SAAB, R4 AIS Class A Automatic Identification System (AIS) transponder

The SAAB R4 AIS is a Class A Automatic Identification System (AIS) transponder designed for commercial vessels to enhance navigation safety and collision avoidance.

It transmits and receives vessel data (position, speed, course, identity) via VHF radio
Provides real-time situational awareness to ships and shore stations
Built using SOTDMA (Self-Organized Time Division Multiple Access) technology for reliable global communication
🔹 Key Features
- Fully IMO / ITU compliant Class A AIS
- Built-in GPS receiver + VHF transceiver
- Multifunction display unit with integrated pilot plug
- Supports:
  - AIS message transmission & reception
  - Safety-related text messages (SRM)
  - Alarm functions for system status
- Upgradeable software platform for future requirements
- Integration with:
  - Radar
  - ECDIS
  - Gyrocompass
  - Speed log

Technical Specification

🔹 General

Type: Class A AIS Transponder
Compliance: IMO / ITU / IEC standards (SOLAS compliant)
System: Fourth-generation AIS platform

🔹 Radio & Transmission

Frequency band: 156 – 162 MHz (VHF maritime band)
Channels: AIS 1 (161.975 MHz), AIS 2 (162.025 MHz)
Channel access: SOTDMA (Self-Organized TDMA)
Modulation: GMSK
RF Output power:
- High: 12.5 W
- Low: 1 W

🔹 Receiver / Transceiver

Configuration:
- 1 × VHF transmitter
- 3 × VHF receivers:
  - 2 × TDMA receivers
  - 1 × DSC receiver
Function: Alternates transmission between AIS channels

🔹 Positioning System

GPS: Integrated GNSS receiver
External GPS: Supported (backup or primary)

🔹 Interfaces

Interfaces for:
- GPS / DGPS
- Gyrocompass
- Speed log
- Radar / ECDIS
Data format: IEC 61162 (NMEA)
Pilot plug: Available
LAN / serial ports: Multiple I/O options

🔹 Display & Control

Display unit: Separate MKD (Minimum Keyboard & Display)
Functions:
- Target list
- Radar-style plot
- AIS messages
- Alarm indications

🔹 Data Handling

Transmits:
- Static data (MMSI, ship name, type)
- Dynamic data (position, speed, course)
Supports:
- AIS messages (VDM/VDO)
- Safety-related messages (SRM)