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This is why we do it! Helping operators, helping missions, helping everyone!
10/09/2016 at 23:16 • 0 commentsI (Andreas) had been the chance to attend the International Astronautical Congress 2016 (IAC) In Guadalajara, Mexico this September. It is the biggest space congress on Earth and I teased about it in the previous logs already. I am back home now and here is the promised longer version.
Actually I attended two space congresses. I had been on the waiting list for the Space Generation Congress 2016 and was lucky enough to received a last minute slot. It is a youth congress in conjunction with the IAC to have "a voice from the youth perspective" in the space community that is meeting during the year and mainly during IAC. More then 150 people from mor than 60 countries gathered and discussed various topics in working groups. The result of these working group are presented as recommendations during the United Nations meeting of COPOUS (United Nations Committee on the Peaceful Uses of Outer Space). So what everyone is doing there is pretty amazing and I try to take part every year since I stumbled across thme by accident in 2011. So it was great to work with other space enthusiasts in our Telecommunications Working Group about how to make it easier for small sat operators to allocate needed frequencies from the ITU. I don't want to spoil too many details already while the reports of our and the other working groups are currently written. So I recommendto you to check their webpage in 1-2 months because they will openly publish it. But summarizing we had a consensus that the speed of development for a current cubesat is way shorter than than the typical frequency allocation process and all parties should be aware of this right from the begining.
Of course I met old friends of mine and found new friends. This is why I like space. Everyone is working together for the betterment of everyone in one way.
And then after SGC2016, the IAC2016 started. Guadalajara and Mexio as the host city and country did a marvelous job! It was a realy pleasure being there. I will directly jump to my personal highlight of the IAC, Elon Musk's plenary talk about his/SpaceX's Mars Mission. I won't go into details, because I linked to the full video here and you can see why I was so impressed. I really hope that he achieves everything he proposed there. Unfortunately I needed to leave his talk early because my own technical session and my paper presentation started right after his talk. I presented the current status of DGSN and what implications a highly distributed, internet connect grid can have. I don't really like the word Internet of Things, but I needed to give the talk a title and you can already find my slides (linked in github) in the previous log. I got great and honest feedback from Mr. Mattas (ITU) about why using Open-Source and also from other cubesat operators. This is why we decided to go for the Small Sat Operations technical session, because DGSN can have an impact with small sat operations. And we also learned, that we transmit with DGSN or any other ground station network on behalf of other missions is complicated and ITU emphasized to respect the rules. For us/DGSN it is okay, because in the current phase, we don't hink about doing that (yet).
Related, the PocketQube team by TU Delft showed a nice graph how long it usually takes for NORAD to release the Two-Line Elements (orbit data) of different small satellites with respect to their radar cross section. The essence is that it takes longer when they are smaller. It can be up to 14 days and that could already be too crucial for some missions. So it was great for us to have been presented the current status of DGSN at IAC to be in close contact with small sat operators. We will look forward to help and assist them during their various missions! (for the full IAC2016 paper, click here).
All in all we know, why we're working on DGSN, because we can help others and all benefit!
This log will be updated....
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NEW SPACE OPERATIONS IN THE INTERNET OF THINGS ERA - ANYWHERE, ANYTIME, ANYTHING! [IAC2016, Guadalajara, Small Sat Operations (B4.3)]
10/02/2016 at 19:06 • 0 commentsHi all,
I am just sitting at the Guadalajara Airoport and need to wait until I can board my flight to Mexco City (=> Paris => Stuttgart). The International Astronautical Congress 2016 was great and I will update this log as soon, as I will be home. But in the meantime the presentation is on Github now.
And my personal highlight was Elon Musk's talk avout SpaceX's Mars mission. Unfortunately, I needed to leave earlier to go to my session. So I didn't had the chance to ask my "serious" question at the end. I like the kissing booth idea a lot! :)
Soon more....
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International Astronautical Congress 2016 in Guadalajara - Biggest Space Congress, Elon Musk's Mars plans, maaaany space presentation, Ant-Man and a touch of magic
09/25/2016 at 22:12 • 0 commentsThis will be a rather short update, because longer updates needs to wait until after I will have presented the current status of DGSN at the International Astronautical Congress 2016 in Guadalajara. IAC2016 will take place next week and I just got my badge and programme book (yes, book, it is 290 pages heavy).
I will present our paper "New space operations in the internet of things era - anywhere, anytime, anything!" in Small Satellite Operations Session (B4.3) on Tuesday, 2016-09-27 14:45. So feel kindly invited to come if you are around!
I will give another log afterwords and I intend to load the paper and presentationto github (if the IAF allows, or I will rewrite it ;) ). In the meantime you can get some impressions about IAC, the SpaceGenerationCongress and how awesome the city of Guadalaraja is on my twitter @andreashornig.
