Live AIS Via Internet

[CarCode]

I guess showing some facts about AIS might be help for better understanding.
My home port is Monastir, Tunisia in the Mediterranean. I use a Mac laptop with OpenCPN, a RO4800 VHF radio with integrated AIS receiver and an antenna about 10 meters high. GPS and AIS signals from the VHF goes to the laptop.

Depending on weather conditions I receive VHF signals in a range up to 85 miles but normally 30 miles. These conditions reflects the stratospheric ducting as shown by this site: Tropospheric Ducting Forecast for VHF & UHF Radio & TV
The mirroring of VHF signals happens here most of the time and is the reason to receive AIS signals from the next AIS Basic Station at Pantelleria about 80 miles away from Monastir. This station Montagna Grande acts also as a relais station for other basic stations and the so called AtoN (Aids to Navigation) which are AIS sending beacons of special points.

So I receive with this equippment AIS signals from targets more than 600 miles away. This shows the most used ships roads of commercial ships which can easily seen also in any sea chart in an area where blue flashes indicates a traffic separation e.g. Cap Bon.

Please regard the example images.

Gerhard

[monte]

Thanks carcode. It's interesting they repeat the signal in that region. They also do it around morocco. I wonder if it's just repeated by the nearest one or two base stations. I think it's a good idea and possibly the technology will also become part of ship station AIS units. It certainly doesn't seem like a difficult task to incorporate mirroring AIS data.

[Robin3]

Am I alone in being frightened by the muddled thinking in threads like this? it seems to me that some people should restrict their time afloat to a virtual sail around the bay on an app and leave the real stuff to proper boaters.


Maybe there should be phone apps to generate virtual fogs, storms, torpedoes, pirates and rogue waves and display these on all devices as well.

[monte]

Haha Robin. The virtual torpedo app isn't as silly as it sounds. A few years back off Italy we were hailed several times (in Italian) by an Italian warship. They eventually chased after us in their launch and politely asked us to alter course as they wanted to fire off some torpedoes in our direction. We politely obliged

[valhalla360]

Originally Posted by hoppy

I'm just saying, that if you desperately want to have AIS even though it is not live, then there are already tools that allow it which don't mix questionable value data with real life navigational tools.

The "do not use for navigation" message is just a legal disclaimer in case the navigator of Vestas wanted to use OpenCPN on VOR.... Those messages are ignored anyway. If OpenCPN offered internet AIS, how will anyone know the difference between the warning for the AIS which is a serious do not trust this feature and the warning for legal purposes.

No one said "desperately". This was a nice to have feature. We've covered a lot of miles, many in very congested waterways and while it would sometimes be nice, it was never a "need".

I guess we will have to disagree what qualifies as "questionable" as you seem set that anything but full data with no possible flaw is a death sentance waiting to happen.

The "do not use for navigation" disclaimer is exactly the same scenario. We already have far too many legal warnings, nothing special about this one. Nor is there any reason to trust the data any less. Just like any other navigation tool, you are required to understand it and know it's limitations.

[valhalla360]

OK, to steer the discussion in a new direction.

I've been working on a project for Connected Vehicles (essentially the roadway version of AIS). Some interesting thoughts come to mind and how they could be incorporated into a new version of AIS.

Obviously, there are still a lot of issues being sorted out but it is coming and it will change the way you drive. I'm not sure if anyone is looking at it from the marine perspective but a lot of it could be applied to make AIS drastically better and if the same devices and technology could be used, drastically cheaper and simpler to install.

One of the issues with AIS is slow message rate and concerns if pleasure boats start using it there will be too many transponders with muck the system up. We currently have a test bed with 3000 units all communicating simultaneously once per second providing similar data to AIS. This is covering an area of about 5miles by 5 miles. Simulations for large scale urban areas have been done. While there will be technical issues to be sorted out, even the test bed which is fully operational has more units in operation than just about any port all with much more frequent updates.

Among other things, it provides, location (down to the lane you are driving in), speed and direction to all other recievers in range.

