Navigation Simulation Research Articles

Case Study of Ship Squat in Sulina Channel Using NTPRO 5000 Navigational Simulator

paper presents a case study of ships passing through shallow and narrow waters in Sulina Channel. The method used in this research was simulation using NTPRO 5000 navigational simulator and it was studied the variation of ship squat, draft and under keel clearance for several military ships similar to Romanian Navy vessels, sailing with different speeds. The purpose of this research was to find out which ship types could navigate through Sulina Channel and what is the maximum speed they could pass without grounding due to ship squat. The integration of the trials results showed what the safe speed for each vessel was and it was concluded that the maximum speeds were 8, 12, and 16 knots. Also, a difference between desired and real speed was observed, caused by the restrictive navigation condition. Numerous researches are being done in ship squat domain and Sulina Channel is one of the canals where this phenomenon is studied, but squat simulation on military ships has never been done before in this canal.

Relative navigation for autonomous formation flying satellites using the state-dependent Riccati equation filter

A relative navigation method for autonomous formation flying using the state-dependent Riccati equation filter (SDREF) is presented. In the SDREF, nonlinear relative dynamics, including J2 perturbation, are parameterized into a state-dependent coefficient (SDC) form without any loss of nonlinearity. The relative navigation algorithm is established based on the carrier-phase differential GPS (CDGPS) and single-frequency GPS data, in which the SDREF is used as a nonlinear estimator. To evaluate the SDREF performance, two different extended Kalman filters (EKFR1 and EKFR2) are introduced. The dynamic models of all the filters are based on relative motion including J2 perturbation. However, the SDREF and the EKFR1 use linear state propagation, whereas EKFR2 employs nonlinear state propagation. The navigation simulation is performed for each filter using live GPS signals simulated by a GPS signal generator, and the result is analyzed in terms of estimation accuracy and computational load. As a result, the SDREF provides a relative navigation solution with 3-D RMS accuracies of 6.0mm and 0.153mm/s for position and velocity, respectively, for a separation of 50km with a computation time of approximately 34s. The simulation results demonstrate that the SDREF estimates the relative states as rapidly as the EKFR1 and as accurately as the EKFR2, which means that the developed SDREF combines the strong points of EKFR1 and EKFR2 and overcomes their disadvantages.

Ship's behaviour during hurricane Sandy near the USA coasts. Simulation results

The aim of this study is to analyze the impact of the stormy weather during hurricane Sandy on an oil tank using the navigation simulator. Meteorological and waves maps from forecast models are used, together with relevant information from the meteorological warnings. The simulation sessions were performed on the navigation simulator from the Constanta Maritime University and allowed us the selection of specific parameters for the ship and the environment in order to observe the ship's behavior in heavy sea conditions. Simulation results are important due to the unexpected environmental conditions and the ship position: very close to the hurricane centre when the storm began to change its track and to transform into an extra tropical cyclone.

Analiza greške inercijskih navigacijskih sustava pomoću test algoritama

Content of this contribution is an issue of inertial sensors errors, specification of inertial measurement units and generating of test signals for Inertial Navigation System (INS). Given the different levels of navigation tasks, part of this contribution is comparison of the actual types of Inertial Measurement Units. Considering this comparison, there is proposed the way of solving inertial sensors errors and their modelling for low – cost inertial navigation applications. The last part is focused on mathematical testing and simulations of the inertial navigation. Given issue is a partial result, which is part of dissertation thesis Integration architectures of navigation systems.

Mars Entry Navigation With Uncertain Parameters Based on Desensitized Extended Kalman Filter

Mars entry phase is the most challenging part among Mars entry, descent, and landing (EDL). One of the main reasons is that the lander suffers tough tests from the uncertainties, which include atmospheric density, lift over drag ratio, ballistic coefficient, and initial conditions. In this paper, the desensitized extended Kalman filter (DEKF) is introduced. State estimations from DEKF are obtained by minimizing a cost function that is composed of the trace of posterior covariance matrix and the weighted norm of the posterior state estimation error sensitivities (PSEES). By applying inertial measurement unit (IMU), Mars orbiters and Mars surface beacons (MSBs) integrated navigation simulations demonstrate that the introduced DEKF is far less sensitive to uncertain parameters than standard EKF during Mars entry. With the increase of uncertainties one by one, the root-mean-square errors (RMSE) of the states are still convergent in case of DEKF as compared to standard EKF where they become larger. At last, the consistency test is carried on to further validate the proposed DEKF.

