In my earlier article on maritime “trainspotting” using AIS, I suggested that for the first time, large numbers of pleasure boaters will consider adding AIS to their onboard navigation systems, both for the navigational value as well as the “cool” factor.

As I thought more about this, it became clear to me that the AIS infrastructure could become a powerful medium for important navigational data well beyond the vessel information for which it was originally designed.

I found myself asking this question: Does the Coast Guard (or other appropriate authority; navy, port authorities, etc.) have the ability to broadcast emergency- and hazard-related AIS data from land-based transmitters? If a buoy’s sunk or gone adrift, stick a notification on AIS-equipped plotters indicating that it’s gone. If a non-AIS-equipped boat is in need of immediate assistance, stick a flashing boat on everybody’s screen, with the best-guess location information attached. If a log boom, shipping container, or other floating hazard is drifting around, stick that onto everybody’s screen with best-guess location and a description.

From an engineering standpoint, nothing stands in the way of implementing this right now; we just need to change the way we think about this data. Conventionally, all AIS data originates from AIS transceivers located aboard vessels. But it wouldn’t have to. AIS transmitters could be located anywhere within VHF range of the relevant navigational area, and transmit data about vessels in distress, hazards to navigation, status of areas of restricted navigation, real-time current velocity and direction data, etc.

It turns out that this idea isn’t original, but it is relatively unexplored, so far. Discussions about it can be found under the headings “Virtual AIS” and “Synthetic AIS”. In Ireland, in fact, both terms are used, and each has a specific meaning. The Irish Commissioners of Irish Lights, it turns out, is home to the only actual implementation of artificial AIS that I’ve been able to confirm. Here’s how they define these terms:

AIS as an aid to navigation can be real AIS where there is an AIS transmitter on the aid; synthetic AIS where a nearby base station transmits the message but it appears to the mariner to have come from the aid; or virtual AIS where there is no physical aid to navigation on the water but a message is transmitted from a shore station which appears on the ship’s receiver as an AIS target.

Why hasn’t this powerful resource been exploited to its full potential to enhance navigational safety? Actually, there’s a pretty good reason: the “powerful potential” just wasn’t there. But it is now, or soon will be. Let me explain.

Up to now, only very large vessels, emergency vessels, and a few smaller commercial craft had access to AIS data, so the benefits I envisioned, particularly for virtual AIS, just aren’t very compelling. In general, big ships can’t alter course to help a vessel in distress, can’t dodge floating debris, and already have professional pilots aboard when navigating in restricted waters. Furthermore, they are operated by professional crews who already monitor VHF traffic and maintain a high standard of situational awareness, so in cases where they could render assistance, such as in the open ocean, they already do so. Incident-response vessels already receive the most recent data about marine emergencies over the radio, so the benefit to these vessels is, as for large ships, marginal to nonexistent. Essentially, there was no “audience” for the artificial AIS transmissions I’m describing; none that could take advantage of the data in any significant way, at any rate.

Here’s what will change: Over the next year or two, there will be an explosion in the number of vessels with access to the AIS data. All of a sudden, lots of SMALL, FAST, MANEUVERABLE boats that happen to be nearby emergency incidents will be looking right at AIS data all the time, even if they’ve got their VHF turned down. They’ll notice that new “vessel” pop onto their screen with a vessel name of “MAYDAY” or “PAN PAN” or “NAV HAZARD”. They’ll turn up their radio. Some will head that way. They’ll become part of the operation, even if just to relay their observations to the Coast Guard over the VHF. Risks will be mitigated. Property will be saved. Lives will be saved. Maybe not very often, but it will happen from time to time. I find that pretty compelling.

Here’s another scenario: Virtual AIS targets could be used to notify vessel traffic about “polygons of activity” producing navigational conditions requiring special attention. These might correspond to scheduled events such as active use of naval restricted areas, marine construction or underwater cable laying, and recreational events (such as races) producing unusually dense vessel gatherings. Using existing technology, virtual “vessels” located at the corners of the polygon could be transmitted, or in the case of naval restricted areas (such as torpedo and missile ranges) already depicted on charts, a single AIS target named “RANGE IN USE” with date/time information could be placed in the middle of the range. Ideally, AIS standards would be expanded to allow these targets to be identified as corners of a polygon, and plotters would have the brains to interpret and draw the polygons on the chart. Which brings us to the next point.

