Pitch Components Research Articles

Investigating the coking performance of ethylene residue pitch components

Ethylene residue pitch (ETP, the heavy component in ethylene residue tar) is widely used as a preferred raw material for preparing petroleum-based artificial carbon materials characterized by high carbon content, high aromaticity, and low heteroatom (S, N) content. To investigate the coking properties of ETP, eight components of ETP (four soluble and four insoluble components) were obtained via extraction and separation using methanol, n-butanol, n-hexane, and dimethyl sulfoxide as solvents. The thermal conversion (temperature = 500 °C) and carbonization treatment (temperature =1400 °C) were carried out on each pitch component. The basic physical properties of ETP components were observed using infrared spectroscopy, thermogravimetric analysis, and 1H-NMR. The microstructure of the petroleum-based pitch coke was studied using polarizing microscopy, X-ray single crystal diffraction (XRD), Raman spectroscopy, and scanning electron microscopy. The aromaticity of the insoluble components in ETP was slightly higher than that of soluble components, and the insoluble components had slightly fewer branching chains than those in soluble components. The microstrength of the ETP coke obtained using insoluble components was higher than that obtained using soluble components, and the true density of ETP coke HS-C was as high as 2.0554 g/cm3.

Catalytic upgrading of Naomaohu coal pyrolysis volatiles over NiAl and NiLiAl oxides

Catalytic upgrading of volatiles is an essential technology to improve the product distribution of pyrolysis for the clean and efficient utilization of low-rank coals. In this work, novel acid-base bifunctional catalysts composed of Ni/Li/Al oxides were designed and prepared using LDH precursors with tunable chemical composition and structural properties. The catalysts were systematically characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), physisorption, NH3-temperature programmed desorption (NH3-TPD), CO2-temperature programmed desorption (CO2-TPD), H2-temperature programmed reduction (H2-TPR), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). A two-stage fixed bed reactor was employed to evaluate the performance of the catalysts. Characterization results suggest that the crystal size of NiO and the surface area of the catalyst decreased with increasing Li content and decreasing Ni content in the catalyst, while the pore volume and pore diameter were positively correlated with Li content. Moreover, the addition of Li reduced the amount of weak acid sites and raised the amount of total basic sites. Consequently, the bifunctional catalysts boosted the yield of light tar and the contents of aromatics and phenols in tar. Specifically, with the highest total acid sites (569 μmol/g) promoting the cracking of heavy pitch components, Ni2.5Li0.5Al1 decreased the content of pitch in tar to 23.8 wt%, representing a 42.7 % drop from the corresponding non-catalytic pyrolysis. Accordingly, it improved the light tar yield to 7.2 wt%, which was 18 % higher than non-catalytic pyrolysis. 450 °C is identified as a suitable temperature for the catalytic upgrading of volatiles from Naomaohu coal; higher catalysis temperatures at 500 °C and 550 °C led to lower tar yield and lower phenols content, along with higher gas yield and more carbon deposition.

Quality assessment of the nominal attitude model of TOPEX/Poseidon using quaternion data

The altimetry mission TOPEX/Poseidon was operational between 1992 and 2005 and provided innovative insight into global and regional sea level changes and their variability. The correct modelling of the spacecraft orbit in precise orbit determination requires detailed information on the attitude of the spacecraft body and the solar array. Since the availability of attitude observations in form of quaternion data for this mission is limited, the nominal orientation model has to be used mainly. In this study, we compare the nominal and quaternion-based approaches of the TOPEX/Poseidon attitude realisation and validate the nominal model w.r.t. the observed attitude. We found good agreement between both approaches in the spacecraft-related roll, pitch, yaw, and solar array angles with slight differences of up to 0.31° on average. The best accordance is obtained in the yaw angles. A general angular offset of 0.12° and -0.19° on average is found in the pitch and solar array angle differences, respectively. Parameters estimated in the orbit computation process also reflect the good agreement between both orientation models with slightly better results when using the observed attitude. However, in some intervals, the nominal model lacks detailed information about the correct attitude. These can be adjusted using the information from the quaternion data. Such intervals indicate off-nominal spacecraft attitude events like drifts or offsets. Purely geometrically analysed, mispointing in the roll and pitch components of about 0.25° results in a change of the altimeter phase centre position in the radial direction of about 7 mm, which directly impacts the sea-level heights determined from altimetry measurements.

