Investigating R-Mode Signals for the VDE System

Wirsing, Markus; Dammann, Armin; Raulefs, Ronald

doi:10.23919/oceans40490.2019.8962635

Cited by 8 publications

(6 citation statements)

References 3 publications

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“…In contrast to the Cramér-Rao bound, the Ziv-Zakai bound takes into account the entire autocorrelation of the signal. We previously applied the Ziv-Zakai bound for range estimation to VDES R-Mode [1], [9], [10].…”

Section: B Ziv-zakai Boundmentioning

confidence: 99%

Direct Position Estimation for VDES R-Mode

Wirsing

Dammann

Raulefs

2023

2023 IEEE/ION Position, Location and Navigation Symposium (PLANS)

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As maritime traffic strongly relies on Global Navigation Satellite Systems (GNSS) such as GPS or Galileo, there are efforts to mitigate the risks that come with this reliance. One such effort is the development of VDES R-Mode, which aims to provide a terrestrial contingency system to GNSS that is based on the VHF Data Exchange System (VDES).Terrestrial VDES provides a bandwidth of 100 kHz. To make best use of the available bandwidth, VDES R-Mode can use a signal that is optimized for a high effective bandwidth. This signal however, has a very regular structure that leads to ambiguities that degrade the ranging performance at lower SNRs. We found that this drawback can be mitigated by evaluating the signals of multiple base stations jointly in a direct position estimation approach.To assess the improvement, we applied the Ziv-Zakai Bound and performed simulations. We found that using the direct position estimation approach can significantly lower the SNR at which it is still possible to resolve the ambiguities caused by the regular signal structure.

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Section: B Ziv-zakai Boundmentioning

confidence: 99%

Direct Position Estimation for VDES R-Mode

Wirsing

Dammann

Raulefs

2023

2023 IEEE/ION Position, Location and Navigation Symposium (PLANS)

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“…In the studies of R-Mode pseudorange measurement method in the VDES, reference [40] used GMSK modulated AIS communication signal for ranging, which had low accuracy. And reference [41] used the special pseudorandom sequence of VDE channel for ranging, which can get higher accuracy. But it needed specific time slots for the sequence transmission and occupied the communication time slots for the ranging.…”

Section: Introductionmentioning

confidence: 99%

A Training Sequence-Based Ranging Method for R-Mode of VHF Data Exchange System

Sun

Jiang

2022

Wireless Communications and Mobile Computing

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The space-time reference provided by GNSS is the basis of the 6G mobile communication integrating land, sea, air, and space. But GNSS has natural vulnerability. In order to solve this problem at sea, ships should be equipped with both space-based and land-based positioning and navigation systems in the future. The Ranging Mode (R-Mode) of the existing maritime communication system is an economical land-based backup positioning system, which is also an important support for e-Navigation. This paper proposes a pseudorange measurement method based on training sequence with multicorrelators, which can be used in the R-Mode of the VHF data exchange system (VDES). This method uses the correlation property of the ASM and VDE training sequence in the VDES for ranging. It reproduces the training sequence in the receiver, and then, noncoherent correlates with the received signal, meanwhile using the pseudorange measurement method with multicorrelators to reduce the influence of pulse shaping on the correlation curve. This paper also gives a design of receiver to implement the proposed method. Experiments are carried out based on the receiver to evaluate the ranging performance. The results show that, compared with the traditional maximum correlation value and E-L methods, the multicorrelator method can effectively reduce the ranging error. When E s / N 0 is greater than 15 dB, the ranging accuracy of the proposed method can be better than 3 m. With the proposed method, the VDES signal can be used for both ranging and communication. Compared with the general VDES function, it does not occupy any additional time slot resources. This provides a reference for the future research of the VDES R-Mode, which can be used to solve the vulnerability problem of the GNSS on maritime communication.

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“…Various approaches to resolve the dependency on GNSS are continuously proposed and developed, including the rangingmode (R-mode) of the Automatic Identification System (AIS) [22], [23] and the R-mode VHF Data Exchange System (VDES) [24], [25]. The Baltic Project is also developing MF R-Mode using the MF beacon infrastructure that transmits DGNSS information.…”

Section: Introductionmentioning

confidence: 99%

eLoran: Resilient Positioning, Navigation, and Timing Infrastructure in Maritime Areas

et al. 2020

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Global navigation satellite system (GNSS) and localization technology have become highly compact and effective. Although GNSS has been proven to be vulnerable to jamming when the signal strength is weak, most vehicles rely on it for navigation. Compared to GNSS, enhanced Loran (eLoran) is more resistant to jamming and is recommended as a realistic alternative to GNSS. Therefore, South Korea embarked on an eLoran testbed development project to provide resilient navigation information for maritime users. The primary goal of this project was to demonstrate that the system can provide a 20-m position accuracy to the maritime user within a 30-km coverage of a differential Loran station. In this paper, we describe the development of the eLoran testbed implementation and the performance of its preliminary experimental results. To confirm the feasibility of the eLoran testbed performance, we installed an eLoran transmitter and two differential Loran stations and subsequently conducted a zero-baseline performance test at the Pyeongtaek differential Loran station with a new eLoran signal. We also conducted a survey to collect conventional Loran signals along the western and southern coastlines of South Korea. Our experimental results show that the eLoran system met the performance requirements of this project, as well as that the signal to noise ratio of the eLoran signals changed over the topographic characteristics of the propagation path. INDEX TERMS GNSS backup, eLoran testbed, resilient PNT, maritime navigation This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

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Investigating R-Mode Signals for the VDE System

Cited by 8 publications

References 3 publications

Direct Position Estimation for VDES R-Mode

Direct Position Estimation for VDES R-Mode

A Training Sequence-Based Ranging Method for R-Mode of VHF Data Exchange System

eLoran: Resilient Positioning, Navigation, and Timing Infrastructure in Maritime Areas

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