Technology

Applications and Vulnerabilities of Satellite Navigation Systems in Global Freight Transportation

The Jin Nui Zou is an oil tanker owned by the China Shipping Tanker Company Ltd. [1] On September 5th, 2019 the vessel entered the Port of Dalian oil terminal in Northeast China. Dalian is the headquarters of two subsidiaries of COSCO shipping which were sanctioned by the U.S. government for importing Iranian crude oil. [2] Like all large cargo and passenger vessels, the Jin Nui Zou is equipped with an automatic identification system (AIS). This system transmits the ship's identity, location, direction, speed and other characteristics to nearby vessels and a network of AIS stations and satellites. AIS tracking of the Jin Nui Zou shows it entered the Port of Dalian on a normal course. [3] As the ship approached the terminal from the southeast, however, the vessel's AIS positions suddenly scatter throughout the port with some showing the vessel traveling at a very high speed. Eventually the vessel's AIS positions settle into a circular pattern centered around a location inside of the oil terminal tank field—on land.

AIS is a cornerstone of modern marine navigation. It is used by vessel operators to avoid collisions with other vessels, and by shipping companies to track and manage their fleet. AIS also is used by a number of authorities to monitor the activities of cargo and fishing fleets, for search and rescue operations, for aids to navigation and for other applications. AIS does not work, however, without the precise location and time provided by GPS and other global navigation satellite systems (GNSS). Global positioning, navigation and timing (PNT) provided by GNSS forms the foundation of marine navigation, railroad operations, trucking operations, military operations, cellular communication, financial exchanges, power systems, driving with Google Maps, Uber, DoorDash, and countless other applications. GPS and the other GNSS constellations are the only true global utility—free, ubiquitous and essential. The economic value of GPS is estimated in the trillions of dollars. And in the U.S. we do not have a backup system.

GPS is one of four global systems—BeiDou (China), Galileo (E.U.), GLONASS (Russia) and GPS (U.S.)—and three regional systems (RNSS)—NavIC (India), BeiDou Compass (China) and QZSS (Japan). Over 75 percent of GNSS devices can use signals from multiple constellations. [4] Developed by the U.S. military in the 1970s, GPS consists of a core constellation of 27 satellites—31 are currently in service—which fly in medium Earth orbit approximately 20,200 km (12,550 miles) above sea level. [5] The satellites and other infrastructure are managed by the U.S. Space Force—a new branch of the military under the Secretary of the Air Force. Each satellite has a precise atomic clock and broadcasts a radio signal providing its location, status and time. Civilian users were given access to the full, non-degraded signal in 2000. GPS has a new, more secure M-Code signal nearing completion that will be restricted to military use. [6] Encryption with M-Code will combat the increasing threat of GPS interference.

The tracking phenomenon seen with the Jin Nui Zou is one of tens of thousands of GNSS "spoofing" incidents documented over the last decade. Similar circular patterns were seen near 15 other Chinese oil terminals in the summer and fall of 2019. [7] A 2019 report by C4ADS—an organization that researches global conflict and security issues—documented 9,883 instances across 10 locations that affected 1,311 civilian vessel navigation systems near Russian occupied territories and overseas military facilities. [8] It also found a correlation between GNSS interference events and movements of the Russian head of state, interference emanating from a Russian airbase in Syria and interference along the Russian coast and Crimea in the Black Sea emanating from a "palace" reported to be built for President Putin.

Interference with GNSS signals is not a new phenomenon. Devices that are able to overpower faint GPS signals ("jamming") were used in the 1991 Persian Gulf War several years before GPS was fully operational and almost a decade before the non-degraded signal was made available to civilian users. Jamming GNSS radio frequencies blocks reception to a receiver, preventing it from calculating a geographic location or accessing the timestamp. The incidents at Chinese oil terminals and Russian facilities used a more sophisticated device with the ability to mimic or "spoof" a legitimate GNSS signal in order to manipulate position and time data. Both jamming and spoofing are a threat to any service relying on PNT. Spoofing, however, poses a more serious threat and there are few countermeasures for the billions of devices in use today.

GPS was originally developed for military navigation and pinpoint weapons delivery—to "drop 5 bombs in the same hole." [9] Today, there is almost one device with a GNSS receiver for every person on the planet. [10] The vast majority of these devices are smartphones, followed in a distant second by wearable devices. [11] While smaller in number, GNSS is used for navigation and timing in transportation, energy, financial markets and other segments of the economy. GNSS satellites are equipped with extremely precise atomic clocks which serve as the reference time for power grids, cellular communications networks, financial markets and other applications. To determine its location, a GNSS device compares the time it receives a signal to the time the satellite sent it and calculates a geometric sphere. With signals from four separate satellites, a precise location can be determined by calculating the point where the spheres intersect.

The accuracy of positioning based on GNSS depends on satellite geometry, signal blockage, atmospheric conditions and the receiver's design/capabilities. To improve accuracy, ground-based and satellite-based augmentation systems have been developed. There are four primary satellite-based augmentation systems (SBAS) serving specific geographic areas including the U.S. Wide Area Augmentation System (WAAS) and European Geostationary Navigation Overlay System (EGNOS). SBAS satellites broadcast correction signals that are used for signal integrity, wide area corrections and as an extra navigation signal in some cases.

Ground-based augmentation systems use a network of stations with precise known locations. These stations continuously compare their position based on GNSS signals with their known location, and broadcast a correction signal that can be used by differential GNSS receivers to improve the accuracy of their position. The U.S. Coast Guard operated a ground-based differential GPS (DGPS) with 85 broadcast stations that provided nationwide coverage for land navigation and 50 nautical miles offshore. Developed in the late 1980's and early 1990's, DGPS improved positioning accuracy from several meters to less than one meter. With the improved accuracy of un-augmented GNSS and the use of satellite-based augmentations systems, however, DGPS was no longer need. After more than 25 years of service, the Coast Guard switched off the final four stations located in the Great Lakes and the St. Lawrence Seaway in June of last year. [12]

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About the Speaker

Kellen Betts is a Project Manager in the Sustainable Supply Chains lab at the MIT Center for Transportation & Logistics. He collaborates with industry, non-profit organizations, and other stakeholders to advance supply chain sustainability. Kellen has over fifteen years of experience in supply chain and analytics working for small businesses and Fortune 500 corporations. He writes the newsletter Supply Chain Weekly and organizes Supply Chain Connect (reCONNECT 2021), an annual conference on supply chain management and technology. Prior to joining MIT, Kellen led a research and development firm, which launched a technology platform for port trucking and logistics, and worked in supply chain, analytics, and engineering at REI, Zulily, PACCAR, JBE Inc., and Vigor Industrial. He received a M.S. degree in Global Supply Chain Management from Portland State University and a M.S. degree in Applied Mathematics from the University of Washington.

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