Figure 2 - Maritime traffic in waters off the coast of Singapore, IKONOS 1-meter color, March 2, 2002

Making Waves for Maritime Criminals

Commercial Satellites Provide Unprecedented Ocean Surveillance Capabilities

Jerry Skaw
Marketing Communications Manager
Vexcel Corporation
Boulder, Colo.

Maritime crime has been with us since man first ventured to sea. From the Phoenicians to the Vikings to the legendary eighteenth century buccaneers that have captured our imaginations, pirates have stalked the high seas preying on merchant vessels throughout history.

Figure 1: Total reported incidents in 2003 by region. Numbers in brackets are for 2002.

Maritime crime, however, is more than lore from another time and is not limited to piracy. Criminal offenses at sea remain a problem today and have tripled in the past decade, according to the International Maritime Bureau (IMB). An early 2004 IMB report indicates that worldwide pirate attacks increased in frequency and violence from previous years with a total of 445 attacks reported in 2003. See Figure 1. Apart from piracy, present day illegal activities at sea include drug trafficking, human smuggling, maritime fraud and terrorism, offenses against the maritime environment, and illegal fishing. The latter has become of serious concern to conservationists and international fishing industries as fisheries dwindle. In Australia’s northern waters alone, about 150 illegal Indonesian fishing boats were apprehended this year and it is believed many more are avoiding capture.

The temptation of perpetrators to participate in maritime crime can be attributed, in part, to their knowledge of the difficulties that countries face in combating it due to inadequate legislation, lack of trained personnel and modern equipment, weak maritime law enforcement capabilities, and the sheer vastness of the ocean. Additionally, maritime offenses are often transnational by nature, with more than one national jurisdiction involved, further complicating law enforcement at sea.

In a move to address this latter issue, the United Nations Convention on the Law of the Sea (UNCLOS) was adopted in 1982 at Montego Bay, Jamaica. Critical to the UNCLOS conventions are articles defining the exclusive economic zone (EEZ)—an area, including the ocean floor, extending 200 nautical miles beyond a coastal nation’s territorial sea.

The EEZ concept serves as an important milestone in building an international framework for maritime law, defining a coastal nation’s sovereign rights and jurisdictions over the exploration and exploitation of marine resources within its EEZ. However, the articles do not authorize nations to limit passage through these waters, presenting law enforcement challenges for responsible nations—how to police such a vast area of ocean.

Surveillance From Space

Until recently, strategic maritime reconnaissance has been performed exclusively by airborne platforms or ship-based radars. The effectiveness of these methodologies is limited by the extent of coverage they are able to provide on a daily basis. Already an expensive proposition, these ocean monitoring approaches become cost-prohibitive for nations with large EEZs. The introduction of space-based surveillance complements existing maritime law enforcement assets and permits aircraft and surface ships to more effectively monitor and track suspect vessels as opposed to conducting broad ocean surveillance.

Low-cost, high-caliber synthetic aperture radar (SAR) earth imagery has been commercially available since 1995 when RadarSat-1, a commercial space-borne SAR satellite, began providing 10- to 30-meter resolution imagery. Since that time, other commercial satellites have become available, including the European Space Agency’s ENVISAT ASAR, and electro-optical (EO) systems such as the Indian Remote Sensing (IRS) 1C/D and ResourceSat-1: SPOT 2, 4, and 5; and IKONOS satellites that are capable of providing broad area imagery with resolutions of 1.0 to 20 meters.

Figure 3 Higher resolution satellites allow detailed analysis for positive identification
of even smaller, faster craft like this, often used for smuggling.
In terms of coverage, these satellites can see vast areas of the ocean—the entire eastern coast of the United States, for example—in a matter of minutes. The swath width of a satellite is a function of resolution; the higher the resolution, the more narrow the swath width. Medium resolution commercial satellites such as IRS and SPOT provide wide swath coverage of 70 and 120 kilometers respectively, ideal for monitoring vast EEZs to detect and classify suspect vessels. A higher resolution satellite such as IKONOS, at a one-meter resolution, is better suited for “point targeting,” allowing detailed analysis for positive identification of even smaller, faster craft often used for smuggling. The combination of these systems provides the ability to detect, classify, and identify vessels operating throughout the world. See Figures 2 and 3.

Leveraging these satellite surveillance capabilities to combat offenses at sea requires a solution that provides rapid processing of the data from the time of image acquisition to the dissemination of reports to surface and air law enforcement units. OceanView, a maritime surveillance system jointly developed by Vexcel Corporation (Boulder, Colo.), a global remote sensing company, and the Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) of the University of Miami (Miami, Fla.) addresses the need for such a solution, providing automated ship detection in real-time and at a fraction of the cost of conventional surveillance methods.

