The synthesized display chart in a given projection mode (when Mercator projection mode is used, the reference latitude of the chart can be appropriately selected to reduce the projection deformation of the chart); Display the chart in a way of "due north up" or "bow up"; Randomly change the scale of electronic charts (zoom display and roaming); Display chart information in layers (hide information that ships don't need under certain conditions).
(2) Chart operation
Design the planned route on the electronic chart (manually design or calculate the great circle route according to the recommended route); Flexibly calculate the distance and orientation between any two points (e.g. using electronic orientation line, variable distance circle, etc.). ) and the expected time to reach the turning point; Mark the position, trajectory and time of the ship. In route design, if the designed route crosses the safety isobath of the ship, the boundary of the restricted area or the boundary of a certain area with special circumstances, the system will give instructions. During the voyage, the planned route will automatically appear on the electronic chart, clearly giving the relationship between the current state of the ship and the planned route. If necessary, it can also display route parameters between routes in tabular form, such as planned speed, heading and estimated arrival time, as well as actual speed, heading and estimated arrival time.
(3) chart correction
ECDIS has many advantages. The most important advantage is that compared with paper charts, electronic charts are easier, faster and more accurate to correct, which greatly reduces the workload of seafarers and reduces the probability of mistakes. ECDIS can accept the official correction data provided by the official ENC production department and the correction data extracted by seafarers from paper chart navigation notices or radio navigation warnings to realize automatic, semi-automatic and manual correction of ENC.
(4) Positioning and navigation
Various navigation sensors continuously receive various information in real time. ECDIS can be connected with log, gyrocompass, GPS, Loran-C, bathymeter and meteorological instruments, and receive the information of these sensors, and get the best position, track, heading and speed after comprehensive processing. Able to perform various landmark positioning calculations. During the voyage, the position of the ship from GPS or DGPS can be continuously and automatically displayed on the electronic chart, and the track can be continuously displayed for comparison with the planned route. According to IMO performance standard, radar information or other navigation information can be superimposed on ECDIS display, but SENC information should not be reduced and clearly distinguished from SENC information. (5) Navigation information consultation
Obtain detailed description information of objects on electronic charts and navigation conditions information on the whole route, such as tides, currents, meteorology, etc. During the voyage, you can capture the target with the mouse and display the target attributes and text descriptions on the screen. For example, if you put the mouse at the pilot station, you can display the communication frequency and call sign of the pilot station. You can also query the local tidal data and calculate the tidal data of the arrival position. Only through complicated drawing calculation can we get the power flow calculation problem at a specific time and place and simplify it into a light blow on the screen.
(6) radar image superposition
In color display, overlapping radar images can be considered as one of the most effective overlapping display methods with electronic charts as the background. It can not only complete the navigation function, but also achieve the purpose of collision avoidance. The combined display of chart background, ship position and radar images of surrounding targets constitutes all the information needed for safe navigation. ECDIS can display radar images or ARPA information on electronic charts, and provide the positional relationship between ships, static targets and dynamic targets around ships, so that sailors can judge the collision avoidance situation and make collision avoidance decisions. At the same time, you can also check whether the collision avoidance decision is feasible on the electronic chart.
(7) Route design
According to IMO performance standards, route design should include straight lines and curves; You can modify the route in the following ways:
(1) Increase turning points on the route;
② Delete the turning point from the route;
③ Change the position of the steering point;
④ Change the order of turning points in the route.
In addition to the selected route, an alternate route should be prepared. The selected route should be clearly distinguished from other routes; If mariner program crosses the ship's safety isobath, he should give instructions; If the route suggested by the navigator will cross the no-fly zone boundary or there is a special area boundary, instructions should be given; Sailors should set the limit of deviation from the planned route and turn on the automatic yaw alarm device according to this limit.
(8) Route monitoring
In the process of ship sailing, the relationship between the current state of the ship and the planned route can be clearly given. ECDIS can automatically calculate the ship's deviation from the planned route, issue instructions and give an alarm when necessary, and realize track maintenance. ECDIS can also automatically detect dangerous sea areas, reefs, no-fly zones and shoals in front of navigation to avoid collision and grounding. When the ship's position deviates from the planned route by more than a set distance, the system will give an alarm.
(9) Navigation records
According to IMO performance standards, ECDIS should store and reproduce the sailing process of 12h and the minimum elements needed to use the official database. ECDIS shall be able to record the following data at intervals of 1 minute:
① Ship track record: time, position, course and speed.
② Records of using official data: ENC source, version, date, unit and correction.
In addition, ECDIS shall record the complete track of the whole voyage, and the time stamp interval shall not exceed 4h; ECDIS cannot process or change the recorded information; ECDIS shall be able to save the navigation records and track records of the previous 12h. In other words, ECDIS should have a function similar to "black box".