Navigation Guidance Research Articles

Optimal Penetration Guidance Law for High-Speed Vehicles against an Interceptor with Modified Proportional Navigation Guidance

Aiming at the penetration problem of high-speed vehicles against a modified proportional guidance interceptor, a three-dimensional mathematical model of attack–defense confrontation between the high-speed vehicle and the interceptor is established in this paper. The modified proportional navigation guidance law of the interceptor is included in the model, and control constraints, pitch angle velocity constraints, and dynamic delay are introduced. Then, the performance index of the optimal penetration of high-speed vehicles is established. Under the condition of considering the 180-degree BTT control, the analytical solutions of the optimal speed roll angle and the optimal overload of high-speed vehicles are obtained according to symmetric Hamilton principle. The simulation results show that the overload switching times of high-speed vehicles to achieve optimal penetration are N − 1, where N is the modified proportional guidance coefficient of the interceptor. When the maximum speed roll angle velocity is [60, 90] degrees per second, the penetration effect of high-speed vehicles is good. Finally, the optimal penetration guidance law proposed in this paper can achieve a miss distance of more than 5 m when the overload capacity ratio is 0.33.

Prenatal exposure to ambient air pollutants and congenital heart defects: An umbrella review

BackgroundPrenatal exposure to ambient air pollutants has been linked to congenital heart defects (CHD), but findings of existing systematic reviews have been mixed. ObjectiveTo assess the epidemiological evidence on associations between prenatal exposure to ambient air pollutants and CHD subtypes, based on a systematic overview of reviews (“umbrella review”). MethodsWe conducted a systematic search for reviews assessing associations between prenatal exposure to criteria air pollutants and CHD. The risk of bias was evaluated using the Risk of Bias in Systematic Reviews (ROBIS) tool. The certainty of the systematic review findings was graded using the Navigation Guide methodology. ResultsWe identified eleven systematic reviews, including eight with meta-analyses, assessing in total 35 primary studies of prenatal exposure to criteria air pollutants and various CHD subtypes. The certainty of the findings of four meta-analyses indicating an increased risk for coarctation of the aorta associated with nitrogen dioxide exposure was rated as moderate. The certainty of findings indicating positive, inverse, or null associations for other pollutant-subtype combinations was rated as very low to low, based on low precision and high statistical heterogeneity of summary odds ratios (SOR), substantial inconsistencies between review findings, and methodological limitations of the systematic reviews. DiscussionThe inconsistent findings and high statistical heterogeneity of many SOR of the included systematic reviews may partly be traced to differences in methodological approaches, and the risk of bias across included reviews (e.g., inclusion criteria, systematic search strategies, synthesis methods) and primary studies (e.g., exposure assessment, diagnostic criteria). Adherence to appropriate systematic review guidelines for environmental health research, as well as rigorous evaluation of risk of bias in primary studies, are essential for future risk assessments and policy-making. Still, our findings suggest that prenatal exposure to ambient air pollutants may increase risks for at least some CHD subtypes.

Transpedicular Onyx embolization of a thoracic hemangioma with robotic assistance: illustrative case.

Hemangiomas are common benign vascular lesions that rarely present with pain and neurological deficits. Symptomatic lesions are often treated with endovascular embolization. However, transarterial embolization can be technically challenging depending on the size and caliber of the vessels. Moreover, embolization can result in osteonecrosis and vertebral collapse. Here the authors report the first case of a T10 vertebral hemangioma treated with transpedicular Onyx embolization aided by a robotic platform that guided pedicle cannulation and Craig needle placement. An intravenous catheter was attached to the needle and dimethylsulfoxide was infused, followed by Onyx under real-time fluoroscopy. Repeat angiography demonstrated significantly reduced contrast opacification of the vertebral body without compromise of the segmental artery. A T9-11 pedicle screw fixation was performed to optimize long-term stability. The patient's symptoms improved and was stable at the 6-month follow-up. Transpedicular embolization of vertebral hemangiomas can be performed successfully under robotic navigation guidance, avoiding complications seen with the intra-arterial approach and allowing for simultaneous pedicle screw fixation to prevent collapse and delayed kyphotic deformity. During the same procedure, a biopsy specimen can be collected for pathology. This technique can help to alleviate patient symptoms while avoiding complications associated with transarterial embolization or open resection.

