronic navigation systems have not been developed. This is critical because AIS and other navigation aids may provide the same type of information (e.g., another vessel’s location) but the information may conflict (e.g., the other vessel’s location identified by the AIS is different from the location for that vessel identified by radar). Thus, when AIS displays are integrated with other bridge displays, the information must be presented to the mariner in such a way that it is clear, unambiguous, and accurate. Additional work is required to determine how to best integrate existing and new systems, and this will affect the entire process of introducing AIS displays aboard vessels. Finally, USCG needs an AIS display implementation plan, schedule, and process to ensure that the underlying research will be accomplished to demonstrate the viability of the AIS display requirements and that the resulting system will meet the needs of the mariners who use it. Recommendation 1: USCG should establish an implementation plan and schedule for AIS shipboard display standards in consultation with stakeholders. Key elements of the plan should include Research in technical and human factors, Requirements determination and analysis, and Development of international and domestic standards. ESTABLISHING REQUIREMENTS FOR SHIPBOARD DISPLAYS An important challenge for achieving a functional AIS is the timing and applicability of carriage requirements. Not all vessels will carry AIS, and AIS carriage requirements will be phased in over time. Thus, especially in the
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 short term, most, if not all, vessels in a typical waterway may not be visible to (i.e., locatable) or identifiable by AIS technology. AIS requires a functioning and reliable transmitter on every vessel that is part of the system and thus requires each carrier of AIS to participate and cooperate with the protocol. While displays are the means by which AIS data are converted into useful information for the operator, little has been done to define the information needs and priorities that would establish display parameters. And ultimately, the information needed by the vessel should determine what data are transmitted, which, in turn, should drive display requirements. During the introduction of AIS in both domestic and international settings, the initial emphasis has been on the shipboard transponder and the system to ensure accurate identification and location transmissions; only recently has much attention been given to shipboard display issues. Consequently, much development work remains to be done in the form and display of both ship-and shore-originated AIS messages. Different types of information require different display strategies. The design of an AIS display interface needs to consider appropriate strategies for delivering information to the mariner in a readily cognizable form. For example, there are many different operating environments in which AIS information will be displayed: rivers and inland waterways, high-density ports with mixed traffic, coastal waterways, urban harbors with scheduled ferry and passenger vessel operations, and major commercial ports accommodating large deep-sea vessels. The mixed nature of carriage requirements for AIS, therefore, can create challenges in developing final recommendations for shipboard display of AIS information. Because of the variety of operating environments, one AIS display may not fit all situations, particularly in domestic operations, and implementation plans need to reflect that reality. For example, the operating environment will greatly affect the configuration of displays that are appropriate as well as the operator training that is adopted. And, unlike large oceangoing vessels, many smaller domestic vessels may not carry all of the equipment (such as gyrocompass or heading indicator) with which an AIS needs to interface for proper operation. These interface issues will also affect shipboard display requirements. The AIS international carriage requirements for oceangoing vessels that came into force during 2002 refer to equipment that is designated as
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 “Class A.” The international bodies have defined two other classes that would be designated for other uses: (a) “Class A derivatives,” which are portable units similar to the carry-aboard equipment now generally used by pilots in several U.S. ports and waterways; and (b) “Class B” units, which have less stringent requirements and are intended for use by domestic, inland, and coastal vessels (e.g., towboats, passenger ferries). The Class A derivative units have received the most attention in the United States because of their similarity to those that pilots have used as carry-aboard units. The definition, role, and display requirements for Class B and Class A derivative units are incompletely specified at the present time, and this will affect display requirements for such units. More analysis of Class A derivatives and Class B AIS units will be necessary before specific display requirements for these units can be established. Display standards are intended to ensure that designs meet user needs, that key requirements are understood, and that a proper certification process can be instituted for all operational units. Standardization of AIS displays is critical to the safety of navigation and the facilitation of commerce because shipping is an international business and it is essential that mariners find similar information displayed wherever they sail. The process of setting standards for AIS equipment in general is under way within international bodies for Class A units, and a similar process has begun for display systems, including the issuance of IMO interim guidelines. However, the display standards process lags the carriage requirements schedule, and much remains to be done. For example, much of the effort on shipboard displays has focused on target data in ship-to-ship use for collision avoidance, with little attention to shore-to-ship data relating to traffic management. Upon examination of existing standards and guidelines for AIS displays published by the international bodies associated with AIS and other related organizations, many gaps were found. Thus, supplementation or revision of these standards and guidelines will be needed to ensure adequate display designs. New requirements should be based on a more comprehensive and rigorous analysis as a basis for identifying operator needs and ascertaining the adequacy of displays and controls to meet those needs. The international carriage requirements for Class A AIS units for SOLAS vessels do not specify any shipboard display except for a minimal numerical system known as MKD (minimum keyboard and display). MKD is
