Automatic Identification System (AIS) is a vital component of modern maritime navigation, enabling ships, shore stations, and navigation aids (AtoN) to communicate essential data wirelessly. One of the most important aspects of AIS technology is its ability to transmit structured messages—each carrying a specific type of navigational or identification data. In this article, we break down AIS message types, their functions, and how they are used in both vessel communications and AtoN (Aid to Navigation) applications. What Are AIS Message Types? AIS messages are digital transmissions that carry structured maritime information. Each message consists of three key elements: MMSI (Maritime Mobile Service Identity): The unique ID of the transmitter (e.g., vessel, base station, buoy). Message ID: A code that identifies the type of message being transmitted. Repeat Indicator: Used to manage retransmissions, especially over obstacles. These messages are automatically broadcast and received over VHF radio frequencies, allowing vessels and stations to share navigation, safety, and environmental data in real-time. Full List of AIS Message Types and Their Functions Below is a summary of all currently used AIS message types, categorized by their function and relevance: Message ID Name Function Notes 1, 2, 3 Position Reports (Class A) Transmit vessel location, heading, speed, and navigational status. Sent every few seconds. 4 Base Station Report Identifies shore station location and time. Provides static reference for vessels. 5 Static and Voyage Data Reports vessel dimensions, draft, destination. Manually entered. 6 Addressed Binary Message Custom data between two specific devices. For proprietary use. 7 Binary Acknowledgement Confirms receipt of Message 6. 8 Binary Broadcast Message Broadcast custom binary data to all. 9 SAR Aircraft Position Report For search and rescue aircraft. Includes altitude. 10 UTC/Date Inquiry Requests time/date from base station. Often triggered by GPS lack. 11 UTC/Date Response Replies to Message 10. Same as Message 4. 12 Safety-Related Message (Addressed) Sends short text to a specific vessel. Free-text or encoded. 13 Safety-Related Acknowledgement Confirms Message 12 receipt. 14 Safety Broadcast Message Public safety announcement. Broadcast to all. 15 Interrogation Used to request information from other AIS units. By base stations. 16 Assigned Mode Command Manages slot allocations. For timeslot coordination. 17 GNSS Binary Broadcast Sends GPS differential corrections. Broadcast by base stations. 18 Class B Position Report For Class B transponders (smaller vessels). Limited data compared to Class A. 19 Extended Class B Report Includes more vessel data. Superseded by Msg 18. 20 Data Link Management Allocates TDMA slots across network. Base station use. 21 AtoN Report Transmitted by Aids to Navigation. Includes position, type, and condition. 22 Channel Management Changes working VHF frequencies. For local coordination. 23 Group Assignment Command Assigns parameters to multiple stations. Broadcast by authorities. 24 Static Data (Class B) Class B vessel info similar to Msg 5. Sent in two parts (A/B). 25 Single Slot Binary Message One-slot custom data. Efficient, low-overhead. 26 Multi-Slot Binary Message Supports communication status field. For larger data payloads. 27 Long-Range AIS Broadcast Satellite detection of vessels. Modified Msg 1/2/3 for satellite use. The Role of AIS AtoN in Modern Maritime Navigation AIS Aids to Navigation (AtoN) are specially designed units that broadcast Message 21 to represent non-vessel objects such as buoys, light towers, and offshore platforms. These devices improve maritime safety by: Broadcasting fixed positions and unique IDs. Reporting environmental data (e.g., tide, current, or weather). Enabling remote monitoring of light status, battery condition, or sensor activity. Transmitting alerts for malfunction or drift. AIS AtoN can be installed on shore (e.g., lighthouses) or offshore (e.g., buoys), and many are solar-powered with integrated GPS, making them autonomous and low-maintenance. Why Understanding AIS Message Types Matters Whether you're a ship operator, port authority, or equipment manufacturer, understanding AIS message types helps: Ensure compliance with IALA standards. Interpret messages correctly from AIS software or monitoring platforms. Design and deploy AIS-based AtoN systems with optimized data functionality. For product manufacturers and system integrators, precise knowledge of AIS messages allows better planning of communication protocols and system capabilities. Final Thoughts AIS continues to revolutionize maritime safety, enabling real-time, standardized communication between ships, authorities, and navigation aids. The structured nature of AIS message types is fundamental to this ecosystem—each message serving a specific role in safe and efficient navigation. If you're integrating AIS into your products, such as AIS-equipped buoys or solar navigation lanterns, ensure compatibility with relevant AIS message protocols and certifications (such as IALA compliance).