Simulating flood events at the Twin Ports of Duluth-Superior using a linked hydrologic-hydrodynamic framework

Generally, ports in the North American Great Lakes are not supported with navigational guidance (water level, water temperature, currents, ice) by NOAA’s Great Lakes Operational Forecast System (GLOFS). To examine the benefit of extending model coverage to this critical infrastructure, a linked hydrologic-hydrodynamic framework was developed for the Twin Ports of Duluth-Superior in western Lake Superior, and tested over three case studies of flooding due to storm surge and/or river flooding. Streamflow from 22 National Water Model (NWM) simulated and 3 gauged inflows within the domain was injected into a hydrodynamic model built on the Finite Volume Community Ocean Model (FVCOM), with a wet-dry grid that covered the harbor and surrounding floodplain. Model results from flood simulations compared well against time-series of water level and streamflow at gauges within the harbor, with root mean square error (RMSE) and bias values small relative to the typical fluctuations. Inclusion of NWM-simulated tributaries improved the accuracy of modeled water levels in the harbor, and increased simulated current speeds in navigational channels by up to 0.5 ms−1. Modeled inundation extent in the floodplain closely matched flood extent surveys conducted in response to a record flood event in 2012, demonstrating the capability of the modeling framework to provide flood guidance in the complex coastal setting.

Robot-assisted percutaneous pedicle screw placement accuracy compared with alternative guidance in lateral single-position surgery: a systematic review and meta-analysis.

While single-position surgery (SPS) eliminates the need for patient repositioning, the placement of screws in the unconventional lateral position poses unique challenges related to asymmetry relative to the surgical table. Use of robotic guidance or intraoperative navigation can help to overcome this. The aim of this study was to compare the relative accuracies offered by these various navigation modalities for pedicle screws placed in lateral SPS. According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the PubMed/Medline, Embase, and Cochrane Library databases were queried for studies reporting pedicle screw placement accuracy using fluoroscopic, CT-navigated, O-arm, or robotic guidance in lateral SPS, and a systematic review and meta-analysis was performed. Included studies all compared evaluated screw placement accuracy in lateral SPS using a single navigation method. Quality assessment was performed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system; risk of bias was assessed using the Newcastle-Ottawa Scale and the Joanna Briggs Institute checklist. The primary outcome, rate of pedicle screw breach, was analyzed using random-effects meta-analysis. Eleven studies were included comprising 548 patients who underwent the placement of instrumentation with 2488 screws. For the fluoroscopic, CT-navigated, O-arm, and robotic guidance cohorts, there were 3, 2, 3, and 3 studies, respectively. Breach rates by modality were as follows: fluoroscopic guidance (6.6%), CT navigation (4.7%), O-arm (3.9%), and robotic guidance (3.9%). Random-effects meta-analysis showed a significant difference between studies, with an overall breach rate of 4.9% (95% CI 3.1%-7.5%; p < 0.001); however, testing for subgroup differences failed to show a significant difference between guidance modalities (QM = 0.69, df = 3; p = 0.88). Heterogeneity between studies was significant (I2 = 79.0%, τ2 = 0.41, χ2 = 47.65, df = 10; p < 0.001). Robotic guidance of screws is noninferior to alternative guidance modalities in lateral SPS; however, additional prospective studies directly comparing different guidance types are merited.

Visual versus visual-inertial guidance in hawks pursuing terrestrial targets.

