05-03-2011, 04:12 PM
Presented by
SYED KALEEM PASHA
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R4 Navigation System
ABSTRACT
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. 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.
1 Product Description
1.1 System Overview
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.
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.