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 inadequate to address minimal information needs of different mariners in different operational settings such as those prevailing in U.S. waters. However, because MKD is the only approved equipment, it poses the danger of becoming, by default, the accepted display until something better is approved. The committee concludes that using MKD as a shipboard display not only does not provide adequate information for the mariner but also, in some cases, could be detrimental to safe vessel navigation. It is important, therefore, to establish new minimal display standards before MKD becomes the default standard for U.S. operations. Because AIS shipboard displays will be introduced over time and for many different operating situations as well as vessel classes, USCG needs a process for establishing requirements for shipboard displays that will accommodate these variables and provide effective leadership for the maritime community. The committee has concluded that this can be accomplished by clearly establishing minimum requirements for U.S. waters and for U.S. vessels first, followed by work with appropriate international bodies to ensure compatibility with international requirements where necessary. The committee also concluded that USCG should institute a process that recognizes the evolving nature of AIS display technology and the need to accommodate future improvements and growth. Recommendation 2: USCG should establish requirements for shipboard display of AIS information in U.S. navigable waters by Defining mariner information needs, Defining key functions for AIS displays aboard different types of vessels and in different operating environments, Developing appropriate requirements for each major vessel class that take into consideration the wide differences in operating environments, Involving the key stakeholders in the entire process, and Developing a new requirement for minimum information display of AIS. USCG should take a leadership role in establishing display requirements for AIS information and work with appropriate international organizations in this process to ensure compatibility with international requirements.
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Recommendation 3: USCG should recognize the evolving nature of AIS display technology in its requirements process and allow for technological change, growth, and improvements in the future. HUMAN FACTORS IN THE DISPLAY DESIGN PROCESS For AIS to meet its stated objective of promoting safe vessel navigation, an effective onboard interface with the vessel’s operator is essential. To provide an effective interface, the focus of the design process must be on the best means to exchange information between the person and the AIS. Although the term “display” is usually used in this report in referring to this interface, it should be noted that, from the perspective of the human operator, the “interface” includes both display and control mechanisms that allow the exchange of information between the operator and the rest of the system. The interface includes not only the display of information through such means as a cathode ray tube, graphics, and auditory warnings, but also data entry and control elements such as keyboards or switches. Development of an effective human interface for the AIS requires a systematic process that considers the capabilities of users and the demands of the operating environment. Three core elements make up a typical design process with human factors as a focus: understanding, design, and evaluation. The process begins with development of an understanding for the operational demands and the needs of the mariner. This provides the basis for the initial design, which is then evaluated. The process is iterated as new factors and inevitable changes are recognized. Within the element of understanding is the notion that advanced technology can increase errors and risk even when appearing to be beneficial. This reinforces the need for attention to the human interface. It is also clear that AIS data need to be translated into decision-relevant information for the mariner. Thus it is important to understand how each task of the mariner is performed and how AIS data can support that task and, in turn, overall performance. There are substantial operating differences among the range of vessels that may be equipped with AIS, and it is clear that interface design needs to reflect that variation if it is to adequately support operator needs.
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 The second element, design, follows from the first and begins with incorporation of the large body of knowledge about human factors interface guidelines that already exists. The committee identified 13 human factors principles that are particularly relevant to AIS interface design, including ensuring that system behavior is completely visible to the operator, avoiding interface management tasks during high-tempo situations, and realizing that the representation of AIS data (e.g., graphic versus numeric) can greatly affect interpretations. Finally, the evaluation element represents the step that tests a design and its performance and leads to either initial adoption or redesign to correct a problem. Heuristic evaluation with multiple evaluators is a very useful approach in identifying design problems. In addition, usability testing and operational evaluation are complementary approaches in identifying problems. Operational evaluations are a critical aspect of this process because important display issues cannot be anticipated and are often only detected when the system is evaluated in the operating environment. Selection of an effective design process will have a large impact on how well a shipboard display and control system provides the promised benefits and avoids unexpected consequences. A combination of design, process, and performance standards is needed to ensure effective designs. Maritime technology and AIS applications will always be difficult to predict. Thus, designers must have the freedom to adapt to changes as they occur or are identified. USCG needs to allow for this in its standards-setting process. Recommendation 4: In its standards, USCG should specify that design, process, and performance standards be used in combination to promote adequate shipboard AIS display design. SYSTEM LIMITATIONS For a shipboard display to function adequately and provide necessary information to the mariner, the overall AIS and supporting infrastructure must also function reliably and accurately. However, current systems are not fail-safe. In addition, the integrity of the data supplied by the carrying vessel is not always assured for a variety of reasons. For example, there can be erroneous input from ship sensors, or the data that are manually entered by an operator can be changed or contain errors.
