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116-414: Information provided by AIS equipment, such as unique identification, position , course , and speed, can be displayed on a screen or an electronic chart display and information system (ECDIS). AIS is intended to assist a vessel's watchstanding officers and allow maritime authorities to track and monitor vessel movements. AIS integrates a standardized VHF transceiver with a positioning system such as

232-502: A Global Positioning System receiver, with other electronic navigation sensors, such as a gyrocompass or rate of turn indicator . Vessels fitted with AIS transceivers can be tracked by AIS base stations located along coastlines or, when out of range of terrestrial networks, through a growing number of satellites that are fitted with special AIS receivers which are capable of deconflicting a large number of signatures. The International Maritime Organization 's International Convention for

348-421: A commutative ring . The use of a coordinate system allows problems in geometry to be translated into problems about numbers and vice versa ; this is the basis of analytic geometry . The simplest example of a coordinate system is the identification of points on a line with real numbers using the number line . In this system, an arbitrary point O (the origin ) is chosen on a given line. The coordinate of

464-439: A right-handed or a left-handed system. Another common coordinate system for the plane is the polar coordinate system . A point is chosen as the pole and a ray from this point is taken as the polar axis . For a given angle θ , there is a single line through the pole whose angle with the polar axis is θ (measured counterclockwise from the axis to the line). Then there is a unique point on this line whose signed distance from

580-611: A Class A type AIS transceiver. This was the first mandate for the use of AIS equipment and affected approximately 100,000 vessels. In 2006, the AIS standards committee published the Class B type AIS transceiver specification, designed to enable a simpler and lower-cost AIS device. Low-cost Class B transceivers became available in the same year triggering mandate adoptions by numerous countries and making large-scale installation of AIS devices on vessels of all sizes commercially viable. Since 2006,

696-687: A Secretary-General. The current Secretary-General is Arsenio Dominguez who took office for a four year term on 1 January 2024, having been elected in July 2023. The previous Secretary-General was Kitack Lim from South Korea elected for a four-year term at the 114th session of the IMO Council in June 2015 and at the 29th session of the IMO's Assembly in November 2015. His mandate started on 1 January 2016. At

812-475: A compass, so this data is seldom transmitted. Output is the standard AIS data stream at 38.400 kbit/s, as RS-232 and/or NMEA formats. To prevent overloading of the available bandwidth, transmission power is restricted to 2 W, giving a range of about 5–10 mi. Four messages are defined for class B units: Coordinate system In geometry , a coordinate system is a system that uses one or more numbers , or coordinates , to uniquely determine

928-570: A competent authority, may not conform to the required AIS published specification and therefore may not operate as expected in the field. The most widely recognized and accepted certifications are the R&;TTE Directive, the U.S. Federal Communications Commission , and Industry Canada , all of which require independent verification by a qualified and independent testing agency. There are 27 different types of top level messages defined in ITU M.1371-5 (out of

1044-408: A computer using one of several computer applications such as ShipPlotter, GNU AIS or OpenCPN . These demodulate the signal from a modified marine VHF radiotelephone tuned to the AIS frequencies and convert into a digital format that the computer can read and display on a monitor; this data may then be shared via a local or wide area network but will still be limited to the collective range of

1160-529: A consortium led by the Norwegian Defence Research Establishment in the frame of technology demonstration for space-based ship monitoring. This is a first step towards a satellite-based AIS-monitoring service. In 2009, ORBCOMM launched AIS enabled satellites in conjunction with a US Coast Guard contract to demonstrate the ability to collect AIS messages from space. In 2009, Luxspace , a Luxembourg -based company, launched

1276-522: A detailed technical specification which ensures the overall integrity of the global AIS system within which all the product types must operate. The major product types described in the AIS system standards are: AIS receivers are not specified in the AIS standards, because they do not transmit. The main threat to the integrity of any AIS system are non-compliant AIS transmissions, hence careful specifications of all transmitting AIS devices. However, AIS transceivers all transmit on multiple channels as required by

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1392-464: A high proportion of Class B type messages, as well as Class A. ORBCOMM operates a global satellite network that includes 18 AIS-enabled satellites. ORBCOMM's OG2 ( ORBCOMM Generation 2 ) satellites are equipped with an Automatic Identification System (AIS) payload to receive and report transmissions from AIS-equipped vessels for ship tracking and other maritime navigational and safety efforts, and download at ORBCOMM's sixteen existing earth stations around

1508-604: A large purpose-built building facing the River Thames on the Albert Embankment , in Lambeth , London. The organisation moved into its new headquarters in late 1982, with the building being officially opened by Queen Elizabeth II on 17 May 1983. The architects of the building were Douglass Marriott, Worby & Robinson. The front of the building is dominated by a seven-metre high, ten-tonne bronze sculpture of

1624-663: A member of the IMO, a state ratifies a multilateral treaty known as the Convention on the International Maritime Organization. As of 2024, there are 176 member states of the IMO, which includes 175 of the UN member states plus the Cook Islands . The first state to ratify the convention was Canada in 1948. These are the current members with the year they joined: The three associate members of

1740-732: A particularly useful attribute when trying to co-ordinate a long-range rescue effort or when dealing with VTS issues. Due to its growing use over time, in some coastal areas (e.g., the Singapore Strait , China's megaports, parts of Japan) there are so many vessels that the performance of AIS has been affected. As traffic density goes up, the system's range goes down, and the frequency of updates becomes more random. For this reason VHF Data Exchange System (VDES) has been developed: it will operate on additional new frequencies and will use them more efficiently, enabling thirty-two times as much bandwidth for secure communications and e-navigation. VDES