June 2024 - Lianyungang, China - Dexonmarine is proud to announce the successful delivery and deployment of 40 integrated AIS AtoNs in partnership with the Lianyungang Aids to Navigation Authority. This project follows a joint technical consultancy phase during which Dexonmarine tailored a solution to meet the specific maritime navigation requirements of the Authority. The fully integrated AIS AtoNs enhance vessel tracking accuracy and real-time communication, significantly strengthening the safety infrastructure along key coastal and port approaches. All 40 units are now installed and fully operational, providing reliable navigation data to support the growing maritime traffic in the region. The AIS AtoNs are designed for long-term deployment and are fully compatible with China's AIS surveillance systems. This achievement reflects Dexonmarine's commitment to providing high-performance, field-proven AtoN solutions that support port authorities and maritime safety authorities worldwide.

Dexonmarine is proud to announce that our project "Development and Application of Buoy Management Systems and Equipment Based on BeiDou and Smart Technologies" was awarded the first prize for scientific and technological progress by the China Institute of Navigation. This prestigious award recognizes our contribution to the integration of BeiDou satellite navigation with smart buoy management systems to enhance maritime safety and operational efficiency. This achievement reflects Dexonmarine's ongoing commitment to innovating smart navigation solutions and supporting the advancement of global maritime technology.

Dexonmarine is proud to announce its contribution to the recent deployment of BeiDou and AIS shore-based stations at the Beijiao and Langhuajiao Lighthouses in the Xisha Islands, South China Sea. These installations mark a significant advancement in maritime navigation and safety in the region. The newly established stations, which use China's BeiDou navigation satellite system and Automatic Identification System (AIS), have effectively eliminated previous coverage blind spots in the Xisha Sea area. This expansion provides robust support for vessel monitoring and ecological protection of the islands and reefs, ensuring safer and more reliable navigational aids for maritime operations. Dexonmarine's involvement in this project underlines our commitment to improving maritime safety through innovative technology. Our expertise in developing and deploying advanced navigation solutions has been instrumental in the successful implementation of these land-based stations. We look forward to continuing to work with maritime authorities to further enhance maritime safety and environmental protection in the South China Sea and beyond.

Dexonmarine, a professional manufacturer of polyethylene marine buoys and solar-powered navigation lights, proudly presented its DMF1500 buoy series at the Kaunas Marine Navigation & Safety Expo, one of the region's key industry events this spring. On display were two 1500mm diameter rotationally molded buoys - in IALA compliant red and green - each equipped with 3NM self-contained solar navigation lights. These solutions are ideal for harbor entrance, river channel and coastal marking applications where reliability and autonomy are critical. The buoys featured are constructed of UV-resistant LLDPE for long-term outdoor durability, with an EPS foam-filled core for enhanced buoyancy and impact resistance. The lanterns feature automatic light activation, low-power solar charging, and customizable flash patterns for operational flexibility. "Kaunas is a strategic entry point for Baltic Sea trade and we're excited to bring Dexonmarine's technology to this market," said Wang Wei, General Manager of Dexonmarine."The response from port authorities and system integrators has been very encouraging - especially for our complete turnkey buoy + lantern packages." Dexonmarine also offers OEM/ODM customization, including logo printing, custom top marks, ballast configuration and light output calibration based on project specifications. With growing interest from European buyers seeking cost-effective and reliable AtoN systems, Dexonmarine reaffirms its commitment to innovation, quality and global maritime cooperation.

Dexonmarine is honored to have participated in the 1st General Assembly of the International Organization for Marine Aids to Navigation (IALA), held in Singapore from February 18 to 21, 2025. This milestone event marked IALA's first assembly since becoming an intergovernmental organization (IGO) in August 2024. Mr. Wang Wei, General Manager of Dexonmarine, was among the nearly 400 delegates from 65 countries, including government officials and maritime industry leaders. Discussions covered the future of aids to navigation (AtoN), vessel traffic services (VTS), maritime autonomous surface ships (MASS), and the integration of emerging technologies in maritime safety. In his keynote speech, Singapore's Senior Minister Teo Chee Hean underscored the significance of international collaboration, emphasizing the necessity of global partnerships to enhance navigational safety. Dexonmarine's involvement highlights its sustained dedication to pioneering advancements in smart navigation systems, encompassing AIS-integrated buoys, solar marine lanterns, and remote monitoring solutions. Mr. Wang expressed his gratitude for the opportunity to support IALA's mission and to contribute to the enhancement of global maritime operations. We are pleased to continue our collaboration with IALA and our global partners in shaping the future of marine navigation.