As a huge Mars fan, my personal highlight will be SpaceX's Elon Musk's plenary about his plans for “Making Humans a Multiplanetary Species”. They will also stream it live in case you will miss it.
IAC will start tomorrow, but today I met Ant-Man so I will look for the Pym Tec booth to check for their space progamme and I felt a touch of magic...
Really excited!
PS: there is Con Comics today at the expo, too. I hope their guests will be also there tomorrow! So cool! :)
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How to use GRAVES radar in France to detect the ISS and metoerite showers
08/15/2016 at 19:58 • 0 commentsIf you want to track the ISS or just want to listen to "blips" generated by meteorites rushing through the atmosphere, then this short how to will show you how to use "passive radar's" reflexion on the ISS metal hull or the plasma tubes in the atmopshere created by the meteorites.
- your location should be in Europe (more great infos here)
- set your SDR# to GRAVES frequency of 143.05 MHz
- set the "Resolution" of the fft window to at least 52488 bins. That was our biggest mistake at first. We couldn't see the signal due to it's smaaaall bandwidth! But then we cranked up the resolution.
- GRAVES radar is always on (at least that is what we experienced), so you wait and check for signals.
- If you check GPREDICT for ISS contact times, you should see the faint relexion signal that is marked with 3) in the image below.
We did this ourselves to learn if it is possible with our RTLSDR dongle and what settings we need for the Distributed Ground Station. And this is our result with our very own crappy code. You also see, we increased the amounts of bins...
We are still not sure, what kind of blips we received there. So if you know, post in in the comments below! That would be awesome! We also asked ONERA. The should know, they operate GRAVES :).
More images will be shown in the next log. Happy blips hunting so far!
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Monitoring the 2m-band: One day of radio contacts by the International Space Station
08/13/2016 at 17:52 • 0 commentstl;dr:
- how does a signal from the International Space Station look like? Like this!
- how often does the ISS switch on the Slow Scan TV? At least not during our testing period.
- what else did we learn? Only use a fixed gain when you have neighboring ham operators in close vicinity of your ground station. Saturation acvoidance!
long:
After monitoring the 70cm-band, we checked back the 2m-band. But not the NOAA satellites, this time we wanted to look for the biggest human-made construction in space so far:
International Space Station, got you!
As a fancy fact, the ISS is not only equiped with special dedicated communication hardware and channels to their mission control. But also there is amateur-radio (ham) equipement installed for redundancy/emergency reasons and also for outreach (check ARISS.org for more infos). And astronauts on board the ISS hold the official ham-operator's license for operating the equipement.
HAMs in space aka astronauts' gobal radio
Unfortunately, we didn't receive voice transmission, because this is mostly done to communicate to special events like school classes, space camps or else. The astronauts' busy schedules are only allowing this from time to time. It was not planned during our tests. The Slow Scan TV was also not active on 145.8 MHz. It is even active even less frequently, but if active it transmits images taken inside the ISS or other interesting footage. (you would have seen it in the video. top left window)
Active packages everywhere
BUT what is always active is the APRS system on 145.825 MHz. You can transmit your APRS packet from earth to the ISS system and it relays it back. And we received APRS packages during each pass. You can easily see it in the video above (top, right window). As you saw before in our other logs, you see the doppler effect on the transmittion. You see packages of several seconds being transmitted.
How to receive the ISS?
Reception was easy. We used the turnstile antenna on our RTLSDR dongle. That's about it. What was tricky for our location and perhaps most of your's as well are other amateur radio channels. We are looking for a rather weak signal from space. What we saw were really ppwerfull transmission on neighboring amateur-radio channels. So autogain was not an option this time due to the high dynamic range of signals in the received frequency band driving the levels to maximum. And during this autogain phases, weak signals like those of ISS were harder to monitor. What solved this was finding a fixed gain that offers anough head-room for pwerful signals and also not effecting the weaker signals. We applied the "you crank up gain as long as the noise floor is not being raised significantly". That worked and with 30dB gain we made the monitoring you see in the video.
The ISS is pretty awesome! We keep on tracking you! :)
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Monitoring the 70cm-band: Finding GOMX-1, GOMX-3 and PRISM, or tracking a CubeSat tracking airplanes!
07/31/2016 at 15:04 • 0 commentstl;dr:
- You could say we automatically tracked GOMX-3 cubesats while it tracked airplanes from space!
- found cubesats in total: GOMX-1, GOMX-3 and PRISM
- strong signals with wideband modulation are detectable easily
- weak small band "beacon" signals are easy to detect too, if no other wideband signal is transmitted on that channel. But stupig people gave me good ideas to solve it.