1856-480: A point P is defined as the signed distance from O to P , where the signed distance is the distance taken as positive or negative depending on which side of the line P lies. Each point is given a unique coordinate and each real number is the coordinate of a unique point. The prototypical example of a coordinate system is the Cartesian coordinate system . In the plane , two perpendicular lines are chosen and

1972-476: A point varies while the other coordinates are held constant, then the resulting curve is called a coordinate curve . If a coordinate curve is a straight line , it is called a coordinate line . A coordinate system for which some coordinate curves are not lines is called a curvilinear coordinate system . Orthogonal coordinates are a special but extremely common case of curvilinear coordinates. A coordinate line with all other constant coordinates equal to zero

2088-415: A possibility of 64) that can be sent by AIS transceivers. AIS messages 6, 8, 25, and 26 provide "Application Specific Messages" (ASM), that allow "competent authorities" to define additional AIS message subtypes. There are both "addressed" (ABM) and "broadcast" (BBM) variants of the message. Addressed messages, while containing a destination MMSI , are not private and may be decoded by any receiver. One of

2204-461: A precise way with all the other defined AIS devices, thus ensuring AIS system interoperability worldwide. Maintenance of the specification integrity is deemed critical for the performance of the AIS system and the safety of vessels and authorities using the technology. As such most countries require that AIS products are independently tested and certified to comply with a specific published specification. Products that have not been tested and certified by

2320-409: A resolution targeting "dark fleet" tankers that form a risk by undertaking illegal and unsafe activities at sea. Primarily working for Iran and Russia to breach international sanctions, the tankers, many of which are elderly and unreliable, often undertake mid ocean transfers in an attempt to evade sanctions. The resolution calls upon flag states to “adhere to measures which lawfully prohibit or regulate”

2436-431: A screen or chart plotter, showing the other vessels' positions in much the same manner as a radar display. Data is transmitted via a tracking system which makes use of a self-organized time-division multiple access (SOTDMA) datalink designed by Swedish inventor Håkan Lans . The AIS standard comprises several substandards called "types" that specify individual product types. The specification for each product type provides

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2552-404: A second (typically referred to as "local") coordinate system, fixed to the node, is defined based on the first (typically referred to as "global" or "world" coordinate system). For instance, the orientation of a rigid body can be represented by an orientation matrix , which includes, in its three columns, the Cartesian coordinates of three points. These points are used to define the orientation of

2668-405: Is a homeomorphism from an open subset of a space X to an open subset of R . It is often not possible to provide one consistent coordinate system for an entire space. In this case, a collection of coordinate maps are put together to form an atlas covering the space. A space equipped with such an atlas is called a manifold and additional structure can be defined on a manifold if the structure

2784-589: Is a specialised agency of the United Nations responsible for regulating maritime transport . The IMO was established following agreement at a UN conference held in Geneva in 1948 and the IMO came into existence ten years later, meeting for the first time on 17 March 1958. Headquartered in London, United Kingdom, the IMO, in 2024, has 176 Member States and three Associate Members. The IMO's primary purpose

2900-691: Is a 1U cubesat, weights 800 grams, solely developed by students from the Department of Electronic Systems. It carries two AIS receivers—a traditional and a SDR -based receiver. The project was proposed and sponsored by the Danish Maritime Safety Administration . It has been a huge success and has in the first 100 days downloaded more than 800,000 AIS messages and several 1 MHz raw samples of radio signals. It receives both AIS channels simultaneously and has received class A as well as class B messages. Cost including launch

3016-603: Is also a non-member. Taiwan is neither a member of the IMO nor of the UN, although it has a major shipping industry. IMO is the source of approximately 60 legal instruments that guide the regulatory development of its member states to improve safety at sea, facilitate trade among seafaring states and protect the maritime environment. The most well known is the International Convention for the Safety of Life at Sea (SOLAS), as well as International Convention for

3132-559: Is at anchor: In addition, the following data are broadcast every 6 minutes: Class B transceivers are smaller, simpler and lower cost than Class A transceivers. Each consists of one VHF transmitter, two VHF Carrier Sense Time Division Multiple Access (CSTDMA) receivers, both alternating as the VHF Digital Selective Calling (DSC) receiver, and a GPS active antenna. Although the data output format supports heading information, in general units are not interfaced to

3248-414: Is called a coordinate axis , an oriented line used for assigning coordinates. In a Cartesian coordinate system , all coordinates curves are lines, and, therefore, there are as many coordinate axes as coordinates. Moreover, the coordinate axes are pairwise orthogonal . A polar coordinate system is a curvilinear system where coordinate curves are lines or circles . However, one of the coordinate curves

3364-422: Is conducted through five committees and these are supported by technical subcommittees. Other UN organisations may observe the proceedings of the IMO. Observer status is granted to qualified non-governmental organisations. IMO is supported by a permanent secretariat of employees who are representative of the organisation's members. The secretariat is composed of a Secretary-General who is periodically elected by

3480-417: Is consistent where the coordinate maps overlap. For example, a differentiable manifold is a manifold where the change of coordinates from one coordinate map to another is always a differentiable function. In geometry and kinematics , coordinate systems are used to describe the (linear) position of points and the angular position of axes, planes, and rigid bodies . In the latter case, the orientation of