What would need to change?

Artificial AIS targets could be generated today to provide updated aids-to-navigation and hazards-to-navigation data, as well as real-time information about emergent maritime incidents. Unfortunately, all AIS targets will be probably be displayed as “vessels” in existing plotters and mapping apps, regardless of the actual nature of the target, so vessel name strings will have to suffice to identify these nonstandard targets. AIS standards might need to be modified to include data about the class of the targets, so that plotters could interpret the new class data and display contextually appropriate symbols. Ideally, onboard displays would be able to generate flashing symbols and trigger audible alarms when rescue operations within a certain range were detected, or when the vessel entered a naval restricted area.

Protocols and regulations might need to be clarified to specify precisely which agencies are authorized to transmit artificial target data over the AIS system; coast guards, navies, vessel traffic systems, etc. Everyone else, of course, would only be authorized to transmit “real AIS” target information from transmitters installed aboard vessels. It might make a lot of sense for each country or region to specify a single clearinghouse for all artificial AIS transmissions. For example, in the United States, authority for all synthetic and virtual AIS transmissions should probably rest with the US Coast Guard. Other organizations (Navy, VTS, yacht clubs, marine construction contractors) could notify the Coast Guard and request generation of a real-time “notice to mariners” related to their scheduled activity. The Coast Guard would have authority to accept or refuse these requests, and would be responsible for generating the AIS transmissions. Each maritime nation will have to establish its own regulations appropriate to the local administrative landscape.

One caveat

It isn’t all wine and roses in the artificial AIS future I envision. There is at least one foreseeable danger worth noting; it goes against tradition and common sense to place symbols on charts that DON’T correspond, as precisely as possible, to the actual locations of the objects indicated. If the estimated position of a distressed vessel is quite inaccurate, as is often the case during the first few minutes of a maritime emergency, misjudgments could occur and time could be wasted due to a responding vessel operator’s natural tendency to just drive straight toward the symbol on the chartplotter. Human cognition being what it is, that target symbol, so solid and definitive, might be subconsciously confused with the real, actual target it represents, even though the displayed location is only a guess, and is labeled as such. “Tunnel vision” might keep personnel looking mostly straight ahead, and not around. This is probably not a major issue for trained incident response personnel, who are accustomed to monitoring and interpreting real-time radio chatter; they’ll remain aware of the accuracy and precision of the available location information. But for the civilian and commercial vessels who happen to find themselves nearby, false confidence in the extremely precise (as in “specific”) but potentially very inaccurate (as in “wrong”) AIS location data could cause a would-be rescuer to drive away from the actual emergency on their way toward an imaginary dot on the chartplotter.

On balance, though, it seems to me that the benefit of having a lot more eyes looking for distressed vessels and uncharted navigational hazards easily outweighs the risk of mistakes due to tunnel vision. Don’t take my word for it, though! I’m only speculating here. Instead, test it.

Let’s give it a go!

The U.S. Coast Guard should identify a region in which to conduct a trial implementation. Set up some AIS Base Station transmitters and start broadcasting synthetic AIS target information for fixed aids-to-navigation, just like the Dublin AIS Trial. Then take the next step: Create an interface to allow Coast Guard telecommunications specialists to create virtual AIS data and direct it to the appropriate base station transmitters, establish some guidelines, train the personnel, inform the public, and see how it goes.

If it doesn’t work out, we’ll learn why, and these important lessons can inform future planning about AIS and other navigational data distribution protocols. If it proves valuable, the experience gained during the trial can help ensure a smooth rollout of synthetic and virtual AIS service throughout the Coast Guard’s jurisdiction.

Either way, the time has come for artificial AIS trials in the United States.