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209 results on '"Sun, Guangfu"'

56. Robust Spoofing Detection for GNSS Array Instrumentation Based on C/N0 Difference Measurements

Author

Liu, Jinyuan, Chen, Feiqiang, Xie, Yuchen, Ge, Beibei, Lu, Zukun, and Sun, Guangfu

Abstract

In recent years, Global Navigation Satellite System (GNSS) spoofing detection techniques have attracted wide attention. Spoofing attacks have posed a greater security threat than jamming and are more difficult to detect due to their strong concealment. One of the key measurements of GNSS instruments is the carrier-to-noise ratio ( $C/N_{0}$ ), which may be affected by spoofing. However, the variations in $C/N_{0}$ are always uncertainty especially for the array instruments under the attack. This article proposes a method for GNSS array instruments to detect the spoofing after anti-jamming. A theoretically model of the effective $C/N_{0}$ in array receiver is deduced. The $C/N_{0}$ single difference (CSD) between satellites is further proposed as a testing statistic for spoofing detection. Simulation results demonstrate that the proposed method can effectively detect the abnormal $C/N_{0}$ feature of counterfeit signals after anti-jamming by the antenna array. The detection performance of the proposed metrics is verified in the jamming and spoofing scenarios using the real data collected by an antenna array instrument. This method does not require modifications to the hardware configuration of conventional array receivers and can provide an effective defense in the combination of jamming and spoofing attacks.

Published
2023
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63. Chirp pseudo‐noise signal and its receiving scheme for LEO enhanced GNSS.

Author

Zhao, Xin, Huang, Xinming, Tang, Xiaomei, Feng, Xiaochao, and Sun, Guangfu

Subjects
LOW earth orbit satellites, GLOBAL Positioning System, GEOSTATIONARY satellites, TIME delay systems
Abstract

Low earth orbit (LEO) constellations for enhancing global navigation satellite systems (GNSS) have been investigated and studied due to their higher floor power and rapid geometric changes. Compared with GNSS based on medium orbit (MEO) and geostationary (GEO) satellites, the higher Doppler frequency is one of the problems faced by the LEO enhanced GNSS. For the traditional BPSK signal, the complexity has been greatly improved in acquisition, especially in the cold start state, which means more requests on the signal design. The periodic chirp signal modulated by the pseudo‐noise code (chirp‐PC) is proposed as the ranging signal of LEO enhanced GNSS. The coupling characteristic of Doppler and delay in chirp‐PC can make the search frequency grid less than the traditional BPSK signal with the same acquisition performance, which can greatly reduce the complexity. However, the delay estimation obtained by the acquisition is biased. A tracking loop based on the chirp phase locked loop (CPLL) was proposed for removing the coupling of Doppler and time delay. The simulations show that the tracking loop can track chirp‐PC signals stably and unbiasedly, and the tracking accuracy is similar to that of the corresponding BPSK signal. Therefore, the chirp‐PC signal is a new choice for LEO enhanced GNSS with low acquisition complexity and equivalent tracking accuracy to BPSK. [ABSTRACT FROM AUTHOR]

Published
2022
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77. A spoofing detection method for motion receiver using single antenna

Author

Guangteng Fan, Guozhu Zhang, Junwei Nie, Sun Guangfu, and Huang Yangbo

Subjects
Spoofing attack, Directional antenna, Computer science, business.industry, Antenna measurement, Direction of arrival, Displacement (vector), Embedded system, Linear motion, Antenna (radio), Omnidirectional antenna, business, Algorithm, Computer Science::Information Theory
Abstract

The direction of arrival (DOA) technique is the most effective mean of spoofing detection, but it is high hardware complexity and cannot be applied to motion vectors. In order to suppress this problem, a method based on carrier phase double-difference detection of single antenna which is used in linear motion vector is introduced. This method uses the difference of distance between GPS satellites and spoofers to the receivers, and makes the detection by carrier phase double-difference which only needs single antenna. The model of carrier phase double-difference of single antenna is established, and the binary hypothesis test of spoofing is given based on the model. In the end, theoretical analysis and simulative results prove the effectiveness of the proposed method. The results indicate that the longer displacement distance of the receiver antenna is, the better spoofing detection performance of the proposed method is; the closer to spoofer from the receiver antenna is, the better spoofing detection performance of the proposed method is; the more vertical between DOA and antenna displacement direction is, the better spoofing detection performance of the proposed method is.

Published
2015

84. BOCC: A new modulation based on chirp subcarriers for future BeiDou LEO navigation‐augmented signal.

Author

Zhao, Xin, Huang, Xinming M., and Sun, Guangfu F.

Abstract

For improving the anti‐interference performance and compatibility of a navigation‐augmented signal in future BeiDou Global Navigation Satellite Systems, a new modulation based on chirp subcarriers is proposed, named binary offset chirp carrier modulation, which is formed by multiplying a periodic binary chirp subcarrier with a spreading code signal. And it can make use of the time‐varying frequency for shaping the spectrum and have superior performance in anti‐interference, similar advantage in tracking accuracy, anti‐multipath capability and compatibility compared with binary offset carrier modulations. The binary offset chirp carrier modulations proposed in this paper provide a potential signal design for the future low earth orbit (LEO) navigation‐augmented Global Navigation Satellite Systems. [ABSTRACT FROM AUTHOR]

Published
2021
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98. A modified sidereal filtering for mitigating the code measurement multipath effects of BeiDou GEO satellites.

Author

Wang, Xing, Liu, Wenxiang, Li, Baiyu, and Sun, Guangfu

Subjects
STARS, BEIDOU satellite navigation system, GLOBAL Positioning System, GEOSTATIONARY satellites, ERROR-correcting codes
Abstract

Multipath delay is one of major error sources which limit global navigation satellite systems positioning accuracy. Due to the orbit characteristics, multipath effects are more evident on the code range observables of BeiDou Navigation Satellite System (BDS) geostationary earth orbit (GEO) satellites. We employed zero-phase filter to extract the low-frequency components of multipath series with the definite cutoff frequency and pass-band gain, and introduced a modified sidereal filtering for mitigating the multipath effects on code measurements of GEO satellites. The applications of this modified sidereal filtering show that the corrections for the standard deviation of code observables residuals on BDS B1, B2, and B3 frequency have reached more than 30, 22, and 14%, respectively. After resolving the GEO satellites code measurement multipath effects, the precisions of code-only single-point positioning were also improved. [ABSTRACT FROM PUBLISHER]

Published
2017
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99. A fast search algorithm for template matching based on inequality criterion

Author

Wang Yang, Sun Guangfu, and Lu Huanzhang

Subjects
Binary search algorithm, Optimal matching, Matching (graph theory), Search algorithm, business.industry, Template matching, 3-dimensional matching, Commentz-Walter algorithm, Best-first search, Pattern recognition, Artificial intelligence, business, Mathematics
Abstract

This paper presents a fast search algorithm for template matching, using the inequality between the square error distortion measure and the difference which is between the sum of template image and the sum of every possible matching block. Firstly the sums of all possible matching blocks and template are computed and sorted. Using the inequality criterion, the algorithm prunes the number of candidate matching positions. When computing the sums of blocks, the algorithm utilizes the overlapping of neighboring blocks to accelerate the calculation. Because the inequality criterion does not rely on any assumption, the search result is equivalent to the result of the full search algorithm. Experimental results show it can save 91.77% to 93.25% execution time comparing with full-search algorithm.

Published
2005

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