Zhe Mao

Restoring Method of Vessel Track Based on AIS Information

Based on Automatic Identification System (AIS) information, the existing vessel track is combined by linking the two adjacent points. The linked track is very different from the real track of the vessel. So a fitting method is needed for restoring the real track vividly. AIS information is processed when the vessel is stand-on and turning by Piecewise Linear Interpolation, Piecewise Cubic Interpolation and Piecewise Cubic Spline Interpolation. The results show that the three tracks are nearly the same when the vessel is stand-on, the track presents by Piecewise Cubic Spline Interpolation is best, which proves that Piecewise Cubic Spline Interpolation is a good method to restore the vessel track in utilizing AIS information.

A Quantificational Description Method of Vessel Track Based on AIS Data

The more accurate the vessel track can be described, the more information can be provided for analyzing the characteristic of vessel traffic, the path of the vessel, and the accidents on the water. Based on AIS information, a new method of describing the vessel track is designed. The line track when the vessel is on a straight course can be described by a line with a quantificational slope. The curve track when the vessel is in the beginning and ending turning process can be described by cubic curve with two quantificational boundary conditions. The curve track when the vessel is in steady circle can be described by an arc with quantificational center point, radius and course angle. For a case study, a serial AIS information is selected to describ the track using this method. The track is analyzed by more frequent GPS information. The results show that the track described by the method in this paper is more similar to the real track, and the errors are smaller, especially when the vessel is turning course.

CPA Calculation Method based on AIS Position Prediction

The information on the Closest Point of Approach (CPA) is required in a potential collision situation as it determines the risk to each vessel. CPA is usually calculated based on the speed and direction of the approaching ship neglecting the Change Of Speed (COS) and the Rate Of Turn (ROT). This will make the CPA less useful. To improve the CPA calculation, the Automatic Identification System (AIS) information containing the Speed Over Ground (SOG), Course Over Ground (COG), COS and ROT is used. Firstly, a model using these four factors is built to predict ship positions better. Secondly, a three-step CPA searching method is developed. The developed CPA calculation method can assist in informing the navigation decisions and reducing unnecessary manoeuvres. Through the analysis of a real collision scenario, this paper shows that the proposed method can help identify and warn anomalous ship behaviours in a realistic time frame.

Denoising Method of Inland AIS Information Based on Vessel Track

Through the analysis of vessel track, the characteristics of traffic flow can be well obtained, and waterway traffic safety can be ensured. In order to restore inland water vessel track which is more consistent with real one, noise in the AIS information is supposed to be removed. This paper presents a denoising method of inland vessel track which consists of three basic steps. Firstly, the points outside the valid range of latitude and longitude are roughly removed. Secondly, the points significantly deviating from the normal course are removed according to vessels speed. Lastly, the points show non-smooth turn in the track are removed according to course over ground(COG). And the effectiveness of the method have been verified on the VC++6.0 platform.

Water traffic simulation based on MAS in the bridge area of Yangtze River

In the recent years, the Yangtze River shipping has been developed rapidly, but the bridge constructions worsen the navigation environment and became some blocks in the navigation. This research selects the waterway of the Wuhan Yangtze River Bridge area as the research object, which is the traffic bottleneck in the middle reaches of the Yangtze River because the bridge has 8 piers in the river. In order to improve the safety and efficiency of the navigation, based on the modeling method of the Multi-Agent System, and implementing a traffic separation to the waters of the Wuhan bridge area. According to the properties of the vessel traffic flow, the vessels were classified by using the cluster analysis, dividing the waterway into the ship sailing and boat channel. Building the vessel channel selection model and the vessel into the channel model. By Simulating the model, the ship through capacity under different conditions is obtained by changing the simulation model parameters such as speed, time of arrival of the ship. A set of data is provided to support the program for the future waterway sector which is divided fairway.

An agent-based simulation on navigational capacity of multi-bridge waterways

Multi-bridge waterways of river can cause the navigational bottleneck phenomenon because of the decreased passing efficiency and the increased ship risk. The navigational capacity calculation not only makes benefits to deck officers in operating safely and efficiently but also assists supervisors in the maritime traffic organizing. An agent-based simulation is proposed to evaluate the navigational capacity of multi-bridge waterways in Wuhan. Automatic Identification System data are collected to characterize the maritime traffic of multi-bridge waterways. The Monte Carlo methods are used to generate agents, while the needed random numbers in terms of ship type, length, width, speed over ground and arrival time are generated according to the estimated parameters. Seven behaviour strategies of the agent are made based on the real operation requirements of multi-bridge waterways. The proposed agent-based simulation is validated by the real sectional maritime traffic volume data. Simulation results show that, under the current navigational conditions, the navigational capacity of the investigated multi-bridge waterways in middle season is approximately 1512 ships (597 upstream ships and 915 downstream ships) per day. In addition, the increase in speed over ground can improve the navigational capacity and facilitate the capacity utilization.

Early Warning Method of Vessel Yaw Risk in Inland Waterways

Inland waterways are relatively narrow, in which vessel yaw risk is high. Without a timely warning and course correction, yaw will lead to grounding or running on the rocks or other accidents. To find an early warning method, a geometric model of vessel yaw risk is established by predicting the possible locations of the vessel after a certain period of time. As vessels yaw under the influence of wind and current, the drift caused by wind and current are taken into consideration when the model is modified. The model is used to quantify vessel yaw risk. According to the value of risk, warning levels are divided and evasive strategies are discussed.

Research on Inland Ship Navigation Status Monitoring System

Inland ship navigation status monitoring system plays an important role in the prevention and reduction of inland ship accident as well as navigation security. The system has functions of ship status data collection and recording, status monitoring and alarming. The hardware and software of the system are designed and the feasibility of the system is discussed. The hardware part of the system achieves the function of data collection, including the collection of ship status information, operation information, speech information, radar information, AIS information and so on. The software part of the system realizes the function of data processing and monitoring.

Research on the Recognition of the Inland Ship Motion Status under the Stopping and Low-Speed Sailing Condition

Due to interferences and some other reasons, the GNSS(global navigation satellite system) module in AIS would provide fault information, it is difficult to distinguish whether is the vessels are stopping or low-speed sailing without the help of Kalman filter algorithm. This paper has proposed a method to handle the error in GNSS information in AIS messages, which turns out to be effective in the experiment.