ACR Electronics AIS Installation Manual

3.6 Sensor notesExternal SensorThe AIS has interfaces (configurable as IEC 61162-1 or 61162-2) for position, bottom track(BT) speed, heading and rate of turn (ROT) sensors. In general, sensors installed incompliance with other carriage requirements of SOLAS Chapter V should be connected tothe AIS System.*1. The sensor information transmitted by AIS should be the sameinformation being used for navigation of the ship. Interfacing problems might occur if theexisting on board sensors do not have serial (IEC 61162) outputs. A converter is needed totranslate the non conform data to IEC 61162 – sensor data. For Example ACR Convertertype P/N 2641.*1) The fact that AIS is fitted on board a vessel does NOT entail the need to install additional sensorsother than those stated in the carriage requirements.External GPSGNSS position sensors normally have IEC 61162 outputs suitable for direct AIS interfacing.However, it is important to note that:• The Geodetic Datum of the position data is transmitted by the sensor in WGS84 so that anIEC 61162 DTM sentence is configured.• AIS is able to process two reference points for its antenna position, one for external, andone for an internal sensor. If more than one external reference point is used, the appropriateinformation needs to be input to the AIS, so that the reference point information is suitablyadjusted.External HeadingA gyrocompass providing heading information is a mandatory sensor input to the AIS. Aconverter unit (synchro or step-signal converter to NMEA 0183 v.3.0 for example ACRConverter type P/N 2641 will be needed for AIS connection in the case that the ship‟sgyrocompass does not provide IEC 61162 output.External Speed and CourseIf a bottom track (BT)log for speed over ground (SOG) is available, it may be connected. Aconverter (for example Raytheon converter type: 133-812) is needed if the BT-log does notprovide IEC 61162 outputsExternal Rate of TurnNot all ships will carry a Rate-Of-Turn (ROT) indicator according to IMO A.526. However, if arate-of-turn indicator is available and it includes an IEC 61162 interface, it should beconnected to the AIS.If ROT information is not available from a ROT indicator, it may (optionally) be derived fromheading information through:• The gyrocompass itself,• An external converter unit (see Heading),• The AIS itself (calculated ROT).Y1-03-0204 Rev. L17