GPS World

Tag: Korea Research Institute of Ships and Oceans Engineering

  • UrsaNav installs eLoran testbed in South Korea

    UrsaNav installs eLoran testbed in South Korea

    The eLoran transmission site at Incheon, South Korea. (Photo: UrsaNav)
    The eLoran transmission site at Incheon, South Korea. (Photo: UrsaNav)

    South Korean is in the early stages of evaluating its eLoran system, but great results are expected based on the UrsaNav-supplied station in Incheon.

    In August 2018, the Korea Research Institute of Ships and Oceans Engineering (KRISO) awarded UrsaNav, through its agent Dong Kang M-Tech, a contract to supply and install an eLoran transmitter testbed system in South Korea. UrsaNav is the exclusive, worldwide distributor of Nautel’s NL Series transmitters, provided eLoran transmitter technology, as well as timing, control and differential reference station equipment for the testbed. The contract represented the first phase in a broader program to upgrade Korea’s Loran-C stations to be the foundation of a sovereign Enhanced Loran (eLoran) positioning, navigation and timing (PNT) service.

    “The Republic of Korea recognizes the challenges associated with relying solely on space-based signals, the relative ease with which those signals can be jammed or spoofed, and the necessity to provide trusted time and trusted position to its citizens and critical national infrastructure,” said Charles Schue, CEO of UrsaNav.

    The 35-meter eLoran transmit antenna in Incheon. (Photo: UrsaNav)
    The 35-meter eLoran transmit antenna in Incheon. (Photo: UrsaNav)

    Many critical infrastructure sectors rely on accurate time and position, including maritime, aviation, electrical distribution, telecommunications, finance/banking, and digital broadcast. A complementary PNT (CPNT) service provides continuity of operations through alternative and diverse timing and positioning information. CPNT is a vital element in ensuring national security and assuring trusted time and position.

    KRISO, in conjunction with the Korea Ministry of Oceans and Fisheries (MOF), is developing an Initial Operating Capability eLoran system to provide complementary PNT services as a part of its Electronic Navigation (E-Navigation) mission. KRISO selected UrsaNav Inc. as its prime eLoran systems contractor through a competitive tender offer.

    UrsaNav provided, installed and tested an eLoran transmission system at a temporary location near Incheon, South Korea, in November 2019. The company also provided ancillary equipment for Additional Secondary Factor (ASF) map measurements and map-generation software, as well as differential reference station equipment to KRISO. Because of land size restrictions at the temporary site at Incheon, the eLoran transmission system was paired to a small footprint 35-meter top-loaded monopole antenna.

    In addition to the equipment provided by UrsaNav, MOF separately contracted a local Korean firm to provide an interim GPS receiver set to synchronize the existing Loran-C sites at Pohang and Kwangju to UTC.

    UN-1300 eLoran transmission equipment. (Photo: UrsaNav)
    UN-1300 eLoran transmission equipment. (Photo: UrsaNav)

    KRISO is in the early stages of measuring the performance of the Korea eLoran system, but results are expected to show better than 20-meter navigational accuracy within 30 kilometers of the differential reference station at the port of Pyeongtaek.

    Once the eLoran performance has been proven, MOF plans to move the Incheon eLoran equipment to a permanent site, potentially on the island of Socheongdo, and pair it with a larger “Tee” antenna to increase the output power and coverage area of the system.

    MOF also plans to upgrade the existing UTC synchronized Loran-C transmission sites at Pohang and Kwangju with new eLoran transmission equipment systems. The ministry will potentially add two additional transmission sites to provide complete coverage of the land and territorial waters of South Korea.

  • Korea institute awards UrsaNav an eLoran test bed contract

    The Korea Research Institute of Ships and Oceans Engineering (KRISO) has awarded UrsaNav a contract to supply an eLoran Transmitter Test Bed System in the Republic of Korea.

    UrsaNav, the exclusive, worldwide distributor of Nautel’s NL Series transmitters, will provide eLoran transmitter technology, as well as timing and control equipment.

    A meeting to kick off the eLoran work. (Photo: UrsaNav)
    A meeting to kick off the eLoran work. (Photo: UrsaNav)

    The contract, awarded through UrsaNav’s agent Dong Kang M-Tech, represents the first phase in a broader program to upgrade Korea’s Loran-C stations to be the foundation of a sovereign Enhanced Loran (eLoran) positioning, navigation and timing (PNT) service.

    The Republic of Korea recognizes the challenges associated with relying solely on space-based signals, the relative ease with which those signals can be jammed or spoofed, and the necessity to provide trusted time and position to its citizens and critical national infrastructure, UrsaNav said in a press release.

    The press release also included the following description of the importance of eLoran.

    Accurate time and position are necessary components upon which many critical infrastructure sectors rely, including maritime, aviation, electrical distribution, telecommunications, finance/banking, and digital broadcast. A complementary PNT (CPNT) service provides continuity of operations through alternative and diverse timing and positioning information. CPNT is a vital element in ensuring national security and assuring Trusted Time and Trusted Position.

    eLoran is the latest in the longstanding series of low-frequency (LF), LOng-RAnge Navigation (LORAN) systems. It meets the accuracy, availability, integrity, and continuity performance requirements for maritime harbor entrance and approach maneuvers, aviation En Route and Non-Precision Approaches, land-mobile vehicle navigation, and location-based services. It provides bearing (azimuth) information, even when the user is not moving, and has built-in integrity. Users within the coverage area can simultaneously synchronize their timing to absolute (not relative) UTC. Of equal importance is that the eLoran signal includes one or more Loran Data Channels that are available to provide one-way, low data rate, “Short Message Service” information.

    eLoran is completely independent of GPS/GNSS, operates in the internationally protected 90 to 110 kHz spectrum, is built on internationally standardized Loran-C, and provides a high-power PNT service for use by all timing and navigation users. SAE International expects to release eLoran standards this year. The RTCM also has maritime-related eLoran standards underway.

    eLoran is a key vertex of a Resilience Triad that would typically include space-based, terrestrial, and at least one other PNT source. It is a very-wide area (i.e., country-wide or “continental”) source of PNT that continues providing a resilient solution even when GNSS may be unavailable or untrustworthy. eLoran delivers information comparable to that of GNSS, but with completely different phenomenology. It is a very high-power, LF, pulsed transmission, whereas GNSS are low-power, UHF, multiple modulation scheme transmissions. eLoran is literally at the other end of the spectrum from GNSS, and has completely dissimilar failure modes. That is, an issue that disrupts GNSS is unlikely to disrupt eLoran. The unique characteristics of eLoran enable its use in environments where GNSS does not work very well, or at all (e.g., indoors, underwater, underground, and in mountain or urban canyons).

    eLoran is exceptionally difficult to spoof or jam, and it is nearly impossible to do so at a distance. Just as equipment required to spoof and jam GNSS must mimic relatively low powered GNSS transmissions, spoofing and jamming eLoran requires very high powered transmissions. Equipment needs alone to disrupt eLoran over a significant area would be almost prohibitive for any actor other than a nation state engaged in open conflict. This is the reason that an independent assessment by researchers at Stanford University described eLoran as “for all practical purposes, unjammable” across any significant area. A MITRE paper concluded: “The analysis shows a very low probability of successfully producing operationally significant interference.”