3596-408: Is defined in ITU M.2092. The original purpose of AIS was solely collision avoidance but many other applications have since developed and continue to be developed. AIS is currently used for: AIS transceivers automatically broadcast information, such as their position, speed, and navigational status, at regular intervals via a VHF transmitter built into the transceiver. The information originates from

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3712-501: Is described by coordinate transformations , which give formulas for the coordinates in one system in terms of the coordinates in another system. For example, in the plane, if Cartesian coordinates ( x ,  y ) and polar coordinates ( r ,  θ ) have the same origin, and the polar axis is the positive x axis, then the coordinate transformation from polar to Cartesian coordinates is given by x  =  r  cos θ and y  =  r  sin θ . With every bijection from

3828-648: Is intended to fully replace existing DSC-based transceiver systems. Shore-based AIS network systems are now being built up around the world. One of the biggest fully operational, real time systems with full routing capability is in China. This system was built between 2003 and 2007 and was delivered by Saab TranspondereTech. The entire Chinese coastline is covered with approximately 250 base stations in hot-standby configurations including 70 computer servers in three main regions. Hundreds of shore-based users, including about 25 vessel traffic service (VTS) centers, are connected to

3944-589: Is lost beyond coastal waters. In addition to port and maritime authority operated transceivers, there is large network of privately owned ones as well. In the 1990s AIS was not anticipated to be detectable from space. Nevertheless, since 2005, various entities have been experimenting with detecting AIS transmissions using satellite-based receivers and, since 2008, companies such as L3Harris , exactEarth , ORBCOMM , Spacequest , Spire and also government programs have deployed AIS receivers on satellites. The time-division multiple access (TDMA) radio access scheme used by

4060-450: Is maintained even in overload situations. In order to ensure that the VHF transmissions of different transceivers do not occur at the same time, the signals are time multiplexed using a technology called self-organized time-division multiple access (SOTDMA). The design of this technology is patented, and whether this patent has been waived for use by SOLAS vessels is a matter of debate between

4176-558: Is one of few industrial areas that still commonly uses non- metric units such as the nautical mile (nmi) for distance and knots (kn) for speed or velocity. In 1982, IMCO was renamed as the International Maritime Organization (IMO). Throughout its existence, the IMO has continued to produce new and updated conventions across a wide range of maritime issues covering not only safety of life and marine pollution but also encompassing safe navigation, search and rescue, wreck removal, tonnage measurement, liability and compensation, ship recycling,

4292-428: Is one where only the ratios of the coordinates are significant and not the actual values. Some other common coordinate systems are the following: There are ways of describing curves without coordinates, using intrinsic equations that use invariant quantities such as curvature and arc length . These include: Coordinates systems are often used to specify the position of a point, but they may also be used to specify

4408-689: Is operating in the open seas or coastal or inland areas. AIS transceivers use two different frequencies, VHF maritime channels 87B (161.975 MHz) and 88B (162.025 MHz), and use 9.6 kbit/s Gaussian minimum shift keying (GMSK) modulation over 25 kHz channels using the high-level data link control (HDLC) packet protocol. Although only one radio channel is necessary, each station transmits and receives over two radio channels to avoid interference problems, and to allow channels to be shifted without communications loss from other ships. The system provides for automatic contention resolution between itself and other stations, and communications integrity

4524-422: Is randomized within a defined interval and tagged with a random timeout of between 4 and 8 minutes. When a station changes its slot assignment, it announces both the new location and the timeout for that location. In this way new stations, including those stations which suddenly come within radio range close to other vessels, will always be received by those vessels. The required ship reporting capacity according to

4640-418: Is reduced to a single point, the origin, which is often viewed as a circle of radius zero. Similarly, spherical and cylindrical coordinate systems have coordinate curves that are lines, circles or circles of radius zero. Many curves can occur as coordinate curves. For example, the coordinate curves of parabolic coordinates are parabolas . In three-dimensional space, if one coordinate is held constant and

4756-492: Is shaped like a cube. On 20 April 2011, Indian Space Research Organisation launched Resourcesat-2 containing a S-AIS payload for monitoring maritime traffic in the Indian Ocean Search & Rescue (SAR) zone. AIS data is processed at National Remote Sensing Centre and archived at Indian Space Science Data Centre . On February 25, 2013—after one year launch delay— Aalborg University launched AAUSAT3 . It

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4872-523: Is the systems of homogeneous coordinates for points and lines in the projective plane. The two systems in a case like this are said to be dualistic . Dualistic systems have the property that results from one system can be carried over to the other since these results are only different interpretations of the same analytical result; this is known as the principle of duality . There are often many different possible coordinate systems for describing geometrical figures. The relationship between different systems

4988-429: Is to develop and maintain a comprehensive regulatory framework for shipping and its remit today includes maritime safety , environmental concerns, legal matters , technical co-operation, maritime security and the efficiency of shipping. IMO is governed by an assembly of members which meets every two years. Its finance and organization is administered by a council of 40 members elected from the assembly. The work of IMO

5104-415: Is to make it viewable publicly, on the internet, without the need for an AIS receiver. Global AIS transceiver data collected from both satellite and internet-connected shore-based stations are aggregated and made available on the internet through a number of service providers. Data aggregated this way can be viewed on any internet-capable device to provide near global, real-time position data from anywhere in

5220-441: Is vital to the proper synchronization and slot mapping (transmission scheduling) for a Class A unit. Therefore, every unit is required to have an internal time base, synchronized to a global navigation satellite system (e.g. GPS ) receiver. This internal receiver may also be used for position information. However, position is typically provided by an external receiver such as GPS , LORAN-C or an inertial navigation system and