Nonlinear Hybrid Controller for a Quadrotor Based on Sliding Mode and Backstepping

<span>In this paper, one nonlinear hybrid controller, based on backstepping and sliding mode, was developed and applied to a quadrotor for waypoint navigation application. After dynamics modeling, the whole quadrotor dynamics system could be divided into two subsystems: rotational system and translational system. Backstepping control law was derived for attitude control whereas sliding mode control law was developed for position control. By using Lyapunov theory and satisfying sliding stable rules, the convergence of system could be guaranteed. A nonlinear equation was proposed to solve the under-actuated problem. To validate the effectiveness of proposed nonlinear hybrid controller, waypoint navigation simulation was performed on the nonlinear hybrid controller. Results showed that the nonlinear hybrid controller finished waypoint navigation successfully.</span>

Development of 3D Terrain Visualization for Navigation Simulation using a Unity 3D Development Tool

3D visualization of navigation simulation is to visualize the environment conditions (e.g. nearby ships, dynamic characteristics, environment, terrain, etc) for any users on ships at sea. Realistic 3D visualization enables the users to be immersed to it and guarantees the reliability of the simulation. In particular, terrain visualization contains many virtual objects, so it is time and cost-intensive for object modelling. This paper proposes a 3D terrain visualization method that can be realized in a short time and with low cost by using the Unity 3D development tool. The 3D terrain visualization system requires bathymetric and elevation terrains, and Aids to Navigations (AtoNs) to be realized. It also needs to include 3D visualization objects including bridges, buildings and port facilities for more accurate simulation. Bathymetric and AtoN elements are acquired from ENC, and the elevation element is acquired from SRTM v4.1 digital elevation chart database developed by NASA. Then, the bathymetric and elevation terrains are generated, and the satellite images are superposed by using this terrain information. The longitudinal and latitudinal information of the AtoNs are converted to the 3-axis information to position the AtoN locations. The 3D objects such as bridges, buildings and port facilities are generated and the terrain visualization is completed. The proposed method realizes more realistic 3D terrain visualization of Busan Port.

Effect of ocean currents on ship navigation in the east China sea

Weather and ocean states such as ocean winds, ocean waves, and ocean currents can significantly affect ship navigation. To fully understand the current׳s effect on navigational fuel and time costs, especially in the case of strong western boundary currents such as the Kuroshio Current, an in-depth examination of how the Kuroshio Current quantitatively affects ships is needed. This article presents simulations, based on the Princeton Ocean Model (POM), in the North Pacific Ocean and focuses on the ocean surface current in the East China Sea (ECS). Then, several numerical simulations of ship navigation are conducted by utilizing a ship-maneuvering model known as the Mathematical Maneuvering Group (MMG). The results show that the POM model can generate a high-quality Kuroshio Current distribution that can be applied to conduct numerical simulations of ship navigation.

Navigation Training Requirements and Technical Support for the Danube Inland Navigation Simulator

In our study we describe the navigation training requirements for simulator training, and analysing the suggested infrastructure of an inland navigation simulator training centre. Intensity of navigation training on the Inland Navigation Simulator depends on its character and the chosen difficulty (complexity). The participant of the navigation training has to be able to carry out the minimum training skills depending on the difficulty. The level of difficulty could be divided according to the education target like: basic trainings for non-professionals, medium level trainings for crew on operational level, high level training for crew on management level (+ practicing Local Knowledge Requirements (LKR) if possible).

Tehnološki i obrazovni zahtjevi simulatora za kontinentalnu navigaciju u području Dunava

Education and practical training of the crew members in water transport have been directed towards harmonisation within the EU. One of the basic goals of the project HINT (Harmonized Inland Navigation Transport through education and information technology) is the implementation of inland navigation simulators into the educational process. They might become an alternative way for practical training of crew members in near future. In this article we analyse the requirements for the functions and complexity of an inland navigation simulator in the educational process within the Danube region. The analysis comes from the research that was carried out by the organisations that work in Inland Water Transport (IWT) in the Danube region in October 2013.

