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Context: Thyroid eye disease (TED) is a complex autoimmune disease process. Orbital fibroblasts represent the central orbital immune target. Involvement of the TSH receptor (TSHR) in TED is not fully understood. IGF-I receptor (IGF-IR) is overexpressed in several cell types in TED, including fibrocytes and orbital fibroblasts. IGF-IR may form a physical and functional complex with TSHR.Objective: Review literature relevant to autoantibody generation in TED and whether these induce orbital fibroblast responses directly through TSHR, IGF-IR, or both.Evidence: IGF-IR has traditionally been considered a typical tyrosine kinase receptor in which tyrosine residues become phosphorylated following IGF-I binding. Evidence has emerged that IGF-IR possesses kinase-independent activities and can be considered a functional receptor tyrosine kinase/G-protein-coupled receptor hybrid, using the G-protein receptor kinase/β-arrestin system. Teprotumumab, a monoclonal IGF-IR antibody, effectively reduces TED disease activity, proptosis, and diplopia. In addition, the drug attenuates in vitro actions of both IGF-I and TSH in fibrocytes and orbital fibroblasts, including induction of proinflammatory cytokines by TSH and TED IgGs.Conclusions: Although teprotumumab has been proven effective and relatively safe in the treatment of TED, many questions remain pertaining to IGF-IR, its relationship with TSHR, and how the drug might be disrupting these receptor protein/protein interactions. Here, we propose 4 possible IGF-IR activation models that could underlie clinical responses to teprotumumab observed in patients with TED. Teprotumumab is associated with several adverse events, including hyperglycemia and hearing abnormalities. Underpinning mechanisms of these are being investigated. Patients undergoing treatment with drug must be monitored for these and managed with best medical practices. [ABSTRACT FROM AUTHOR]

The absolute error of ellipsoidal heights that may be achieved from Real-Time Kinematic/Network Real-Time Kinematic Global Navigation Satellite Systems (RTK/NRTK GNSS) measurements varies between 3 and 5 cm. Although the vertical root mean square (RMS) error reported by receivers generally has smaller values, it can only be treated as a measure of the precision of the obtained results. Nowadays, real-time GNSS measurements are commonly used to implement surveys with increased accuracy. In some cases, it may be of concern to determine the height difference with real-time techniques than the height itself. The use of height difference may be applicable when a point with a known height is available. This offers the possibility of transferring the known height to a distant point using GNSS technology instead of geometric leveling, which is more labor-intensive. The aim of the study was to verify if achieving accuracy better than 2 cm in ellipsoidal height difference using RTK/NRTK GNSS is possible, providing special conditions of measurement. In this paper, the results of research consisting of RTK/NRTK measurement of specific points with fixed heights in various terrain conditions are presented. A single GNSS reference station was used as a base station to determine ellipsoidal height in RTK mode and Ground-Based Augmentation System (GBAS) for measurements in NRTK mode. Comparison of the ellipsoidal height difference to the results of precise leveling allows us to determine ellipsoidal height measurement errors. The measurements were carried out in open terrain, with the covered horizon (under trees) and in urbanized areas (high buildings). The method proposed by the authors in this paper does not require knowledge of the quasi-geoid model, neither normal correction to obtain measurement results. [ABSTRACT FROM AUTHOR]

In recent years, Global Navigation Satellite System (GNSS) technologies, which take full advantage of both real-time kinematic (RTK) and precise point positioning (PPP), managed to reach centimeter-level positioning accuracy with ambiguity resolution (AR) quick convergence techniques. One great advantage over traditional structural health monitoring (SHM) systems is that GNSS technologies will be functional in disaster management situations, when terrestrial communication links become unavailable. In this study, a multi-GNSS system, based on GPS and Galileo constellations and exploiting advanced RTK and PPP-AR technologies with update rate of 100 Hz is tested on two benchmark structures as an SHM system. The first case study served as a baseline to outline the methodology: first, a setup phase of the instrumentation, then a signal processing phase and last, the validation of the results. The methodology was then applied to a real-case scenario, in which the GNSS was tested on a road bridge. A comparative analysis with the results acquired by a set of accelerometers showed that the GNSS was able to identify the crossing of heavy vehicles. The work is paving the way for the development of an affordable and efficient multi-GNSS-based tool for the monitoring of civil infrastructures. [ABSTRACT FROM AUTHOR]

Multi-GNSS multi-frequency observations improve the accuracy, availability and reliability of the single-site RTK positioning but also simultaneously raise the communication bandwidth needed for the transmission of differential corrections. A RTK positioning algorithm is proposed that transmit the phase-only differential corrections to achieve the ambiguity-fixed RTK positioning, significantly reducing the communication bandwidth requirements. The essence of the presented method is that the code differential positioning solution implied in the conventional RTK positioning procedure can be replaced by the single point positioning solution of the rover receiver to realize RTK positioning. For typical application scenarios, the transmitted bits in a single epoch can be reduced by more than 25% when the corrections are sent with the RTCM protocol. The experiments by the GPS dual-frequency data over the 10 km and 180 km baselines shown that the performance of the presented RTK algorithm are comparable to that of the conventional RTK positioning, which verifies its feasibility and effectiveness. [ABSTRACT FROM AUTHOR]

Inter-system Biases (ISBs) between BDS-2 and BDS-3 is of great importance for BDS-2/BDS-3 joint processing, which is meaningful to make full use of BDS observations and improves PNT (positioning, navigation, timing) performance. In this contribution, we derive ISBs models with undifferenced ionospheric-free (IF) combination and double-differenced model, corresponding to the IF-PPP and RTK technologies respectively. To analyze code ISB in PPP, we processed data from 55 multi-GNSS experimental (MGEX) stations including 7 receiver types and conduct a detailed analysis on the effect of frequency, receiver types and precise products from 4 IGS Analysis Centers (ACs). It is concluded that both the overlapping frequency and the non-overlapping frequency of BDS-2/BDS-3 exist code ISB. The code ISB of overlapping frequency is within 10 ns, and that of the non-overlapping frequency can reach 100 ns. Moreover, code ISB is influenced by receiver types as well as satellite geometry. The average ISB of stations with the same manufactures tend to be the same while that of stations from different manufactures are different. Affected by the satellite geometry, the ISB characteristics exhibit periodicity and correlation with the location of stations. By comparing ISB calculated by different precise clock products from the GeoForschungsZentrum (GFZ), European Space Agency (ESA), Center for Orbit Determination in Europe (CODE) and Wuhan University (WHU), the results show that the daily STD of ISB COD , ISB WHU , ISB ESA and ISB GFZ is about 0.2 ns, which means that ISB can be calibrated by constant estimation when these products are used. As for Differential Inter-system Biases (DISBs) in RTK, it is discovered that the BDS-2/BDS-3 joint differenced system has a Differential Inter-system Code Bias (DISCB) that exceeds 3.4 ns when the rover and base receivers are made by different manufactures and the hardware delay characteristics for BDS-2 and BDS-3 are different. However, the Differential Inter-system Phase Bias (DISPB) doesn't exist and can be neglected in RTK. [ABSTRACT FROM AUTHOR]