The aerial interception behaviour of falcons is well modelled by a guidance law called proportional navigation, which commands steering at a rate proportional to the angular rate of the line-of-sight from predator to prey. Because the line-of-sight rate is defined in an inertial frame of reference, proportional navigation must be implemented using visual-inertial sensor fusion. By contrast, the aerial pursuit behaviour of hawks chasing terrestrial targets is better modelled by a mixed guidance law combining information on the line-of-sight rate with information on the deviation angle between the attacker's velocity and the line-of-sight. Here we ask whether this behaviour may be controlled using visual information alone. We use high-speed motion capture to record n = 228 flights from N = 4 Harris' hawks Parabuteo unicinctus, and show that proportional navigation and mixed guidance both model their trajectories well. The mixed guidance law also models the data closely when visual-inertial information on the line-of-sight rate is replaced by visual information on the motion of the target relative to its background. Although the visual-inertial form of the mixed guidance law provides the closest fit, all three guidance laws provide an adequate phenomenological model of the behavioural data, whilst making different predictions on the physiological pathways involved.

Capurability analysis for arbitrarily high-speed maneuvering targets

The capturability of an arbitrarily maneuvering target featuring speed superiority over an interceptor is analyzed for Augmented Pure Proportional Navigation (APPN) and Retro-Augmented Proportional Navigation (RAPN) guidance. This paper focuses on intercepting arbitrary maneuvers to study more general interception problems. A comparative analysis of the capture region between head-on interception related to APPN and head-pursuit interception related to RAPN is proposed. The results indicate that RAPN performs better than APPN in capturability. It is concluded that increasing the target velocity, which increases the velocity ratio, significantly weakens the capturability of the interceptor, and the average acceleration and relative distance affect the location of the capture region but not its size. The analysis is based on prior knowledge of the target maneuver, which inevitably leads to deviations from actual maneuvers in practical engagement, so a deviation analysis is implemented. The effective capture region shrinks as the absolute value of acceleration deviation increases, and the RAPN has a better deviation fault tolerance compared with the APPN. The results reveal that a larger relative distance can weaken the deviation fault tolerance, and the target velocity has opposite effects on head-on and head-pursuit interception.

The Dead-reckoning Navigation Guidance Law Based on Neural Network Collaborative Forecasting

For predicting missile’s interception point, the current guidance law based on neural networks avoids to model the strong nonlinear motion of a missile and simultaneously improve the anti-jamming ability of the guidance law. Although the advantages of solving the predicted intercept point problem based on neural networks are obvious, the difficulty in obtaining the target missile information still exists. In this work, we propose a dead-reckoning navigation guidance (DRNG) law. First, a neural network-based collaborative forecast scheme is proposed and utilize the advantages of different neural networks to greatly reduce the difficulty in acquiring the target information. Second, we construct an approximate realistic aerodynamic characteristics environment to simulate the motion parameters of missiles and targets. We also introduce real-time error correction for increasing the prediction accuracy of the network and improve the robustness of the proposed DRNG by using the model self-update algorithm. Finally, through a large number of simulation experiments, results show that the proposed DRNG completes the interception task in a noisy environment, when only the position parameters of a target missile are known. Moreover, it has a more optimized ballistic trajectory as compared with the traditional guidance law.

Histogram Refined Local Ternary Pattern-based Bilateral LPP for Vision Sensor-based Robot Navigation Guidance under Challenging Environments

The present paper proposes a new variant of bilateral locality preserving projection (BLPP), a nonlinear manifold learning technique, for vision sensor-based robot navigation guidance in challenging environments, suffering from both variations in ambient illumination levels and vision sensor noises and uncertainties in image acquisition. In its basic form, the adjacency graph in BLPP is formulated both in feature subspace and spatial subspace, simultaneously. The present work proposes to compute the feature weights using local ternary pattern (LTP), a lesser noise-sensitive feature descriptor, which is also robust against illumination variations. In addition, histogram refinement has been performed on the feature descriptor to encode the local neighborhood structure of the data, proposing a further augmented version of BLPP named histogram refined local ternary pattern-based BLPP (HRLTP-BLPP). Extensive real-life experiments with challenging photometric conditions and sensor noises have been performed to show the usefulness of HRLTP-BLPP over other competing, state-of-the-art approaches, utilized for robot navigation guidance.