Effect of Microstructural Change under Pressure during Isostatic Pressing on Mechanical and Electrical Properties of Isotropic Carbon Blocks.

In this study, carbon blocks were fabricated using isotropic coke and coal tar pitch as raw materials, with a variation in pressure during cold isostatic pressing (CIP). The CIP pressure was set to 50, 100, 150, and 200 MPa, and the effect of the CIP pressure on the mechanical and electrical properties of the resulting carbon blocks was analyzed. Microstructural observations confirmed that, after the kneading, the surface of isotropic coke was covered with the pitch components. Subsequently, after the CIP, granules, which were larger than isotropic coke and the kneaded particles, were observed. The formation of these granules was attributed to the coalescence of kneaded particles under the applied pressing pressure. This granule formation was accompanied by the development of pores, some remaining within the granules, while others were extruded, thereby existing externally. The increase in the applied pressing pressure facilitated the formation of granules, and this microstructural development contributed to enhanced mechanical and electrical properties. At a pressing pressure of 100 MPa, the maximum flexural strength was achieved at 33.3 MPa, and the minimum electrical resistivity was reached at 60.1 μΩm. The higher the pressing pressure, the larger the size of the granules. Pores around the granules tended to connect and grow larger, forming crack-like structures. This microstructural change led to degraded mechanical and electrical properties. The isotropic ratio of the carbon blocks obtained in this study was estimated based on the coefficient of thermal expansion (CTE). The results confirmed that all carbon blocks obtained proved to be isotropic. In this study, a specimen type named CIP-100 exhibited the best performance in every aspect as an isotropic carbon block.

Comprehensive studies of coal tar pitch components

By methods of electron microscopy, adsorption porometry, NMR, IR- EPR spectroscopy, X-ray diffractometry, thermal analysis, chromatography-mass spectrometry the composition, structure and particle morphology of β- and α2-fraction powders of medium-temperature coal ash were investigated. The morphology and structure of coke residues depending on the heating temperature were investigated. Polyaromatic hydrocarbons in the composition of volatile products of coal ash thermolysis were found to be formed mainly by the decomposition of components of β-fraction. The results obtained are of interest from the point of view of the feasibility of using the isolated fractions of coal ash as precursors for the production of functional carbon materials.

PVGAN: A Pathological Voice Generation Model Incorporating a Progressive Nesting Strategy

The voice generation task is to solve the problem of limited samples in the voice dataset using computer technology. By increasing the number of samples, the accuracy of voice disorder diagnosis can be improved, which has a wide range of application value in medical diagnosis and other fields. At present, there are insufficient models for detailed features such as pitch, timbre, and different frequency components in pathological voice data. Therefore, this paper proposes a PVGAN network for learning different frequency information of audio to generate pathological voice data. The proposed network captures the multi-scale features and different periodic patterns of audio signals by designing multiscale perceptual residual blocks and periodic discriminators. At the same time, a progressive nesting strategy was proposed to combine the generator and the discriminator to improve the learning ability of different resolution information. In addition, a latent mapping network is designed to fuse the latent vector with the condition information to generate sound features related to specific diseases or pathological states. The loss function is optimized to further improve the model performance. On the Saarbruecken Voice Database(SVD), the average values of each index of the data generated after training with different pathological types as conditional information are similar to the original data. Finally, the generated data were used to expand the SVD dataset, and the accuracy of the two classification experiments was improved to a certain extent.

Drive‐by frequencies extraction by means of synchrosqueezed wavelet transform

AbstractBridges and viaducts are facing growing traffic, increasing loads as well as ageing and deterioration. Nowadays, vibration‐based Structural Health Monitoring (SHM) represents an effective solution to extract quantitative information regarding bridge structural condition. Bridge frequencies are fundamental parameters capable to reflect and summarize bridge dynamics and health condition. Typically, their identification is performed by direct approaches, which rely on the use of sensors installed on the structure under analysis. A cost‐efficient, movable, and flexible alternative is offered by drive‐by methods, consisting in the use of instrumented vehicles to extract bridge frequencies. This paper presents an experimental campaign carried out on a multiple‐span mixed railroad bridge, with the aim to identify its frequencies through onboard measurements. A set of MEMS wireless accelerometers is deployed on the vehicle, firstly allowing for vehicle pitch component mitigation. Vehicle accelerations were then used to extract bridge frequencies, by means of a Most Probable Modal Frequencies approach, relying on synchrosqueezed wavelet transform. At a cruise speed of 30 km/h promising results in terms of indirect frequency estimation were found, with no traffic disruption.

