A subspace-based code tracking loop design for GPS multi-antenna receiver in multipath environment

Hong, Xi; Wang, Wenjie; Chang, Ning; Yin, Qinye

doi:10.1007/s10291-020-01020-y

Cited by 9 publications

(4 citation statements)

References 35 publications

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“…ε The code tracking bias can be solved referring to the multipath analysis method in references [16] and [18]. However, since the synchronization error of the spoofing signal may be positive or negative, and the amplitude ratio may be larger or smaller than 1, the cases of the S-curve zero-crossings are more complicated under ε d spoofing than under multipath.…”

Section: Code Tracking Errormentioning

confidence: 99%

“…Here, we try to check all possible spoofing signal states and identify the meaning of each effective solu- tion with the assistance of computer enumeration. Such enumeration has been used to obtain the closed-form expression of the multipath error envelope (MEE) [16], [18], [23]. However, the analysis is much more complicated for the spoofing cases, as the 3 possible solutions with 2 lock points and 1 boundary imply the ambiguity of the S-curve and thus the diversity of the CTL behavior.…”

Section: Range Ofmentioning

confidence: 99%

“…As indicated in [13], spoofing and multipath have something in common. The methodology used in multipath effect analysis can be used to analyze spoofing intrusion [16], [17]. Overall, the spoofing signal will change the shape of the S-curve and introduces a lock point bias [18].…”

Section: Introductionmentioning

confidence: 99%

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Necessary Condition for the Success of Synchronous GNSS Spoofing

2023

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A synchronous GNSS generator spoofer aims at directly taking over the tracking loops of the receiver with the lowest possible spoofing to signal ratio (SSR) without forcing it to lose lock. This paper investigates the factors that affect spoofing success and their relationships. The necessary conditions for successful spoofing are obtained by deriving the code tracking error in the presence of spoofing and analyzing the effects of SSR, spoofing synchronization errors, and receiver settings on the S-curve ambiguity and code tracking trajectory. The minimum SSRs for a successful spoofing calculated from the theoretical formulation agree with Monte Carlo simulations at digital intermediate frequency signal level within 1 dB when the spoofer pulls the code phase in the same direction as the code phase synchronization error, and the required SSRs can be much lower when pulling in the opposite direction. The maximum spoofing code phase error for a successful spoofing is tested by using TEXBAT datasets, which coincides with the theoretical results within 0.1 chip. This study reveals the mechanism of covert spoofing and can play a constructive role in the future development of spoofing and anti-spoofing methods.

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Section: Code Tracking Errormentioning

confidence: 99%

Section: Range Ofmentioning

confidence: 99%

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Necessary Condition for the Success of Synchronous GNSS Spoofing

2023

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“…Recent work presented a graph Fourier transform (GFT) filter denoising the complex correlator outputs to replace the old GNSS tracking loop, which can be considered a direct way to steer the code phase in challenging cases [9]. Except for the separation using the state-of-the-art SRAs or the GNSS antenna changes [10][11][12], modeling the superposition signals formed with LOS and NLOS rays is mainstream in the current GNSS community as a means to overcome multipath interference [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

High-Accuracy Absolute-Position-Aided Code Phase Tracking Based on RTK/INS Deep Integration in Challenging Static Scenarios

et al. 2023

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Many multi-sensor navigation systems urgently demand accurate positioning initialization from global navigation satellite systems (GNSSs) in challenging static scenarios. However, ground blockages against line-of-sight (LOS) signal reception make it difficult for GNSS users. Steering local codes in GNSS basebands is a desirable way to correct instantaneous signal phase misalignment, efficiently gathering useful signal power and increasing positioning accuracy. Inertial navigation systems (INSs) have been used as effective complementary dead reckoning (DR) sensors for GNSS receivers in kinematic scenarios, resisting various forms of interference. However, little work has focused on whether INSs can improve GNSS receivers in static scenarios. Thus, this paper proposes an enhanced navigation system deeply integrated with low-cost INS solutions and GNSS high-accuracy carrier-based positioning. First, an absolute code phase is predicted from base station information and integrated solutions of the INS DR and real-time kinematic (RTK) results through an extended Kalman filter (EKF). Then, a numerically controlled oscillator (NCO) leverages the predicted code phase to improve the alignment between instantaneous local code phases and received ones. The proposed algorithm is realized in a vector-tracking GNSS software-defined radio (SDR). Results of the time-of-arrival (TOA) and positioning based on real-world experiments demonstrated the proposed SDR.

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