The possibility to detect automatic identification system ais messages from low earth orbit leo satellites paves the road for a plurality of new and unexplored services. Getting started with open broadcaster software obs duration. Satellite ais automatic identification system is a vessel identification system that is used for collision avoidance, identification and location information. Today, fleetmons antennas offer live coverage of all major waterways and ports, with about 40,000 vessels detected in every single moment. Displays ais class a and b vessels, search and rescue helicopters, base stations, aids to. An ais message can be best received by the receiver at a low satellite elevation angle, meaning that the satellite can best capture ais signals when it is close to the horizon.
The powerful nature of these communicationgrade satellites allows for near realtime decoding and. Overview spacecraft launch mission status sensor complement ground segment references. Zooms to chart location on receiving first ais data no need for gps. Digital optical systems based on coherent and direct detection. Satellite software free download satellite top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. A multichannel coherent receiver allows signal samples from two different antennas to be synchronized against time, allowing for all sorts of interesting applications such as passive radar and direction finding.
Access to accurate, reliable and timely data about the position and. The main purpose of this chip and the same dongle of the same name was to receive tv in the dvbt format. Ais is a maritime wireless system designed to identify basic parameters relating to the position, heading, destination and cargo of larger vessels with the main purpose of collision avoidance. Cls has developed a wide range of satellite applications. The matched receiver is the logical conclusion of the optimal receiver calculation. The fleetmon explorer allows its customers to watch marine. Sdr based single channel sais receiver for satellites. Constellation of small quicklaunched and selfdeorbiting nanosatellites with ais receivers for global ship traffic monitoring thu vu trong 1, tri dinh quoc 1, thang dao van 1, hung pham quang 1, hugo nguyen 2 1 fspace laboratory, fpt technology research institute, fpt university, hanoi, vietnam phone. Noncoherent sequence detection scheme for satellitebased. The coherent detection based demodulation algorithm proved to be a. Rcm is a constellation of three satellites, all in the same orbit plane, and all equally spaced around the orbit plane. With its landbased ais receiver station network, fleetmon provides undelayed signals with superior resolution for vessel tracking and monitoring.
Abstractza002 is the second south african satellite, and is scheduled to be launched in december 2006. This paper covers the software defined radio sdr based receiver. Advanced receiver design for satellitebased automatic identification system signal. Ais is a universal shipborne automatic identification system recently introduced for traffic monitoring and safety at sea. Since ais was not originally designed for space detection, two challenges arise. We will make the use of the general framework developed in 7, 9, 10 in order to derive the system level performance of such advanced ais receiver.
A software defined radio sdr automatic identification system ais receiver is proposed as a possible experimental payload for this satellite. The ais receiver can be used to track and store movement of ships at sea, and. Coherent applications rtlsdr multichannel coherent. Satellite ais automatic identification system orbcomm.
Cls, operating a data centre fed with multiple spaceborne sources and delivering satais high valueadded services. Reconfigurable softwaredefined radio sdr technology is used, enabling. Coherent receiver for ais satellite detection by m. Artes 5 specific technology predevelopment activities, including antenna miniaturisation, receiver developments, and a performance testbed in the form of an endtoend simulator. Accordingly, radar detection equipment must provide accurate information of the returned radio wave. This unique solution has been trusted by government and commercial operators in over 50 countries since 2001. Coputing and novel software technology, tianjin university of technology, tianjin 300384, china email. A softwaredefined radio implementation of maritime ais core. Communication systemscoherent receivers wikibooks, open. This marine ais receiver works great with opencpn, openplotter, ship plotter and any other software that accepts serial data input. A carrier recovery system is a circuit used to estimate and compensate for frequency and phase differences between a received signals carrier wave and the receivers local oscillator for the purpose of coherent demodulation. The postcorrelation algorithms, however, can be using standard measurements such as satellite orbit information and signal to noise ratio snr measurements either from our dedicated software receiver or. Satellite automatic identification system satais overview. Constellation of small quicklaunched and selfdeorbiting.
Advanced receiver design for satellitebased automatic identification. Also this receiver system was tested on a space grade fpga and the performance was found to be satisfactory. Satellite ais view marine traffic in realtime vessel. Evaluation of fpgabased software radio beamformers for 3g wireless. Since the ground track repeat for each satellite is 12 days, there is a constellation ccd period of 4 days. Improved satellite detection of ais 2009 1 introduction satellite detection of ais messages has been requested by administrations. Blue sky network offers the most advanced vessel monitoring system vms by combining its proprietary realtime tracking and satellite communication products with global satellite automatic identification system ais technology. In this work we propose a directdetection coherent receiver that combines the advantages of coherent transmission and the costeffectiveness of direct detection. Related works rtlsdr multichannel coherent receivers.