AR Indoor Navigation System

Abstract: Nowadays, the field of abstract- augmented reality is starting to boom. In business, education, and now in the navigation of enormous multi-complexes, augmented reality is utilized. With its many capabilities and fewer hardware requirements at the same time, augmented reality makes work simpler and more exciting. When utilized for navigation, augmented reality can give a person additional directions from where they are now to where they want to go in an unknown environment. The purpose ofour research is to investigate every technology that is practical for indoor navigation and to propose a simple prototype as a remedy. Augmented Reality employs its inherent properties toassess a person's position and provide the appropriate navigational guidance in the case of indoor navigation.

Three-dimensional impact-time-constrained proportional navigation guidance using range-varying gain

This paper presents a novel feedback guidance law to address the impact time control problem of homing missiles in three-dimensional (3D) space. First, a range-varying gain is incorporated into the conventional proportional navigation guidance (PNG) law, which leads to globally precise time-to-go solution and achievable impact time region. Next, an impact time control guidance (ITCG) law is developed by augmenting the proposed varying-gain PNG law with a feedback biased term. Unlike most existing studies, the proposed ITCG law does not involve any linearized approximations or numerical iterative schemes. Furthermore, it can achieve the desired impact time and high-precision interception for a wide launch envelop with arbitrary initial leading angles. Finally, extensive numerical simulations, including comparison studies and Monte Carlo assessments, are carried out to validate the theoretical findings.

Adaptive Finite Time Intercept Guidance

This paper summarizes several key issues of importance related to intercept of high-speed maneuvering targets under stratospheric altitude conditions, where it is unlikely that the interceptor will have a significant speed and/or maneuverability advantage. It explains why one cannot rely on traditional proportional navigation guidance and presents simulation results for a recently developed finite time method of guidance. A simplified version of finite time intercept guidance is derived, and a modification required to allow it to be practically implemented is described. Simulation results are presented to illustrate the advantages of the simplified version.

Practice patterns in revision dacryocystorhinostomy

ABSTRACT Purpose This study aimed to report the practice patterns while performing revision dacryocystorhinostomy (RevDCR) amongst oculoplastic surgeons from several regions across the globe. Methods The survey consisted of 41 specific questions sent via email that contained a link to the Google forms. The questions covered several aspects of the respondents’ practice profiles, evaluation methods, pre-operative choices, surgical techniques, and follow-up preferences while dealing with patients of prior failed DCRs. Questions were answerable either as multiple choice or free text typing. The survey respondents were anonymized. The responses were collected and analyzed, and data were tabulated to understand the preferred practice trends. Results A total of 137 surgeons completed the survey. Most respondents identified themselves as experienced surgeons managing failed DCRs (76.6%, total respondents (n) = 137). The commonly preferred modalities for evaluation of a failed DCR were lacrimal irrigation (91.2%) and nasal endoscopy (66.9%). About 64% (87/137) of the respondents performed a combination of nasal endoscopy, lacrimal irrigation, and probing to localize the area of the failed DCR. A majority of the respondents used anti-metabolites (73.3%, n = 131) and stents (96.4%, 132/137) during the revision surgery. Most surgeons preferred endoscopic approach (44.5%), (61/137) for revising a failed DCR and most preferred general anaesthesia with local infiltration (70.1%, 96/137). Aggressive fibrosis with cicatricial closure was identified as the most frequently encountered cause of failure (84.6%, 115/137). The osteotomy was performed on an as-needed basis by 59.1% (81/137) of the surgeons. Only 10.9% of the respondents used navigation guidance while performing a revision DCR, mainly for post-trauma scenarios. Most of the surgeons completed the revision procedure within 30–60 minutes (77.4%, 106/137). The self-reported outcomes of revision DCRs were good (80–95%, median-90%, n = 137). Conclusion A significantly high percentage of oculoplastic surgeons who responded to this survey from across the globe performed nasal endoscopy in their pre-operative evaluations, preferred endoscopic surgical approach, and used antimetabolites and stents while performing revision DCRs.

