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Hillbilly Tracking of Low Earth Orbit

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    applaus
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    First I need to apologize for typesetting this in Open Office.
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    I know that the text looks like a ransome note, but that's what's happens when you don't use Latex.
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    I I'd also like to give a shoutout call if Mallnarf? is here
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    and our dinosaur rock band. We are a Christian rock band - we are called Jesus lives in the ISS
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    and we know he's always watching us but we think that it's easier for him to hear our prayers
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    when his you know in an orbit that the passes over us
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    so we need is orbital tracking know when to pray
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    as I'm shure you can gess that we are not recognized as a legal minority religion in Germany
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    I also like to thank Skytee and Fabienne
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    and Adami Lori and Jim for some prior satellite tracking work
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    and the skuby crew at Dartmouth College
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    for all sorts of fun whenever I bounce out there
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    This is the mission patch of the southern appalachians space agency
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    applaus
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    This was drawn by Scot Biben and there are a few pieces of my people's native culture that I need to point out here.
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    On the right the little dinosaur type with thing with it's finger going out.
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    You might call him E.T. but we call this things buggers,
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    they're like this tall and they're green
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    and that's why the man on the left has a shotgun.
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    Because he doesn't want to be inducted.
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    Is's got satellite dish in the middle
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    It looks like there are snowpeaks, but our mountains aren't high enough to have snow
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    ..
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    in the top in space you can see the ISS and you can see a banana
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    this is to signify space trash. You know' it's symbolism that matters in these things.
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    In Berlinsides in 2012, I did a talk about reverse engineering the spot connect.
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    The spot connect is a litte hockey pot type thing – this is what it looks like
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    These things are great, it weighs a bit more than your phone, it runs off a batteries,
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    It connects to your phone via bluetooth. Originally these were emergency locator beacons.
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    Has any body seen the movie where the guy has to cut off his arm with a dull knife
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    If you're hiking and you don't want the same experience, you buy one of these things,
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    this device will also allow you to tweet and make facebook posts.
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    there's an emergency button you can push that transmits your GPS coordinates by satellite to rescue workers
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    but that was boring so they had to add social media. So in addition to keeping you from chewing of your own arm
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    The idea is as you're running – here I'm crossing the Schuylkill River in Philadelphia and the Android phone the left is making a post
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    and i did an article on reverse engineering the bluetooth side of these things
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    because I use a weird brand of phones that Microsoft decided to cut off and I'm quite bitter about it.
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    But I also figured out the physical layer and that's to this diagram shows.
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    This transmits it 1.126125 GHz and it send a pseudo random stream so each one of the zeros
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    is along chunk where it's bouncing back and forth between two different frequencies
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    The same for the ones, but the way that the pattern works, is that it switches the signal whenever it is going from 0 to 1.
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    Internally there these little pops that you can actually identify on a software defined radio recording
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    This is how you can reverse engineer the signal that the Spot Connect sends up to the satellite network.
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    Everything is clear text on this and it's completely unencrypted.
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    It just has your gym you serial number, your GPS coordinates and a bit as of ASCII text
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    If you listen on this frequenzy and have the correct recording software
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    you can actually watch all the spot connect messages that are transmitting up from your location
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    this be great except that this is designed for hiking in areas where there's no cell phone service
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    So having an antenna on the uplink freq is kind of useless.
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    you know you actually have to go out to a national park find some guy who is about to chew his arm and
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    then you could listen to his uplink where he is liked reading hey I'm gonna chew my arm of you know laughing
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    So that's great as a proof of concept, but it's not really anything practical.
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    the current stated that was that I knew the protocol and I could sniff the uplinks, but I wanted to sniff the downlinks.
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    It's easy to get the thing that goes up to the satellite, but I wanted to get that what comes down from the satellite.
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    and that requires a a satellite dish
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    but a geostationary dish isn't good enough
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    because the satellites that run this network there are a lot of them
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    – it's called the Globalstar network –
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    They fly really low across the earth, and they fly on very tight and fast orbits
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    they move from horizon to horizon in 15 to 20 minutes
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    which means that you either need like a sweatshop army of kids trying aim the satellite dishes is going across
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    or you have to make it computer controlled.
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    Stepping back from the SC a little, Adam laurie made some work on geostationary satellites
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    that stay in one position in the sky
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    he gave two sets of talks – one in 2008 and the second in 2010
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    He used a DVB-S card connected to a sat dish with a diseqc motor
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    so they could move the satellite dish in order to scan a region of the horizon.
