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ABSTRACT
Space-based detection of Automatic Identification System (AIS) transmissions is increasingly being used as a means of collating vessel information for building Maritime Domain Awareness (MDA). With the introduction of “Long-Range AIS” through a specific AIS message (Message 27), designed for reception from space, some of the existing problems with space-based vessel detection would be obviated. Nonetheless, the system cannot replace terrestrial detection. In some cases, interaction between the two segments – space and ground based – of the system may even render one segment totally ineffective. From the user-perspective, an examination of the underlying technical issues will help understand the capabilities and limitations of the system as an aid to global vessel tracking. Designing future sub-systems to optimally exploit the changes is important.
Notes on contributors
Commodore Arun Pratap Golaya is a serving Indian Naval Officer, an Associate Member of the National Maritime Foundation and currently pursuing doctoral research in the field of vessel tracking. The views expressed are his own and do not reflect the policies or views of the Indian Navy and Government of India. Email: [email protected]
Dr. Nithiyanandam Yogeswaran is an Assistant Professor at TERI School of Advanced Studies. An interdisciplinary researcher, he is currently working in the field of applied Geo-informatics. Email: [email protected]
Notes
1 Resolution MSC.74(69), “Adoption of New and Amended Performance Standards,” International Maritime Organisation, 1998.
2 International Convention for the Safety of Life at Sea (SOLAS), Chapter V, “Carriage Requirements for Shipborne Navigational Systems and Equipment”.
3 Recommendation ITU-R M.1371-4, “Technical Characteristics for an Automatic Identification System Using Time-Division Multiple Access in the VHF Maritime Mobile Band,” Radiocommunication Sector of International Telecommunication Union, 2010.
4 Arun Pratap Golaya, “Maritime Domain Awareness: Challenges and Effective Exploitation,” in Indian and American Perspectives on Technical Developments in the Maritime Domain and Their Strategic implications in the Indian Ocean Region, ed. Pradeep Kaushiva and K.K Agnihotri (New Delhi: KW Publishers, 2013), 107.
5 In the SOTDMA multiplexing system, time is divided into slots, with each ship that is transmitting in a particular slot also “reserving” a subsequent vacant slot for itself. Other ships in the vicinity are free to transmit in the slots that are vacant and have not been reserved. In this way, two ships would not transmit at the same time. The AIS system has 2250 time slots per minute.
6 Ibid.
7 “Reliability of Ship-Identification System in Doubt,” Tradewinds, September 7, 2007, 42.
8 Martin N. Murphy, “Lifeline or Pipedream? Origins, Purposes, and Benefits of Automatic Identification System, Long-Range Identification and Tracking, and Maritime Domain Awareness,” in Lloyd’s MIU Handbook of Maritime Security, ed. Rupert Herbert-Burns et al. (Boca Raton Florida: CRC Press, 2009), 13–25. (Quoting a 2007 interview with an unnamed “maritime official”).
9 Steve Carmel (Senior Vice President, Maritime Services for Maersk Line) as quoted by Matt Hilburn, “Broader Picture,” Sea Power 50, no. 12 (2007): 33.
10 GNSS is a generic term covering satellite-based navigation systems with global coverage such as the Global Positioning System or GLONASS. Any of these can be used to provide positional information about the ship to the AIS. The position so received is then transmitted to other ships by the AIS.
11 Arun Pratap Golaya, “Maritime Domain Awareness: Challenges and Effective Exploitation,” note 4, 111.
12 M. Baldauf, K. Benedict, and F. Motz, “Aspects of Technical Reliability of Navigation Systems and Human Element in Case of Collision Avoidance” (paper presented at Navigation Conference and Exhibition, London, UK, October 28–30, 2008).
13 Recommendation ITU-R M.1371-4, “Technical Characteristics for an Automatic Identification System Using Time-Division Multiple Access in the VHF Maritime Mobile Band,” note 3.
14 Ibid.
15 Mariusz Kościelski, Ryszard K. Miler, and Mariusz Zieliński, “Automatic Identification System (AIS) as a Main Tool of NCAGS ADP Systems,” 2007, https://www.amw.gdynia.pl/images/AMW/Menu-zakladki/Nauka/Zeszyty_naukowe/Numery_archiwalne/2007/Koscielski,_Miler,_Zielinski.pdf (accessed July 10, 2018).
16 ANAPROP conditions are said to exist when extended ranges are obtained due to radio waves travelling in “ducts”, which are formed due to specific atmospheric conditions.
17 Martin N. Murphy, “Lifeline or Pipedream? Origins, Purposes, and Benefits of Automatic Identification System, Long-Range Identification and Tracking, and Maritime Domain Awareness”, note 8.
18 INMARSAT terminals are satellite communication terminals provided commercially by a number of companies.
19 COMSAR/Circ.32 dated August 16, 2004, “Harmonization of GMDSS Requirements for Radio Installations on board SOLAS Ships”.
20 Alice Lipowicz, “Coast Guard Plans Data Center to Monitor Vessels,” Washington Technology, May 1, 2008.
21 Ibid.
22 The cost of each report is 25 cents thereby entailing a cost of 1 USD per ship tracked per day for six-hourly reports.
23 U.S. Coast Guard. “LRIT Frequently Asked Questions,” https://www.navcen.uscg.gov/?pageName=lritFaq (accessed July 18, 2018).
24 G. Hoye, “Observation Modelling and Detection Probability for Space-Based AIS Reception – Extended Observation Area,” Norwegian Defense Research Establishment, FFI/RAPPORT-2004/04390, 2004.