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Several infrastructure issues also affect the display of AIS information: transponder coverage and the spacing of shore-based repeater stations, the adequacy and accuracy of digital charting in a given waterway, the availability of existing vessel instrumentation, and the need for standardized interfaces between existing equipment. In many U.S. waterways, surveys need to be updated to prepare accurate charts, and real-time environmental and hydrological data are inadequate for providing accurate waterway forecasts. International standards development efforts have inadequately considered such infrastructure issues and have not considered the impact of infrastructure issues on shipboard display of AIS information. In addition to infrastructure, it is important to consider shipboard operating environments that will shape shipboard display of AIS information. For example, display designs will depend on such factors as the range of data that will be received by ships from shore stations; the areas and routes used by vessels with AIS; the work environment, tasks, and workload of the shipboard bridge watchstanders; and the skill levels and training of individuals using the AIS displays. These and other operating parameters affect AIS performance in general, and especially the design and implementation of shipboard displays. For example, a potential problem with the use of AIS displays aboard vessels is that the human interfaces can, in some cases, mislead operators into believing that a complex system is well represented by a simple display. Some of this risk can be addressed by good display design. However, the general problem suggests that operator training may be needed in communication systems, AIS capabilities and limitations, and AIS operations. These and other factors suggest that the identification of skill requirements and concomitant AIS training needs will be an important consideration. Recommendation 5: USCG should identify critical AIS limitations and infrastructure requirements and coordinate them with display requirements. USCG should establish a mechanism to inform all users about system limitations if they cannot be readily corrected. Recommendation 6: USCG should work with stakeholders to develop appropriate training and certification guidelines for AIS users that will lead to effective use and an understanding of system functions and limitations.
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 NEED FOR ONGOING RESEARCH ON HUMAN INTERFACES The development of AIS display and control requires a full consideration of human interface attributes that affect what information to display, how to present it to the operator, how to integrate other displays or other bridge information systems, and how to give the operator what is most needed to perform critical tasks. The term “AIS display” connotes a visual presentation of data; however, there are other methods of providing effective human interfaces that may be appropriate for shipboard use. Continuing evolution in the form and function of technology also suggests a range of presentation options for AIS information that may be appropriate in different shipboard settings. AIS interface design should be subject to further analysis and critical investigation. For example, the system image and its physical representation may determine its use. A key consideration is whether AIS data will be presented to the operator separately or will be integrated with other existing equipment and information flows. This is a key research area and has received little attention to date. On board certain vessels, AIS units need to fit within existing bridge configurations to remain within the mariner’s peripheral vision while not interfering with his or her view of the outside or other equipment. This condition might suggest that different types of AIS interfaces could be adopted, such as wearable computing devices, enhanced binoculars, or a mix of tactile and auditory devices. In addition, AIS interfaces could consider multimodal approaches in order to adequately address competing attention demands. Aboard smaller vessels, AIS visual displays will need to balance the need to be large enough to convey the necessary AIS information and small enough to fit unobtrusively among other equipment. Another consideration aboard small inland vessels is the ambient noise level in the wheelhouse that might interfere with audio signals. This effect of ambient noise on the hearing of auditory signals is not, however, limited to inland vessels. Another area of necessary research relates to whether and how mariners need to input data into the AIS during the normal conduct of vessel operations and how this might interfere with other duties. Some mariners may have limited opportunities to input data into the system, given competing demands for operational task performance and decision making, particularly
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 on board smaller vessels with one-person wheelhouses. Different types of information may require different data input strategies. Symbology for visual displays is a fertile area for research and development. While some display symbology requirements have been articulated by international bodies, they have not been harmonized across different shipboard electronic navigational displays, nor across different operating environments (e.g., from inland waterways to coastal waterways to open ocean). There are several human factors interface research topics that are particular to the operation of smaller inland and coastal vessels, including the evaluation of competing operator attention demands on board vessels with one operator, high noise levels, multiple communications links, and needs for multiple operational tasks. Furthermore, there is little commonality in bridge layouts, even for vessels of the same class, and this lack