Critical government and industry sectors (such as law enforcement, transportation, communication, finance) are growing increasingly dependent on Global Navigation Satellite Systems (GNSS) for positioning, navigation, timing. At the same time, availability of low-cost GNSS jamming devices presenting a serious threat to increasing likelihood outages infrastructures relying GNSS. The attacks range from malicious parties intentionally signals within targeted geographical region uninformed users...

With the completion of experimental and regional phases, China's BeiDou Navigation Satellite System (BDS) is being speedily expanded to a global multifunctional satellite navigation system, BDS III. Confronted with challenges such as limited frequency resources diversified user requirements, new signals novel modulation techniques are adopted in In addition legacy B1I B3I signals, open service B1C B2a/B2b, well some authorized will be broadcast by III satellites. Among them, B2a compatible...

The sine-BOC (binary offset carrier) modulation is used in several signals of the new European Global Navigation Satellite System, Galileo, and modernized GPS. It provides these with enhanced robustness against multipath increases precision range measurement. However, this presents some drawbacks. most severe ambiguity problem acquisition tracking, which introduces a large bias pseudo-range In order to solve problem, an unambiguous tracking technique for proposed. This based on pseudo...

In the signal design of new generation global navigation satellite systems, there is a strong demand for multiplexing multiple binary spreading signals on two adjacent frequencies into an integrated with constant envelope. this paper, dual-frequency envelope (DCEM) technique high-design flexibility based subcarrier waveform reconstruction, named asymmetric offset carrier (ACE-BOC), presented. This can be seen as generalized alternate BOC. It combine four or fewer independent, bipolar, direct...

This paper describes a robust integrated positioning method to provide ground vehicles in urban environments with accurate and reliable localization results. The problem is formulated as maximum posteriori probability estimation solved using graph optimization instead of Bayesian filter. Graph exploits the inherent sparsity observation process satisfy real-time requirement only updates incremental portion variables each new incoming measurement. Unlike Extended Kalman Filter (EKF) typical...

Localization systems utilizing Ultra-WideBand (UWB) have been widely used in dense urban and indoor environments. A moving UWB tag can be located by ranging to fixed anchors whose positions are surveyed advance. However, manually surveying the is typically a dull time-consuming process prone artificial errors. In this paper, we present an accurate easy-to-use method for anchor self-localization, using measurements readings from low-cost Inertial Measurement Unit (IMU). The locations of...

The emerging Global Navigation Satellite Systems (GNSS) including the BeiDou System (BDS) offer more visible satellites for positioning users. To employ those new in a real-time kinematic (RTK) algorithm to enhance precision and availability, data processing model dual constellation of GPS BDS is proposed analyzed. A Kalman filter-based developed estimate float ambiguities short baseline scenarios. entire work process high-precision based on deeply investigated detail. validated with real...

In two-way time-of-arrival (TOA) systems, a user device (UD) obtains its position and timing information by round-trip communications to number of anchor nodes (ANs) at known locations. Compared with the one-way TOA technique, scheme is easy implement has higher localization synchronization accuracy. Existing methods assume stationary UD. This will cause uncompensated errors. this article, we propose an optimal maximum likelihood (ML) based method, namely TWLAS. Different from existing...

Digital twin technology provides insight to solve the problems of state monitoring and life evaluation electromagnetic devices. When performing digital system design, it is necessary face challenges multi-physical field multi-scale modeling, dynamic time-varying parameters, data interaction. In this paper, a design scheme for DC contactors proposed. The modeling approach describes defines model at three levels: geometric, mechanistic, data. Based on constructed model, knowledge acquisition...

In this letter, a side-peak cancellation unambiguous acquisition technique is proposed for sine-phased binary offset carrier (BOC) modulated signals. The test criterion used in based on synthesized correlation function which has no major positive side peak. This obtained by subtracting the cross-correlation between received sin-BOC signal and an auxiliary from autocorrelation of signal. For different types BOC signal, employs corresponding symbols common solution symbol shape vector derived,...

Jamming and spoofing are the two main types of intentional interference for global navigation satellite system (GNSS) receivers. Due to entirely different signal characteristics they have, a few techniques can deal with them simultaneously. This paper proposes two-stage suppression scheme based on antenna arrays, which detect mitigate jamming before despreading GNSS First, subspace projection was adopted eliminate high-power signals. The output is still multi-dimensional vector so that...