Traffic signals provide information regarding the curent state of the signal and when it will change. I could see a marine equivilent for bouys, locks, drawbridges, etc...

Currently, the system is designed to provide communications and specific information. Manufacturers and application developers then can develop uses (ie: do they just warn you if you are about to run a red light or do they hit the brakes for you). A marine application would have new issues but even if limited to operator warnings, would be a dramatic improvement. Large ships are problematic because of thier slow reaction times to turn or stop. The real benefits could be found with smaller fast moving pleasure craft which can react much more quickly and even 10-15 seconds delay could be the difference between an accident and a near miss.

While independent units have thier benefits, the biggest benefits come from large scale market penetration (ie: no commercial vs pleasure craft debate). This is the opposite of some of the AIS discussions where.

Colision avoidance with current AIS quickly becomes impractical in congested waterways with lots of small fast moving targets. Mostly because the message frequency is too slow, so programs have to make estimates too far into the future. Unlike in open areas, where you can predict where a boat will be in 30 seconds, in a congested harbor, it's only a rough idea and you often have to pass within a 30 second range of other traffic. But with once per second messages, real time warnings become practical.

[Robin3]

Originally Posted by monte

Haha Robin. The virtual torpedo app isn't as silly as it sounds. A few years back off Italy we were hailed several times (in Italian) by an Italian warship. They eventually chased after us in their launch and politely asked us to alter course as they wanted to fire off some torpedoes in our direction. We politely obliged

Fred Drift but we once responded to an all ships broadcast warning of live missile firing, centred on our exact lat/long. We asked the warship (took multiple vhf calls for them to respond) if they had us on their radar( we had them on ours and also visual) They had NOT seen us and asked us to divert 5 miles westwards straight into the F6 westerly wind we were sailing in. We politely declined and they said, no matter, sir, we will move our exercise area, which they did and proceeded to broadcast new target coordinates. I did trim the sails to get maximum speed out of there, IIRC we were on a beam reach making 7-8kts plus.....


This was in international waters 60 miles off the UK coast and about the same off the French coast


Maybe if we had put our position in on a smartphone app ( didn't exist back then) we would have been safer.

[DotDun]

Originally Posted by valhalla360

OK, to steer the discussion in a new direction.

I've been working on a project for Connected Vehicles (essentially the roadway version of AIS). Some interesting thoughts come to mind and how they could be incorporated into a new version of AIS.

Obviously, there are still a lot of issues being sorted out but it is coming and it will change the way you drive. I'm not sure if anyone is looking at it from the marine perspective but a lot of it could be applied to make AIS drastically better and if the same devices and technology could be used, drastically cheaper and simpler to install.

One of the issues with AIS is slow message rate and concerns if pleasure boats start using it there will be too many transponders with muck the system up. We currently have a test bed with 3000 units all communicating simultaneously once per second providing similar data to AIS. This is covering an area of about 5miles by 5 miles. Simulations for large scale urban areas have been done. While there will be technical issues to be sorted out, even the test bed which is fully operational has more units in operation than just about any port all with much more frequent updates.

Among other things, it provides, location (down to the lane you are driving in), speed and direction to all other recievers in range.

Traffic signals provide information regarding the curent state of the signal and when it will change. I could see a marine equivilent for bouys, locks, drawbridges, etc...

Currently, the system is designed to provide communications and specific information. Manufacturers and application developers then can develop uses (ie: do they just warn you if you are about to run a red light or do they hit the brakes for you). A marine application would have new issues but even if limited to operator warnings, would be a dramatic improvement. Large ships are problematic because of thier slow reaction times to turn or stop. The real benefits could be found with smaller fast moving pleasure craft which can react much more quickly and even 10-15 seconds delay could be the difference between an accident and a near miss.

While independent units have thier benefits, the biggest benefits come from large scale market penetration (ie: no commercial vs pleasure craft debate). This is the opposite of some of the AIS discussions where.