5336-693: The Titanic disaster. Under the name of the Inter-Governmental Maritime Consultative Organization (IMCO), IMO's first task was to update the SOLAS convention; the resulting 1960 convention was subsequently recast and updated in 1974 and it is that convention that has been subsequently modified and updated to adapt to changes in safety requirements and technology. Since 1978, every last Thursday of September has been celebrated as World Maritime Day, commemorating

5452-401: The ( n − 1) -dimensional spaces resulting from fixing a single coordinate of an n -dimensional coordinate system. The concept of a coordinate map , or coordinate chart is central to the theory of manifolds. A coordinate map is essentially a coordinate system for a subset of a given space with the property that each point has exactly one set of coordinates. More precisely, a coordinate map

5568-545: The International Regulations for Preventing Collisions at Sea (COLREG). The IMO has also enacted a Port state control (PSC) authority, allowing domestic maritime authorities such as coast guards to inspect foreign-flag ships calling at ports of the many port states. Memoranda of Understanding (protocols) were signed by some countries unifying Port State Control procedures among the signatories. Conventions, Codes and Regulations: Recent initiatives at

5684-776: The International Space Station (ISS). In November 2009, the STS-129 space shuttle mission attached two antennas—an AIS VHF antenna, and an Amateur Radio antenna—to the Columbus module of the ISS. Both antennas were built in cooperation between ESA and the ARISS team (Amateur Radio on ISS). Starting from May 2010 the European Space Agency is testing an AIS receiver from Kongsberg Seatex (Norway) in

5800-573: The RUBIN-9.1 satellite (AIS Pathfinder 2). The satellite is operated in cooperation with SES and REDU Space Services. In late 2011 and early 2012, ORBCOMM and Luxspace launched the Vesselsat AIS microsatellites, one in an equatorial orbit and the other in a polar orbit ( VesselSat-2 and VesselSat-1 ). In 2007, the U.S. tested space-based AIS tracking with the TacSat-2 satellite. However,

5916-457: The cylindrical coordinate system , a z -coordinate with the same meaning as in Cartesian coordinates is added to the r and θ polar coordinates giving a triple ( r ,  θ ,  z ). Spherical coordinates take this a step further by converting the pair of cylindrical coordinates ( r ,  z ) to polar coordinates ( ρ ,  φ ) giving a triple ( ρ ,  θ ,  φ ). A point in

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6032-552: The exactEarth system and made available worldwide as part of their exactAIS(TM)service. On July 12, 2010, the Norwegian AISSat-1 satellite was successfully launched into polar orbit. The purpose of the satellite is to improve surveillance of maritime activities in the High North . AISSat-1 is a nano-satellite, measuring only 20×20×20 cm, with an AIS receiver made by Kongsberg Seatex. It weighs 6 kilograms and

6148-428: The position of the points or other geometric elements on a manifold such as Euclidean space . The order of the coordinates is significant, and they are sometimes identified by their position in an ordered tuple and sometimes by a letter, as in "the x -coordinate". The coordinates are taken to be real numbers in elementary mathematics , but may be complex numbers or elements of a more abstract system such as

6264-535: The "appropriate international body to address greenhouse gas emissions from ships engaged in international trade". Nonetheless, there has been widespread criticism of the IMO's relative inaction since the conclusion of the Paris conference, with the initial data-gathering step of a three-stage process to reduce maritime greenhouse emissions expected to last until 2020. In 2018, the Initial IMO Strategy on

6380-463: The 176th Member State of the organization. Most UN member states that are not members of IMO are landlocked countries. These include Afghanistan, Andorra, Bhutan, Burkina Faso, Burundi, Central African Republic, Chad, Eswatini, Laos, Lesotho, Liechtenstein, Mali, Niger, Rwanda, South Sudan, Tajikistan and Uzbekistan. The Federated States of Micronesia , an island-nation in the Pacific Ocean,

6496-663: The 31st session of the Assembly in 2019 he was re-appointed for a second term, ending on 31 December 2023. The technical work of the International Maritime Organisation is carried out by five principal Committees. These include: It is regulated in the Article 28(a) of the Convention on the IMO: ARTICLE 28 (a) The Maritime Safety Committee shall consider any matter within the scope of

6612-460: The AIS standards. Consequently, single-channel or multiplexed receivers will not receive all AIS messages. Only dual-channel receivers will receive all AIS messages. AIS is a technology which has been developed under the auspices of the IMO by its technical committees. The technical committees have developed and published a series of AIS product specifications. Each specification defines a specific AIS product which has been carefully created to work in

6728-406: The AIS system creates significant technical issues for the reliable reception of AIS messages from all types of transceivers: Class A, Class B, Identifier, AtoN and SART. However, the industry is seeking to address these issues through the development of new technologies and over the coming years the current restriction of satellite AIS systems to Class A messages is likely to dramatically improve with

6844-495: The AIS technical standard committees have continued to evolve the AIS standard and product types to cover a wide range of applications from the largest vessel to small fishing vessels and life boats. In parallel, governments and authorities have instigated projects to fit varying classes of vessels with an AIS device to improve safety and security. Most mandates are focused on commercial vessels, with leisure vessels selectively choosing to fit. In 2010 most commercial vessels operating on