Effects of high temperatures and heatwaves on dengue fever: a systematic review and meta-analysis

Studies have shown that dengue virus transmission increases in association with ambient temperature. We performed a systematic review and meta-analysis to assess the effect of both high temperatures and heatwave events on dengue transmission in different climate zones globally. A systematic literature search was conducted in PubMed, Scopus, Embase, and Web of Science from January 1990 to September 20, 2022. We included peer reviewed original observational studies using ecological time series, case crossover, or case series study designs reporting the association of high temperatures and heatwave with dengue and comparing risks over different exposures or time periods. Studies classified as case reports, clinical trials, non-human studies, conference abstracts, editorials, reviews, books, posters, commentaries; and studies that examined only seasonal effects were excluded. Effect estimates were extracted from published literature. A random effects meta-analysis was performed to pool the relative risks (RRs) of dengue infection per 1°C increase in temperature, and further subgroup analyses were also conducted. The quality and strength of evidence were evaluated following the Navigation Guide systematic review methodology framework. The review protocol has been registered in the International Prospective Register of Systematic Reviews (PROSPERO). The study selection process yielded 6367 studies. A total of 106 studies covering more than four million dengue cases fulfilled the inclusion criteria; of these, 54 studies were eligible for meta-analysis. The overall pooled estimate showed a 13% increase in risk of dengue infection (RR=1.13; 95% confidence interval (CI): 1.11-1.16, I2=98.0%) for each 1°C increase in high temperatures. Subgroup analyses by climate zones suggested greater effects of temperature in tropical monsoon climate zone (RR=1.29, 95% CI: 1.11-1.51) and humid subtropical climate zone (RR=1.20, 95% CI: 1.15-1.25). Heatwave events showed association with an increased risk of dengue infection (RR=1.08; 95% CI: 0.95-1.23, I2=88.9%), despite a wide confidence interval. The overall strength of evidence was found to be "sufficient" for high temperatures but "limited" for heatwaves. Our results showed that high temperatures increased the risk of dengue infection, albeit with varying risks across climate zones and different levels of national income. High temperatures increased the relative risk of dengue infection. Future studies on the association between temperature and dengue infection should consider local and regional climate, socio-demographic and environmental characteristics to explore vulnerability at local and regional levels for tailored prevention. Australian Research Council Discovery Program.

Navigational guidance – A deep learning approach

This paper addresses the navigation problems facing many companies, including logistics companies, couriers, and Uber, helping users find the best route to multiple destinations in the shortest amount of time. Navigation problems involving multiple destinations are formulated in this paper as Directed Steiner Tree (DST) problems on directed graphs. We propose an end-to-end deep learning approach to tackle the DST problems in a supervised and non-autoregressive manner. The core of our approach is Graph Neural Networks (GNNs) in estimating whether a node belongs to the optimal solution. Experiments are conducted to evaluate the proposed approach, and the results suggest that using our approach can effectively solve the DST problems with at least 95.04% accuracy. Compared to solving DST problems using traditional methods, our approach significantly improves the solvability of DST problems with acceptable execution time. We further explore how our approach can be applied to different scenarios, such as large-scale graphs. Moreover, we show that our approach can be smoothly applied to solve several variants of the Steiner Tree problem, including Steiner Forest problems. In summary, the proposed approach shows promising results and can be implemented in practice. Research limitations and future directions are also discussed.

Navigation guidance in neuroendoscopic management of complex hydrocephalus

Patients with multiloculated hydrocephalus have multiple, separate abnormal CSF collections with no communication between them. Causes include complications of neonatal meningitis, germinal matrix hemorrhage in neonates, head trauma, and intracranial surgery. Endoscopic fenestration with shunt insertion is a safe and less invasive technique as the initial treatment. In this video, the authors demonstrate a few cases in which electromagnetic navigation was used with a stylet inserted through the operating endoscope to guide the surgeon. Modalities such as insertion of intraventricular contrast and fluorescein may be used as adjuvants, as demonstrated. The use of navigation helps to identify distorted anatomical landmarks and guides surgery. The video can be found here: https://stream.cadmore.media/r10.3171/2023.1.FOCVID22152.