The BeiDou Navigation Satellite System (BDS) is fully operational and provides positioning, navigation, and timing services to users worldwide. To comprehensively evaluate the BeiDou-3 Navigation Satellite System (BDS-3) global real-time kinematic (RTK) positioning performance, five sets of IGS/MEGX stations with different baseline lengths are selected in this research, and the visibility of current BDS-3, BDS-2+BDS-3, and Global Positioning System (GPS) system satellites are analyzed. The single frequency, dual-frequency, and triple-frequency positioning accuracy as well as ambiguity fixing rate under short baseline and long baseline are also analyzed. The experimental results show that the positioning accuracies of B1C, BII, L1, and B3I single-frequency bands were about the same, while for band B2a it was lower. For the short baseline dual-frequency RTK positioning mode, the accuracy of BDS-3 (B1C/B2a), BDS-3 (B1I/B3I), triple-frequency BDS-3 (B1C/B2a/B3I), and GPS (L1L2) is comparable and slightly better than that of BDS-3 (B1I/B3I). With the increase in baseline length, the advantages of dual-frequency BDS-3 (B1C/B2a) and triple frequency BDS (B1C/B2a/B3I) are more obvious, with triple-frequency BDS-3 (B1C/B2a/B3I) having the best positioning accuracy. In terms of ambiguity fixing performance, dual-frequency BDS-2+BDS-3 (B1I/B3I) and dual-frequency GPS (L1L2) have the highest ambiguity fixing rate. The ambiguity fixing rate of dual-frequency BDS-3 (B1C/B2a) and triple-frequency BDS-3 (B1C/B2a/B3I) can be higher than 90% within 100 km. In the case of positioning using only the BDS-3 system, the triple-frequency BDS-3 (B1C/B2a/B3I) is superior to both the dual-frequency BDS-3 (B1I/B3I) and dual-frequency BDS-3 (B1C/B2a) in terms of both positioning accuracy and ambiguity fixing rate. The BDS-2+BDS-3 (B1I/B3I) dual-frequency RTK, which has reached a level comparable to GPS, can provide global users with real-time centimeter-level differential positioning services. [ABSTRACT FROM AUTHOR]

Precise anticancer therapies employing cytotoxic conjugates constitute a side-effect-limited, highly attractive alternative to commonly used cancer treatment modalities, such as conventional chemotherapy, radiotherapy or surgical interventions. Receptor tyrosine kinases are a large family of N-glycoproteins intensively studied as molecular targets for cytotoxic conjugates in various cancers. At the cell surface, these receptors are embedded in a dense carbohydrate layer formed by numerous plasma membrane glycoproteins. The complexity of the cell surface architecture is further increased by galectins, secreted lectins capable of recognizing and clustering glycoconjugates, affecting their motility and activity. Cell surface N-glycosylation is intensively remodeled by cancer cells; however, the contribution of this phenomenon to the efficiency of treatment with cytotoxic conjugates is largely unknown. Here, we evaluated the significance of N-glycosylation for the internalization and toxicity of conjugates targeting two model receptor tyrosine kinases strongly implicated in cancer: HER2 and FGFR1. We employed three conjugates of distinct molecular architecture and specificity: AffibodyHER2-vcMMAE (targeting HER2), vcMMAE-KCK-FGF1.E and T-Fc-vcMMAE (recognizing different epitopes within FGFR1). We demonstrated that inhibition of N-glycosylation reduced the cellular uptake of all conjugates tested and provided evidence for a role of the galectin network in conjugate internalization. In vitro binding studies revealed that the reduced uptake of conjugates is not due to impaired HER2 and FGFR1 binding. Importantly, we demonstrated that alteration of N-glycosylation can affect the cytotoxic potential of conjugates. Our data implicate a key role for cell surface N-glycosylation in the delivery of cytotoxic conjugates into cancer cells. [ABSTRACT FROM AUTHOR]

To improve the positioning accuracy and reliability of autonomous navigation agricultural machinery and reduce the cost of high-precision positioning, an integrated navigation system based on Real-Time Dynamic Kinematic BeiDou Navigation Satellite System (RTK-BDS) and Inertial Navigation System (INS) is designed in this study. On the one hand, an autonomous navigation control board is designed and made in the system, which integrates BDS high-precision analysis module, Inertial Measurement Unit (IMU) module, and radio module, and realizes the integrated navigation algorithm on the control board. On the other hand, low-cost RTK technology is realized by building differential reference stations and vehicle-mounted mobile stations. Experiments are carried out on actual farm machinery under different road conditions including open road, signal-shielded road, and urban congested road. According to the angular velocity and acceleration information from INS and the position and velocity information from the BDS high-precision analysis module, the system uses Kalman filter algorithm for data fusion to calculate the precise position, velocity, and attitude information of agricultural machinery in real time. The experimental results show that the position error of the integrated navigation system on the open road is within 3 cm, the azimuth error is within 0.6°, and the inclination error is within 1°, all of which converge rapidly when encountering bad road conditions. It can be known from the experimental results that the RTK-BDS/INS integrated navigation system has high positioning accuracy, strong adaptive anti-interference ability, and low implementation cost of RTK technology, which provides a reliable way for automatic navigation control of agricultural machinery. [ABSTRACT FROM AUTHOR]

Namibia currently undergoes a rapid process of urbanisation of 4% annually, visible through an exponential informal settlement growth. Alternative measurement methods in cadastral mapping could secure land tenure in these settlements and fasten land registration. This article investigates the performance of five alternative measurement methods within the Flexible Land Tenure System (FLTS): orthophoto-based boundary demarcation, mapping applications on mobile devices, hand-held GPS, low-cost GNSS with u-blox receiver and GNSS RTK based on the Namibian CORS. The article evaluates all five methods on technical performance, affordability, time efficiency, feasibility, and simplicity. Based on the evaluation, all methods are appropriate for Namibia except for the hand-held GPS method. Low-cost approaches are appropriate for starter titles, whereas high-technology methods are better when requiring higher positioning accuracy (land hold title). Orthophoto-based boundary demarcation is surprisingly less suitable for the Namibian case. Overall, the results support a fit-for-purpose land administration in Namibia. [ABSTRACT FROM AUTHOR]

Usually, it is difficult to implement integer ambiguity resolution within a short amount of time for GNSS positioning in urban areas due to the contamination of non-line-of-sight signals and multipath. This study proposes a sequential ambiguity selection strategy for partial ambiguity resolution. First, the ambiguities are selected based on the filtered residuals of the phase and code measurements. In addition, the elevation angle and decorrelated variances are used as the metrics for selecting ambiguity subsets. Two kinematic experiments are carried out in urban areas to evaluate the performance of the strategy. Among the three independent strategies, the first one performs better than the others, as the dependency of observation quality on the elevation angle is low and the decorrelated variances are prone to be contaminated by biased ambiguities. When the proposed sequential ambiguity selection strategy is used, the percentage of correctly fixed epochs is increased by approximately 10–20%. The RMS of N/E/U is improved from the decimeter level (for full ambiguity resolution) to the centimeter level. The improvement is more obvious in the obstructed area and during the re-initialization phase. [ABSTRACT FROM AUTHOR]