- asking the operators of the found cubesats for confirmation is pending... :)
long:
After monitoring the 2m-band for weather satellites, we told you will will check what is going on in the 70cm band. So we hacked in some frequencies from this CubeSats list to see, what will happen. The result you see in the video above. Within a 13 hours window on a cloudless day/night, you can clearly see the signals in the waterfall diagram (center) and in their zoomed windows (above).
The automatic detection algo processes the information shown in the zoomed windows. Inside, it applies an edge detection and the sum of all edges within the zoomed area is taken. With this, the signal level graph (on the bottom) is calculated. You see high peaks for strong signas and wideband modulation, and lower peaks for small band beacon signals. That is good news, because it means it is working as intended. The bad news (for now) is, that there is still some work to do for two cases.
- If there is too much noise, there are also high peaks and the algo cannot distinguish between noise and cubesat signal.
- if the channel is not only used by one satellite, which is often the case, then it's getting more difficult to detect strong sat signals from weak sat signals.
For case 1, we wil try to match the noise in one channel with the noise in the neighbouring channel. If there is noise in both channels at the same time, then it can be clearly detected as noise and not as a signal.
For case 2, we will try to apply the standard devition of the signal levels as the detection threashold two times. With the first iteration, we intend to detect the strong peaks and thus signals. And with the second iteration, these found strong signals will be ruled out and corrected standard devition will be calculated generating a ower standard devition and this threshod. And in that way, lower peaks can be detected leading to find small bandwidth signals. This idea was proposed by stupig,org members who were interested to hear what we do with DGSN. So we discussed it during their meetup at Stuttgart hackerspace shackspace.
Nevertheless, with the current method we were able to match the signal levels with three cubesats, namely GOMX-1, GOMX-3 and PRISM. We did that again with GPREDICT, but to be sure, we will ask them also if they can confirm our findings.
It was funny to find out, that we most likely tracked an airplane tracking cubesat and seeing them transmitting their data. That is GOMX-3's mission and you can all see the results on FlightRadar24. Pretty awesome, isn't it? :)
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Monitoring the 2m-band: NOAAs, it matches perfectly
07/08/2016 at 17:57 • 0 commentstl;dr:
- heureka, DGSN monitoring of 2m-band works
- we have contacts with NOAA satellites
- contact times matches super with simulations by GPREDICT (image above)
- crappy code is slow but monitors (on github) (image below)
- next step, weaker signal monitoring in 2m-band and 70cm-band (ISS, cubesats)
too long:
Small baby steps we do with DGSN to achieve to track satellites that are on yet unknown orbits. One of these baby steps we did last week with monitoring the spectrum in the 2m-band. We tried to match the signal intensity with the method mentioned in the previous log to the contact times of a simulation with NORAD orbit data by GPREDICT.
We didn't know what to expect, but we did it! We can hunt NOAAs now! As you can see in the image above, our intensity monitoring (top half) matches pretty well with the predicted contact time by GPREDICT (bottom half). So we're pretty happy as you can guess.
You see several effects in the graph (top half). The spikes are bundled in groups and the middle spikes are higher and wider. This is due to the periodic behaviour of the satellite's orbit and thus the revisit time. In short, the Earth moves a bit in between the revisit times and the satellite seems to shift position each time in relation to the groundstation. So the slant length is changing and ths the signal intensity and the contact time. And you nicely see the different orbits of the NOAAs. There is hardly any gap between groups of contacts. When one NOAA is not visible for 4 hours, the next one takes over. This constellation is designed to be able to deliver an update of the weather map to ships every 100 minutes.
We used a "crappy code" version of our monitoring software that you can find on github. It's not really stable and it's slow as hell on a Raspberry Pi 3. We did some (not representative!) measurements with hardware we had in reach. The same 90 seconds input file were fed to all of them, the Raspberry Pi 3 (Arm), a LattePanda (Intel Atom), an Intel Compute Stick (Intel Atom) and a Surface Pro 3 (Intel Core i3).
As you can see above, the Raspi3 takes 4x as long as the input file is recorded by the RTLSDR dongle. And even with several cores, the Raspi3 cannot compute/process the input files in "realtime". But this is due to the "crappy code" version we used as a proof of concept.
If you like improving and boosting up code, feel free to sent a pull-request. That would be really awesome!
We also don't stop here. Our next goal is to monitor the 2m-band for fainter signals of cubesats and the International Space Station with our LattePanda makerboard. This will be a bit more difficult because unlike the NOAAs those sats don't have such transmission power and are not that strongly at our turnstile antenna. But if it's not working as intended, we will use one of the other, high-gain antennas on our Antenna Forest. And of course we will check the 70cm-band.
to be continued....
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planting antennas on the AntennaForest on shackspace & enabling more collaborative science!