6960-647: The Assembly or the Council, or any duty within the scope of this Article which may be assigned to it by or under any other international instrument and accepted by the Organization. (c) Having regard to the provisions of Article 25, the Maritime Safety Committee, upon request by the Assembly or the Council or, if it deems such action useful in the interests of its own work, shall maintain such close relationship with other bodies as may further

7076-566: The English Channel The Torrey Canyon grounding was the largest oil pollution incident recorded up to that time. This incident prompted a series of new conventions. IMO held an emergency session of its council to deal with the need to readdress regulations pertaining to maritime pollution. In 1969, the IMO Assembly decided to host an international gathering in 1973 dedicated to this issue. The goal at hand

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7192-546: The European Inland Waterways were required to fit an Inland waterway certified Class A, all EU fishing boats over 15m must have a Class A by May 2014, and the US has a long-pending extension to their existing AIS fit rules which is expected to come into force during 2013. It is estimated that as of 2012, some 250,000 vessels have fitted an AIS transceiver of some type, with a further 1 million required to do so in

7308-636: The IMO are the Faroe Islands , Hong Kong and Macau . In 1961, the territories of Sabah and Sarawak , which had been included through the participation of United Kingdom, became joint associate members. In 1963 they became part of Malaysia. The most recent members to join were Armenia and Nauru (which became IMO members in January and May 2018, respectively). Botswana , joined the IMO in October 2021. On 27 February 2024, Kyrgyzstan became

7424-827: The IMO facilitated the adoption of the International Grain Code . In December 2002, new amendments to the 1974 SOLAS Convention were enacted by the IMO. These amendments gave rise to the International Ship and Port Facility Security (ISPS) Code , which went into effect on 1 July 2004. The concept of the code is to provide layered and redundant defences against smuggling, terrorism, piracy, stowaways, etc. The ISPS Code required most ships and port facilities engaged in international trade to establish and maintain strict security procedures as specified in ship and port specific Ship Security Plans and Port Facility Security Plans. The IMO headquarters are located in

7540-718: The IMO have included amendments to SOLAS , which among other things, included upgraded fire protection standards on passenger ships , the International Convention on Standards of Training, Certification and Watchkeeping for Seamen(STCW) which establishes basic requirements on training, certification and watchkeeping for seafarers and to the Convention on the Prevention of Maritime Pollution ( MARPOL 73/78 ), which required double hulls on all tankers . The IMO's e-Navigation system has harmonised marine navigation systems with supporting shore services, as available to seamen and shore-side traffic services called. An e-Navigation strategy

7656-546: The IMO performance standard is a minimum of 2,000 time slots per minute, though the system provides 4,500 time slots per minute. The SOTDMA broadcast mode allows the system to be overloaded by 400 to 500% through sharing of slots, and still provides nearly 100% throughput for ships closer than 8 to 10 nmi to each other in a ship to ship mode. In the event of system overload, only targets further away will be subject to drop-out, in order to give preference to nearer targets, which are of greater concern to ship operators. In practice,

7772-532: The Organization concerned with aids to navigation, construction and equipment of vessels, manning from a safety standpoint, rules for the prevention of collisions, handling of dangerous cargoes, maritime safety procedures and requirements, hydrographic information, log-books and navigational records, marine casualty investigation, salvage and rescue, and any other matters directly affecting maritime safety. (b) The Maritime Safety Committee shall provide machinery for performing any duties assigned to it by this Convention,

7888-869: The Prevention of Pollution from Ships (MARPOL). Others include the International Oil Pollution Compensation Funds (IOPC). It also functions as a depository of yet to be ratified treaties, such as the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea, 1996 ( HNS Convention ) and Nairobi International Convention of Removal of Wrecks (2007). IMO regularly enacts regulations, which are broadly enforced by national and local maritime authorities in member countries, such as

8004-541: The Safety of Life at Sea requires AIS to be fitted aboard international voyaging ships with 300 or more  gross tonnage  (GT), and all passenger ships regardless of size. For a variety of reasons, ships can turn off their AIS transceivers. AIS is intended, primarily, to allow ships to view marine traffic in their area and to be seen by that traffic. This requires a dedicated VHF AIS transceiver that allows local traffic to be viewed on an AIS enabled chartplotter or computer monitor while transmitting information about

8120-474: The addition of Class B and Identifier messages. The fundamental challenge for AIS satellite operators is the ability to receive very large numbers of AIS messages simultaneously from a satellite's large reception footprint. There is an inherent issue within the AIS standard; the TDMA radio access scheme defined in the AIS standard creates 4,500 available time-slots in each minute but this can be easily overwhelmed by

8236-533: The assembly, and various divisions such as those for marine safety, environmental protection and a conference section. IMO was established in 1948 following a UN conference in Geneva to bring the regulation of the safety of shipping into an international framework. Hitherto such international conventions had been initiated piecemeal, notably the Safety of Life at Sea Convention (SOLAS), first adopted in 1914 following

8352-697: The axes of the local system; they are the tips of three unit vectors aligned with those axes. The Earth as a whole is one of the most common geometric spaces requiring the precise measurement of location, and thus coordinate systems. Starting with the Greeks of the Hellenistic period , a variety of coordinate systems have been developed based on the types above, including: International Maritime Organization The International Maritime Organization ( IMO ; French : Organisation maritime internationale ; Spanish : Organización Marítima Internacional )