Activating anaplastic lymphoma kinase (ALK) receptor tyrosine kinase (RTK) mutations occur in pediatric neuroblastoma and are associated with poor prognosis. To study ALK-activating mutations in a genetically controllable system, we employed CRIPSR/Cas9, incorporating orthologs of the human oncogenic mutations ALKF1174L and ALKY1278S in the Drosophila Alk locus. AlkF1251L and AlkY1355S mutant Drosophila exhibited enhanced Alk signaling phenotypes, but unexpectedly depended on the Jelly belly (Jeb) ligand for activation. Both AlkF1251L and AlkY1355S mutant larval brains displayed hyperplasia, represented by increased numbers of Alk-positive neurons. Despite this hyperplasic phenotype, no brain tumors were observed in mutant animals. We showed that hyperplasia in Alk mutants was not caused by significantly increased rates of proliferation, but rather by decreased levels of apoptosis in the larval brain. Using single-cell RNA sequencing, we identified perturbations during temporal fate specification in AlkY1355S mutant mushroom body lineages. These findings shed light on the role of Alk in neurodevelopmental processes and highlight the potential of Alk-activating mutations to perturb specification and promote survival in neuronal lineages. This article has an associated First Person interview with the first author of the paper.

The spatial accuracy of unmanned aerial vehicles (UAVs) and the images they capture play a crucial role in the mapping process. Researchers are exploring solutions that use image-based techniques such as structure from motion (SfM) to produce topographic maps using UAVs while accessing locations with extremely high accuracy and minimal surface measurements. Advancements in technology have enabled real-time kinematic (RTK) to increase positional accuracy to 1–3 times the ground sampling distance (GSD). This paper focuses on post-processing kinematic (PPK) of positional accuracy to achieve a GSD or better. To achieve this, precise satellite orbits, clock information, and UAV global navigation satellite system observation files are utilized to calculate the camera positions with the highest positional accuracy. RTK/PPK analysis is conducted to improve the positional accuracies obtained from different flight patterns and altitudes. Data are collected at altitudes of 80 and 120 meters, resulting in GSD values of 1.87 cm/px and 3.12 cm/px, respectively. The evaluation of ground checkpoints using the proposed PPK methodology with one ground control point demonstrated root mean square error values of 2.3 cm (horizontal, nadiral) and 2.4 cm (vertical, nadiral) at an altitude of 80 m, and 1.4 cm (horizontal, oblique) and 3.2 cm (vertical, terrain-following) at an altitude of 120 m. These results suggest that the proposed methodology can achieve high positional accuracy for UAV image georeferencing. The main contribution of this paper is to evaluate the PPK approach to achieve high positional accuracy with unmanned aerial vehicles and assess the effect of different flight patterns and altitudes on the accuracy of the resulting topographic maps.

When surveying a large target area with a real-time kinematic unmanned aerial vehicle (RTK-UAV), the RTK signal tends to be disconnected when city canyons or macrocells are included. Thus, the accuracy is reduced due to the lack of RTK signal or the fact that RTK signal is not available in certain areas. The available methods to solve this problem are costly. Therefore, we used one GCP and performed post-process kinematics (PPK) to verify whether the accuracy reduction caused by the lack of RTK signal in certain areas could be solved. A data set detailing the percentage of time during which the RTK signal was received (100%, 90%, 5%, and 0%) was obtained, and ATs were conducted both with and without PPK using GCPs located at the four corners and center. In 40 experiments, the trend of root mean square error (RMSE) values based on the distance between the GCP used and the 41 check points (CPs) was analyzed. In the absence of PPK, the error tended to increase depending on the distance between the GCP and CPs, but there was no significant difference after PPK as up to 10 cm horizontal error and up to 20 cm vertical error were observed within a 1 km radius of the GCP. As a result, even if the RTK signal is disconnected during shooting, it is possible to achieve an accuracy within 3 GSD up to a radius of 1 km from the GCP.

At present, various applications have a high demand for navigation systems. With the example of self-driving cars, the navigation system has to provide pinpoint accuracy for positioning. Inertial navigation system (INS) and global positioning system (GPS) are some of the common ways to navigate. However, these two systems have the disadvantages of continuity, cumulative error, divergence over time, and reliability. A solution based on the extended Kalman filter (EKF) and long- and short-term memory (LSTM) is proposed in this study to correct the divergence due to cumulative errors in INS. It has been proven effective by a number of studies to combine a Kalman filter with GPS and INS data. However, there are still issues in the integration of the Kalman filter with INS/GPS, such as random error model, noise resistance, and observability of inertial sensors. The proposed system is designed to incorporate deep learning to comb through long-, medium-, and short-term memories as well as predict INS and GPS errors using recurrent neural network (RNN), as LSTM is used to learn INS errors while the GPS is working well and to predict GPS errors when GPS signals are lost. Unlike the traditional way of learning, LSTM contains time variants. To verify the accuracy of the proposed design, the EKF is introduced as a means to compare with LSTM. EKF is very suitable for more flexible coordination between INS and GPS, so EKF is used for deep learning comparison with LSTM for prediction and control in a nonlinear environment. Then, the LSTM deep learning is used to correct the predictions. This computation reduces the errors in position and speed. Finally, an emulation model developed in MATLAB is used to simulate the INS-GPS integrated system error compensation model. The experiment results indicate that the errors in parameters are the smallest with the integration of LSTM in INS and GPS, thus providing the effects of error correction and compensation. [ABSTRACT FROM AUTHOR]

Much cell‐to‐cell communication is facilitated by cell surface receptor tyrosine kinases (RTKs). These proteins phosphorylate their downstream cytoplasmic substrates in response to stimuli such as growth factors. Despite their central roles, the functions of many RTKs are still poorly understood. To resolve the lack of systematic knowledge, we apply three complementary methods to map the molecular context and substrate profiles of RTKs. We use affinity purification coupled to mass spectrometry (AP‐MS) to characterize stable binding partners and RTK–protein complexes, proximity‐dependent biotin identification (BioID) to identify transient and proximal interactions, and an in vitro kinase assay to identify RTK substrates. To identify how kinase interactions depend on kinase activity, we also use kinase‐deficient mutants. Our data represent a comprehensive, systemic mapping of RTK interactions and substrates. This resource adds information regarding well‐studied RTKs, offers insights into the functions of less well‐studied RTKs, and highlights RTK‐RTK interactions and shared signaling pathways. Synopsis: A combination of interaction proteomics methods (AP‐MS and BioID) and mass spectrometry‐based substrate mapping identifies interactors and substrates of the human receptor tyrosine kinase (RTK) protein family. The combined dataset represents a comprehensive, systemic map of human RTK interactions, substrates and functions. Affinity purification‐mass spectrometry (AP‐MS) and proximity‐dependent biotin identification (BioID) identifies 6,500 binary interactions for 52 RTKsOver 10,000 substrate phosphorylation sites are identified for 45 RTKsThe resource contains both, known and novel RTK‐RTK interactions [ABSTRACT FROM AUTHOR]

