IS data on the Internet
AIS position data are available on the Internet through privately operated geographic information systems. In December 2004, theInternational Maritime Organization's (IMO) Maritime Safety Committee condemned the Internet publication of AIS data as follows:[3]
In relation to the issue of freely available automatic identification system (AIS)-generated ship data on the world-wide web, the publication on the world-wide web or elsewhere of AIS data transmitted by ships could be detrimental to the safety and security of ships and port facilities and was undermining the efforts of the Organization and its Member States to enhance the safety of navigation and security in the international maritime transport sector.
Others[who?] have countered that AIS provides the same information that can be obtained with a pair of binoculars and that ships have the option of turning off AIS when they are in areas with security concerns.
Shipboard AIS transponders have a horizontal range that is highly variable but typically only about 74 kilometers (46 mi). They reach much further vertically, up to the 400 km orbit of the International Space Station (ISS).
In June 2008, ORBCOMM launched new low-earth orbit (LEO) satellites for their machine-to-machine communications constellation. In parallel with ORBCOMM's contract with the United States Coast Guard to launch its AIS receiver-equipped Concept Demonstration Satellite (CDS), all of these new satellites were equipped with AIS receivers. ORBCOMM became the first commercial service provider of satellite AIS, having licensed satellite AIS data service to qualified government and commercial subscribers since the beginning of 2009. Additionally, ORBCOMM has incorporated AIS receivers in its next 18 ORBCOMM Generation 2 (0G2) satellites under development. As additional satellites are launched, ORBCOMM will increase its capability by providing greater redundancy and more frequent updates of AIS data. ORBCOMM's established terrestrial network of 15 Gateway Earth Stations around the world ensures timely delivery of the satellite AIS data to its subscribers.[4]
ORBCOMM has also contracted with Luxspace to provide 2 dedicated AIS detection satellites, one a polar orbiting satellite, and the other an equatorial orbiting satellite, to be launched mid-2011.
On April 28, 2008, Canadian company COM DEV International, became the first company to launch a space-based AIS nano-satellite designed to detect AIS signals from space,[5] and is currently deploying a full micro-satellite constellation, global ground network and centralized data processing center in order to offer global AIS data services. The service is operational and available worldwide as of mid-2010 through exactEarth, COM DEV's data services subsidiary. exactEarth uses a patent-pending ground and space-based processing technology to minimize interference of collided AIS signals, therefore dramatically improving detection compared with all other satellite-based systems. As more satellites are launched, refresh rates will continue to increase as well.
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 two different AIS receivers, one from Luxspace (GdL), one from FFI (Norway) in the frame of technology demonstration for space-based ship monitoring. This is a first step towards a satellite-based AIS-monitoring service.[6]
In 2009, LUXSPACE, a Grand Duchy of Luxembourg based company has launched PathFinder2, (ex-Rubin) and is now the only European company to have an operational system in orbit providing data from all over the world on a daily basis. The satellite is operated in cooperation with SES ASTRA and REDU Space Services. [7]
In 2007, a previous test of space-based AIS tracking by the U.S. TacSat-2 satellite suffered from signal corruption because the AIS signals interfered with each other.[8]
In July 2009, SpaceQuest launched AprizeSat-3 and AprizeSat-4 with AIS receivers.[9] These receivers have been able to pick up the USCG's SART search and rescue 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 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 20 x 20 x 20 cm. It weighs six kilograms and is shaped like a cube.[10][11]
Class A AIS products are for ships over 300 tonnes or which are SOLAS vessels and are required to meet the guidelines set out in the Marine Equipment Directive.
Class B AIS products are for non-SOLAS vessels. They need testing and certification under the R&TTE Directive for the European Union and FCC and Industry Canada certification for North America.
[edit]
No comments:
Post a Comment