Is Supply Chain Visibility in China at Risk?

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We share our view on China’s AIS Coverage Drop.

Recently the maritime industry became aware of what has been stated in the media as “China’s terrestrial AIS data blackout”. Following two new data security laws in China, the reception of data from China became challenging. The new Data Security Law (DSL) and Personal Information Protection Law, both coming into effect on Nov 1, 2021, intend to increase government control over domestic and overseas companies collecting and exporting China’s data. Industry experts are concerned about how those changes might impact ocean supply chain visibility in China, especially taking into account the country’s leading role in global container shipping and coal and iron ore import. Besides, mainland China is home to six of the world’s ten largest container ports.

FleetMon collaborates with several Chinese companies and AIS Partners to receive terrestrial vessel position data from Chinese coastal waters. The new rules restrict foreign access to important data like vessels’ AIS signals collected in China without the government’s prior notice and approval. Some of our loyal AIS Partners and data sharers from China have paused transmitting data in fear of massive fines announced by the Chinese government in case of law violations.

Now, how severe is the impact of China’s new Data Security Laws on AIS coverage in the region?

Terrestrial vs. Satellite AIS Coverage in China

Before addressing this question, one needs to understand some basics about AIS. The tracking system AIS (Automatic Identification System) is used for collision avoidance on the seas and maritime traffic monitoring. Vessels transmit their unique identification, position, and voyage information multiple times per minute using AIS transponders onboard. These AIS reports can be captured by nearby ships, satellites, and by AIS receiver stations (terrestrial) mounted onshore. Shipping firms and logistics companies rely on AIS data to predict vessel movements, improve port efficiency, and more.

Vessels that sail far away from shore can be covered by satellite AIS, which fills in part of the data gap left by China’s new laws. The position updates may vary from a few minutes up to several hours depending on traffic, weather, and other factors. If you compare satellite AIS to terrestrial, you will see the lack of port data location that shows how valuable terrestrial data is. In China’s busy harbors and waterways, hundreds of vessels may be broadcasting in the same small area, making it hard for satellite receivers to pick those tightly-packed signals apart. For heavily congested areas or places where frequent updates are needed, terrestrial AIS data is the means of choice, enabling real-time vessel tracking and port monitoring. One may say, losing access to terrestrial AIS data means a fall-off in tracking precision but not in vessel tracking as a whole.

How Severe is the China Drop Impact on AIS Coverage?

First of all, it’s essential to understand that China did not “go dark” in terms of AIS coverage. Quantitatively, we see the same number of ships as before the Chinese Data Security Laws came into effect. Though, the update frequency is reduced at the expense of monitoring precision in ports. We register a decline in terrestrial AIS coverage for minor Chinese ports and a few coastal areas. But all major Chinese ports being key to maintaining logistics and supply chain visibility in China are covered and not severely affected.

AIS Coverage: 2021-11-06 vs 2021-11-08

How Fleetmon Guarantees Best China Coverage on the Market

A smart combination of all available kinds of AIS signal reception helps to overcome the current situation in China. FleetMon combines data from multiple AIS data sources to increase global maritime transparency and create a precise picture of international shipping. When it comes to Sat AIS, we have access to global AIS data streams of all major Satellite Data Providers. Partnering with Exact Earth, Orbcomm and Spire is key to maintaining constant signal coverage of the vessel traffic far away from the Chinese shore. Besides, FleetMon provides AIS equipment to partners around the globe, enabling us to operate a broad AIS antenna network worldwide. When it comes to terrestrial coverage in China, we still receive AIS data from land stations in South Korea, Taiwan, and Singapore which adds to coverage in the region. Illustrated by the following chart, port monitoring in the most important Chinese ports is secured.

Local Distribution of Available Satellite AIS vs Lost Share of Terrestrial AIS

Which of Our Products Are Affected and How?

Real-Time Vessel Tracking with FleetMon Explorer


Fortunately, many of our products and services are hardly affected at all by the drop in terrestrial AIS coverage because other AIS sources fill in the gap. Historical data exports for Chinese waters, ETA calculations for the merchant fleet with routes via Chinese ports and all non-live APIs continue to deliver exact results as you’re used to. However, the live-tracking of vessels in Chinese waters might be impaired. In FleetMon Explorer, the frequency of AIS updates per day declined in some smaller Chinese ports.

Port Monitoring / Port Calls

Regarding the number of port calls, we have not seen any significant changes for the major Chinese ports since the new Chinese data protection laws came into force. All Chinese ports relevant for commercial shipping are still well covered. When analyzing all Chinese ports, the number of registered port call updates of the merchant fleet has decreased by 17% since Nov 2021. A missing share in terrestrial AIS data causes a delay in port call reception. This has reduced the precision of port monitoring, which is only challenging for a few business cases requiring real-time data.

Top 10 Chinese Ports, Number of AIS Updates per Day, Oct-Dec 2021
Average Number of Daily Port Calls, Top 20 Chinese Ports, before vs after China’s Data Restrictions

When comparing the average number of daily port calls we received from the Top 20 ports in China before and after the new data regulations came into effect, we see no significant decline.

Port Calls: Number of Moving Vessels in Largest Chinese Ports, Aug-Dec 2021

Fleet Tracking / My Fleet

Fleet monitoring over time is still possible based on the available AIS coverage in Chinese waters. Before the Chinese Data Law came into effect, we received signal updates of 10 minutes for international shipping fleets such as Maersk. This update frequency enabled maximum precision. Due to combining all available sources of AIS signal reception, you’re still able to track all ships of the merchant fleet by IMO number in Chinese ports and coastal regions. Though, the precision of fleet tracking has slightly reduced because of a 40% decline in update frequency in the Chinese area since November 2021. The recent update frequency is sufficient for most maritime business cases to ensure global fleet monitoring.

Selection of MAERSK Fleet, Daily Number of Updates per Vessel, Oct-Dec 2021

ETA Calculations

FleetMon’s ETA calculations for containers, bulkers, and tankers in global commercial shipping are still exact. Most container ships and vessels of the merchant fleet have schedules of up to three weeks and Estimated Times of Arrival are calculated based on the holistic route. Only real-time ETA calculations might be affected. Reach out to our Sales Team to discuss our vessel schedule data offerings and enrich your logistics monitoring.

FleetMon’s Quintessence

There has been a reduction in terrestrial AIS coverage off the Chinese coast. However, China did not “turn dark” in terms of vessel tracking or port monitoring at all. AIS coverage in Chinese coastal waters and all major ports is secured. Thanks to an intelligent combination of all available AIS reception sources, smart partnering, and our extensive network of own AIS land stations in the region, FleetMon is optimally equipped to maintain offering maritime services and products of the highest quality.

This article will be updated continuously. As soon as there are any changes regarding the situation, we will inform you about it. We practice and value an open and transparent means of communication with our customers and users. Please drop us a line if you have specific questions about AIS coverage off the Chinese coast. Our support team will be happy to assist you.