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    His tool is publicly available at satmap you can grab it at this URL
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    And then after he finds a signal, he has a feed scannner.
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    Normally when you have sat TV, you provider gives you a listing of the frequencies
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    and your provider gives you an exact orbital position to aim your satellite dish at
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    But adam's tool allows you to scan to see which frequencys are in use
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    and which protocols are in use once you've correctly aimed your dish
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    he also describes a technique from moving your dish left and right while doing this in order to identify where the satellites are
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    This recording here is from reimplementation and I made as Adams work in order to catch up with it
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    In this diagram the x-axis shows the azimuth, this shows how much left or right my sat dish has moved.
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    the y-axis shows the frequency and all these dots are strong signals
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    Every vertical bar in which you see chunks of frequencies, that's a satellite.
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    but the stay in the same position so it's easy for me to repeat this experiment its easy for me to rerun it
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    and to find the same satellites in the same position. It's easy to debug this.
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    But it can't move in elevation. This diagram is just a small slice of the sky.
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    We're looking at a single line maybe 10 degrees across. Maybe only five degrees across.
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    Hacking KU-band – the television satellites – has the advantage that you can use cheap standardized hardware.
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    I bought one one of this DVB-S cards in Mauerpark, Berlin for 3 euros.
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    You can use standardized disecq motors, you can but them at a satellite TV shop.
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    TV signals come with video feeds, so you can actually see pictures.
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    There was a scandal a couple of years ago, where you could actually see drone feeds bouncing off satellites.
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    I in the the nineties it was very popular to listen to the sorta unedited sections of interviews
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    when people would be interviewed over a satellite before Skype and such things became options
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    and and the there also networking signals here using TCP IP packets
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    So you can actually turn your DVB-S card as promiscuous ethernet adapter.
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    and start sniffing all the traffic that comes across
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    this is also a great way to get free down link bandwidth because you can just fled packets at an address
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    that you know will be routed to you or several addresses and then used if it out as the legitimate receiver ignores them
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    But it also has some disadavntages. It only works with geostationary satellites. If the satellite moves, you can't track it.
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    you dish awesome is very slowly and it only moves left and right it won't move up and down
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    You're limited on standardized signals. While it's great that you get video and his TCP/IP
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    you're never going to get anything weird – you not gonna get any the mobile data
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    are you not going to get brazilian truck-drivers – we will get to those in a bit
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    I misspoke, you will actually get brazilian truck-drivers in this.
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    I bought a satellite dish – one of the best things about living in america is that you can buy
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    an industrial hardware cheap as dirt on e-bay
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    I know things are likely used to be XXXX in human children anymore
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    This sat dish here on the left – the one in the radome – that's my dish.
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    And to the right, that's the boat it came from. applaus
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    This came from a military ship. But the dish itself is also available to civilians for very large yachts.
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    the dish itself as a fellcom 81 and it was intended for use with the network called in Inmarsat
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    Imarsat allows for telephone connections and also data connections when you're on a boat.
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    If the crew wants to call home or wants to go to AOL keywords
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    or whatever was popular back when this was common they could do that
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    Teh dish was desgined to be at the very top of a ships' mast.
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    The reason why is that at the top of the mast there aren't any obstructions – it has a clear view of the sky in all directions.
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    But there's a complication for being on the top of the mast.
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    which is that the ship is rocking beneath you and you're moving more than the rest the ship
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    So they have stepper-motors for azimuth elevation and tilt and they have spinning gyroscopes.
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    back before the iPhone there is this dark dark time whens gyroscopes actually spun
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    this is the sort of gyros that it has – actually four of them so that it can measure its movement
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    and than it has a control computer. The idea is that the dish itself can be moved while remaining absolutely stable with regard to the gyroscopes
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    it compensates for the rocking of the ship beneath it as it's targeting a stationary satellite
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    In america this costs two hundred and fifty dollars
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    but its electronics equipment so while you think that would only be a 180 euro it's more like 2500
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    that's before import duties and it being impounded
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    But if you wanted this, you'd have to carry this in your carry-on luggage and it could be awkward.
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    It's ok, I know europeans suck at history. [laughing]
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    what i did is i took these motors which were designed to be able to move the dish
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    This allows me to track things that are moving through the sky, but it doesn't actually matter where they're moving, because that's just a software problem.