Synthesis and formation mechanism of pitch-based carbon foam for three-dimensional structural applications

Carbon foam is a three-dimensional porous, rigid, and permeable material with applications in many fields owing to its excellent electrical and thermal properties. Pitch is a promising carbon source for carbon foam production, and its modification with nitric and sulfuric acids has been widely investigated. However, the foaming phenomenon resulting from the acid treatment of pitch and the resultant formation of porous structures remain poorly understood. Herein, we clarified the mechanism by which the porous structure of pitch-derived carbon foam is formed by analyzing the components of pitch modified by nitric acid treatment and identifying essential conditions for foam production. Carbon foam was obtained by pitch modification at a high concentration of nitric acid (60 wt%), whereas no carbon foam was formed at low nitric acid concentrations (<60 wt%). Furthermore, at high nitric acid concentrations, carbon foam formation proceeded at a relatively low temperature (280 °C). The formation of carbon foam from modified pitch was attributed to the synergistic effect of the functional groups introduced onto pitch and the low-molecular-weight components resulting from cracking. This work provides new insights into pitch as a precursor and provides a straightforward method for producing carbon foam.

Power quality disturbance detection based on IEWT

With the continuous development of distributed generation, power quality problems are more complex. In order to ensure that the power quality of the active distribution network meets the requirements of users, it is of great significance to accurately obtain the power quality disturbance parameters. For the problem that the traditional empirical wavelet transform needs to manually select the number of frequency bands when analyzing unknown power quality disturbances, this paper proposes an improved empirical wavelet transform (IEWT) algorithm. The algorithm uses the Piecewise Cubic Hermite Interpolation (PCHIP) method and the improvement of the transition region to achieve adaptive frequency band division and noise interference reduction, and different amplitude (AM) and pitch (FM) components can be obtained. Then the Normalized Direct Quadrature (NDQ) algorithm and Singular Value Decomposition (SVD) algorithm are used to extract frequency, amplitude and time parameters of the AM-FM components. Simulation and experimental results show that the power quality disturbance parameters extracted by the proposed method are more accurate and less affected by noise.

Distribution of Metallic Elements in Four Group Components of High-Temperature Coal Tar Pitch.

The metallic elements in high-temperature coal tar pitch (HCTP) will affect the properties of carbon materials produced from the HCTP. The study on the metallic elements in HCTP is essential for the quality improvement of its derived carbon materials. In this paper, the content of 15 metallic elements in HCTP and its four group components, including n-heptane-soluble substance (HS), n-heptane-insoluble-toluene-soluble substance (HI-TS), toluene-insoluble-quinoline-soluble substance (TI-QS), and quinoline-insoluble substance (QI), was determined. The results show that the content of Na, Ca, Fe, Mg, Zn, K, Pb, and Al is more than 100 ppm and is much higher than that of other metallic elements. The content of Ni, V, Cr, Mo, Sb, Cu, and Mn ranges from 0 to 50 ppm. By mass calculation of the contents of four group components in HCTP, it can be concluded that Na and Fe are randomly distributed in the group components. Al, Zn, Pb, V, and Mn are mainly distributed in the inorganic form in the QI component. Ca, Mg, K, Ni, Cr, Mo, Sb, and Cu are mainly distributed in the small molecular group components such as HS and HI-TS.

Lasting alteration of spatial orientation induced by passive motion in rabbits and its possible relevance to mal de débarquement syndrome.