The Google Smartphone Decimeter Challenge (GSDC) was a competition held in 2021, where data from a variety of instruments useful for determining a phone's position (signals from GPS satellites, accelerometer readings, gyroscope readings, etc.) using Android smartphones were provided to be processed/assessed in regard to the most accurate determination of the longitude and latitude of user positions. One of the tools that can be utilized to process the GNSS measurements is RTKLIB. RTKLIB is an open-source GNSS processing software tool that can be used with the GNSS measurements, including code, carrier, and doppler measurements, to provide real-time kinematic (RTK), precise point positioning (PPP), and post-processed kinematic (PPK) solutions. In the GSDC, we focused on the PPK capabilities of RTKLIB, as the challenge only required post-processing of past data. Although PPK positioning is expected to provide sub-meter level accuracies, the lower quality of the Android measurements compared to geodetic receivers makes this performance difficult to achieve consistently. Another latent issue is that the original RTKLIB created by Tomoji Takasu is aimed at commercial GNSS receivers rather than smartphones. Therefore, the performance of the original RTKLIB for the GSDC is limited. Consequently, adjustments to both the code-base and the default settings are suggested. When implemented, these changes allowed RTKLIB processing to score 5th place, based on the performance submissions of the prior GSDC competition. Detailed information on what was changed, and the steps to replicate the final results, are presented in the paper. Moreover, the updated code-base, with all the implemented changes, is provided in the public repository. This paper outlines a procedure to optimize the use of RTKLIB for Android smartphone measurements, highlighting the changes needed given the low-quality measurements from the mobile phone platform (relative to the survey grade GNSS receiver), which can be used as a basis point for further optimization for future GSDC competitions. [ABSTRACT FROM AUTHOR]

The Real-Time Kinematic (RTK) positioning algorithm is a promising positioning technique that can provide real-time centimeter-level positioning precision in GNSS-friendly areas. However, the performance of RTK can degrade in GNSS-hostile areas like urban canyons. The surrounding buildings and trees can reflect and block the Global Navigation Satellite System (GNSS) signals, obstructing GNSS receivers' ability to maintain signal tracking and exacerbating the multipath effect. A common method to assist RTK is to couple RTK with the Inertial Navigation System (INS). INS can provide accurate short-term relative positioning results. The Extended Kalman Filter (EKF) is usually used to couple RTK with INS, whereas the GNSS outlying observations significantly influence the performance. The Robust Kalman Filter (RKF) is developed to offer resilience against outliers. In this study, we design an algorithm to improve the traditional RKF. We begin by implementing the tightly coupled RTK/INS algorithm and the conventional RKF in C++. We also introduce our specific implementation in detail. Then, we test and analyze the performance of our codes on public datasets. Finally, we propose a novel algorithm to improve RKF and test the improvement. We introduce the Carrier-to-Noise Ratio (CNR) to help detect outliers that should be discarded. The results of the tests show that our new algorithm's accuracy is improved when compared to the traditional RKF. We also open source the majority of our code, as we find there are few open-source projects for coupled RTK/INS in C++. Researchers can access the codes at our GitHub. [ABSTRACT FROM AUTHOR]

Targeted tumor therapies of receptor tyrosine kinases (RTK) do not work for every patient with cancer, owing to differences in the level of RTK heterogeneity, RTK co-activation mechanisms, and other aspects of disease biology. Over the last years, the combination of non-invasive positron emission tomography (PET) with non-pharmacological doses of an RTK-specific antibody has shown the ability to study cancer biology in real-time and in the whole body of living subjects at the early stages of the disease and in response to therapies. Many RTK-specific antibody-PET imaging conjugates exist in the clinics and show potential for earlier diagnosis and accurate management of oncology patients. Herein, our review concisely focuses on clinical and preclinical data of RTK-targeted PET imaging to detect two significant biological mechanisms of tumor resistance — RTK heterogeneity and RTK co-activation. This mini-review provides an overview of RTK-targeted PET imaging studies of the last 4 years and gives collective information on how it may assist prognostic information and image disease recurrence. [Display omitted] [ABSTRACT FROM AUTHOR]

Recent progress in using real-time kinematic (RTK) positioning has motivated the exploration of its application due to its high accuracy and efficiency. However, poorly-observed satellite data will cause unfixed ambiguities and markedly biased solutions. A novel partial ambiguity resolution method, named the irrespective of integer ambiguity resolution (IIAR) model, is proposed and applied to improve the reliability of ambiguity resolution. The proposed method contains initial ambiguity resolution and irrespective of integer ambiguity processes. The initial ambiguity resolution process applies an iterative partial ambiguity resolution method to obtain an approximate solution. The irrespective of integer ambiguity process transforms the approximate solution to a high-precision solution. Experiments show that the approximate solution is unreliable when the initial ambiguity resolution process has small redundancy, and the proposed method can obtain better results for those cases. The IIAR method showed about a 40% improvement of multi-GNSS ambiguity success rate and about a 25% improvement of standard deviation. Therefore, these results show that the proposed IIAR method can improve the results of multi-GNSS RTK positioning significantly. [ABSTRACT FROM AUTHOR]

In emergency response and disaster rescue, unmanned aerial vehicles (UAVs) onboard thermal infrared (TIR) sensors are an essential means of acquiring ground information in the nighttime working environment. To enable field personnel to make better decisions based on TIR video streams returned from a UAV, the geographic information enhancement of TIR video streams is required. At present, it is difficult for low-cost UAVs to carry high-precision attitude sensors and thus obtain high-precision camera attitude information to meet the enhanced processing requirements of UAV TIR video streams. To this end, this paper proposes an improved Kalman filter algorithm to improve the geographic registration (geo-registration) accuracy by fusing the positioning and heading data from the dual-antenna real-time kinematic global positioning system (RTK-GPS) with onboard internal measurement unit (IMU) data. This method can yield high-precision position and attitude data in real time based on low-cost UAV hardware, based on which high-precision geo-registration results can be obtained. The computational complexity can be reduced compared with video stream feature tracking algorithms. Furthermore, the problem of unstable matching due to the low resolution and texture level of TIR video streams can be avoided. The experimental results prove that the proposed method can reduce the registration error by 66.15%, and significantly improve the geo-registration accuracy of UAV TIR video streams. Thus, it can strongly support the popularization and practicality of the application of augmented reality (AR) technology to low-cost UAV platforms. [ABSTRACT FROM AUTHOR]

Extreme space weather events affect the stability and quality of the global navigation satellite systems (GNSS) of the second generation (GPS, GLONASS, Galileo, BeiDou/Compass) and GNSS augmentation. We review the theory about mechanisms behind the impact of geomagnetic storms, ionospheric irregularities, and powerful solar radio bursts on the GNSS user segment. We also summarize experimental observations of the space weather effects on GNSS performance in 2000–2020 to confirm the theory. We analyze the probability of failures in measurements of radio navigation parameters, decrease in positioning accuracy of GNSS users in dual-frequency mode and differential navigation mode (RTK), and in precise point positioning (PPP). Additionally, the review includes data on the occurrence of dangerous and extreme space weather phenomena and the possibility for predicting their impact on the GNSS user segment. The main conclusions of the review are as follows: 1) the positioning error in GNSS users may increase up to 10 times in various modes during extreme space weather events, as compared to the background level; 2) GNSS space and ground segments have been significantly modernized over the past decade, thus allowing a substantial increase in noise resistance of GNSS under powerful solar radio burst impacts; 3) there is a great possibility for increasing the tracking stability and accuracy of radio navigation parameters by introducing algorithms for adaptive lock loop tuning, taking into account the influence of space weather events; 4) at present, the urgent scientific and technical problem of modernizing GNSS by improving the scientific methodology, hardware and software for monitoring the system integrity and monitoring the availability of required navigation parameters, taking into account the impact of extreme space weather events, is still unresolved.

