Orbcomm, a global satellite messaging company, today announced the successful launch of VesselSat1 (pdf), an Automatic Identification Service (AIS) satellite built by LuxSpace, an affiliate of OHB System AG.
VesselSat1 was launched by the Indian Space Research Organization (ISRO) near the Bay of the Bengal. The satellite has successfully separated from the launch vehicle in a proper equatorial orbit and is undergoing initial in-orbit testing. It is expected to enter into commercial service before year end.
Orbcomm is the exclusive licensee for AIS data collected by VesselSat1. AIS data is used for ship tracking and other maritime navigational and safety efforts.
Orbcomm launched six AIS-equipped satellites in 2008. But the AIS satellites ceased functioning “toward the end of the fourth quarter 2010.” As part of its settlement with OHB Technology of Bremen, Germany, OHB and its Luxspace affiliate built the two dedicated AIS spacecraft for Orbcomm, following the failure of their six “Quick Launch” satellites.
The U.S. Coast Guard gave Orbcomm an initial AIS contract, but that ended in late 2010 when the last of Orcomm’s six AIS-equipped satellites failed in orbit.
VesselSat1 will expand the coverage of ORBCOMM’s satellite AIS service in the equatorial region, where there is significant shipping activity and critical need for maritime surveillance. VesselSat2, which will have a polar orbit, is planned to be launched later this year. They will supplement ORBCOMM’s next generation constellation (pdf). Some 18 AIS-enabled satellites are currently under construction by Sierra Nevada Corporation. SpaceX will launch these 18 satellites.
Orbcomm’s 27 current-generation satellites operate for the most part in an 825-kilometer orbit inclined 45 degrees relative to the equator. The second generation will be placed into a 52 degree inclination, an orbit that gives better coverage of northern latitudes to enhance Orbcomm’s AIS maritime coverage.
Orbcomm is in a race to be first to market with a global AIS service. Canada’s Com Dev, and its subsidiary ExactEarth, and several government agencies in Europe are developing competing systems. The first Norwegian AIS Satellite, AISSat-1, has been operational for over a year.
Canada’s Com Dev claims their patented technology for “message de-collision” is superior to what Orbcomm uses. Com Dev’s technology is based on bypassing on-board processing on the satellites in favor of sending down raw message data to ground terminals. These terminals then separate hundreds of thousands of ship messages — up to 1.5 million per day per satellite — and deliver them to coastal authorities.
ExactEarth claims to be the world’s leading Satellite-based vessel monitoring service. They successfully launched two advanced AIS satellites this summer. Their spacecraft were built by SpaceQuest.
Their COM DEV core technology is said to enable ExactEarth to filter out all but a very specific VHF portion of the signals dedicated to AIS. To achieve global AIS coverage with a latency of about 10 minutes about 30 satellites are required.
COM DEV has calculated that only three satellites are needed to provide a six hour “revisit time”. According to CEO John Keating, “If you put three satellites in polar orbits that takes 100 minutes to complete, 120 degrees apart from one another, then [due to the earth’s rotation] you can see any point on earth within six hours – you may be over the poles once every 30 minutes, but you are everywhere over the equator once every six hours.”
ExactEarth AIS satellites pass over Norway’s Svalbard Earth Station every 90 to 100 minutes. AIS tracks vessel movements in near real-time and updates every two minutes when near shore stations. Terrestrial AIS transponders, using frequencies near 150 MHz, can’t reach ships in the open ocean. Small messaging satellites can.
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