Mal de débarquement syndrome (MdDS) is a chronic disorder of spatial orientation with a persistent false sensation of self-motion, whose onset typically follows prolonged exposure to passive motion of a transport vehicle. Development of similar but transient after-sensations mimicking the exposed motion and associated postural instability, indicative of central vestibular adaptation, are common. The cause of MdDS is thought to be a subsequent failure to readapt to a stationary environment. However, vestibular plasticity pertinent to this illness has not been studied sufficiently. Because the rabbit's eye movement is sensitive to three-dimensional spatial orientation, characterizing maladaptation of the vestibulo-ocular reflex (VOR) induced in the animal may open an approach to understanding MdDS. Three rabbits underwent a series of 2-h conditioning with an unnatural repetitive motion that involved a complex combination of roll, pitch, and yaw movements in a head-based reference frame, consisting of periodic rolling in darkness in a frame of reference that rotated about an earth-vertical axis. Eye movement in three dimensions was sampled during the conditioning stimulus as well as during test stimuli before and up to several days after conditioning. During roll-while-rotating conditioning, the roll component of the VOR was compensatory to the oscillation about the corresponding axis, but the pitch component was not, initially prominently phase-leading the head pitch motion but subsequently becoming patently phase-delayed. Unidirectional yaw nystagmus, weak but directionally compensatory to the earth-vertical axis rotation, was seen throughout the period of conditioning. After conditioning, simple side-to-side rolling induced an abnormal yaw ocular drift in the direction that opposed the nystagmus seen during conditioning, indicating a maladaptive change in spatial orientation. The impact of conditioning appeared to be partially retained even after 1 week and could be partially reversed or cumulated depending on the rotation direction in the subsequent conditioning. The observed reversible long-term maladaptation of spatial orientation as well as the depth of knowledge available in relation to the vestibular cerebellar circuits in this species support the potential utility of a rabbit model in MdDS research.

Multi-objective optimization for simultaneously designing active control of tower vibrations and power control in wind turbines

For wind turbines operating in the full load region, stabilizing the generated power at its nominal value is a key objective. Furthermore, the control of tower vibrations is a major constraint in wind turbine structures because diverse loading sources can induce fatigue damage. These goals are often conflicting, and a trade-off solution must be found. To reduce tower vibrations, an additional damping method can be implemented by ensuring coordination between the pitch and torque control scheme. This study proposes a control scheme that balances these two objectives: power generation and tower vibration reduction. The control design is based on a collective pitch combined with two active tower damping controls: one for frontal oscillations to the wind, which generates an extra pitch component, and another for lateral displacements, which produces an additional component of the generator torque. The control parameters are tuned through multi-objective optimization and multi-criteria decision methods with FAST software along with MATLAB/Simulink. The proposed control scheme was simulated according to the extreme wind direction change in the IEC 61400–1 standard. The results show that the proposed procedure achieves a notable reduction in tower vibrations, whereas the generated power is almost unaffected. To support this conclusion, a set of performance indices and the time and frequency responses are analyzed from the simulations Comparisons with other control schemes illustrate the superior performance of the proposed methodology.

Evaluation of the utility of isotropic pitches as solvent components of spinnable mesophase pitch precursors for highly graphitizable functional carbon materials

Spinnable mesophase pitch (SMP) is an important graphitizable precursor for high-performance carbon materials. Generally, SMPs show fully developed anisotropic texture, and the pitches contain isotropic contents more than 30 wt%, which plays the role of solvent for the mesogenic components in the lyotropic liquid crystalline system of the pitch. Here, we prepared SMP by blending the mesogenic components of AR mesophase pitch with various isotropic pitches to evaluate the usability of isotropic pitches as solvents. The mesogenic components were prepared by tetrahydrofuran fractionation of AR mesophase pitch. Isotropic pitches with a softening point of 140–220 °C were prepared separately by simple heat treatment of slurry oil (SO) and coal tar pitch (CTP). SMPs were prepared by thermal blending of the above mentioned mesogenic components and isotropic pitches in various blending ratios. CTP-derived isotropic pitch showed better solvent performance than a SO-derived pitch in terms of anisotropic texture. SMP prepared by blending of the mesogenic components and CTP-derived isotropic pitch with a softening point of 180 °C at the ratio of 4/6 (w/w) showed almost 100% anisotropic texture; the carbon fiber derived from the pitch showed tensile strength of 2.7 GPa and Young’s modulus of 470 GPa after graphitization at 2,800 °C.

Guidance and Control of Spin-Stabilized Projectiles Based on Super Twisting Algorithm

In this paper, a hybrid integrated guidance and control design exploiting the time-scale separation principle for a canard-guided dual-spin projectile (DSP) is proposed. The DSP consists of two parts: i) the aft part, which has a high spin rate for providing gyroscopic and aerodynamic stability, and ii) the forward part, which contains a course correction fuze that houses two pairs of movable canards to ensure precise interception. The guidance and control algorithms operate in a two-loop structure where the outer guidance loop generates required pitch and yaw rate commands, whereas the inner loop tracks these commands by generating canard deflections. The rolling motion of the forward part is controlled using a coaxial motor. The multibody dynamic model of DSP has seven degrees of freedom and is highly coupled and nonlinear. For the guidance, a finite horizon optimal control problem is formulated as an output regulation problem with output vector taken as pitch and yaw components of zero effort miss vector. A coupled pitch–yaw autopilot for pitch and yaw rate command tracking and a roll autopilot for roll stabilization of the forward part are designed based on super twisting algorithm. The efficacy of the control design is shown through numerical simulations.