This paper is devoted to construction of reference walking trajectories for developing pedestrian navigation algorithms for smartphones. Such trajectories can be used both for verification of classical algorithms of navigation or for application of machine learning technics. Reconstruction of closed trajectories based on data from foot-mounted inertial measurement units (IMU) is investigated. The advantages of the approach are the use of inexpensive sensors and the simplicity of the presented method. We propose algorithms for reconstruction of smooth 2D pedestrian trajectories based on measurements from a single IMU as well as on combined measurements from two IMU’s. Introduced algorithms are based on application of modified Kalman filter with an assumption of IMU having zero velocity when foot contacts the ground. In case of two measurement units, it is additionally assumed that the positions of the sensors cannot differ significantly from each other. The algorithms were tested on trajectories lasting from 1 to 10 minutes, passing indoors on horizontal surfaces. Obtained results were compared with high precision trajectories acquired with GNSS RTK receivers. Additionally, the process of inter-device time synchronization is investigated and detailed description of the experiments and used equipment is given. The dataset used for verification of proposed algorithms is freely available at: http://gartseev.ru/projects/rtj2021.

Technologies for autonomous navigation of MASS (Maritime Autonomous Surface Ship) in open waters are advancing rapidly. However, the autonomous berthing technology, which represents the final phase of MASS achieving fully autonomous navigation, is still in the process of maturing. Consequently, the study of autonomous berthing control technology holds significant practical importance for the realization of fully autonomous navigation in MASS. This paper proposes an autonomous berthing control program for MASS, based on a MFAC (Model Free Adaptive Control) algorithm that integrates control technology and perception technology. The program encompasses the design of both the berthing logic algorithm and control algorithm. For the controllers, the Preview Deviation Yaw Control System and Speed Control System are designed using the CFDL-MFAC (Compact Form Dynamic Linearization based MFAC) algorithm. The RTK (Real Time Kinematic) data are utilized as inputs for the controller. The experiments are conducted in Lingshui Bay, Dalian, China. The results demonstrate that the lateral distance between the vessel's midship and the berth is less than 1.5 times the vessel's breadth, and the approaching angle is within the range of 0 ° to 10 ° , which shows that the proposed program could effectively help vessels achieve desirable berthing states. • A berthing logic algorithm was designed. According to the distance from the current vessel position and the target location, 3 decision points are designed during the berthing process. The expected berthing state is contained as that the lateral distance from the berth is less than 1.5 times the vessel's breadth, the approaching angle is within the range of 0 ° to 10 °. • An autonomous berthing control system based on RTK real-time data is designed, which consists of a Preview Deviation Yaw Control System and a Speed Control System. • An unmanned boat experiment from the fairway to the berth is conducted using RTK as the real-time data source for the controller. [ABSTRACT FROM AUTHOR]

In a complex monitoring environment, GNSS signals, which are extremely susceptible to environmental interference, can produce multipath errors, and the observation data contain a large number of poor observation values, resulting in reduced GNSS monitoring accuracy or even unavailability. Considering that the base station in the monitoring network is usually deployed in an open and unobstructed environment, and the same satellite information tracked by the base station and the monitoring station has a strong correlation, the method of identifying multipath errors in GNSS observation data based on prior information of base station's signal-to-noise ratio(SNR)was proposed. This method utilizes the strong correlation between satellite SNR observations and multipath errors, identifies poor data seriously affected by multipath through making inter-station differences in SNR observations, and removes them to resist the multipath effects of complex monitoring environment. Taking the monitoring environment of one landslide with serious occlusion in Sanmenxia area of Henan as an example, the verification based on the measured data shows that the proposed method can effectively identify the poor observation values with serious multipath effect affected by mountains, vegetation and artificial facilities, has stronger environmental adaptability, and significantly improves the fixed rate of ambiguity and positioning accuracy. Compared with the traditional fixed cut-off(TFC)model and the azimuth-dependent elevation mask(ADEM)model, the proposed method's ambiguity fixed rates are improved by the average of 39.6% and 28.6%, respectively; the positioning accuracy of the fixed solution is better than 4 mm in the E and N directions, and better than 9 mm in the U direction. [ABSTRACT FROM AUTHOR]

Background: Neuroblastoma is a devastating disease accounting for 15% of all childhood cancer deaths. Yet, our understanding of key molecular drivers such as receptor tyrosine kinases (RTKs) in this pathology remains poorly clarified. Here, we provide a systematic analysis of the RTK superfamily in the context of neuroblastoma pathogenesis. Methods: Statistical correlations for all RTK family members' expression to neuroblastoma patient survival across 10 independent patient cohorts were annotated, synthesized, and ranked using the R2: Genomics Analysis and Visualization Platform. Gene expression of selected members across different cancer cell lines was further analyzed in the Cancer Cell Line Encyclopedia, part of the Cancer Dependency Map portal (depmap portal (http://depmap.org)). Finally, we provide a detailed literature review for highly ranked candidates. Results: Our analysis defined two subsets of RTKs showing robust associations with either better or worse survival, constituting potential novel players in neuroblastoma pathophysiology, diagnosis, and therapy. We review the available literature regarding the oncogenic functions of these RTKs, their roles in neuroblastoma pathophysiology, and potential utility as therapeutic targets. Conclusions: Our systematic analysis and review of the RTK superfamily in neuroblastoma pathogenesis provides a new resource to guide the research community towards focused efforts investigating signaling pathways that contribute to neuroblastoma tumor establishment, growth, and/or aggressiveness and targeting these druggable molecules in novel therapeutic strategies. [ABSTRACT FROM AUTHOR]

