R4 NAVIGATION SYSTEM



The R4 Navigation System is available in two configurations: GPS and DGPS. Both configurations feature an R4 Display. The GPS configuration also features an R4 GPS Navigation Sensor and an MGA-2 GPS antenna, while the DGPS configuration features an R4 DGPS Navigation Sensor and an MGL-4 combined GPS/Beacon antenna.

The R4 Display provides a graphical interface to the system. Via the display it is possible to create, edit and modify routes and waypoints, navigate following a route, plot the route, view sensor data, perform setup as well as supervise the systems status.

The R4 GPS Navigation Sensor features a high-precision GPS receiver, capable of receiving WAAS, EGNOS and MSAS differential corrections. The R4 DGPS Navigation Sensor has all the features of the GPS Sensor, as well as a dual channel beacon receiver for reception of IALA radio beacon DGPS corrections.

The R4 Navigation Sensor is connected to the antenna, either an MGA-2 GPS antenna or an MGL-4 combined GPS/Beacon antenna. The MGL-4 antenna is capable of receiving and interpreting both radio beacon and satellite signals.

Together the R4 Display and the R4 Navigation Sensor provides three configurable serial user ports, of which two are bidirectional and one used only for output of data. There are also a binary Speed Log and an Alarm Output port, as well as an Alarm Acknowledge input port.

1.2 Main Features

• High resolution, sunlight readable, 6'' graphic day and night display.
• Signal integrity monitoring calculations (RAIM) according to the IEC 61108-1 (2nd  
   edition) standard. The RAIM function detects whether an expected user defined 
   navigation accuracy is achieved.
• Reception and use of differential corrections from SBAS, from the serial interface in 
   RTCM SC-104 format and, in the DGPS configuration, from IALA radio beacons.
• Automatic or manual SBAS satellite selection modes.
• Navigational views with next waypoint information and cross-track error visualization.
• Display of latitude, longitude, speed over ground and course over ground.
• Up to five user defined views providing a large variety of graphical as well as numerical 
  presentation options according to customer preferences.
• Capability to handle and store up to 2000 individually named waypoints and up to 100  
  different routes.
• Man Over Board (MOB) and Event Mark functionality.
• Two trip log counters with indication of average speed and accumulated time during 
   motion.
• Anchor Watch position deviation alarm.
• Scheduled Alerts, user configurable time alarms and time to ETA alarms.
• Time frame related to UTC or user defined local offset.
• Synchronization of waypoint/route database and settings with an external R4 
   Navigation system in dual redundant installations.
• Input and output of IEC 61162-1 sentences configurable on sentence level and per port,
    providing control over interpreted, ignored and transmitted sentences.
• User interface design centred around modes of operation corresponding to typical 
  operator activities such as voyage planning, status monitoring and ship navigation.
• Upgradeable without hardware modifications due to fully integrated DSP solution.
• Output of GPS positioning information on User port 1 and 2, enabling external systems
   to connect to and use the GPS information from the R4 Navigation Sensor.
 •  Meets the following standards:
 • IMO Performance Standard for GPS
 • IEC 61108-1, second edition
 • IEC 61162-1, second edition


1.3 Concepts and Terminology

This chapter describes some of the commonly used terms of this Operator’s Manual, and
the implied meaning when used in this manual.

Waypoint
A waypoint is a position on the earths surface, represented by latitude and longitude, which is given a unique name. A waypoint is typically used for navigation direct to a certain position or as part of a route.


MOB Waypoint
A waypoint created when using the Man Over Board (MOB) functionality. The system can store up to 20 MOB waypoints at the same time, if more are created the oldest one is deleted. It is not possible to use MOB waypoints in routes.

Route
A route is a named, ordered sequence of waypoints, which together describes a path from
the start to the end waypoint. The route that currently is being sailed is called the active route.

Active Route
The active route is the route currently being sailed and used for navigation. When starting to sail a route, a copy of the route is made into the active route. Changes made to the active route does not affect the source route, unless the active route is explicitly stored. Only one route can be active at any point in time.

Leg
A leg is the segment of a route between two consecutive waypoints. A route with the waypoints A, B and C has two legs: “A to B” and “B to C”. For each leg in a route, the navigation algorithm and RAIM accuracy level can be set.

