e- Loran antenna for handheld devices
Last Updated: 10/09/2024 08:35 Created at: 10/09/2024 08:34
Final Presentation of NAVISP Project EL1-065 now available:
On Wednesday, September 04th, 2024, Roke presented the results of the NAVISP EL1-065 project "e- Loran antenna for handheld devices”.
Enhanced Long Range Navigation (eLORAN) is a terrestrial positioning system that operates at a frequency of 100kHz in the Low Frequency (LF) band, with a signal bandwidth of 20kHz. As with its predecessor LORAN-C, eLORAN utilizes a network of ground-based transmitters to provide positioning, navigation, and timing services. The system's long wavelength (λ=3000m) traditionally necessitates large antennas for efficient signal reception. This size requirement has been a significant limitation for portable applications, as conventional monopole antennas proportional to the signal wavelength are impractical for hand-held devices. Despite this challenge, eLORAN's potential as a complement or backup to satellite-based navigation systems like GPS has maintained interest in its development and application (see for example the development in South Korea).
The primary objective of this project was to significantly reduce the size of the eLORAN antenna while maintaining acceptable performance. This trade-off between size and efficiency is a critical aspect of the research and development process. The project was structured into several research and development tasks, beginning with a comprehensive state-of-the-art survey of current and potential eLORAN antenna technologies. This was followed by the selection and proposal of a preferred antenna option, establishment of design requirements, and culminated in the development and testing of a prototype miniature antenna.
The research phase involved an evaluation of various antenna technologies, including Short E-Field Whip, Conventional Ferrite Rod, Black Hole, MILOR, Magnetoelectric, Dual eLORAN, and Zero-Impedance antennas. After extensive analysis, the MILOR (Miniature Low-frequency Orthogonal Receiver) antenna design was selected as the foundation for further development. This decision was based on its suitable dimensions for handheld devices and demonstrated performance at eLORAN frequencies. The subsequent development process focused on enhancing the MILOR concept, incorporating two ferrite rods per channel to improve the signal-to-noise ratio. The design was optimized with the integration of operational amplifiers to enhance manufacturing robustness and reduce current consumption, with component selection made to minimize the risks of obsolescence.
The project yielded a miniature eLORAN antenna prototype with significantly reduced Size, Weight, and Power (SWaP) characteristics compared to traditional designs. The antenna demonstrated improved manufacturability while maintaining a form factor suitable for hand-held applications. Although initial tests revealed slightly lower sensitivity than anticipated, potential solutions were identified for future iterations. The successful development of this miniature antenna represents a significant advancement in eLORAN technology, potentially expanding its applicability in portable devices and enhancing navigation options in areas where satellite-based systems may be limited. Future work will focus on field trials, further performance optimizations, and integration with dual-channel eLORAN receivers, ultimately aiming to produce a fully integrated hand-held unit. This ongoing development, in collaboration with the European Space Agency, ensures that eLORAN continues to evolve as a viable complement to GNSS, contributing to more robust and reliable positioning, navigation, and timing solutions.
The project was carried out in the scope of NAVISP Element 1, which is dedicated to technology innovation of the European industry in the wide PNT sector.
More detailed information can be found in the slides of the Final Presentation.