06/24/2016 at 21:43 • 1 commentThe team had some busy weeks. We're not only working on DGSN, but also bringing space to the general public by other small activities ike the SpaceUp Stuttgart 2016 unconference. This will take place at the Space Center Baden-Württemberg on the University of Stuttgart campus and it's an unconventional conference aka BarCamp, where everyone can have a talk about his/her space related project or else. We just like doing those sma things, too. And interaction with people is always fun and everyone benefits. It's hard work, but rewarding.
Nevertheless, as you can see on the starting image, we improved our satellite reception a lot! We already had some ham-radio antennas on the Stuttgart hackerspace shackspace, but they were at places with lot's of hemispherical view blocking and other noise sources.
Luckily, we have a smal community of people at shackspace that are also into ham-radio and software defined radio. And we decided to have a joined effort to bring more radio to shack together. That lead to the principe "one Antenna Forest on a hackerspace for all". It safes some money and more importantly, it's more fun working together with a bigger goal where everyone benefits. With some small money from the first round at hackaday prize 2016 (~16$) and more of our own money, we bought some Bosch-Rexroth profile beams. With those easy connectabe beams, we have now a great basis to quickly attach new atennas, rearrange them and include more interested people and organisations to utilize the awesome field of view abouf Stuttgart - Wangen.
You can already see the wifi antenna on the left. We promised a fellow member to use his abandoned antenna for Freifunk (Wikipedia: a non-commercial open grassroots initiative to support free computer networks) if we need to have his wallmount for our AntennaForest. Of course we did so, because we like free stuff to play with and we like his idea to support Freifunk. Furthermore you see on the right hand side of the image that there are still places for "your antenna". We already planned to share this nice rooftop with other people. So you are also invited to get up there and put your antenna for good use (like ham-radio or science).
We leave it to the other project page's log to show and explain you more how we built this. But you can already find some cool photos of the building process (did you ever try to maneuver 6 meter beams through a tight hallway? ;)) and nice views of Stuttgart in Spring time on this google photos album.
For our DGSN project, we have a much better satellite reception now. We used an Ultraflex10 cable that is 3.5 times longer than the previous RG58 cable, but with even less absolut dampening. It was ~20dB cable dampening before, now it's ~13dB. Furthermore the higher position surpassing almost all neighbouring buildings is formidable! We now have NOAA reception below 5° Elevation and we received ISS APRS signals even behind the smal hill of Wangen blocking the lower part from 10° degrees.
Working with software and electronics is fun, but doing some real mechanic work is great! And as a side note: This collabrotive work is enabling further citizen science not just for us, but for more people at shackspace. We know, it is on a low level, but somewhere you need to start. And being on top the 5th floor's elevator room is not that low level anymore! :)
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Just a small update (it doesn't really count as an update)
06/24/2016 at 18:55 • 0 commentsJust a small update (it doesn't really count as an update):
In case you missed it, there is a fine small article about DGSN titled "Hackaday Entry: Reverse GPS" that nails it pretty well.
Thanks, Brian Benchoff. We also found it by accident and were luckily surprised!
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Hunting NOAA19, automatically
05/27/2016 at 19:31 • 0 commentsYesterday was Corpus Christi day and it is a holiday in some parts of Germany. A lot of people use it as a long, five day weekend and taking a day off on Fridays after Corpus Christi day. The long weekend started fine and sunny but was sometimes interrupted with short periods of rain.
So what a good excuse to use those periods to work on DGSN and detect the NOAA weather satellites with our tiny ground stations.
NOAA satellites are a small fleet of weather satellites, that are serve as "weather telefafax machines in space". They optically scan Earth's surface in their polar Low Earth Orbit as some kind of "line scanner" and directly transmit their data to Earthvia radio frequencies. Some of their data is free and not encrypted and you can receive it. The main goal is to provide weather information to ships so that the crew can plan their course according to the weather that is ahead of them. This is a really awesome service by the US. National Oceanic and Atmospheric Administration because everyone can use it.
So did we. What you see below in the image below is the "weather telefax" in the upper waterfall diagram. For visibility it is boxed and zoomed. There are several frequencies used within their allocated frequency band.
For out purpose, we need to have an automatic detection of this signal. So whenever this signal pattern occurs, the ground station algorithm shall detect it. For that, a pattern filtern is applied reducing the noise and emphasizing the parts of the waterfall diagram, that is most likely a signal.
The current test of the detector algorithm was done with NOAA 19 on 137.1 MHz and 80% of the time it was above the DGSN ground station, it evaluated the signal correctly as a NOAA 19 signal.
The algorithm still needs some improvements to detect the NOAA satellites more robustly. But it shows that it is possible with our Python setting to detect it without 3rd party software. This is important to release the code to be used by everyone.
Please stand by for more news....