OceanView automatically locates ships and other maritime objects within the imagery provided by satellites. It is designed to operate within the processing queue of a ground system and to process image data as soon as it is required. The entire process, from data downlink to report generation, requires little human intervention and takes just under an hour for SAR data—half that for EO data. Once the satellite imagery has been received, the detection process begins with the separation of land data from water data. After this land mask has been established, the system detects objects in the ocean imagery, automatically pre-screening and removing detected objects situated near known stationary points, such as oil platforms. Remaining objects are assigned a ship probability score based on the value of parameters calculated for the detected object that include: length, width, heading, cross-section (integrated brightness), position (line pixel or latitude/longitude), brightness, and ratio of object brightness to mean neighborhood brightness.

Additionally, the system can estimate vessel speed and course through the detection and measurement of ship wakes and can provide ship analysis through image sharpening techniques.

Image analysts control the acquisition of imagery and maritime targets to discern whether detected objects require a closer look by the human eye. They may also interactively adjust the parameter values used to discern ship probability. The entire process can be operated onsite or the data can be quickly moved to a remote location for analysis. Once the results have been reviewed, the analyst may then generate and distribute reports in the NATO standard OTH-GOLD format and in the form of a web page with imagery available worldwide from an encrypted web site.

Because the operations occur in real-time, land and sea forces can be immediately mobilized to intercept suspect vessels. The ability of a satellite to perform electronic intelligence while being completely unobserved by suspect vessels, with real-time streaming of data to other assets, allows maritime law enforcement the element of surprise and reduces the number of manned aircraft placed in harm's way, particularly in a war zone. An additional and significant advantage is the ability to monitor maritime activities at night and in bad weather when movement of clandestine vessels may be most likely.

Seeing Is Believing

In mid 2004, Vexcel and CSTARS demonstrated the OceanView ocean surveillance system installed and operational at the CSTARS ground station facility in South Miami to representatives of the US Navy, Coast Guard, Homeland Security, and the office of the Secretary of Defense.

Figure 4 OceanView-processed image showing detected vessels (indicated by color crosshairs) in waters off Florida Keys.

RADARSAT-1, operated by Radarsat International, was used to provide a real-time, real-world test of the system, structured to prove the suitability of the project for U.S. Homeland Security and coastal surveillance. Within minutes, a detailed picture of the nearby ocean ranging from the Caribbean Sea to the Gulf of Mexico near the panhandle of Florida—a pass of about 4600 km—was captured and available for processing.

As the satellite made its pass, the SAR data was downlinked and archived at the CSTARS facility. Under the careful observation of the distinguished guests, the data were then processed and the ships were automatically detected by the system in real-time.

Figure 5 - Detected objects displayed in OceanView in order of probability. Objects in the top window have been flagged as potential vessels while the objects in the bottom window have been identified as unlikely to be vessels and will not be exported as ships to the Gold Report.

The representatives looked on as quality control was performed on the automatic ship detection and displayed on one of the facility’s large computer monitors. The entire exercise from downlink to ship detection, including verification by experienced imagery analysts, occurred within 60 minutes. The exercise demonstrated the existence of a readily available, low-cost, proven solution to detect and classify ships within a probability range of 95 to 98 percent—an alternative to the traditional methods of ship detection involving aircraft and high resolution government satellites, allowing an unprecedented broad surveillance range through inexpensive, medium-resolution commercial satellites.


Maritime crime today is much more complex and sophisticated than in earlier centuries when legendary pirates terrorized the high seas, and presents serious security and law enforcement concerns for coastal nations. Order at sea must be secured to permit the free flow of sea-borne trade and to ensure the preservation and protection of marine environments. To step up actions to counter this growing menace, maritime law enforcement agencies must now look to innovative technology solutions for effective ocean surveillance.

Satellite maritime surveillance systems such as OceanView offer a new approach to tracking objects in the oceans and is based on technology already proven for other SAR and EO applications such as coastline monitoring, oil-slick detection, ground motion detection, coherent change detection, and coherent target monitoring. This new application allows cost-effective, broad-range ocean monitoring capabilities through readily available commercial satellite imagery. In doing so, solutions like OceanView allow coastal nations to respond to maritime crime in a proactive and coordinated manner, and to give no quarter to today’s pirate vessels.

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