Ship detection using high resolution satellite imagery and. Advanced receiver design for satellitebased automatic identi. It was developed to provide identification and positioning information to both vessels and shore stations. Exactearth satellite marine traffic fleet monitoring. The automatic identification system ais is a shortrange coastal tracking system currently used on ships. The enhanced receiver makes use of a coherent receiver for the low signaltonoise ratio snr region, while for medium to high snrs, a differential viterbi receiver is used. Gnss interference detection with software defined radio. Coherent receiver for ais satellite detection ieee conference. Satellite ais is also used for maritime domain awareness, search and rescue, environmental monitoring and maritime intelligence applications. In a receiver using coherent detection, local oscillation is arranged to be synchronous with the signal produced by the transmitter that is radiated by the radar system antenna. An rtlsdr multichannel coherent receiver is at its most basic, two or more rtlsdr dongles multichannel that are running from a single clock source coherent. The proposed receiver is based on the viterbi algorithm with cyclic redundancy check crc trellis. Besides worldwide tracking of vessels, maritime traffic monitoring, analysis of vessel routes employing big data, and oceans monitoring are just few of the fields, where satelliteaided ais is beneficial.
Terrestrial vs satellite ais was developed as a short range, high intensity system with a lineofsight range of 1020 miles between the transponders and terrestrial shore and vessel based receivers. Satellite software free download satellite top 4 download. The coherent detection based demodulation algorithm proved to be a viable option in terms of both performance and simplicity for the sdr based receiver system. Just plug in your ais receiver works with nmea 0183 or usb connection. Cyclic redundancy checkbased detection algorithms for. Multiuser leosatellite receiver for robust space detection of ais messages. The interest for shortreach links of the kind needed for interdatacenter communications has fueled in recent years the search for transmission schemes that are simultaneously highly performing and cost effective. Crcbased detection algorithms for ais signals received by satellite. In order to solve the problem, a new design of pll is proposed based on the theory of conventional pll. Coherent demodulation of aisgmsk signals in cochannel interference. Satais satellite automatic identification system esa. Advanced receiver design for satellitebased automatic.
Due to a wide range of doppler frequency shift and low snr existing in the ais transmission, it is difficult to decode correctly in satellitebased ais receiver. Sorger, coherent receiver for ais satellite detection. A software defined radio ais for the za002 satellite. The ship detection or recognition is achieved in two steps. Improving upon existing technology already deployed aboard most large vessels across the globe, satellite ais is truly revolutionary in providing a complete and global picture of the worlds shipping. On the performance analysis of a satellitebased ais system. Orbcomm launched six of the industrys most powerful ais satellites in 2014, significantly improving our ability to provide global ais datathe volume of ais receptions increased, while latency and satellitevessel revisit times decreased.
Crcbased detection algorithms for ais signals received by. Furthermore, no new advanced random access schemes tailored to ais satellite reception have yet been introduced clazzer et. The report considered the operational and technical characteristics. Coherent receiver for ais satellite detection request pdf. The satellitebased automatic identification system ais receiver has to encounter the frequency offset caused by the doppler effect and the oscillator instability. The reception of ais signals by satellite was investigated in 2, 3, where an enhanced sensitivity receiver was designed.
An advanced ais receiver using a priori information. Our ais receiver in a satellite extends the range considerably and make it. Ais signals sent from the landbased stations have a range of 40 nautical miles. The receiver is powered by an onboard dsp which performs the lowlevel signal processing functions, assisted by its accompanying windows application software.
This paper proposes a noncoherent sequence detection scheme for the satellitebased ais signal transmitted over the white gaussian noise channel. The work in 7, shows that the mac protocol of ais as perceived at a. Vesselsat refers to a constellation of two microsatellites, a ground station, all related software, and the operations framework. Design of frequency tracking loop for satellitebased ais.
The dsp controls functions such as the dpll, decoding, decoder bit rate selection, bit sync, word sync and the removal of the manchester encoding from the baseband signal. Performance of ais sensors in space maritime forum. The ais is a selforganized time division multiple access communication system, which has been primarily designed to avoid collisions between large vessels. For vessels in distress, orbcomms ais service can identify exactly where a vessel is located anywhere in the world even if it continues to drift from the distress location.
Satellite ais overview exactearth ais vessel tracking. Sdr based single channel sais receiver for satellites using system. Coherent detection can provide a potential improvement up to 20 db in the receiver sensivity unlike directdetectionbased systems for a given power budget, this would allow to increase the total length of an. Ships of 300 gross tonnage or more sailing on international voyages, cargo ships of 500 gross tonnage or more sailing in local waters, and all passenger ships irrespective of size. A radar system may have a coherent or a noncoherent receiver. Additional novelty of our work is in the exploitation of previously decoded packets from one vessel that is still under the leo reception range, to improve the vessel detection probability. The church media guys church training academy recommended for. Chapter 5 satellite signal acquisition, tracking, and data. However, since installation of the ais transmitter and the location of the antenna are not tightly regulated, it might be possible that parts of the superstructure of. An advanced ais receiver using a priori information elib dlr.
Sais satelliteautomatic identification system payload. The matched receiver convolves the signal with itself, and then tests the output. With its small size and very low power consumption, daisy is. A noncoherent receiver for automatic identification system ais signals is proposed in this paper. Chapter 5 satellite signal acquisition, tracking, and data demodulation phillip w. Testbed for performance evaluation of satais receivers core.
In response, studies were made that were documented in report itur m. A satellitebased ais system will increase this range tremendously to cover larger ocean areas, thus making. Enhanced ais receiver design for satellite reception. Radarsat constellation eoportal directory satellite. Aisgmsk receiver on fpga platform for satellite application. Satellite detection of automatic identification system. Operation of a constellation of leo satellites targeting ais detection is currently. Coherent receiver for ais satellite detection core.
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