8468-639: The bow of a ship, with a lone seafarer maintaining a look-out. The previous headquarters of IMO were at 101 Piccadilly (now the home of the Embassy of Japan ), prior to that at 22 Berners Street in Fitzrovia and originally in Chancery Lane . The IMO consists of an Assembly, a Council and five main Committees. The organization is led by a Secretary-General. A number of Sub-Committees support

8584-431: The capacity of the system is nearly unlimited, allowing for a great number of ships to be accommodated at the same time. The system coverage range is similar to other VHF applications. The range of any VHF radio is determined by multiple factors, the primary factors are: the height and quality of the transmitting antenna and the height and quality of the receiving antenna. Its propagation is better than that of radar, due to

8700-601: The community of competent authorities work together to maintain a regional register of these messages and their locations of use. The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA-AISM) now established a process for collection of regional application-specific messages. Each AIS transceiver consists of one VHF transmitter, two VHF TDMA receivers, one VHF Digital Selective Calling (DSC) receiver, and links to shipboard display and sensor systems via standard marine electronic communications (such as NMEA 0183 , also known as IEC 61162). Timing

8816-432: The coordinates of a point are taken to be the signed distances to the lines. In three dimensions, three mutually orthogonal planes are chosen and the three coordinates of a point are the signed distances to each of the planes. This can be generalized to create n coordinates for any point in n -dimensional Euclidean space. Depending on the direction and order of the coordinate axes , the three-dimensional system may be

8932-467: The disposal of engine room wastes. By tonnage, the aforementioned was a bigger problem than accidental pollution. The most significant development to come out of this conference was the International Convention for the Prevention of Pollution from Ships, 1973 (MARPOL). It covers not only accidental and operational oil pollution but also different types of pollution by chemicals, goods in packaged form, sewage, garbage and air pollution. The original MARPOL

9048-409: The end-user to rapidly identify all types of vessel. A great strength of S-AIS is the ease with which it can be correlated with additional information from other sources such as radar, optical, ESM, and more SAR related tools such as GMDSS SARSAT and AMVER . Satellite-based radar and other sources can contribute to maritime surveillance by detecting all vessels in specific maritime areas of interest,

9164-459: The establishment of the International Maritime Organisation in 1958. When IMCO began its operations in 1959 certain other pre-existing conventions were brought under its aegis, most notable the International Convention for the Prevention of Pollution of the Sea by Oil (OILPOL) 1954. In January 1959, IMO began to maintain and promote the 1954 OILPOL Convention. Under the guidance of IMO, the convention

9280-634: The first uses of ASMs was the Saint Lawrence Seaway use of AIS binary messages (message type 8) to provide information about water levels, lock orders, and weather. The Panama Canal uses AIS type 8 messages to provide information about rain along the canal and wind in the locks. In 2010, the International Maritime Organization issued Circular 289 that defines the next iteration of ASMs for type 6 and 8 messages. Alexander, Schwehr and Zetterberg proposed that

9396-1071: The globe. In July 2014, ORBCOMM launched the first 6 OG2 satellites aboard a SpaceX Falcon 9 rocket from Cape Canaveral, Florida. Each OG2 satellite carries an AIS receiver payload. All 6 OG2 satellites were successfully deployed into orbit and started sending telemetry to ORBCOMM soon after launch. In December 2015, the company launched 11 additional AIS-enabled OG2 satellites aboard the SpaceX Falcon 9 rocket. This dedicated launch marked ORBCOMM's second and final OG2 mission to complete its next-generation satellite constellation. Compared to its current OG1 satellites, ORBCOMM's OG2 satellites are designed for faster message delivery, larger message sizes and better coverage at higher latitudes, while increasing network capacity. In August 2017, Spire Global Inc. released an API that delivers S-AIS data enhanced with machine learning (Vessels and Predict) backed by its 40+ constellation of nano-satellites. Correlating optical and radar imagery with S-AIS signatures enables

9512-540: The internal receiver is only used as a backup for position information. Other information broadcast by the AIS, if available, is electronically obtained from shipboard equipment through standard marine data connections. Heading information, position (latitude and longitude), "speed over ground", and rate of turn are normally provided by all ships equipped with AIS. Other information, such as destination, and ETA may also be provided. An AIS transceiver normally works in an autonomous and continuous mode, regardless of whether it

9628-401: The internet are mostly run by a large number of volunteers. AIS mobile apps are also readily available for use with Android, Windows and iOS devices. See External links below for a list of internet-based AIS service providers. Ship owners and cargo dispatchers use these services to find and track vessels and their cargoes while marine enthusiasts may add to their photograph collections. At

9744-408: The large satellite reception footprints and the increasing numbers of AIS transceivers, resulting in message collisions, which the satellite receiver cannot process. Companies such as exactEarth are developing new technologies such as ABSEA, that will be embedded within terrestrial and satellite-based transceivers, which will assist the reliable detection of Class B messages from space without affecting

9860-486: The latter being similar to that of conventional marine radar. Each AIS station determines its own transmission schedule (slot), based upon data link traffic history and an awareness of probable future actions by other stations. A position report from one station fits into one of 2,250 time slots established every 60 seconds on each frequency. AIS stations continuously synchronize themselves to each other, to avoid overlap of slot transmissions. Slot selection by an AIS station

9976-510: The longer wavelength, so it is possible to reach around bends and behind islands if the land masses are not too high. The look-ahead distance at sea is nominally 20 nmi (37 km). With the help of repeater stations, the coverage for both ship and VTS stations can be improved considerably. The system is backward compatible with digital selective calling systems, allowing shore-based GMDSS systems to inexpensively establish AIS operating channels and identify and track AIS-equipped vessels, and

