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A model of the LOng‐RAnge Navigation signal can provide a mathematical model for the development of related technology research. The propagation variations of the signal exhibit non‐stationary and non‐linear characteristics due to the time‐varying nature of the atmospheric dielectric constant in the channel. A Dirichlet process mixtures method is used by the authors to model the statistical properties of radio wave attenuation, and the Gibbs sampling method is used to flexibly estimate the parameters of the model. The model as a non‐parametric model can be applied to capture the dynamics of time‐varying signals with the parameters being adaptively inferred. A receiver is used as a measurement device to obtain real propagation data to check the performance of the model. Kullback–Leibler Divergence (KL‐Div) was used to evaluate different datasets. The results showed that the model's statistical properties were consistent. Its flexibility allows it to represent complex distributions without prior knowledge. [ABSTRACT FROM AUTHOR]

In this study, a real‐time high accuracy signal simulation technique for an enhanced Loran (eLoran) signal simulator is proposed, which can be used to verify the performance of the eLoran receiver. The proposed method is based on a maximumly flat design of the low‐pass filter, and high simulation accuracy can be obtained in the low‐frequency band. The simulator structure is based on the variable fractional delay Farrow structure, which can regenerate eLoran signals with high‐precision time of arrival (TOA) in real‐time based on discrete samples on a hardware platform. By comparison of existing methods and the true TOA data validation, the proposed method has high performance for low‐frequency narrow‐band eLoran signals and the proposed technology can apply to arbitrary TOA real‐time simulations. [ABSTRACT FROM AUTHOR]

In this article, we present a method for designing miniaturized and broadband quadrifilar helix antenna, which has better bandwidth than other smaller antennas and more compact than larger bandwidth antennas. The antennae in this design have same size with axial lengths of 24 mm and diameters of 18 mm. The antennae are miniaturized by folded arms and dielectric loading. In both cases, a short pin is added to adjust the impedance matching and broaden the bandwidth. Inside and outside diameters of the loading dielectric cylinder are the parameters used for controlling the center frequency, which can be shifted between 1.2 and 1.8 GHz. An antenna with a central frequency of 1.5 GHz was simulated and measured to verify the design. In addition, this design could provide bandwidth of 100 MHz for satellite navigation application. Two antennae, operating at 1.227 and 1.575 GHz with 100 MHz bandwidth, are simulated. The 1.227 GHz antenna covers GPS L2, BEIDOU B2 and B3, GLONASS G2, and Galileo E5b bands. The 1.57 GHz antenna covers GPS L1, BEIDOU B1, B1C, B1I, and Galileo E1 bands. [ABSTRACT FROM AUTHOR]