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    And then i added an SDR which allows me to record a signal now and demodulate it later. Which is handy when you want to reverse engineer a signal.
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    You also need a recording of decent quality to reverse engineer later on.
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    having high quality signals for reverse engineering is necessary.
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    I built a software farmework as a collection of phython daemons.
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    there's a beagle board inside the radome, and there's a server in my home.
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    For maintenance, i can make my laptop pretend to be my dish, and have steppers on my desk
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    Voyager 2 doesn't acutally come into the sky because of my position in the northern hemisphere.
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    This isn't accurate enough to target the dish, so
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    This is skytee helping out with the dish. He's zip-tying it because we know everything about duct-taping wehre i come from, but we know nothing about zip ties, so I had to bring in a german engineer.
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    As this thing spins around, by original design there's a ring connector where all the signals go through.
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    And that worked in the 90s because it had no reason to send anything faster than 9600 baud.
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    It can only move 400 degrees around,
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    We've got hte beagle board on the left, a usb-hub on the right and a
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    it also takes care of updating the motor position
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    The stepper motors themselves are the originals that the dish was designed with. They run into an EggBot-Board, which was designed to
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    so you can actually aim a satellite dish that's taller than you with technology easier than what's needed for a 3d printer.
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    The satellite dish sits in Tennessee,
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    So instead we took the radomeâthat's frank, that's my catâgive him cheers.
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    We took tape and we ran tape down the edges of the radome and then marked it.
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    And then you can sort of scan the sky for a stationary
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    and you can recover your position.
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    But I can also arrange it as a polar plot, which gives me a plot of what the radome is seeing.
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    [applause] A significant portion of the gui client was written while i was stuck on the U-Bahn connected using 3g
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    You can take the data out of this and run it through scientific software
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    The daemons that build this up, you need a norbit prediction daemon.
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    You need to update the orbits themselves.
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    But this format isn't incredibly accurate for satellites that correct their orbit.
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    So you need a daemon that grounds the new files from spacetrack and this is just a matter of a recursive
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    you also need motor control because you need to move the dish physically to
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    and then you need radio daemons to
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    and then after that you start to take software recorderings of that
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    So for orbit prediction i began with a DOS program that had been ported to Unix called predict. This works but it's garbage. It only supports 20 stars
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    because it's designed for astronomy photographers that want to take pictures of things
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    because otherwise you have to set an alarm clock for the half-hour pass where you can record them.
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    So i managed to track every single item in geostat orbit this thick ring here is the clarke-bell of all geostationary satellites as viewed from my northern hemisphere [?]
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    All IPC is running through this PostreSQL
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    you then send it simple commands, like SM,3000,500,-400
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    And then it will count that out, and send me back an OK. If i want to disable the motors, i'll send them em,0,0
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    EM,1,1 will enable both motors in 1/16s
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    You can see the motors themselves with the belts and the geartrains. This thing on the right would probably be illegal for me to turn on
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    The belts and stuff need to be measured to figure out what the reduction is
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    the IMU unit , this vectornav vn100 is a
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    it costs 500$ which was more than all of the other components together.
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    Now for position calculation, the elevation itself comes from the IMU. The azimuth
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    so the accelerometer will drift while the compass will be confused by the magnetic fields while the
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    and the IMU will be come of a backup how to make it reliable, but at the moment the position
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    The radio daomens. The first is a spectrum analyzer. It just measures the strength of the frequency
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    the downlink recorder dumps the IQ values
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    directly to an NFS share.
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    Client GUI is PyGame
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    Also notes these faint blue lines are positions where i saw particularly strong signals
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    I'm running out of time by these markers. does this mean we skip Q&A or that I get kickd off of stage?
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    It takes SDR, it can provide maps of used different satellites in the sky.
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    I'd also like to make other ground stations. The software that I wrote should be portable
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    Another way that you can do it, the way that it's traditionally done to track stationary satellites is with a YAGI antenna
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    This is my van, my van is amazing. [applause] Thanks to nick farr. I had a bit to much too drink in
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    But you want a news-van. And I said Hell yes, I want a news van!
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    But most importantly, it does SECAM
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    This is the control panel, and that's my talk! [applause]
Title:
Hillbilly Tracking of Low Earth Orbit
Video Language:
English
Duration:
47:03
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