Colision avoidance with current AIS quickly becomes impractical in congested waterways with lots of small fast moving targets. Mostly because the message frequency is too slow, so programs have to make estimates too far into the future. Unlike in open areas, where you can predict where a boat will be in 30 seconds, in a congested harbor, it's only a rough idea and you often have to pass within a 30 second range of other traffic. But with once per second messages, real time warnings become practical.

In the context of your land-based traffic system, the biggest challenge with AIS is the 25khz channel yielding ~9600bps of shared bandwidth (and xmt time-slots, etc.). I have to assume what you are looking at with vehicles has much higher bandwidth.

[Schooner Chandlery]

I think the thread discussion shows us a couple things:

1. If you really are out there sailing, you'll likely have AIS receiver or transponder on your vessel the normal VHF way.
2. There are some folks who like to plan their sailing sort of like a NASA mission. Enough data for those folks includes a statistical analysis of the shipping traffic for some indefinite period of time before they decide to go sailing.
3. A lot of people not out there sailing have a lot of time on their hands.

I suggest that anyone who has such time on their hands to consider going sailing rather than simulating the potential conditions. And with that, I'm off for today's sail. Fair winds.

[leftbrainstuff]

Originally Posted by hsi88

I'm a little surprised that no developers have replied to this. After playing with this over the weekend there is NO doubt that Internet AIS will soon be made available within most other laptop/tablet chart plotters moving forward. I can assure you if OpenCPN does not provide this capability, it will go the way of the Do Do bird for many existing users like me. Posters on other related threads have said this capability was dangerous when compared to real AIS receivers. Those posters have simply never tried it. The "free" webpage screens might have significant delays as noted, but the downloaded software does not.

I downloaded Sea Nav (w/Boat Beacon), SEAiq and Marine Traffic onto my iPhone. When comparing the data with my real time AIS SDR receiver (used on OpenCPN) and my Standard Horizons GX2100, they are pretty much dead on with very little delay. Where there is a delay in the data, you can quickly see how old the data is and make your own assessments. Generally speaking, the only data older than a few minutes was that for ships at anchor.

The HUGE advantage to providing Internet AIS is the much greater number of ships/boats seen on the display. While OpenCPN showed ONLY the ships transmitting AIS signals, Marine Traffic also showed the boats using AIS apps on iPhones which doubled the amount of marine traffic seen on the screen. As more and more people hook up to these shared boat location networks (with and without real AIS/GPS transmitter data), it becomes possible to get a much better view of the traffic around you during the night and in fog.

AIS will never replace Radar, but considering how poor our own senses are at viewing targets at night or in fog, this capability can be a lifesaver to any boats without Radar. Internet AIS is here to stay and live data transmitted from cell phones is in my opinion little different than live data from AIS transponders. Both provide boat location in real time. One to a server that instantly transmits the data via the Internet and the other that transmits the data to our receivers. Both travel at near light speed. The Internet delay would only be significant for boats traveling at very high speeds. Something I hope nobody does at night or in fog.

OpenCPN has its own warnings that it should not be used to replace "real" navigation equipment. But I'm sure there are more and more people that use it as a primary source because it outperforms the older small screen chart plotters the average Joe can afford. I have a CPF190i on one boat and a Garmin 3205 on the other (both with AIS). And I prefer the laptop software to both of them.

Yes, Internet AIS doesn't really help anyone out at sea. But lets face it, 99 of the heavy recreational boat traffic is now within range of cell phone service. I'm on the Chesapeake and have yet to find a location where my cell phone does not have a good strong signal. And if you use Internet AIS on your laptop/tablet/iPhone chart plotter, you will see my boat, every time I go out (even though I cannot transmit an AIS signal). And every time I go out, I will see a lot more boats around me on my iPhone then you guys do on OpenCPN !

I wouldn't consider any system dependent on an internet connection for a mission or safety critical system.

We use internet based services for convenience but not as our main means of situational awareness.

Smartphones and the like use a myriad of gps solutions that are not reliable. Drift, inaccuracy and outages are so common to make them at best toys.

You can see the discrepancies when comparing routes and locations. Also applies with gps based fitness devices.