선박 및 선원의 인명 안전을 고려한 북극해 항로 운항 연구

Arctic Ocean has rapidly melted due to global warming, by this, commercial ship has been operating through the area. Reason to develop the Northern Sea Route(NSR) even in extreme conditions, the distance than the existing route is shortened, which bring economic benefits. For these reason, the International Maritime Organization(IMO) established safety standards of the Arctic navigation(Polar Code) in order to ensure safe operation in the Northern Sea Route. In this study, it has been described ice types and safety standards of Artic vessel what officer needs to know for safe navigation on the Arctic Ocean. And It was verified by simulation the theoretical knowledge for the safe operation of the Arctic vessel. As a result, it was found that ship needs to reduce speed and analyze ice for safe operation before enter into the ice, it is necessary to enter at right angle to break ice safety and efficiently. Also according to the result of the simulation of navigation entering in ice channel(Lead), it was difficult to change course, it is believed that require emergency training for passing Vessel. In the future, It shall be analyzed precisely under various conditions of scenario.

The Validity and Reliability of a Hybrid Reality Simulator for Wire Navigation in Orthopedic Surgery

Creating training simulators for orthopedic surgery presents unique and largely unexplored engineering challenges. One of these challenges is simulating both the large forces and subtle haptic feedback involved in drilling into bone. This paper involves a hybrid reality wire navigation simulator that combines a physical drill and plastic foam bone surrogate with 3-D graphics to mimic the radiographic imaging often used in a common surgical task. This paper describes experiments to test the simulator's face, content, and construct validity, as well as the precision of the motion-tracking system. The results suggest that the simulator has sufficient face validity to engage trainees and recreates the critical aspects of the wire navigation task. Experimental simulator trials reveal time and accuracy differentials between experts and novices, suggesting construct validity. The results also show that the tracking system is accurate within 3.6 mm.

Control System Design for a Ducted-Fan Unmanned Aerial Vehicle Using Linear Quadratic Tracker

Tracking control system based on linear quadratic (LQ) tracker is designed for a ducted-fan unmanned aerial vehicle (UAV) under full flight envelope including hover, transition, and cruise modes. To design the LQ tracker, a system matrix is augmented with a tracking error term. Then the control input can be calculated to solve a single Riccati equation, but the steady-state errors might still remain in this control system. In order to reduce the steady-state errors, a linear quadratic tracker with integrator (LQTI) is designed to add an integral term of tracking state in the state vector. Then the performance of the proposed controller is verified through waypoint navigation simulation under wind disturbance.

A nonlinear quaternion-based fault-tolerant SINS/GNSS integrated navigation method for autonomous UAVs

The fault-tolerant integrated navigation methods using strapdown inertial navigation system (SINS) and global navigation satellite system (GNSS) for unmanned aerial vehicles (UAVs) are studied herein to address two types of possible faults, system fault and measurement fault. Two typical approximation-based nonlinear filters, extended Kalman filter (EKF) and divided difference Kalman filters (DDKFs), are modified to be fault-tolerant for accurate navigation even in the presence of these faults. Criteria are presented to detect the faults, and related covariance matrices of the predicted errors are enlarged using fault accommodation factors to make the faulty state or measurement components be normally treated. Navigation simulations using the nonlinear quaternion-based navigation error model are given to demonstrate the effectiveness of the proposed methods.

Submarine Navigation Team Resilience

Advances in the assessment of submarine piloting and navigation teams have created opportunities for linking behavioral observations of team performances with neurodynamic measures of team organization, synchrony and change. Submarine navigation teams (n=12) were fitted with EEG headsets and recorded while conducting required navigation simulations. In parallel, their performances were assessed for team resilience by two evaluators using a team process rubric adopted by the Submarine Force. EEG models of team synchrony were created symbolically which identified times when there was increased across-team cognitive organization induced by the simulation and / or interactions with other crew members. One set of these organizations was observed in the 10 Hz EEG frequency band and coincided with the periodic activity of updating the ship’s position (e.g. Rounds). There were also periods of increased team synchrony between 25-40 Hz which were present during some Rounds events but were more prominent with task changes or when the team was stressed. More resilient teams had fewer periods of team synchrony and these were of smaller magnitude than those found in less resilient teams. These results indicate that both routine and unexpected activities trigger increased neurophysiologic synchrony / coherence in teams and that periods of persistent synchrony may signal a team being challenged.

