
Flightradar24 ADS-B Receivers On-board a Surface Ocean Robot - dewey
https://blog.flightradar24.com/blog/setting-sail-for-global-coverage-flightradar24-ads-b-receivers-on-board-a-surface-ocean-robot/
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prplhaz4
For anyone interested in how this robot is getting around the ocean...

>> Wave energy is greatest at the water’s surface, decreasing rapidly with
increasing depth. The Wave Glider’s unique two-part architecture exploits this
difference in energy to provide forward propulsion.

[http://www.liquid-robotics.com/platform/how-it-works/](http://www.liquid-
robotics.com/platform/how-it-works/)

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cagey_vet
while i love the platform, fr24 filters results so you arent likely to see
ultra-cool stuff. adsbexchange does a more open job of not filtering submitted
data.

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shocks
Can you give an example of this ultra-cool stuff? :)

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ZanyProgrammer
Military aircraft?

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cagey_vet
if you give a man a URL he will surf for a day, if you tell him to go to
adsbexchange and set up his own filter to see ultra-cool stuff, he upvotes the
source.

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nippoo
A network of these, with logging of historical data, would very possibly have
helped with MH370 / Air France 447 etc. If they can maintain coverage of most
of the oceans, this'll be an incredibly useful tool for future lost flights...
not to mention real-time updates for flight arrival times etc. I'm amazed that
we currently don't have any idea where aircraft are (except self-reporting)
over most international waters...

~~~
swingbridge
Not likely as I believe they turned off the transponder, which is what these
devices listen for.

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verelo
Planes have a variety of transponder options available, all of which can be
turned on/off independently. Mode C (and sometimes Mode S) is the most common
today and most important for entering controlled airspace (most airspace in
the US is controlled). While ADS-B is an option, it's not yet mandatory
(making its practical uses less than ideal in many cases). It won't be
mandated until Jan 1 2020 in the US, and the first FAA laws on the ADS-B
transponders were not published until May 2010.

Source:
[https://www.faa.gov/nextgen/programs/adsb/faq/#g1](https://www.faa.gov/nextgen/programs/adsb/faq/#g1)

ADS-B is amazing, yet I also find it's amazing it took so long to become more
popular given how helpful it is. With an ADS-B receiver (I always have a
stratus 2S on board while i fly) you get info like the call signs, speeds,
positions and altitudes of other aircraft, while a Mode C transponder simply
is a pinging beacon that air traffic can use to identify primary (radar based)
targets. Mode C/S will give the pilot no advantage other than knowing that ATC
can see them.

Sadly in my case I only have an ADS-B receiver and no transmitter combined
with a Mode C transponder, so i get some situational awareness and weather
updates, but I do not contribute to the 'vision' of other pilots with my
device.

Stratus 2S: [http://www.sportys.com/pilotshop/ipad-iphone-android/ipad-
gp...](http://www.sportys.com/pilotshop/ipad-iphone-android/ipad-gps-and-
weather/stratus-2s-ads-b-receiver-for-ipad.html/)

~~~
furyg3
Amazing.

Maybe I'm extremely naive, but it seems to me that you shouldn't be able to
turn the transponder off in a commercial passenger flight, and that
international medium/long-haul flights that are likely to be in areas with
reduced transponder coverage should be required to have some sort of Iridium
beacon (which also cannot be turned off).

Even sending the coordinates every 15 minutes would greatly reduce the area to
search, and preventing disabling the transponder safeguards against nefarious
or suicidal crew/passengers/terrorists.

If I didn't know better (MH370), as a laymen I would have assumed all major
flights would be sending their GPS locations constantly via satellite already,
for a slew of reasons (one of them being it's 2016).

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fbender
There's always a fuse you can pull. And there needs to be a fuse, per
regulations on how to build aircraft.

The stray MH370 signal was coming from the engines directly, presumably
powered by the engine's internal power system, and it was engine performance
telemetry to be sent to the engine manufacturer. The pilot might not have
known about that system or unable to disable it (without shutting down the
engines).

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verelo
This is the key point, in the case that there is a fire on board (one of the
likely possibilities with MH370) you want to be able to disable the offending
circuit immediately. If that happened to be your transponder, so be it...the
transponder really adds no value to the plane in terms of its ability to stay
in the air, so disabling it and extinguishing the fire is the key priority
over giving ATC the ability to identify you on radar via the transponder.

~~~
furyg3
But there can be a luggage fire? What fuse can you pull to disable that? I
assume there are extinguishers for the luggage compartment?

Put a GPS/Iridium suitcase in the plane?

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verelo
The point is that you should be able to disable anything that is connected to
the planes electrical system, to stop fires and prevent damaged systems
causing issues with other functional systems (i.e. broken GPS causing
electrical surges should be disabled to ensure other controls continue to
work).

Unless your luggage is plugged in, this is something that ground based
security should be assessing the risk of prior to placing it in the plane,
followed by the redundant fire suppression systems in the luggage hold as a
last resort, this should be fairly under control by the time the plane is in
the air.

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anotheryou
Who are Flightrarad24 clients? Why do they care about planes in the middle of
nowhere :) ?

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w32stuxnet
My company pays to license their feeds for our own use. I think that their
business model is fairly solid.

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anotheryou
what does your company do?

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MrBuddyCasino
If I had to guess, something with finance. Observing meatspace logistics
allows one to draw certain conclusions earlier than the rest of the market.

Right now, there are people observing chinese factories, reporting number of
shifts etc. to some guy in a remote office.

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seanp2k2
They do it with satellites too, e.g.
[https://en.m.wikipedia.org/wiki/Terra_Bella](https://en.m.wikipedia.org/wiki/Terra_Bella)

Indeed what a way to spend your short life, chasing currency by watching
parking lots empty and fill while clicking buttons to move sums of digital
funds around.