10092-401: The management of ships which will ensure that agreed operational procedures are in place and followed by the ship and shore-side staff. The MSC and MEPC are assisted in their work by a number of sub-committees which are open to all Member States. The committees are: The names of the IMO sub-committees were changed in 2013. Prior to 2013 there were nine Sub-Committees as follows: To become

10208-583: The manufacturers of AIS systems and the patent holder, Håkan Lans . Moreover, the United States Patent and Trademark Office (USPTO) canceled all claims in the original patent on March 30, 2010. In order to make the most efficient use of the bandwidth available, vessels that are anchored or moving slowly transmit less frequently than those that are moving faster or are maneuvering. The update rate ranges from 3 minutes for anchored or moored vessels, to 2 seconds for fast moving or maneuvering vessels,

10324-564: The mid to late 20th century, including the International Convention on Load Lines in 1966 (replacing an earlier 1930 Convention), the International Regulations for Preventing Collisions at Sea in 1972 (also replacing an earlier set of rules) and the STCW Convention in 1978. In 1975, the assembly of the IMO decided that future conventions of the International Convention for the Safety of Life at Sea (SOLAS) and other IMO instruments should use SI units only. As such, sea transportation

10440-407: The near future and even larger projects under consideration. 1 AIS was developed in the 1990s as a high intensity, short-range identification and tracking network. Shipboard and land-based AIS transceivers have a horizontal range that is highly variable, but typically only up to about 74 kilometres (46 mi). Approximate line-of-sight propagation limitations mean that terrestrial AIS (T-AIS)

10556-507: The network and are able to see the maritime picture, and can also communicate with each ship using SRMs (Safety Related Messages). All data are in real time. The system was designed to improve the safety and security of ships and port facilities. It is also designed according to an SOA architecture with socket based connection and using IEC AIS standardized protocol all the way to the VTS users. The base stations have hot-standby units (IEC 62320-1) and

10672-464: The network is the third generation network solution. By the beginning of 2007, a new worldwide standard for AIS base stations was approved, the IEC 62320-1 standard. The old IALA recommendation and the new IEC 62320-1 standard are in some functions incompatible, and therefore attached network solutions have to be upgraded. This will not affect users, but system builders need to upgrade software to accommodate

10788-400: The new standard. A standard for AIS base stations has been long-awaited. Currently ad-hoc networks exist with class A mobiles. Base stations can control the AIS message traffic in a region, which will hopefully reduce the number of packet collisions. An AIS transceiver sends the following data every 2 to 10 seconds depending on a vessel's speed while underway, and every 3 minutes while a vessel

10904-448: The origin is r for given number r . For a given pair of coordinates ( r ,  θ ) there is a single point, but any point is represented by many pairs of coordinates. For example, ( r ,  θ ), ( r ,  θ +2 π ) and (− r ,  θ + π ) are all polar coordinates for the same point. The pole is represented by (0, θ ) for any value of θ . There are two common methods for extending the polar coordinate system to three dimensions. In

11020-453: The other two are allowed to vary, then the resulting surface is called a coordinate surface . For example, the coordinate surfaces obtained by holding ρ constant in the spherical coordinate system are the spheres with center at the origin. In three-dimensional space the intersection of two coordinate surfaces is a coordinate curve. In the Cartesian coordinate system we may speak of coordinate planes . Similarly, coordinate hypersurfaces are

11136-421: The performance of terrestrial AIS. The addition of satellite-based Class A and B messages could enable truly global AIS coverage but, because the satellite-based TDMA limitations will never match the reception performance of the terrestrial-based network, satellites will augment rather than replace the terrestrial system. AIS has much longer vertical (than horizontal) transmission – up to the 400 km orbit of

11252-422: The plane may be represented in homogeneous coordinates by a triple ( x ,  y ,  z ) where x / z and y / z are the Cartesian coordinates of the point. This introduces an "extra" coordinate since only two are needed to specify a point on the plane, but this system is useful in that it represents any point on the projective plane without the use of infinity . In general, a homogeneous coordinate system

11368-549: The position of more complex figures such as lines, planes, circles or spheres . For example, Plücker coordinates are used to determine the position of a line in space. When there is a need, the type of figure being described is used to distinguish the type of coordinate system, for example the term line coordinates is used for any coordinate system that specifies the position of a line. It may occur that systems of coordinates for two different sets of geometric figures are equivalent in terms of their analysis. An example of this

11484-579: The purposes of the Organization The Maritime Safety Committee is the most senior of these and is the main Technical Committee; it oversees the work of its nine sub-committees and initiates new topics. One broad topic it deals with is the effect of the human element on casualties ; this work has been put to all of the sub-committees, but meanwhile, the Maritime Safety Committee has developed a code for

11600-458: The radio receivers used in the network. Because computer AIS monitoring applications and normal VHF radio transceivers do not possess AIS transceivers, they may be used by shore-based facilities that have no need to transmit or as an inexpensive alternative to a dedicated AIS device for smaller vessels to view local traffic but, of course, the user will remain unseen by other traffic on the network. A secondary, unplanned and emerging use for AIS data

11716-467: The received signals were corrupted because of the simultaneous receipt of many signals from the satellite footprint. In July 2009, SpaceQuest launched AprizeSat -3 and AprizeSat-4 with AIS receivers. These receivers were successfully able to receive the U.S. Coast Guard's SART test beacons off of Hawaii in 2010. In July 2010, SpaceQuest and exactEarth of Canada announced an arrangement whereby data from AprizeSat-3 and AprizeSat-4 would be incorporated into

