"ADS-B in" For Ships/Boats That Pilots Can Use Over Water?

Sinistar

Sinistar

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This question is totally derived from @Katamarino's epic cross country yesterday....absolutely incredible!!!

His flight was to simulate the big flight from Hawaii to California. That got me thinking.

When he does that flight, can he bring with a gadget much like our Adsb in devices but instead see ships locations?

Sure, not every drug runner and weirdo would be broadcasting their GPS location. But i could see big corporate shipping, Cruise Ships :), and boats/yachts sending their info for better mariner rescue purposes. Does any maritime system like this exist? If so, is it open? Is it made by Garmin? Does it cost $17,995 and 2wks labor LOL :)

You probably see where this is going: While way out over open water, if you could see several ships you could be continually considering those as ditching locations. Maybe even slightly altering course to minimize distance to them. And with a marine radio you could probably SOS them before feet get wet.
 
I have an app on my phone called "marine traffic". It is flight aware for ships. Works well, but you'll need a cell signal for it to work.
 
chartbundle said:
I run an AIS receiver with a raspberry Pi and an antenna and upload to MarineTraffic, would seem to be simple enough to slap a display on it.
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Damn that's cool. So it's like Stratux but for ships. So for about $100 he could bring with something that would directly receive the transmissions from the closer ships. With enough altitude and how high ship masts and antennae are, you could probably pick them up over 100 miles away.
 
There is some really cool tech that is used by high altitude balloons that takes the APRS messages and reformats them for transmission over an HF radio using WSPR.

Rather than rely on a ground station or digipeater to receive the data, an HF receiver connected to a Raspberry Pi or computer decodes the balloon's position, time and altitude and plots it on a global map. The data is also sent to aprs.fi for everyone to see!

Since the range of these transmissions at ten to twelve thousand feet can reach land from anywhere over the Pacific Ocean, that would be one way to follow along with his flight...
 
Groundpounder said:
Derp
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You could have said that it was already posted, which I missed, instead of calling me stupid. I had to look up what Derp meant.

"derp
/dərp/
informal
exclamation
exclamation: derp; exclamation: herp derp
  1. 1.
    used as a substitute for speech regarded as meaningless or stupid, or to comment on a foolish or stupid action.
    "Lower tax rates and far lower job creation. Derp"
noun
noun: derp
  1. 1.
    foolishness or stupidity.
    "the derp heard outside apparently was only the tip of the iceberg"
 
Giving it a bit more thought, I wonder if there is any trend in shipping that would useful to know in advance to pick a "optimal" date for most ships. Heck, other than Navy I wonder how many ships run from San Diego, LA Area and San Fran to Hawaii. Of course there might always be a decent number of boats/yachts.

I am guessing a PI could handle it all along with an app. But the antennae they used was pretty long for the 162MHz signal...maybe that could be one problem. And it sounded like the biggest players are only 12watts...is that enough for smaller inside the cockpit antennae to use?

Otherwise, yeah if something small, USB powered and works I could see looking once every 5min or so and if lucky you'd have a better ditching point.

Better yet if the marine radio you carry could be preset to a known channel like our 121.5 you might even reach them after Aviate, Navigate, Communicate.
 
Just saw there's a race called "The Pacific Cup" that sails from San Fran to Ohau in the summers. Pick the right day and you might have several boats staggered along the way.
 
Sinistar said:
I am guessing a PI could handle it all along with an app. But the antennae they used was pretty long for the 162MHz signal...maybe that could be one problem. And it sounded like the biggest players are only 12watts...is that enough for smaller inside the cockpit antennae to use?

Otherwise, yeah if something small, USB powered and works I could see looking once every 5min or so and if lucky you'd have a better ditching point.

Better yet if the marine radio you carry could be preset to a known channel like our 121.5 you might even reach them after Aviate, Navigate, Communicate.
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Comant makes a marine compatible antenna you could have it with a coax that you could hook to an AIS receiver or a hand-held Marine transceiver for emergency use. I know Marine channel 16 is the emergency channel, I assume it's monitored even in the open ocean where HF would be more common.
 
AIS requires a VHF radio to receive the signal and process the information underway GPS tells the AIS transponder the info and is then broadcast locally through the VHF and reverse...AIS targets are virtually line of sight of your VHF antenna on your boat...20 miles or so practically more or less depending on equipment. I spend a a lot of time offshore in sailboats transiting open ocean (2500 or so miles last year and probably about the same this year) I have been two days without an AIS target transiting from ST Thomas to NYC where we thout we might have equipment failure but just turned out to be no traffic...AIS is much better than Radar for traffic avoidance and works great afloat but probably cumbersome to put together in a airplane...even a receiver only needs a AIS capable VHF
 
Warlock said:
AIS requires a VHF radio to receive the signal and process the information underway GPS tells the AIS transponder the info and is then broadcast locally through the VHF and reverse...AIS targets are virtually line of sight of your VHF antenna on your boat...20 miles or so practically more or less depending on equipment. I spend a a lot of time offshore in sailboats transiting open ocean (2500 or so miles last year and probably about the same this year) I have been two days without an AIS target transiting from ST Thomas to NYC where we thout we might have equipment failure but just turned out to be no traffic...AIS is much better than Radar for traffic avoidance and works great afloat but probably cumbersome to put together in a airplane...even a receiver only needs a AIS capable VHF
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Line of sight is 20 miles if you're on the surface... But an airplane at 13,000 feet can see about 140 miles. That's way farther than it can glide...
 
