Accuracy Improvement Technique for Timing Application of LORAN-C Signal

Yang, Sung Hoon; Lee, Chang Bok; Lee, Young Kyu; Lee, Jong Koo; Kim, Young Jae; Lee, Sang Jeong

doi:10.1109/tim.2010.2096970

Cited by 23 publications

(12 citation statements)

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“…In RF signal processing, the input Loran-C signal is sampled by analogue-to-digital and filtered by an adaptive notch and finite impulse response band-pass, thus obtaining the digital signal. (2). The complex envelope of the Loran-C pulse is obtained through orthogonal down conversion.…”

Section: Experimental Verificationmentioning

confidence: 99%

“…The positioning, navigation, and timing (PNT) system is the key infrastructure in any country considering national economy and security. It provides PNT services for military, commercial, and civil users worldwide [1,2]. One of the high-precision ground-based PNT systems is Loran-C, which has advantages such as long-distance propagation, low frequency, high power, and goodstability [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

Yuan

Yan

et al. 2020

Sensors

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Loran-C is the most important backup and supplement system for the global navigation satellite system (GNSS). However, existing Loran-C demodulation methods are easily affected by noise and skywave interference (SWI). Therefore, this article proposes a demodulation method based on Loran-C pulse envelope correlation–phase detection (EC–PD), in which EC has two implementation schemes, namely moving average-cross correlation and matched correlation, to reduce the effects of noise and SWI. The mathematical models of the EC, calculation of the signal-to-noise ratio (SNR) gain, and selection of the EC schemes are given. The simulation results show that compared with an existing method, the proposed method has clear advantages: (1) The demodulation SNR threshold under Gaussian channel is only −2 dB, a reduction of 12.5 dB; (2) The probability of the demodulated SNR threshold, being less than zero under the SWI environment, can reach 0.78, a 26-fold increase. The test results show that the average data availability of the proposed method is 3.3 times higher than that of the existing method. Thus, our demodulation method has higher engineering application value. This will improve the performance of the modern Loran-C system, making it a more reliable backup for the GNSS.

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Section: Experimental Verificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

Yuan

Yan

et al. 2020

Sensors

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“…The positioning, navigation, and timing (PNT) systems are important to the national economy and security of any country [ 1 , 2 , 3 ]. One of the high-precision ground-based PNT systems is Enhanced LOng-RAnge Navigation (eLORAN).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of a Signal Modulation Method to Improve eLORAN Data Channel Communications

Yang

Wang

et al. 2020

Sensors

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There are mainly two types of data modulation methods used for enhanced LOng-RAnge Navigation (eLORAN) systems: pulse position modulation (PPM) and supernumerary interpulse modulation (SIM). The typical application for PPM is tri-state PPM (3S-PPM), also known as Eurofix. The typical application for SIM is ninth pulse modulation. Both of these methods are phase modulation methods. Phase modulation coding, a very mature technology, is used at present. To achieve a better demodulation success rate of eLORAN digital modulation signals at longer distances, a method of using the transmitting station duplex mode to transmit a digital modulation pulse group after LORAN-C transmitting a pulse group is proposed to realize modulation pulse on–off modulation. In this method, a broadcasting experiment was performed on the BPL (The call sign of eLORAN time service system in China) broadcaster station. After monitoring, a good receiving demodulation effect was initially obtained.

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“…As GNSS (GPS and GLONASS) are inherently vulnerable to interference, disruption, jamming and spoofing, many governments and civilian organisations around the world are devoting to the upgrading research of Long Range Navigation System (Loran-C) [6][7][8][9][10]. Loran-C was a ground-based navigation system administered by the U.S. Coast Guard.…”

Section: Introductionmentioning

confidence: 99%

“…Global Positioning System (GPS) by US government and GLONASS (Globalnaya Navigatsionnay Sputnikovaya Sistema) by the Russian Federations are both satellite based positioning systems. As GNSS (GPS and GLONASS) are inherently vulnerable to interference, disruption, jamming and spoofing, many governments and civilian organisations around the world are devoting to the upgrading research of Long Range Navigation System (Loran‐C) [6–10]. Loran‐C was a ground‐based navigation system administered by the U.S. Coast Guard.…”

Section: Introductionmentioning

confidence: 99%

Long‐range Loran‐C ground‐wave propagation prediction based on adaptive moving window finite‐difference time‐domain method with compute unified device architecture parallel computing techniques

Zhou

et al. 2015

IET Microwaves, Antennas & Propagation

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Modelling long-range Loran-C signal propagation numerically is challenging because of its extremely high computational cost. Other analytical/semi-analytical methods are not accurate enough because of unavoidable approximations. In this study, the authors put forward a solution using the adaptive moving window finite-difference time-domain (FDTD) method to compute unified device architecture parallel computing techniques. The moving velocity of the window is dependent upon the wave speed adaptively. To achieve the adaptive moving window technique, the original Loran-C signal is truncated first. A further method employed to extract the electric field amplitude and phase is proposed. The electric field amplitude and phase data of each mesh in the computational space are synchronously obtained from the spatial domain as the FDTD updates, without additional storage cost and post processing in the time domain. With all these efforts, a 400 km propagation path was simulated successfully within 22 min. Measurement results between Jinxian and Shangrao in Jiangxi Province, China were taken to validate the numerical approach.

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Accuracy Improvement Technique for Timing Application of LORAN-C Signal

Cited by 23 publications

References 1 publication

Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

Demodulation Method for Loran-C at Low SNR Based on Envelope Correlation–Phase Detection

Experimental Study of a Signal Modulation Method to Improve eLORAN Data Channel Communications

Long‐range Loran‐C ground‐wave propagation prediction based on adaptive moving window finite‐difference time‐domain method with compute unified device architecture parallel computing techniques

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