Research on Bluetooth AOA-based Indoor Navigation System for Hospitals

Bluetooth 5.1 introduces the direction-finding function which can detect the direction of Bluetooth signal, on this basis, this project combines the actual hospital scenario and uses Bluetooth AOA method and IoT technology to design the implementation of intelligent navigation system in hospital. The project uses WebGL technology to provide real-time cross-floor hybrid spatial guidance navigation for patients by interfacing with the hospital's HIS and realizing in-hospital intelligent navigation with the help of WeChat applets to help patients quickly and accurately locate their consultation locations. The application of the hospital indoor navigation system can shorten patients' in-hospital wayfinding time, reduce the work pressure of front desk staff, improve patients' medical experience, and effectively improve the digital management level of the hospital.

Branched Endovascular Thoracoabdominal Aneurysm Repair Under Electromagnetic Guidance in an in Vitro Model.

We report a new approach to perform endovascular treatment of thoracoabdominal aneurysms under electromagnetic navigation guidance using a modified system (IOPS; Centerline Biomedical, Inc., Cleveland, OH, USA) and a modified branched endograft (E-nside TAAA Multibranch Stent Graft System; Artivion Inc., Kennesaw, GA, USA). We performed this case in an aortic in vitro model made from transparent polyurethane in our research hybrid room (Discovery IGS 730; GE HealthCare, Chicago, IL, USA). While the implantation of this device typically involves several challenging steps, including precise endograft implantation, snaring of preloaded guide wires, and cannulation of target visceral arteries, all were successfully performed using electromagnetic navigation guidance. Our preliminary experience suggests that endograft implantation under electromagnetic navigation guidance in an integrated hybrid operating room is an innovative option to address technical challenges and reduce patient and operator radiation exposure associated with complex endovascular surgery. Most steps of a branched endografting procedure can be performed without X-Ray exposure when using electromagnetic navigation guidance and a modified branched endograft.

Quantification of Mechanical Characteristics of Conventional Steerable Ablation Catheters for Treatment of Atrial Fibrillation Using a Heart Phantom.

Accurate and reliable catheter navigation is important in formation of adequate lesions during radiofrequency cardiac catheter ablation. To inform future device design efforts and to characterize the limitations of conventional devices, the focus of this study is to assess and quantify the mechanical performance of manual ablation catheters for pulmonary vein isolation procedures within a phantom heart model. We measured three important metrics: accuracy of catheter tip navigation to target anatomical landmarks at the pulmonary veins (PVs), orientation of the catheter relative to the tissue at the targets, and the delivered force values and their stability and variations at those targets. A stereovision system was used for navigational guidance and to measure the catheter's tip position and orientation relative to the targets. To measure force, piezoelectric sensors were used which were integrated at the targets, whereby operators were instructed to stabilize the catheter to achieve a chosen reference force value. An overall positioning accuracy of 1.57 ± 1.71mm was achieved for all targets. No statistical significance was observed in position accuracy between the right and left PVs (p = 0.5138). The orientation of the catheter relative to tissue surface was 41° ± 21° with no statistical significance between targets. The overall force stability was 41 ± 6g with higher difficulty in force stabilization in the right compared to the left PV (40 ± 8 vs. 43 ± 2g, p < 0.0001). Based on our results, future improvements to manual catheter navigation for ablation should focus on improving device performance in orientation control and improved force stability.

Abstract No. 222 Accuracy of a Novel Augmented Reality Navigational Guidance Platform for Percutaneous Procedures

Abstract No. 222 Accuracy of a Novel Augmented Reality Navigational Guidance Platform for Percutaneous Procedures