Spoofing attacks are threatening the global navigation satellite system (GNSS). The maximum likelihood estimation (MLE)-based positioning technique is a direct method originally developed for multipath rejection and weak signal processing. We find this also has potential ability GNSS anti-spoofing since spoofing attack that misleads timing result will cause distortion to MLE cost function. Based on method, an estimation-cancellation approach presented detect recover solution. A statistic...

This paper presents a Lidar/ultra-wideband (UWB) fusion algorithm for simultaneous localization and mapping (SLAM) with anti-degeneration capability. In the proposed algorithm, sensor states are estimated by minimizing sum of Mahalanobis norm all measurement residuals associated Lidar UWB sensors. Additionally, considering that poor geometric distribution measurements will introduce large estimation uncertainties in trade-off parameter its self-adjustment strategy is introduced to adjust...

Localizing moving targets in unknown harsh environments has always been a severe challenge. This letter investigates novel localization system based on multi-agent networks, where multiple agents serve as mobile anchors broadcasting their time-space information to the targets. We study how target can localize itself using sequential time of arrival (TOA) one-way broadcast signals. An extended two-step weighted least squares (TSWLS) method is proposed jointly estimate position and velocity...

Spatiotemporal information plays crucial roles in a multiagent system (MAS). However, for highly dynamic and dense MAS unknown environments, estimating its spatiotemporal states is difficult problem. In this article, we present BLAS-a wireless broadcast relative localization clock synchronization to address these challenges. Our BLAS exploits architecture, under which categorized into parent agents that packets child are passive receivers, reduce the number of required among synchronization....

This article presents a two-step stochastic hybrid estimation (TS-SHE) algorithm for robust and accurate carrier phase tracking of global navigation satellite system (GNSS) signals in urban environments with significant power degradation fluctuation. The proposed adaptively combines bank parallel Kalman filters (KFs) different dynamic state models to cope the nonstationarity GNSS signals. Different from conventional approaches, including lock loop (PLL), KF, interacting multiple-model (IMM)...

Performance analysis of Global Navigation Satellite Systems (GNSS) collaborative positioning accuracy is a challenging task since there are too many impact factors. To simplify the analysis, dilution precision (CDOP) model proposed to specify multiplicative effect various factors on positioning. Based this CDOP model, theoretical and simulation tests performed, results compared with GNSS standalone The impacts number users their distribution relative distance measurement also analyzed...

Security of global navigation satellite systems (GNSS) is important since the capability provided by GNSS a key enabler for many civilian and military applications. Spoofing attacks threaten security have caught much attention recently. The spatial processing method one most robust spoofing countermeasures, which detects signals with moving antenna or multi-antenna, but it cannot work in static single-antenna receiver. In this paper, we propose countermeasure based on power measurements...

The new generation global navigation satellite systems will broadcast multiple direct sequence spread spectrum signals on different central frequencies, with complex spreading chip waveforms. There is a strong demand for efficient and flexible multiplexing techniques to combine these into constant envelope composite signal. In this paper, high efficiency generalized multicarrier joint (CEM) technique multilevel DSSS proposed. basic idea of adding an auxiliary component the superposition keep...

Robust and centimeter-level Real-time Kinematic (RTK)-based Global Navigation Satellite System (GNSS) positioning is of paramount importance for emerging GNSS applications, such as drones automobile systems. However, the performance conventional single-rover RTK degrades greatly in urban environments due to signal blockage strong multipath. The increasing use multiple-antenna/rover configurations attitude determination above precise just well, allows more information involved improve areas....

Cooperation of multiple robots in simultaneous localization and mapping (SLAM) systems has more advantages compared to single robot configurations such as a faster exploration speed the environment ability perform tasks with high complexity. In this paper, we present an online multi-robot SLAM system which merges range measurements provided by UWB sensors Lidar data different mobile build globally-consistent map that contains individual point cloud maps trajectory estimations all robots. The...

In order to meet the demands of high-precision positioning and constraints limited spectrum resources, BeiDou Global Navigation Satellite System (BDS-3) has implemented advanced signal structures multiplexing techniques in B1 B2 bands. Specifically, signals adjacent subbands are dual-frequency multiplexed into Wideband Multiplexed Signal (WMS). The high-frequency complex subcarriers, serving as components, not only enable satellites achieve higher broadcast efficiency, but also show...