A back-propagation approach to compensate velocity and position errors in an integrated inertial/celestial navigation system using unscented Kalman filter

This article aims to compensate the velocity and position errors that exist when the star sensor starts to work in a strapdown inertial navigation system aided by celestial navigation. These systems are integrated via unscented Kalman filter to estimate the current attitude and the gyros fixed bias, precisely. Since an accurate integration is desired, the nonlinear attitude equations are utilized in filter and these equations are propagated through a precise discretization method. Then, implementing the back-propagation and smoothing techniques, the initial attitude and the accelerometers fixed bias are also estimated. Finally, carrying out a parallel navigation, the velocity and position errors are compensated. The validity of the proposed method is investigated through simulation of launch vehicle navigation. Simulation results show a great reduction in velocity and position errors.

Exploration of Navigation Simulator Applying in Maritime Trial

Navigation simulator is a product of highly developed maritime technology, the STCW 78/95 Convention puts forward the corresponding requirements on the application of the navigation simulator. This paper analyzes the current applying status of navigation simulator, discusses the professional technical characteristics of maritime cases and limitations of traditional maritime trial, points out the relative hysteresis quality of the maritime trial in application of navigation technology, and makes a prospect for the application of navigation simulator in trial maritime, including assisting the judges to ascertain the facts of cases and fix the evidence to promote case hearing rapidly and improve the scientific judgment.

CT scan merging to enhance navigation in interventional radiology simulation.

We present a method to merge two distinct CT scans acquired from different patients such that the second scan can supplement the first when it is missing necessary supporting anatomy. The aim is to provide vascular intervention simulations with full body anatomy. Often, patient CT scans are confined to a localised region so that the patient is not exposed to more radiation than necessary and to increase scanner throughput. Unfortunately, this localised scanning region may be limiting for some applications where surrounding anatomy may be required and where approximate supporting anatomy is acceptable. The resulting merged scan can enhance body navigation simulations with X-ray rendering by providing a complete anatomical reference which may be useful in training and rehearsal. An example of the use of our CT scan merging technique in the field of interventional radiology is described.

The Prediction of Spacecraft Disturbance Starlight Refraction and Navigation Simulation Research

The methods of starlight refraction navigation has very strict geometric requirements to starlight refraction direction, in order to capture the refraction of stars accurately, and avoid emerging the serious loss of accuracy of lost star, a forecasting method of interference refractive starlight is proposed in this paper. This method can consider all sorts of bodies under the influence of interference, and predict starlight direction that can happen refraction in the instant position of the corresponding spacecraft, so as to adjust the star sensor posture in advance for quick capture starlight refraction. At the same time, from the geometric relationships researching and analyzing the influence mechanism between refraction stars number and distribution by various interference, the influence of the simulation results show that refraction star distribute on both sides of the spacecraft orbit zonally, its number is closely related to the altitude. While through to accurately forecast on the starlight refraction direction, we can make the spacecraft navigation precision and capture refraction star speed increased by more than one times. Therefore, this paper has important value of engineering application.

Nonlinear Modeling and Virtual Scene Simulation of the Z-Propeller Tug

Ship maneuvering model and ocean scene are the core parts of navigation simulator, on the basis of MMGs model, the dual-engine and dual-propelling equipment of the Z-propeller tug were researched, the tugs mechanical model and propulsion model were established, speed, course and path of the tug were calculated with the Runge-Kutta method; virtual ocean was built at the meantime based on waves statistic spectrum and fast fourier transform; at last, data communication between different softwares was realized by means of UDP and ADO protocol, and virtual marine navigation system was established based on the Z-propeller tugs maneuvering model.