Evaluating of the oxidative behaviors of isotropic pitch fractions for optimal the mechanical properties of isotropic pitch-based carbon fibers

Oxidative stabilization plays an extremely important role in maintaining shape and structural integrity and preventing inter-filament fusing of isotropic pitch fibers during the subsequent carbonization. However, the actual chemical processes and mechanism of the stabilization reaction are complex and as yet poorly defined because of the complexity of the isotropic pitch. In the study, an isotropic pitch synthesized through the co-carbonization of aromatic-rich distillate oil and polyethylene glycol was fractioned into seven fractions by n-heptane, toluene, and their mixtures. The chemical structure and oxidative reaction features of each pitch fraction were systematically analyzed and investigated by FT-IR, 13C NMR, TG-DSC, SEM, etc. The results revealed that the light pitch fractions with more and longer alky side chains attached to the aromatic nucleus exhibit higher oxidative reactivity and appear to induce a higher content of oxygen uptake to achieve stabilization as compared with the heavy pitch fractions. The stabilization reactions of the pitch fractions were carried out in multiple stages, which was confirmed by the conversion of oxygen-containing functional groups ketones and aldehydes to anhydrides and esters as oxidation temperature increased from 150 ℃ to 290 ℃. Three commercial isotropic pitches produced from petroleum-based raw material were oxidized under different conditions. The results confirmed that it is feasible to predict and optimize the stabilization process by tailoring the pitch components.

Integral Plugged Blind via in Printed Wiring Boards

Adoption of fine pitch and high lead count area array components in high-reliability applications such as military and space electronics demands high-density interconnect (HDI) features in multilayer printed wiring boards (PWBs). Usage of cap-plated fine vias that are plugged with dielectric material is one of the approaches to meet the circuit density requirements. In this article, a novel method called &#x201C;integral plugged blind via&#x201D; without secondary processing steps, such as curing and planarization, is described to realize HDI multilayer PWBs. In this method, through vias are epoxy plugged during the lamination of inner layer circuits in vacuum-assisted hydraulic press cycle. Plugged blind vias are formed as an integral part of the fabrication process. It is observed that there is no excess ooze out of resin material from the blind vias in the laminated substrate and blind vias are found to have a negligible dimple and no voids. This is attributed to the gasket effect due to the elastomeric property of specialty release films, which conform (follow) to the contour of plated through vias during the vacuum lamination cycle. Plugged blind vias are subjected to critical thermomechanical stress to evaluate interconnection integrity. It is found that there is negligible change in the resistance of vias and resin plugged vias are free from defects such as barrel crack or knee crack of plated through hole (PTH) or delamination in the cured plugged material. Robustness of these resin-filled blind vias is attributed to anchored plated barrel with the additional support provided by plugged material, which restricts the thermomechanical deformation of plated copper.

A Gauge Study of an Intercomparison Evaluation to Implement the use of Fine-Pitch Test Patterns for Surface Insulation Resistance (SIR) Testing of Solder Fluxes

SIR is a recognised tool for establishing electrochemical reliability of electronic assemblies. Currently the test patterns in the standards reflect coarse pitch components. An intercomparison has been completed with the aim of establishing the introduction of a fine pitch SIR pattern with a 200µm gap. This exercise included the contribution from seven international participants. This new pattern moves the test method forward into the realm of current technologies where components of this pitch are common place. The study reported here validates the basis for the introduction of the new pattern, and confirms acceptable Gauge R&amp;R for the SIR technique. The analysis also highlights the challenges in controlling humidity to achieve comparable results between different users. The results also point to the challenges in achieving acceptable Gauge R&amp;R when measuring resistances &gt;1011Ω.