11832-466: The reduction of GHG emissions from ships was adopted. In 2021, The New York Times wrote that the IMO "has repeatedly delayed and watered down climate regulations". The IMO has also taken action to mitigate the global effects of ballast water and sediment discharge, through the 2004 Ballast Water Management Convention , which entered into force in September 2017. In December 2023 the IMO adopted

11948-504: The ship itself to other AIS receivers. Port authorities or other shore-based facilities may be equipped with receivers only, so that they can view the local traffic without the need to transmit their own location. All AIS transceivers equipped traffic can be viewed this way very reliably but is limited to the VHF range, about 10–20 nautical miles. If a suitable chartplotter is not available, local area AIS transceiver signals may be viewed via

12064-420: The ship's navigational sensors, typically its global navigation satellite system (GNSS) receiver and gyrocompass . Other information, such as the vessel name and VHF call sign, is programmed when installing the equipment and is also transmitted regularly. The signals are received by AIS transceivers fitted on other ships or on land based systems, such as VTS systems. The received information can be displayed on

12180-419: The simplest level, AIS operates between pairs of radio transceivers, one of which is always on a vessel. The other may be on a vessel, on-shore (terrestrial), or on a satellite. Respectively, these represent ship to ship, ship to shore, and ship to satellite operation and follow in that order. The 2002 IMO SOLAS Agreement included a mandate that required most vessels over 300GT on international voyages to fit

12296-399: The space to itself two coordinate transformations can be associated: For example, in 1D , if the mapping is a translation of 3 to the right, the first moves the origin from 0 to 3, so that the coordinate of each point becomes 3 less, while the second moves the origin from 0 to −3, so that the coordinate of each point becomes 3 more. Given a coordinate system, if one of the coordinates of

12412-416: The technical basis for the reduction mechanisms that may form part of a future IMO regime to control greenhouse gas emissions from international shipping, and a draft of the actual reduction mechanisms themselves, for further consideration by IMO's Marine Environment Protection Committee (MEPC). The IMO participated in the 2015 United Nations Climate Change Conference in Paris seeking to establish itself as

12528-608: The training and certification of seafarers, and piracy. More recently SOLAS has been amended to bring an increased focus on maritime security through the International Ship and Port Facility Security (ISPS) Code . The IMO has also increased its focus on smoke emissions from ships. In 1983, the IMO established the World Maritime University in Malmö, Sweden and also facilitated the adoption of the IGC Code . In 1991,

12644-476: The transfer of cargoes at sea, known as ship-to-ship transfers. The IMO Cape Town Agreement is an international International Maritime Organization legal instrument established in 2012, that sets out minimum safety requirements for fishing vessels of 24 metres in length and over or equivalent in gross tons. As of 2022, the Agreement is not yet in force but the IMO is encouraging more member States to ratify

12760-456: The work of the main technical committees. The governing body of the International Maritime Organization is the Assembly which meets every two years. In between Assembly sessions a Council, consisting of 40 Member States elected by the Assembly, acts as the governing body. The technical work of the International Maritime Organization is carried out by a series of Committees. The Secretariat consists of some 300 international civil servants headed by

12876-446: The world. Typical data includes vessel name, details, location, speed and heading on a map, is searchable, has potentially unlimited, global range and the history is archived. Most of this data is free of charge but satellite data and special services such as searching the archives are usually supplied at a cost. The data is a read-only view and the users will not be seen on the AIS network itself. Shore-based AIS receivers contributing to

12992-415: Was amended in 1962, 1969, and 1971. The first meetings of the newly formed IMCO were held in London in 1959. As oil trade and industry developed, many people in the industry began to recognise a need for further improvements in regards to oil pollution prevention at sea. This became increasingly apparent in 1967, when the tanker Torrey Canyon spilled 120,000 tons of crude oil when it ran aground entering

13108-492: Was less than €200,000. Canadian-based exactEarth's AIS satellite network provides global coverage using 8 satellites. Between January 2017 and January 2019, this network was significantly expanded through a partnership with L3Harris Corporation with 58 hosted payloads on the Iridium NEXT constellation. Additionally exactEarth is involved in the development of ABSEA technology which will enable its network to reliably detect

13224-586: Was ratified in 2005, and an implementation plan was developed through three IMO sub-committees. The plan was completed by 2014 and implemented in November of that year. IMO has also served as a key partner and enabler of US international and interagency efforts to establish maritime domain awareness . The IMO has a role in tackling international climate change . The First Intersessional Meeting of IMO's Working Group on Greenhouse Gas Emissions from Ships took place in Oslo, Norway (23–27 June 2008), tasked with developing

13340-518: Was signed on 17 February 1973, but did not come into force due to lack of ratifications. The current convention is a combination of 1973 Convention and the 1978 Protocol. It entered into force on 2 October 1983. As of January 2018, 156 states, representing 99.42 per cent of the world's shipping tonnage, are signatories to the MARPOL convention. As well as updates to MARPOL and SOLAS, the IMO facilitated several updated international maritime conventions in

13456-399: Was to develop an international agreement for controlling general environmental contamination by ships when out at sea. During the next few years IMO brought to the forefront a series of measures designed to prevent large ship accidents and to minimise their effects. It also detailed how to deal with the environmental threat caused by routine ship duties such as the cleaning of oil cargo tanks or

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