AISb transmits at 2w and AISa at 12.5w good luck with 140 miles..effectively b is less than 10 miles and a is out to about 20miles and for practical purposes can be a lot less depending on where the antennas are mounted on both sides of the system...
 
Warlock said:
AISb transmits at 2w and AISa at 12.5w good luck with 140 miles..effectively b is less than 10 miles and a is out to about 20miles and for practical purposes can be a lot less depending on where the antennas are mounted on both sides of the system...
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I thought they had enough power to reach a satellite...no?....So it's just ship anti-collision at relatively near, line of site...bummer?

Do you think a plane could still pick it up at 40 miles with a smaller than ideal antenaee?
 
Sinistar said:
I thought they had enough power to reach a satellite...no?....So it's just ship anti-collision at relatively near, line of site...bummer?

Do you think a plane could still pick it up at 40 miles with a smaller than ideal antenaee?
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A 1/4 wave vhf attenna is about 1.6 meters...probably minimum to be effective I am sure you could build some system and but this is not satalight based system other than using the gps to show location heading and speed broadcast over specific Marine AIS channel. Similar to TCAS for airplanes...except they use VHF

AIS- Satalight is on the horizon and catching on but is not what is universally in place...not sure what type of equipment would be required...
 
Antenna for AIS/Marine would just be a bit shorter than a standard aviation comm antenna(about 40CM 1/4 wave). My system receives about 50-70 miles regularly from my hill overlooking the ocean even though my reciver is deaf as a post. The power levels and frequency are similar to aviation comm transmitters, so how far can you hear other planes in flight. Admittedly there you will have the benefit of an external antenna.

I would go try it out, but my plane remains in the shop for a while longer.
 
Okay, lets see if I have this right:

AIS (for shipping) is a bit like ADSBin/out in that the ship must be equipped with a GPS source and then transmits it basic location data periodically. As stated earlier above and in the video, there are different update rates and transmit power requirements for different classes of ships/boats and if they are moored or not.

Unlike ADSB - the ships broadcasting their positions are not fed back into any type of central system where they'd be put together. Basically if ships are near enough to each other (most likely line of site from one transmitting antennae mast to the other) they will receive the other ships location and basically use it for collision avoidance. The higher up the antennae is the farther the line of site.

The AIS transmit power seems a lot lower than aviation transponders so that means a "in-plane" AIS receiver might not even pick up a ship until is relatively close w/r to flying.

If I was flying my fixed gear 182 I'd probably be cruising between 4000msl and 10000msl. A typical leaned out cruise speed is about 2miles/minute. Our best glide is just shy of 1000ft/minute. So at 4000msl that gives 4 minutes or 8 miles to reach a ship and ditch. At 10000, that gives 10 minutes and 20 miles. Being way over MTOW with fuel for an ocean crossing will definitely cut down that distance and time, especially during the earlier portion of the flight.

So even if you could pick up a ship 20 miles away you might not get close enough that they would see you and be able to find you.

However, if the tech worked you could make slight course adjustments along the route to have more favorable ditching options.

I am starting to think if this technology is even practical perhaps its more for when "passing the point of no return" and then having an issue. Lets say I reached the point of no return and knew I wouldn't make it (eg. headwinds, wx divert, etc)...but I had 3hrs fuel left. That would give me 3hrs to look for a ship. However, in that amount of time you might be able to raise someone on the marine HF radio and fly to them. If they give exact GPS coordinates you can always manually enter a waypoint, verify it can be reached and divert.

Complicating matters more isn't the processing: even a Raspberry Pi could probably be used like a Stratux kit. Its the antennae!!! For our ADSB we are using these short (and often dash mount) antenna's but I suppose that's because its much higher frequencies (around 1000Mhz) have such short wavelengths. It would seem to make this work this little "box" would have to be connected to a external antennae so that is where the hassle is.

Maybe w/r to ditching options this is not that practical. Bummer :(

If there was someway you could download ships movements prior to departure you could plot their projected locations as waypoints (just use 3 and interpolate in between based on time). Do that for 5 or 10 ships that seem to align with the flight date and path. Then you might have several divert/ditch possibilities in advance which makes that part of the flight way less dynamic.
 
Sinistar said:
If I was flying my fixed gear 182 I'd probably be cruising between 4000msl and 10000msl. A typical leaned out cruise speed is about 2miles/minute. Our best glide is just shy of 1000ft/minute. So at 4000msl that gives 4 minutes or 8 miles to reach a ship and ditch. At 10000, that gives 10 minutes and 20 miles. Being way over MTOW with fuel for an ocean crossing will definitely cut down that distance and time, especially during the earlier portion of the flight.
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Time yes, distance no. Weight does not affect glide ratio. If you're heavier, you'll come down faster but your best glide speed is also faster, and your glide ratio will be the same.
 
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