Purpose: Hepatocellular carcinoma (HCC) is one of the most common cancers in the world with a high mortality rate. Receptor tyrosine kinases play important roles in the occurrence and development of various cancers. Discoid protein domain receptor 1 (DDR1) is a special type of transmembrane receptor tyrosine kinase. Here, we show that the expression of DDR1 is significantly increased in HCC and is related to a poor clinical prognosis. Methods: The expression of DDR1 in HCC cell lines and primary HCC specimens was evaluated using Western blotting and immunohistochemistry. A correlation between DDR1 and SLC1A5 expression was also investigated in primary HCC specimens. Cell proliferation was evaluated using in vitro CCK8 and colony formation assays. Gene knock-down and overexpression assays, CHX, NH4CL and Mg132 interference tests and immunoprecipitation, as well as nude mouse xenograft models were used to assess the mechanism by which DDR1 promotes tumorigenesis in vitro and in vivo. Results: We found that DDR1 promotes the proliferation of HCC cells and accelerates the growth of HCC tumor xenografts, while DDR1 downregulation had the opposite effect. We also found that loss or gain of DDR1 expression affected HCC cell cycle progression. Mechanistically, we found that DDR1 interacts with SLC1A5, which belongs to the solute carrier (SLC) family of transporters, and regulates its stability, thereby affecting the mTORC1 signaling pathway. In addition, we found that SLC1A5 regulation by DDR1 can be restored by lysosome inhibitors. We also found that DDR1 is highly expressed in HCC tissues and that increased DDR1 expression predicts a shorter overall survival (OS) time. We additionally found that the expression of SLC1A5 was positively correlated with that of DDR1. Together, our data indicate that DDR1 acts as a tumor-promoting factor that can control HCC cell proliferation and cell cycle progression by stabilizing SLC1A5 in a lysosome-dependent way. Conclusions: Our study reveals a new mechanism by which DDR1 plays a liver cancer-promoting role. We also found that DDR1 expression serves as an independent prognostic marker, and that DDR1 and SLC1A5 expression levels are positively correlated in clinical samples. Our findings provide a new perspective for understanding HCC development and offers new targets for the treatment and management of HCC. [ABSTRACT FROM AUTHOR]

The Real Time Kinematic (RTK) method is widely used in the land surveying. Whereas RTK method has the advantage of practical use, positioning accuracy depends mostly on the baseline length due to the atmospheric errors. In general, RTK measurements are made by using GPS and GLONASS satellite systems. For this reason, the positioning performance of the technique is adversely affected under restricted satellite geometry conditions such as urban canyons. At present, most receivers on the market have the ability to track signals of Galileo and BeiDou satellites. Therefore, in this study, the positioning performance of RTK with different satellite combinations (GPS-only, GPS+GLONASS, GPS+GLONASS+GALILEO+BeiDou) was examined with a comparative approach. A field test was carried out considering approximately 20, 40, 60, and 80 km length of baselines. Three different cut off elevation angles - namely, 10°, 20°, and 30° - were chosen for the field test. The results were investigated in terms of accuracy and precision. Also, the ground truth coordinates of the rovers were obtained by post-processing relative method using GAMIT/GLOBK software. The results showed that multi-GNSS combinations provided better repeatability at the 10° cut off angle option. The accuracy of GPS-only solutions varied between 0.63/2.17 cm and 2.40/4.94 cm for horizontal and vertical components, respectively. However, the multi-GNSS combinations did not have a remarkable superiority in terms of position accuracy even at high satellite cut off angle (30°) compared to the GPS-only RTK. [ABSTRACT FROM AUTHOR]

Misuse and improper parceling of land, such as: the construction of houses in topographically unsuitable areas, due to the lack of planning or public policies, constantly causes human and infrastructure losses in several Brazilian cities. The identification of areas at risk of landslides and flooding, using precision equipment, can contribute to the development of research related to this topic, generating more efficient public policies. Therefore, this research has identified and analyzed risk areas in Cachoeirinha district, in Viçosa, Minas Gerais, with the use of equipment such as: Global Navigation Satellite System GNSS / Real Time Kinematics (RTK), to collect control points, Pilot Aircraft Remotely (RPA), for collection of images, methodologies and tools of the Geographic Information System. As a result, the mapping of vulnerable risk areas was obtained. It was elaborated using multicriteria analysis, with the variables: slope, density of buildings, distance from watercourse and land use and coverage, determined in the field. Material was produced that can serve as a reference for future research and to provide resources for the definition of public policies which contribute to solving this major problem in urban areas. [ABSTRACT FROM AUTHOR]

The ionospheric delay is one of the major error sources in GNSS precise data processing. In most scenarios, only the first-order ionosphere delay was fully considered, which contributes to about 99% of the total ionosphere delay. Recent research reveals that the higher-order ionospheric (HOI) delay can also introduce up to 2 cm biases for the GPS L1 observations. This bias is generally not considered in the underlying function model and consequently, it introduces unintentional biases, which may degrade the reliability of the ambiguity estimation in long-baseline RTK. This study examined the impact of the HOI on the observations and the ambiguity estimation procedure. We considered the HOI bias in the underlying model to evaluate the unintentional HOI bias on the success rate (SR) of ambiguity estimation. The numerical results showed that the double-differenced HOI effect reaches about 7 mm in the ionospheric active period, and can affect the ambiguity estimation success rate by up to 30% in the GNSS data processing and the HOI impact is more significant when a new satellite arose. The presence of the HOI biases may change about 0.3% ambiguity fixing results. In addition, the HOI bias can also introduce several millimeters biases in positioning solutions. [ABSTRACT FROM AUTHOR]

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The main technical characteristics of industrial robots are considered, notably nominal load capacity, number of degrees of mobility, magnitude and speed of movement by degrees of mobility, working area, working space and service area of industrial robots, positioning error or trajectory processing. The classification division of industrial robots into groups according to their speed and accuracy is analyzed. It is established that as a result of the motion of any mechanical system, including the manipulation system of an industrial robot, there is always a deviation of the real vector of the state of the system from the planned one. As a result, the center of the grip of the industrial robot when performing any technological operations at any time occupies a certain position in the vicinity of the corresponding program-defined coordinate. Considering the question of determining the accuracy of the robot is necessary to analyze the design features and characteristics of the manipulation system, the nature of the load and mode of operation. Thus, it is expedient to consider separate components of accuracy of functioning the robot depending on the factors causing various errors. It is established that the error of positioning, or working off, thea trajectory can be considered both as a whole for a working body (total), and for separate executive mechanisms of industrial robot. The main types of errors of manipulation systems of industrial robots are described and the method of determining their estimation is given.

O posicionamento em tempo real por meio do emprego dos sinais de satélites foi um avanço nas navegações aérea, marítima e terrestre com o surgimento do GPS (Global Positioning System). Contudo as precisões horizontais e verticais de 100 m e 150 m (nível de probabilidade de 95%) alcançadas, estando a SA (Selective Availability) ativada, passaram a não ser satisfatórias para muitas aplicações e os usuários buscaram galgar outros níveis de precisões. Esforços foram investidos no chamado posicionamento diferencial DGPS (Differential GPS), o qual possibilitou obter precisões em torno de dez vezes melhores do que as do posicionamento absoluto. Posteriormente, usando-se a fase da onda portadora, conseguiu-se realizar posicionamento com maior acurácia por meio do método RTK (Real Time Kinematic), atingindo qualidade centimétrica. Na sequência, houve uma evolução para posicionamentos em rede, empregando, por exemplo, o algoritmo de VRS (Virtual Reference Station). Vários erros nas observáveis dos satélites passaram a ser modelados com uma solução de multiestações em tempo real. A partir de 2012, surgiram serviços e produtos que favoreceram o desenvolvimento do RT-PPP (Real-Time Precise Point Positioning) baseado no conceito SSR (State Space Representation). A busca da solução das ambiguidades no RT-PPP deu origem ao PPP-RTK com menor tempo de fixação das ambiguidades e convergência para a solução acurada do posicionamento. Neste artigo apresenta-se como foi a evolução do posicionamento em tempo real, algumas das aplicações no âmbito nacional e as perspectivas desta modalidade de posicionamento para o futuro.