of bridge layout standardization affects potential shipboard displays of AIS information. This leads to the need to consider specific display requirements for specific operating environments rather than universal display requirements for all vessels. The process of determining the proper shipboard display of AIS information will be dynamic and reflect the needs and requirements of different operating areas. Integration requirements for shipboard display of AIS information raise questions about appropriate task and function allocation between technology and people. For example, designers must strike the right balance between human integration and information processing and automation support for each key task. A research program could address these questions about AIS display and control design and support. The research should be part of the iterative design process that would allow for improvements and inevitable future change without detracting from the urgent tasks of implementing initial requirements for use of AIS in U.S. waters. Recommendation 7: USCG should establish an ongoing research program to investigate information displays and controls that might be appropriate for AIS. The research program should consider AIS use with other navigational and communication technologies. The research program should include Human factors aspects of interface design and the subsequent process of determining requirements, setting standards, and evaluating performance;
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 Evaluation of multimodal interfaces (tactile, auditory) that could effectively support mariners’ needs for attention management; Allowance for technological change and leverage of lessons learned from other fields (such as aviation) and related applications of similar technology; and Investigation of trade-offs between information requirements and the associated cost for shipboard display of AIS. CONTINUED OPERATIONAL TESTING OF AIS DISPLAYS USCG and other authorities have conducted a number of operational tests of AIS and transponder-based technology in the United States and abroad. Anecdotal reports from most of these tests have identified benefits and limitations of the equipment and shown the operators how it might be used within their operational environments. However, none of the tests with displays has resulted in evaluations of performance measured against specific standards. Also, few of the tests on displays have been performed on AIS equipment that was built to IMO standards. International standardization has occurred late in the AIS development process, and this has caused difficulties in producing functional and reliable systems that provide information the mariner can use with ease. It has also hindered operational tests of AIS displays because no consistent performance standards have been developed against which to measure results. The committee reviewed several operational tests of shipboard AIS displays. Most of these tests have not resulted in evaluation reports that clearly and critically document the functioning and usefulness of displays. Anecdotal reports from certain operations using AIS displays suggest that operators have gained confidence in the systems and used them successfully as navigational aids. From this experience, it appears that the whole community would benefit from more rigorous operational testing with clear functional requirements against which to measure performance, followed by critical evaluations. Recommendation 8: USCG should sponsor continuing operational tests, evaluation, and certification of new display and control technology in consultation with stakeholders and prepare test and evaluation
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Shipboard Automatic Identification System Displays: Meeting the Needs of Mariners - Special Report 273 reports. To conduct tests and evaluations, USCG should develop standards for human performance with display and control technology. It should use heuristic evaluation, where multiple designers assess how well a design conforms to human factors rules of thumb or heuristics. It should also incorporate usability tests and operational evaluations as complementary approaches to assess how well AIS displays and controls support mariner performance. SUMMARY The introduction of AIS technology with effective displays aboard vessels can enhance the safety of vessel operations and the prudent management of waterway traffic. The benefits to the maritime community and the nation as a whole will depend on how well the industry, government authorities, and mariners work together to design effective systems, establish comprehensive standards and guidelines, and implement technologies that provide useful tools for the vessel operator. USCG should take specific actions to ensure an implementation process that meets safety improvement goals. These actions include preparing an implementation plan, establishing requirements for displays and their functions, including human factors in the display design process, addressing system limitations and shortfalls, developing training guidelines, establishing human performance standards, establishing a focused research program, and conducting operational tests and evaluations of display systems. USCG cannot ensure that this new technology will bring the promised benefits to all without the involvement and cooperation of all the stakeholders, and without formal evaluation of such systems. Manufacturers, mariners, and the maritime industry as a whole need to be a part of the process to develop effective systems and to successfully implement this technology. While the focus of this report is on shipboard display of AIS information, the process of implementation and the use of human factors principles have wider application to many systems used aboard vessels operating in U.S. waters.
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