(this-1) week @ ULSF
Alex Csete
Linear transponder downlink of VO-52 satellite:
http://www.youtube.com/watch?v=Y4x-LpCs918
On the left side there is a wide and strong peak that pops up
periodically. This is the packet radio (AX.25) downlink from the
International Space Station using the Russian callsign RS0ISS. I was
lucky that both sats were in range at the same time. Decoding of the
packets is shown here: http://www.youtube.com/watch?v=i4Td2WKdAUo
For decoding the AFSK, I used a very old software modem called
"multimon" which was connected to the FM receiver using a Unix pipe (I
am very proud of myself that I thought about this ;-). This way I
could eliminate sending the data through audio hardware and software
that could degrade the signal quality. A video tutorial showing how to
set up is also available: http://www.youtube.com/watch?v=GBmli8Vflig
I hope it's enough for one week ;-)
Alex
John Pritchard
I hope it's enough for one week ;-)
most excellent!
Joshua
I hope it's enough for one week ;-)
most excellent!
tobias krieger
Pretty busy week, assisting Carlo Gavazzi Space with some test / Project Marslander. Had the change to work with esa SCOS-2000.
Best regards,
Tobias
Date: Tue, 20 Jul 2010 18:27:26 +0200
Subject: Re: (this-1) week @ ULSF
From: trist...@gmail.com
To: ultra-light-...@googlegroups.com
http://groups.google.com/group/ultra-light-space-flight?hl=en
Hotmail: Free, trusted and rich email service. Get it now.
Alex Csete
<tobio...@hotmail.com> wrote:
> Had the change to work with esa SCOS-2000.
My condolences. I hope you don't loose any hope in the future of space
flight ;-)
Alex
John Pritchard
Hi guys,
Pretty busy week, assisting Carlo Gavazzi Space with some test / Project Marslander. Had the change to work with esa SCOS-2000.
Best regards,
Tobias
So, what's wrong with SCOS? ;)
Alex Csete
Maybe it is just bad chemistry between S2K and myself, but I'd rather
spend the rest of my life using windows xp without any antivirus
software installed than ever touch S2K again. I have to say though, I
have only used version 4.x and rumors say version 5 has been rewritten
so that it no longer looks and feels like a huge distributed system
written in ANSI C by people who have never programmed before they were
assigned to S2K development, but I am very happy never touching it
again.
Alex
John Pritchard
Maybe it is just bad chemistry between S2K and myself, but I'd rather
spend the rest of my life using windows xp without any antivirus
software installed than ever touch S2K again. I have to say though, I
have only used version 4.x and rumors say version 5 has been rewritten
so that it no longer looks and feels like a huge distributed system
written in ANSI C by people who have never programmed before they were
assigned to S2K development, but I am very happy never touching it
again.
Ah!
The pride of position is the undoing.
John Pritchard
I know I didn't do this justice (inadequate), but to avoid people getting overdosed on our quietude i threw in hamming's open shop philosophy promoted to principle that's been rattling around in my head for weeks, now, and tied in nasa's recent nebula + openstack announcement
http://spacetweepsociety.org/blogs/jdpsyntelos/ultralight-spaceflight-open-shop-principle
Alex Csete
Here something new & hot, straight out from the labs:
http://www.youtube.com/watch?v=XtlyNlRAHGM
> --
> http://groups.google.com/group/ultra-light-space-flight?hl=en
>
Joshua
John Pritchard
So cool!JoshuaOn Sun, Jul 25, 2010 at 11:53 PM, Alex Csete <a...@ulsf.net> wrote:
It's just fine.
Here something new & hot, straight out from the labs:
http://www.youtube.com/watch?v=XtlyNlRAHGM
yea, so it seems the fpga/cyclone is running (some kind of) "twice" the load it would for a transmission?
Alex Csete
>>
>> On Sun, Jul 25, 2010 at 11:53 PM, Alex Csete <a...@ulsf.net> wrote:
>>>
>>> It's just fine.
>>> Here something new & hot, straight out from the labs:
>>> http://www.youtube.com/watch?v=XtlyNlRAHGM
>>>
>>>
>
> yea, so it seems the fpga/cyclone is running (some kind of) "twice" the load
> it would for a transmission?
>
No, the USRP (which has the fpga) is not connected at all. This is a
pure software simulator where the noisy transmission channel is
simulated within GNU Radio. There are 3 processes running:
1. GStreamer video source: generates test pattern, adds text overlay,
encodes H.264, puts into MPEG-TS container and writes it to a file
(named pipe)
2. GNU Radio app that contains (a) transmitter -> (b) channel
simulator -> (c) receiver.
(a) Reads the input pipe, creates baseband RF using GMSK
modulation (this is what you would send to USRP)
(b) mixes the GMSK modulated baseband signal with Gaussian noise
to simulate transmission through a noisy channel
(c) Takes the noisy GMSK baseband signal, demodulates and writes
to a file (named pipe)
3. Another gstreamer app that simply reads the output from GNU Radio
and displays the video
The whole setup is running on a single laptop with a quad core i7
processor, though one can easily split it up on different machines and
use TCP or UDP instead of named pipes.
The idea with such a software only simulator is that it can simulate
any transmission e.g. from the Moon or Pluto using analytical
approximation of the transmission channel (noise, fading, etc.). While
it is not 100% realistic, it allows to study performance of various
components in the loop, e.g. video codec, modulation scheme, FEC.
John Pritchard
ok, thanks. got it this time. :)
btw, what has 300k lines of flight software, one tbd, and is soon ready for prime time?
Alex Csete
> btw, what has 300k lines of flight software, one tbd, and is soon ready for
> prime time?
>
That's the work people pay me to do so I can't give much details. I
was just positively shocked because the previous version I have tested
few weeks ago had hundreds of "TODO", "TBD", "TBC", etc. and I was
expecting more than one this time.