The trend in spatial data accuracy has gone from meters to decimeters and even centimeter levels in the last two decades. In large part, the centimeter(s) level spatial accuracies of geospatial products result from the use of LiDAR data and both low altitude manned and unmanned aerial systems for imagery and for topographic and surface models. All these sources are dependent on high precision/accuracy GNSS technologies to achieve such accuracies. The cost of L1/L2 receivers capable of centimeter(s) level position accuracy has rapidly, in the last year, decreased from over $15k – $20k to (in early 2019) to about $300 (in 2020). Such recent low costs provide an economically affordable revolution in the use of centimeter(s) level accuracies in aerial remote sensing, ground support, field data collections, and classroom instruction with GNSS RTK technologies. Except for the marketing literature little is known about their performance in the typical applications of the remote sensing and GIS communities. How accurate are the new low-cost dual-frequency multi-constellation receivers? What is the reliability in typical landscapes and mountainous landscapes? Answers to these questions are important to control the bundle-adjustment in SfM approaches using ground control points, setting confidence limits in topographic change detection, collecting ground reference data, and evaluating orthoimagery. The problem of assessing performance in typical applications is the lack of a reference source of higher precision and accuracy than the low-cost GNSS receivers themselves. In this study, a low-cost receiver/antenna was evaluated using height modernization monuments in the National Geodetic Survey network. These monuments are typically of sub-centimeter positional accuracy. Thirty-six monuments in four piedmont counties of South Carolina were surveyed (in RTK FIX mode). Resulting accuracies for these typical environments were 2.2-cm RMSE in both horizontal and height dimensions. The 95% confidence level accuracies for the horizontal and height dimensions were 3.7-cm and 4.2-cm (95%), respectively. Performance tests in the South Carolina mountains revealed numerous issues with the low cost survey grade GNSS receiver (cellular connections, availability of reference sites, and satellite signal occlusion from mountains) that also plagues more expensive receivers.

On February 11, 2019, the latest batch of four Galileo satellites has been commissioned for operational use, accelerating the evolution of the Galileo system toward Full Operational Capability (FOC). To exploit the advantages of the European GNSS constellation, all the Galileo signals in the E1 and E5 frequency band have been successfully integrated in Leica GNSS positioning technologies, with the expectation of improved availability, accuracy and reliability. From the user's perspective, this paper assesses the benefits of Galileo to high-precision GNSS in the real-time kinematic (RTK), real-time precise point positioning (PPP) and post-processing scenarios. Representative measuring conditions, such as open sky, multipath environments and tree canopy, are considered. The RTK results show that in challenging environments, the integration of Galileo significantly improves the RTK fix availability and effectively reduces decimeter-to-meter-level position errors caused by incorrect ambiguity fixes. To characterize the RTK performance of individual GNSS systems, Galileo-only positions are compared with GPS-only and GLONASS-only solutions. The PPP results demonstrate how Galileo benefits the convergence time and positioning accuracy. The post-processing studies show that the inclusion of Galileo provides more accurate solutions for short data durations and long baselines, particularly for data collected under strong multipath conditions. [ABSTRACT FROM AUTHOR]

Oncoprotein expression is controlled at the level of mRNA translation and is regulated by the eukaryotic translation initiation factor 4F (eIF4F) complex. eIF4A, a component of eIF4F, catalyzes the unwinding of secondary structure in the 5'-untranslated region (5'-UTR) of mRNA to facilitate ribosome scanning and translation initiation. Zotatifin (eFT226) is a selective eIF4A inhibitor that increases the affinity between eIF4A and specific polypurine sequence motifs and has been reported to inhibit translation of driver oncogenes in models of lymphoma. Here we report the identification of zotatifin binding motifs in the 5'-UTRs of HER2 and FGFR1/2 Receptor Tyrosine Kinases (RTKs). Dysregulation of HER2 or FGFR1/2 in human cancers leads to activation of the PI3K/AKT and RAS/ERK signaling pathways, thus enhancing eIF4A activity and promoting the translation of select oncogenes that are required for tumor cell growth and survival. In solid tumor models driven by alterations in HER2 or FGFR1/2, downregulation of oncoprotein expression by zotatifin induces sustained pathway-dependent anti-tumor activity resulting in potent inhibition of cell proliferation, induction of apoptosis, and significant in vivo tumor growth inhibition or regression. Sensitivity of RTK-driven tumor models to zotatifin correlated with high basal levels of mTOR activity and elevated translational capacity highlighting the unique circuitry generated by the RTK-driven signaling pathway. This dependency identifies the potential for rational combination strategies aimed at vertical inhibition of the PI3K/AKT/eIF4F pathway. Combination of zotatifin with PI3K or AKT inhibitors was beneficial across RTK-driven cancer models by blocking RTK-driven resistance mechanisms demonstrating the clinical potential of these combination strategies. [ABSTRACT FROM AUTHOR]

• Dopamine (DA) increased kainate-induced γ oscillations in the CA3 area of rat hippocampal slices. • DA-mediated increase in γ power is associated with dopamine receptor (DR) 1 and 2 activation. • Receptor tyrosine kinase (RTK) and ERK are the main intracellular kinases that mediate DA enhancement of γ. • DA-mediated enhancement of γ oscillation is involved in the activation of DR1/2-RTK-ERK signaling pathway. Network oscillations at γ frequency band (30–80 Hz), generated by the interaction between inhibitory interneurons and excitatory neurons, have been proposed to be associated with higher brain functions such as learning and memory. Dopamine (DA), one of the major CNS transmitters, modulates hippocampal γ oscillations but the intracellular mechanisms involved remain elusive. In this study, we recorded kainate-induced γ oscillations in the CA3 area of rat hippocampal slices, and found that DA strongly enhanced γ power, which was largely blocked by dopamine receptor 1 (DR1) antagonist SCH23390, receptor tyrosine kinase (RTK) inhibitor UNC569 and ERK inhibitor U0126, partially blocked by D2/3R antagonist raclopride, PKA inhibitor H89 and PI3K inhibitor wortmannin, but not affected by AKT inhibitor TCBN or NMDAR antagonist D-AP5. Our results indicate that DA-mediated γ enhancement is involved in the activation of signaling pathway of DR1/2-RTK-ERK. Our data demonstrate a strong, rapid modulation of DA on hippocampal γ oscillations and provide a new insight into cellular mechanisms of DA-mediated γ oscillations. [ABSTRACT FROM AUTHOR]