From a UI and UX perspective consumer devices and apps are way better than many of the previous generation marine systems.

We are about to upgrade all our old datamarine, furuno and garmin kit to B and G. The integrations between charts, radar, forward facing sonar, ais and nmea feeds are quite good now. This is our real time safety critical environment.

In comparison using an ipad at the helm is a poor experience from a situational awareness point of view. We use opencpn on a laptop which interfaces with our ssb and pactor for accessing weather info. This is mission critical but part of our real time helm nav system.


Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[valhalla360]

Originally Posted by DotDun

In the context of your land-based traffic system, the biggest challenge with AIS is the 25khz channel yielding ~9600bps of shared bandwidth (and xmt time-slots, etc.). I have to assume what you are looking at with vehicles has much higher bandwidth.

Definetly would need to sort out the bandwidth but take NY Harbor, throwing all the boats in the harbor in into the vehilce system would have almost no impact on the overall number of transmitters.

The connected vehicle does allow for other vehicle types, even pedestrians (presumed to be carrying cell phones with an app). I have to check if they include boats. I know they accomodate draw bridges on the infrastructure side, though it may be from the passenger car perspective.

I'm thinking really congested areas with fast moving boats where it's common to pass within seconds of each other. Current AIS is very limited due to the low message frequency.

[valhalla360]

Originally Posted by leftbrainstuff

I wouldn't consider any system dependent on an internet connection for a mission or safety critical system.

I think a big part of the difference is the definition of Mission Critical.

In my mind Mission Critical, implies if it's not functional, I'm not heading out. Say your steering system, I think most would say that is a Mission Critical item. If you can't steer the boat reliable, most are not going to head out until it's sorted out.

Since I don't have AIS and I still go out regularly and the vast majority of pleasure craft follow a similar pattern, I don't think it qualifies as Mission Critical.

Therefore, if I can get some additional nice to have info cheaply and easily, I'll accept the limitations of an internet based system.

[DotDun]

Originally Posted by valhalla360

Definetly would need to sort out the bandwidth but take NY Harbor, throwing all the boats in the harbor in into the vehilce system would have almost no impact on the overall number of transmitters.

The connected vehicle does allow for other vehicle types, even pedestrians (presumed to be carrying cell phones with an app). I have to check if they include boats. I know they accomodate draw bridges on the infrastructure side, though it may be from the passenger car perspective.

I'm thinking really congested areas with fast moving boats where it's common to pass within seconds of each other. Current AIS is very limited due to the low message frequency.

Actually, AIS does very good with it's limited resources. The system can handle 4500 updates a minute with fast-moving Class A updating every 2 seconds. That's 1500 fast-moving Class A vessels within range. Yep, Class B updates every 30 seconds by design.

But what you are talking about is outside the marine VHF spectrum, most likely requiring a use of commercial mobile radio, which would not work on the open ocean and most likely have very low acceptance rate.

[conachair]

Originally Posted by valhalla360

Therefore, if I can get some additional nice to have info cheaply and easily, I'll accept the limitations of an internet based system.

After playing around with both real and Web ais on the same screen, I think a potential major problem is you *won't* accept the limitations, thats not how are monkey brains work. We tend to believe anything on a computer screen is real and exact, even if we know it might not be. That's a big worry I have for Web based ais especially when it gets busy out there. In high traffic areas often it can be worse than not having anything imho. Based on playing with both, not sitting in an armchair.

[hoppy]

Just to highlight limitations of "iAIS"

I still have internet access as I am close to the coast but AIS coverage from the internet pretty much dies out here for Class B although the A's still work. The photo shows my last known location (using me because I know I am still transmitting)

I was just using marinettaffic to see if I could find a boat I know, but he vanished a few miles further north which perhaps means my signal is a little stronger



There is no real navigational benefit.

AIS receivers are not that expensive and used ones must be very cheap and easy to find as people realise the benefits and upgrade their RX to a RX/TX


Sent from my iPhone using Cruisers Sailing Forum