RAIM
RAIM is a GPS integrity monitoring scheme that evaluates the quality of the position data and is able (under normal circumstances) to detect a satellite malfunction that results in a large range error.

RAIM Accuracy Level
The RAIM accuracy level is the radius that is used to calculate current RAIM status.

RAIM Status
The RAIM status can be one of safe, caution and unsafe, and is indicated by the LEDs on the front of the R4 Display.

Navigation Algorithm
The navigation algorithm is the algorithm used for calculating the course to steer to reach
the next waypoint. It is also used for calculating the distance to the waypoint. The navigation algorithm can be either great circle or rhumb line. 10

Great Circle Navigation
The great circle navigation algorithm calculates a course line that is the shortest path between two points on the surface of the earth. Using this navigation algorithm, course to steer when navigating towards a waypoint is not constant. The resulting track of this navigation algorithm will differ from the straight line drawn on a Mercator projected chart.

Rhumb Line Navigation
The rhumb line navigation algorithm calculates a course line that corresponds to a straight line on a Mercator projected chart, and cuts across all meridians at the same angle.

Waypoint Pass Criterion
The criterion used to determine when a waypoint in the active route is considered passed. The waypoint pass criterion can be any of Manual, Distance, Bisector Line and Perpendicular Line.

2 R4 NAVIGATION SYSTEM TIDAL PREDICTION

2.1 General

The R4 Navigation Display, sw version 5.0.94 onwards, can be used for calculation of tidal predictions based on user input of data from the Admiralty Tide Tables published by the U.K Hydrographic Office. The user is required to input data for the specific port and select the point in time for which the prediction is to be calculated. The tidal prediction features in the R4 Navigation Display are centered around three views, the Port List, Tide Plot and Tide Table views available in the Plan Voyage mode. Note that meteorological effects (e.g wind and barometric pressure) as well as other factors not accounted for in the generalized tidal models may cause significant deviation between actual and predicted tide.


2.5  Units of Predicted Tide

Predicted tide can be displayed in meters, feet or fathom units as defined by  the ‘Depth Unit’ configuration parameter. This parameter is accessed from the Units Configuration view in Configuration mode.

2.6  Treatment of Local Time Frames

For each port, a ‘Zone’ parameter shall be entered as defined in ATT part III. This parameter defines the relationship of data published in ATT with respect to UTC.
When a tide prediction is generated, a graph will be displayed for 00 to 24 hours of a selected date. This time  will be in UTC or with any user selectable local time offset as defined in the Time Configuration view. If  UTC is used, times will be denoted ‘UTC’. If a local time frame is used, times will be denoted ‘LOC’.This is in analogy with how all times generally are treated by the display.
Thus, it is important to realize that a tide displayed in ‘LOC’ time not necessary is the local time in port defined by the ‘Zone’ parameter. If this is desired, the user must manually define a local time in the  Time Configuration view that corresponds to the ‘Zone’ value for the actual port.
 To make things more complicated, the ‘Zone’ parameter in ATT part III is defined as (UTC time – Local Time) and thus being negative when moving  eastwards from Greenwich. On the other hand, the local time offset in the Time Configuration  view is to be added to UTC and thus positive when moving eastwards. Thus, a negative ‘Zone’ value is equivalent to a positive offset of time configuration and vice versa.
Thus, in general: always enter ‘Zone’ for the port as indicated in ATT part III and select local time offset in  Time Configuration  view to obtain the desired local time frame for which the prediction is to be obtained.    
Examples of ‘Zone’ setting and corresponding local time configuration are shown in the following two figures. 

3  DUAL DISPLAY MODE

The R4 Navigation System supports a dual display mode where two R4 Navigation Displays can be interconnected and used together with a single R4 Navigation Sensor. One of the displays (the primary display or dual display master) will have the full functionality of the R4 Navigation System whereas the other display (the secondary display or dual display slave) will be somewhat limited in terms of mainly configuration related tasks. Normal operational functions and databases for waypoints and routes will be shared by both displays.  