Aiming at the problems of scale uncertainty, traj ectory drift caused by accumulated errors in large scenes and relative pose in a local coordinate system when monocular vision SLAM was used for pose estimation of U AV aerial images, this paper proposed a real-time pose estimation scheme for U AV aerial images. Firstly, this scheme tracked the visual image in real time, then obtained the transformation relationship between the visual coordinate system and the world coordinate system by introducing RTK information, and solved the problems of scale uncertainty and trajectory drift. Finally, it obtained a pose in the world coordinate system. Considering that the video stream processed by visual SLAM would process redundant images and increase the pressure of image storage, shooting and calculation, this scheme used the processing of discontinuous low overlap images to calculate the pose to avoid these problems. In real scene experiments, the experimental results show that the accuracy of the scheme is higher than that of the current mainstream open source frameworks ORB-SLAM2, DSO and OpenMVG, and the average of the overall trajectory error is less than 10 cm. [ABSTRACT FROM AUTHOR]

Establishing reliable elevation differences is imperative for most geoscience and engineering applications. This work has traditionally been accomplished through spirit leveling techniques; however, surveyors have been utilizing satellite positioning systems in measuring height differences for more than a decade. Yet the quality of these heights needs to be evaluated in order to adopt them in different applications. In this article, we present the outcome of an accuracy assessment of height differences obtained with static and RTK surveys. Twenty control points with an average baseline length of 1 km were occupied with dual-frequency GNSS receivers for different time periods. Collected signals were processed using open-source software and verified with an online processing tool. Heights were estimated by processing the GPS and the GLONASS data individually, and combined (i.e. GNSS). Height differences were determined and compared with those measured by spirit levels and corrected through geoid models. Best results were achieved by combining GPS and GLONASS solutions for both static and RTK surveys. Solutions with either GPS or GLONASS satellites were comparable, but in most cases, the GPS solutions performed better. For the static surveys, longer occupation provided much accurate height differences. Inconsistencies among 10 different RTK surveys were minimum for the GPS + GLONASS solutions and worst for the GLONASS solutions. The ANOVA, LSD, F, and χ² statistical tests confirmed our findings at the 95% confidence level.

Demanding for warehousing automation and intelligence is critical with the rapid development of information and big data teleology. In most storehouses, cargos are mainly carried by Automatic Guided Vehicles (AGVs) or even manpower. Most AGVs follow predefined paths that are normally paved by some marks detected by AGVs. It largely limits the application of AGVs. Some AGVs relies on highly accurate Light Laser Detection and Ranging (LiDAR) devices for navigation. The paper presents a low-cost localization approach for indoor AGVs with the localization accuracy up to centimetres. The proposed method not only allows an AGV to move precisely without any predefined paths, but also reduces the cost largely. The Ultra Wide Band (UWB) technology is used in our approach. In the paper, a gradient decent method cooperated with a least square method is developed to deal with the nonlinearity of UWB ranging data. An optimal localization result is achieved within a small amount of iterations. The positioning results are also compared to a high-accuracy Real-Time Kinematic (RTK) satellite system. Meanwhile, the approach is able to diagnose the original UWB data and will discard any data corrupted by non-ignorable noises. Thus, the robustness is guaranteed.

In this paper, a parking evaluation system based on the BDS (BeiDou Navigation Satellite System) and IDS (Intensity Distance Scoring) algorithm has been proposed. Real-time kinematic (RTK) positioning technology and an extended Kalman filter (EKF) algorithm were applied to the BDS to achieve centimeter-level positioning. A dynamic error experiment was performed to verify the positioning accuracy. The parking evaluation system was developed using the IDS algorithm to score parking trajectories. A parking experiment was carried out in a simulated field to prove the effectiveness of the parking evaluation system. With the IDS algorithm, a parking lot in the simulation was modeled using an 8-bit grayscale map image. The map contains 1 departure area, 5 obstacle areas, and 2 parking areas. The intensity of each pixel in the remaining area is inversely proportional to its shorter distance to the two parking areas. The IDS algorithm evaluates parking through three aspects, the choice of different parking trajectories, parking time, and whether an obstacle area is passed through, which can effectively judge the driver's parking technology.

The navigation technology has developed rapidly and immensely over the past few decades. Among the multiple navigation technologies, the representative and promising techniques are Real-time Kinematic (RTK) technique and Simultaneous Localization and Mapping (SLAM). RTK can provide real-time positioning results with high accuracy, while SLAM can not only locate the user but also construct a map of the new ambient. The first smartphone, the Xiaomi MI 8, equipped with the dual-frequency Global Navigation Satellite System (GNSS), hit the market in May 2018, providing valid carrier-phase measurements for RTK owe to the developer option of ”Force full GNSS measurements.” Nevertheless, RTK underperforms in urban areas as the buildings and trees can block the satellite signals. RTK cannot even provide positioning results when the GNSS outage happens. However, SLAM can effectively make up the drawbacks of RTK as it utilizes no more information than the images. SLAM can also be combined with the Inertial Measurement Unit (IMU) called Visual-Inertial SLAM (VI-SLAM,) with the improvement of accuracy and robustness. Therefore, our study mainly aims to confirm the feasibility of continuous positioning based on RTK and VI-SLAM with the Xiaomi MI 8. An application is developed to execute the functions, including logging images, measurements of IMU, and GPS measurements in Receiver INdependent EXchange (RINEX) format with the Xiaomi MI 8. The performances of RTK with and without the assistance of VI-SLAM are assessed respectively in the urban area. The experimental results demonstrate that the combination of RTK and VI-SLAM based on smartphones can effectively provide continuous positioning results. We believe our application will facilitate research and development in relation to positioning algorithms. Readers have access to this application at https://github.com/Nronaldo/CIGRLogger.

Nowadays, the need for a more precise positioning is a very high, therefore very demanding one, and this is one of the reasons why very large research funding is allocated in satellite technology, the second reason being global geopolitics situation. New satellite constellations are being developed existing satellites that have completed their mission are being replaced with satellites that incorporate technology far superior to their predecessors. Currently we have four constellations with global coverage, NAVSTAR-GPS and Glonass, Galileo and Compass. With the development of these global satellite systems, it is also necessary to develop the user segment, so this requires terrestrial reference stations to be updated to recognize the new signals from them. The article presents the situation of the global satellite systems and the situation of the permanent reference networks in Romania, which are developed by state or private companies.

Centimetre accurate geolocation service is beneficial to a wide range of applications, ranging from sports engineering, civil infrastructure, autonomous vehicles, surveying to digitisation of historically significant structures. Previously, these features were confined to prohibitively expensive commercial hardware, requiring technical knowledge and experience to operate. Continued technological advancements have seen the miniaturisation of electronics and antennas, coupled with an increase in the number and performance of global navigation satellite systems (GNSS) by various nations and organisations, providing global signal coverage. This paper demonstrates a low-cost, mobile, real-time kinematic (RTK) geolocation service for engineering and research applications, fabricated from components readily available from commercial suppliers. This solution, consisting of a mobile RTK base station and RTK rover, provides centimetre-accuracy performance up to a distance of 15 km away from the base station. Correction data is transmitted over the internet using free and open software solutions. The small footprint of both the RTK base station and RTK rover, provides versatile applications even in remote locations. The performance of the geolocation service is validated using field experiments, comparing measurements against state-of-the-art photogrammetry, light detection and ranging (LiDAR) and digital level measurement technologies. The authors encourage the adoption of the RTK geolocation solution based on the calibrated results.