Any transponder system needs navigation input. Saab's R4 GPS and DGPS Navigation System is type-approved for SOLAS and any other precision navigation application. 

Navigation Integrity

Includes RAIM and support for DGPS corrections from an external receiver, from an internal beacon receiver (R4 DGPS) or from satellite differential services, e.g. WAAS or EGNOS

Reliability and Availability

The products are designed to meet the highest availability requirements. Dual, redundant configuration is supported, as well as combination with our R4 AIS. 

The R4-series products from Saab are self-monitoring and extremely user friendly. They perform continuous RAIM (Receiver Autonomous Integrity Monitoring) calculations. This allows the Officer Of the Watch (OOW) to set the required navigation accuracy for any stage of the journey. The R4 – GPS and DGPS Navigation System from Saab will give continuous feedback and alarm if the accuracy limit is exceeded.

Standard features 

  • Compliant with IMO requirements
  • Highly versatile multifunctional display unit
  • Integrates with AIS, gyro compass, speed log, chart systems and radars
  • Large number of input and output ports to support integrated bridge systems
  • Displays navigation warnings broadcast by marine beacon system.
  • Fully software-upgradable to support future features

Optional features

  • Redundant DGPS system, according to DNV AW requirements.
  • Combined AIS/navigation system with single display unit, using the R4 AIS transponder
  • Junction box with factory connected cables
  • Gimble or flush mounting for display unit
Waypoints 2000 waypoint memory
Routes 100 routes, using a total of 2000 waypoints
Functions Navigation (rhumb line and great circle), Position, Route, Waypoint, Event Mark, Plot, Sail To, MOB, GPS/DGPS, Alarms, Time Alerts, Trip Logs, Anchor Watch Alarm, Configuration
Integrity The product performs RAIM calculations in accordance with IEC 61108-1 Ed. 2
Supply 22 - 30 V DC, 12.5 W
Display High Resolution 6 inch, ¼ VGA monochrome, Sunlight Readable. Yoke or flush mounting of Display Unit
GPS Receiver
  • L1, C/A-code with carrier phase smoothing
  • 12 channels (2 channels dedicated to SBAS)
  • DGPS by SBAS or externally input RTCM corrections
  • Update rate 1 Hz default, 5 Hz max
  • Position accuracy: GPS*: 5 m, DGPS** 1 m (2D RMS)

* Dependent on ionospheric activity and multipath

** SVs >5, HDOP <2, RTCM SC-104 correction data from a dual frequency reference station, short baseline, and low multipath environment

DGPS Beacon Receiver
Dual receiver Manual or Automatic tuning
Frequency 283.5 to 325.0 kHz
MSK Bit Rates 50, 100, and 200 bps
Sensitivity 25 ?V/m for 6 dB SNR @ 200 bps
Interfaces 2 bi-directional user ports RS422, 1 output port RS422, Alarm output port, Alarm acknowledge input discrete
Log pulse output Ports are configurable 4,800 - 38,400 bps
Dimensions (WxHxD)
Control and Display unit 270 x 207 x 102 mm
Navigation Sensor 128 x 39 x 137 mm


Control and Display unit 1.1 kg (2.4 Ib)
Navigation Sensor 0.5 kg (1Ib)


Compliance with the following Standards
  • IMO Performance Standard for GPS
  • IEC 61108-1 Ed2, GPS
  • IEC 61162-1/2 Ed.2, NMEA 0183, version 2.0 through 3.0