The NAVITWIN IV Heading Management System has a list of specifications relating to displays, data inputs, signal and status inputs, alarm and status outputs, type approval, environmental requirements and EMC. View the full list of NAVITWIN IV specifications below:

The following data can be displayed on the TFT LCD:

  • Gyro 1 heading
  • Gyro 2 heading
  • Gyro 3 heading
  • Magnetic compass heading
  • Speed, manual or auto (when provided)
  • Position in lat. and lon. (when provided)
  • Date and time, manual or auto (when provided)
  • Alarms
  • Heading difference alarm threshold
  • Off heading alarm threshold
  • North speed error correction


Data Inputs

  •     Three gyrocompass headings: NMEA 0183 or PLATH protocol
  •     One magnetic heading, analogue: sine / cosine from fluxgate
  •     One magnetic heading, serial: NMEA 0183, PLATH protocol or NAVIPILOT protocol
  •     Autopilot set heading: NMEA 0183 or NAVIPILOT protocol
  •     Speed, position, time and date, magnetic variation from GPS: NMEA 0183


Signal and Status Inputs

  •     Magnetic compass heading from fluxgate (sine/cosine)
  •     Steering mode status (auto / man)
  •     External alarm acknowledgement status (mute)
  •     Heading offset 180°
  •     External dim


Alarm and Status Outputs

  • Power failure / general alarm*
  • Heading difference alarm*
  • Off heading alarm*   
  • Watch alarm timer reset        


*through potential-free relay contacts rated 30 W max. or 125 V, 1A  

Type Approval

  • Germanischer Lloyd to the Marine Equipment directive (MED) 96 / 98 / EC (Wheelmark)
  • Fulfills IMO Resolution A.694 (17) as well as IEC 60945, IEC 61162 and NMEA-0183


Environmental Requirements and EMC

  • In accordance with EN 60945 (IEC 945 +A1)
  • Magnetic clearance to:

    • standard magnetic compass 0.7 m
    • steering magnetic compass 0.4 m
  • Reduced magnetic clearance to:

    • standard magnetic compass 0.45 m
    • steering magnetic compass 0.30 m
  • Ambient temperature range:

    • operation -15°C to +55°C
    • storage  -25°C to +70°C


For more information about Northrop Grumman Sperry Marine’s NAVITWIN IV Heading Reference Management System, please contact us.