3.1  Dual Display Installation

The primary display is to be installed as in a basic R4 Navigation System.The secondary display shall be added to the basic system as follows:

•  The Rx lines of the secondary R4 Navigation Display sensor port shall be connected to the Tx lines of the R4 Navigation Sensor system port (in parallel with the Rx lines of the primary display sensor port). The Tx lines of the secondary display sensor port shall not be connected 
•  The User 3 ports of the primary and secondary displays shall be interconnected (Rx to Tx and vice versa)
•  Power may be supplied to the secondary display in parallel with the power supply to the primary display. One common or two individual 2A fuses may be used for the display power supply 

The signal connections between the dual displays and the R4 Navigation sensor are illustrated in the figure below. Note that this is not a complete installation diagram. For details  about power connections and other connections to the R4 Navigation Sensor refer to the R4 Navigation System installation manual.

3.2  Dual Display Configuration and Initial Synchronization

1.  In the Port Rate Configuration view make sure that the User 3 port rate is set to 57600 in both displays. This view is accessed by pressing the MODE key followed by function key Config, the PAGE key, function keys I/O Config and Port Rate Config

2.  The displays must be configured for operation in dual display mode.This is determined by the ‘Mode’ parameter in the Redundant System Configuration view. This view is  accessed  by pressing the MODE key followed by function key  Config,  the  PAGE key and function key Redund Config.  In the primary and secondary displays, set the ‘Mode’ parameter to ‘Dual Display Master’ and ‘Dual Display Slave’ respectively

3.  A warning will be displayed with request for confirmation as illustrated below. Press the ENTER key to accept.

4.  An ‘R’ icon will be shown in the status bar at the top of the display as an indication of connection between the two displays. A crossed-over ‘R’  icon with additional text ‘No Com’ indicates that there is a problem with  the connection. In this case, check electrical connection between the User 3 ports on the displays (Rx lines on one display connected to the  Tx lines with same polarity on the other display and vice versa). Also recheck that the User 3 port rate is 57600 in both displays per above.   

5.  The databases and settings of both displays will now be compared. If they differ, the user will be requested to select which of the displays to  synchronize from. The contents of the selected display will be transferred to and overwrite the previous contents of the other display  unit. The Later option can be used to perform any desired changes  before synchronization begins. In this case, function keys Synch This and  Synch Remote will be available in the  Redundant System Configuration view

6.  During synchronization, small chevrons will be displayed below the ‘R’ icon on the display unit receiving data. If a large number of waypoints and routes are to be transferred, initial synchronization may take a few  minutes. During this time some functionality (e.g. the active route) will  be temporarily disabled. It is recommended that no attempt to modify  the database in either system is done during this period. Once initialsynchronization has been performed, changes to synchronized items will be applied to both displays automatically without the need for any  actions by the operator.

3.3   Dual Display Operation

During operation, most normal tasks can be performed from either display. Most functions are also synchronized between the displays. However, there are some functions that work individually in each display and also some functionality that is available in the primary display only. In general, normal operation of the system can be performed from either display while system  configuration tasks e.g. definition of serial output messages and GPS  receiver settings shall be performed from the primary display. 

The following functions are synchronized between the displays in the dual display mode of operation:
            •  Waypoint and route databases
            •  Active route
            •  Anchor Watch function 
            •  MOB function
            •  RAIM settings
            •  Acknowledge of alarms
            •  Time configuration
            •  Nav, Alarm and Units configuration settings  

The following functions works independently in each display:
            •  Trip logs
            •  Tidal calculations
            •  Display configurations 
            •  Compass & depth input configurations

The following functions are available in the primary display only:
            •  Scheduled alerts
            •  Beacon receiver ‘Auto’ tuning function key in Beacon Status view
            •  SBAS Information view 
            •  Upload of waypoints and routes to external equipment
            •  All GPS/DGPS configuration settings
            •  User 1 & 2 port rate settings 
            •  Serial port output settings
            •  Wp/Rte Input configuration settings
            •  Nav configuration ‘Rnn Wp Limit’ parameter
            •  Alarm configuration parameters ‘Use External Ack’ and ‘Ack  Disables External                           Alarm’
            •  R4 Navigation Sensor SW/HW version

No comments:

Post a Comment

leave your opinion