The pre-process DV-UKF algorithm for high-precision attitude measurement with low-cost inertial sensor

PurposeThe purpose of this paper is to propose a high-precision attitude solution to solve the attitude drift problem caused by the dispersion of low-cost micro-electro-mechanical system devices in strap-down inertial navigation attitude solution of micro-quadrotor.Design/methodology/approachIn this study, a three-stage attitude estimation scheme that combines data preprocessing, gyro drifts prediction and enhanced unscented Kalman filtering (UKF) is proposed. By introducing a preprocessing model, the quaternion orientation is calculated as the composition of two algebraic quaternions, and the decoupling feature of the two quaternions makes the roll and pitch components independent of magnetic interference. A novel real-time based on differential value (DV) estimation algorithm is proposed for gyro drift. This novel solution prevents the impact of quartic characteristics and uses the iterative method to meet the requirement of real-time applications. A novel attitude determination algorithm, the pre-process DV-UKF algorithm, is proposed in combination with UKF based on the above solution and its characteristics.FindingsCompared to UKF, both simulation and experimental results demonstrate that the pre-process DV-UKF algorithm has higher reliability in attitude determination. The dynamic errors in the three directions of the attitude are below 2.0°, the static errors are all less than 0.2° and the absolute attitude errors tailored by average are about 47.98% compared to the UKF.Originality/valueThis paper fulfils an identified need to achieve high-precision attitude estimation when using low-cost inertial devices in micro-quadrotor. The accuracy of the pre-process DV-UKF algorithm is superior to other products in the market.

Aeroelastic Stability of Combined Plunge-Pitch Mode Shapes in a Linear Compressor Cascade

Modern aeroengine designs strive for peak specific fuel and thermal efficiency. To achieve these goals, engines have more highly loaded compressor stages, thinner aerofoils, and blended titanium integrated disks (blisks) to reduce weight. These configurations promote the occurrence of aeroelastic phenomena such as flutter. Two important parameters known to influence flutter stability are the reduced frequency and the ratio of plunge and pitch components in a combined flap mode shape. These are used as design criteria in the engine development process. However, the limit of these criteria is not fully understood. The following research aims to bridge the gap between semi-analytical models and modern compressors by systematically investigating the flutter stability of a linear compressor cascade. This paper introduces the plunge-to-pitch incidence ratio, which is defined as a function of reduced frequency and pitch axis setback for a first flap (1F) mode shape. Using numerical simulations, in addition to experimental validation, aerodynamic damping is computed for many modes to build stability maps. The results confirm the importance of these two parameters in compressor aeroelastic stability as well as demonstrate the significance of the plunge-to-pitch incidence ratio for predicting the flutter limit.

High-Rate Attitude Determination of Moving Vehicles With GNSS: GPS, BDS, GLONASS, and Galileo

We investigate the long-term performance and improvement of high-rate multiconstellation Global Navigation Satellite System (GNSS) or multi-GNSS attitude determination in a dynamical environment and evaluate how much each GNSS contributes to such an improvement with applications to land vehicle navigation. We build a multiantenna GNSS system with three nondedicated receivers and conduct two experiments with quad-constellations in GNSS-friendly and GNSS-challenged environments on January 19 and 23, 2018, respectively. A high-grade inertial measurement unit (IMU) provides a reference of comparison for dynamic attitude solutions. In the static case, the global positioning system (GPS), BeiDou navigation satellite system (BDS), and GLObal NAvigation Satellite System (GLONASS) single-constellation solutions have basically the same performance for both experiments. In the dynamic case, GPS achieves the best accuracy in the experiment on January 19, while on January 23, GPS and GLONASS achieve very similar accuracy and significantly outperform BDS in the pitch and roll components. The different dynamic performances of these single constellations are primarily attributed to their differences in observation noise level and satellite geometry strength. By combining GPS, BDS, GLONASS, and Galileo, the multi-GNSS solution performs significantly better than any single-constellation solution. The average improvements in the dynamic cases are 26.2%, 40.7%, and 36.0% on January 19 and 19.2%, 30.0%, and 36.2% on January 23 in the yaw, pitch, and roll components, respectively. The attitude solutions on January 19 are always better determined than on January 23 in the dynamic cases, which should clearly indicate the importance of combining multiple GNSS constellations and the benefit of more observed satellites and a stronger satellite geometry in GNSS-challenged environments. We also introduce the concept of “influence rate” and quantitatively analyze the contribution of each GNSS system to the combined attitude solution.