~~~
CPLX
As opposed to making the world a better place by optimizing remote databases
to speed the distribution of semi-nude selfie photographs or something?

Don't know how to break it to you, but I am pretty sure we're all just on a
very brief stint scurrying around pointlessly on a rock near an unregarded
yellow sun located at the unfashionable end of the western spiral arm of the
Galaxy.

~~~
hueving
>As opposed to making the world a better place by optimizing remote databases
to speed the distribution of semi-nude selfie photographs or something?

Yes, that's not the same thing if you believe that people should generally
work towards improving social utility[1]. It takes some significant mental
gymnastics to convince yourself that getting a market edge over other funds to
improve your hedge fund's performance at the expense of theirs is improving
social utility. It's just concentrating wealth from some rich people (one
fund's shareholders) to other rich people (your fund's shareholders). Maybe if
you're lucky you'll even be taking money from retirement accounts.

Even if you argue that someone else would take the money if you didn't, that's
not enough to offset the loss of so many people doing something so wasteful
from an intelligence perspective. The current incentives draw significant
portions of intelligent people away from doing something constructive for
society (science, medicine, engineering, math) to competing in an information
game for rich people.

1\. [https://www.quora.com/What-is-social-utility](https://www.quora.com/What-
is-social-utility)

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CPLX
It doesn't take mental gymnastics at all. One could easily make the argument
that market intelligence improves the allocation of capital and makes the
world more productive. One could also argue that creating web apps for wealthy
westerners is even less useful to society. One could note that being a
subsistence farmer doesn't really contribute to anything or leave much of a
mark for the future at all, and be ok with that too. All of these are just
ways of surviving, and none of them seem particularly indefensible morally.
You gotta do something to get by.

As for your link to Quora, that's a completely incomprehensible rant, just
FYI.

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hueving
Ok, try to make that argument. How is pouring the limited resources of very
intelligent people into deriving information correlated with unreleased sales
figures making the market that much more efficient to offset that cost? It's
effectively the same thing as having them wiretap company executives, just
much less efficient.

Just FYI, it was an explanation of the term 'social utility'.

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deutronium
I thought this was interesting "The GOMX-3 satellite orbits the earth
approximately every 90 minutes at a speed of 27440 kilometers per hour" \-
[https://blog.flightradar24.com/blog/tracking-flights-with-
sa...](https://blog.flightradar24.com/blog/tracking-flights-with-satellite-
based-ads-b-receivers/)

I was assuming it would be a geostationary satellite they would be using.

~~~
8bitben
Does that mean they can only get ADS-B data from the tracker every 90 minutes?

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deutronium
I would assume so yeah. I'd be interested to know if there's any reasonably
affordable satellite system that you could use for closer to real-time data.

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mirashii
My company, Spire, is doing fundamentally the same type of tracking as is
described here, except for ships using AIS. By building a constellation of
satellites with different orbits, and using a network of groundstations, you
can achieve near-real time data. These would be no exception, it's just a
matter of scaling up from one to n satellites and having the coverage of a
groundstation network to support them.

~~~
lorenzhs
Oh I read about your company in the Economist recently, I thought that was
really cool! Here's the article, for anyone interested:
[http://www.economist.com/technology-
quarterly/2016-25-08/spa...](http://www.economist.com/technology-
quarterly/2016-25-08/space-2016) (the bit on Spire is in section 3). That
you're also doing atmospheric measurements for weather forecasting seems
pretty neat.

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beambot
> we have received and processed ADS-B signals collected by our autonomous
> boat...

I wish the article would've explained: (1) What is ADS-B, and (2) why does it
matter. Without that context, I have no idea if this is significant or not...

EDIT: Given FlightRadar's business... I'm guessing it helps with flight
tracking. This wasn't entirely apparent from an outsider reading that blog for
the first time.

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avh02
ADS-B signals (from my limited knowledge) are transmitted by aircraft showing
some basic data like location, altitude, speed, callsign, aircraft model and a
few other things. They only have a range of a few hundred kilometers so a
website that does flight tracking using a global network of (volunteer)
receivers, it's a step in their coverage to be picking up signals over the
oceans.

Also it's just cool.

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dv_dt
Why ADS-B instead of a transponder system for ships? e.g. AIS?
[https://en.wikipedia.org/wiki/Automatic_identification_syste...](https://en.wikipedia.org/wiki/Automatic_identification_system)

Hmm, maybe ADS-B systems are more compact...

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nacnud
Given that the antennae are at surface level and the aircraft are probably
between 25,000ft and 40,000ft, I wonder what the ideal maximum range of the
receivers would be?

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pricechild
With VHF a handy formula is miles = 1.25sqrt(feet)

So 25000ft gives a range of ~190 miles, 40000ft gives ~240 miles.

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mduell
ADS-B is not on a VHF frequency.

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pricechild
It is indeed UHF.

I should've put "VHF/UHF" in the original comment as the formula is reasonable
for both. They're both Line of Sight and that's really what the approximation
is about.

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mkj
Won't barnacles be a problem?