25 For example, see T. Eriksen et al., “Maritime Traffic Monitoring Using a Space-based AIS Receiver,” Acta Astronautica 58 (2006): 537–49 and O.F.H. Dahl, “Space-based AIS Receiver for Maritime Traffic Monitoring Using Interference Cancellation” (M.S. thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2006).
26 Technical Report ITU-R M.2123, “Long Range Detection of Automatic Identification System (AIS) Messages Under Various Tropospheric Propagation Conditions,” International Telecommunications Union, 2007.
27 For example, see M.A. Cervera, A. Ginesi, and K. Eckstein, “Satellite-based Vessel Automatic Identification System: A Feasibility and Performance Analysis,” International Journal of Satellite Communications and Networking 29 (2011): 117–42; F. Hennepe et al., “Space-based Detection of AIS Signals” (5th Advanced Satellite Multimedia Systems Conference (ASMA) and the 11th Signal Processing for Space Communications Workshop (SPSC), 2010), 17–24; and, P. Burzigotti, A. Ginesi, and G. Colavolpe, “Advanced Receiver Design for Satellite-Based AIS Signal Detection” (5th Advanced satellite multimedia systems conference (ASMA) and the 11th signal processing for space communications workshop (SPSC), 2010), 1–8.
28 T. Eriksen et al., “Tracking Ship Traffic with Space-Based AIS: Experience Gained in First Months of Operations” (paper presented at International Waterside Security Conference (WSS), Carrara, Italy, November 3–5, 2010).
29 Andis Dembovskis, “AIS Message Extraction From Overlapped AIS Signals for SAT-AIS Applications” (PhD dissertation, University of Bremen, 2015).
30 Demodulation is simply the process of “extracting” information embedded in a radio signal.
31 Collision could occur when two messages are received simultaneously at the receiver, possibly resulting in neither of them being demodulated.
32 O.F.H. Dahl, “Space-Based AIS Receiver for Maritime Traffic Monitoring Using Interference Cancellation” (M.S. thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2006).
33 A. Burzigotti et al., “Advanced Receiver Design for Satellite-Based AIS Signal Detection,” note 27.
34 M. Zhou, A.J. Veen and R. Leuken, “Multi-User LEO-Satellite Receiver for Robust Space Detection of AIS Messages” (paper presented at IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Kyoto, Japan, March 25–30, 2012).
35 F. Hennepe et al., “Space-Based Detection of AIS Signals,” note 27.
36 A. Burzigotti et al., “Advanced Receiver Design for Satellite-Based AIS Signal Detection,” note 27.
37 Presentation made during the Workshop on International Standardisation of Next Generation AIS (VDE) organised by the Japanese Coast Guard at Tokyo, Japan 3–7 December 2017, http://www.sjofartsverket.se/pages/41996/e-NAV13-38%20Tokyo%20workshop%20report.pdf (accessed August 12, 2018).
38 G.K. Høye et al., “Space-Based AIS for Global Maritime Traffic Monitoring,” Acta Astronaut 62 (2008): 240–5.
39 CMRE, earlier known as NATO Undersea Research Center, based in La Spezia, Italy is the executive body of NATO’s Science and Technology Organisation which conducts research focused on technology development for the maritime domain.
40 G. Cimino et al., “Sensor Data Management to Achieve Information Superiority in Maritime Situational Awareness” (CMRE Formal Report, NATO, Brussels, Belgium, 2013).
41 Giuliana Pallotta, Michele Vespe, and Karna Bryan, “Vessel Pattern Knowledge Discovery from AIS Data: A Framework for Anomaly Detection and Route Prediction,” Entropy 15 (2013): 2218–45.
42 B.T. Narheim and R. Norsworthy, “AIS Modeling and a Satellite for AIS Observations in the High North, Draft New ITU-R Report Improved Satellite Detection of AIS” (Radiocommunication Sector of International Telecommunication Union, ITU-R Working Party 5B, 2008).
43 ITU Report ITU-R M.2169, “Improved Satellite Detection of AIS,” Radiocommunication Sector of International Telecommunication Union, 2009.
44 “Class B” AIS can be used by vessels such as pleasure craft and yacht on which the system is not mandatory but which may want to install the system to reap its benefits. The specifications for this are less stringent.
45 Message 1 is the standard position report message used by AIS.
46 Andis Dembovskis, “AIS Message Extraction From Overlapped AIS Signals for SAT-AIS Applications,” note 29.
47 E.R. Bruin, “On Propagation Effects in Maritime Situation Awareness: Modelling the Impact of North Sea Weather Conditions on the Performance of AIS and Coastal Radar Systems” (Utrecht University Master’s Thesis, 2016).
48 Ibid.
49 D. Green et al., “VHF Propagation Study,” Contractor report DRDC-ATLANTIC-CR-2011-152, Defence R&D Canada, 2012.
50 Technical Report ITU-R M.2123, “Long Range Detection of Automatic Identification System (AIS) Messages Under Various Tropospheric Propagation Conditions,” note 26.
51 Ibid.
52 The International Standard Atmosphere is an atmospheric model (established to provide a common reference) to describe how pressure, temperature, density and viscosity of the Earth’s atmosphere change over altitude. At Mean Sea Level (MSL), the values are 15 degrees centigrade temperature, 1013.25 hpa pressure and a lapse rate of −1.98 degrees centigrade per 1000 feet gain in altitude.
53 Andreas Nordmo Skauen, “Quantifying the Tracking Capability of Space-Based AIS Systems,”Advances in Space Research 57 (2016): 527–42.
54 Ibid.
55 Defence R&D Canada Technical Memorandum, 2006–32. “The Implications of Self-Reporting Systems for Maritime Domain Awareness,” http://pubs.drdc.gc.ca/inbasket/hammond.061031_1017TM%202006-232.pdf (accessed April 21, 2012).