Hi Marcus, Thanks for your very quick response! I will look at the links you’ve pointed me towards. Maybe much of what amateur radio astronomers need is already available.
I agree that we don’t necessarily want “post-processing” code in GNU radio. But it would be good to include a few processing hooks to enable realtime detection and writing of values for later processing. Do you think that a Radio Astronomy GSoC topic merits consideration? Thanks Glen > On Feb 7, 2017, at 4:45 PM, Marcus D. Leech <mle...@ripnet.com> wrote: > > On 02/07/2017 04:20 PM, Glen I Langston wrote: >> Hello GNU radio folks, >> >> A few radio astronomer friends have had a very active interest in GNU Radio, >> but >> I’m aware of relatively few Radio Astronomy oriented contributions to GNU >> radio. >> >> This email is a request to start a discussion on >> some requirements of Radio Astronomy and the software support they would >> need. >> >> The main GNU Radio enhancement items on my short list are: >> 1) Averaging of spectra for long periods (minutes to hours), while capturing >> every spectrum. >> 2) Writing average and transient spectra based on internal and external >> events. >> >> >> a) Maybe this already exists, but a spectrum message is needed so that >> averaging can be separated from writing. >> >> >> b) Transient event detection with spectrum (or time sequence) passed to a >> writing thread. >> >> >> c) When sudden increases of signal are noted, time sequences would be >> written. (When auto-detected). >> 3) Keeping tracking of information associated with the observing setup. >> There are large numbers of ancillary data >> values needed to calibrate and map spectral observations (geographic >> location, precise time, horn/antenna azimuth, elevation >> gains, device types used for the observations, flags to indicate calibration >> spectra etc). >> >> I’ve greatly appreciated the GNU Radio software and excellent quality of the >> GRC and all the code I’ve seen. >> I’ve extensively modified the ‘FFT sink' to optimize for averaging and added >> a write component inside that code. >> Writing inside averaging is probably a mistake, as writing suspends data >> collection for a short time. I need to learn >> how to bring my code up to the GNU Radio quality standards etc and put the >> existing code in GNU Radio distribution. >> >> Further, can we add a spectra message type in GNUradio so that spectral can >> be passed to different blocks? >> >> To show that good progress has already been made, but still needs quality >> integration into GNU Radio, >> three figures are attached. Using an AIRSPY (10 MHz bandwidth) and GNU >> radio, I’ve mapped the Milky Way Galaxy in Neutral >> hydrogen (1420.406 MHz). It would be great if we can get this functionality, >> with a few significant >> enhancements, into the standard GNU Radio release. >> >> Observations are just recorded steadily, and spectra written every minute. >> I’ve left GNU radio recording sky brightness for a week >> and the system was still functioning well when I returned. After the data >> are gathered, the 1 minute spectra are >> calibrated and averaged. After averaging, the data are plotted and mapped. >> All data are ascii format. >> >> 1) The first figure shows one 24 hour observation of the Sky, averaging the >> signals every hour. The x axis is velocity of the parts of the >> galaxy observed and Y axis is intensity. The telescope (horn) was left >> outside for a day, pointed south with elevation of 29 degrees >> above the horizon. The different wiggly curves show different arms of the >> Milky Way Galaxy. >> <Mail Attachment.png> >> The thick blue and thick blue dashed lines are observations of the Center of >> the Milky Way galaxy, but one is 24 hours >> later than the other. These observations are made with a home made horn >> antenna, with about 3x3 foot square opening. >> >> A few days of data were collected to observe much of the northern sky: >> Image shows Right Ascension on the X axis, >> which is the time of day in astronomical coordinates. A 24 hour period is >> shown on the X axis. The Y axis >> is Declination ( Roughly the Geographic Latitude) of the observation on the >> Sky. >> <Mail Attachment.png> >> The Dark red regions show the Milky Way galaxy. The dark blue regions are >> away from the plane of our galaxy. >> The top line is close to the north pole. >> >> Final figure shows the Galactic Coordinate of the same data. >> The X axis is Galactic Longitude, with the center of the Milky Way at >> Galactic Longitude = 0, Latitude = 0. >> The Y axis is Galactic Latitude, with the plane of the Galaxy at Latitude = >> 0.0, where most of the Hydrogen is seen. >> >> <Mail Attachment.png> >> This is the very same data from the previous figure, but with coordinates >> converted to show the flatness of the galaxy more clearly. >> Empty region is below the horizon and can not be observed from my back yard. >> After the software is in GNU Radio, >> hopefully someone in the southern hemisphere can fill in the gaps. >> >> All the code to do the plotting is in python, but probably is not >> appropriate for GNU Radio. >> What should be discussed is how to add a relatively few additional book >> keeping and data recording >> features to GNU radio appropriate for astronomy. >> >> Thanks >> >> Glen > Glen: > > Your results are excellent. > > What I will observe is that many of the things you want properly belong in > post-processing, rather than in real-time signal processing. > > Please look at the ccera GIT repository for relevant RA software written for > Gnu Radio: > > https://github.com/ccera-astro > > In particular, "spectro-radiometer" uses bog-standard Gnu Radio blocks and > does both real-time display of averaged spectra, and > derivation of continuum, and logs both on a regular basis. There's also a > pulsar processor, which is still under heavy development. > But again, it all uses bog-standard Gnu Radio blocks, and the > relatively-new "Python Module" features. > > It's entering the territory of "wildly inappropriate" for the Qt GUI (or > WxGUI) FFT sinks to also do necessarily-custom data-logging. > Take a look at how spectro_radiometer does things efficiently in this > regard. > > Cheers > Marcus > >> >>> On Jan 31, 2017, at 6:33 AM, sushil iyer <iyersus...@gmail.com> wrote: >>> >>> GSoC Proposal for GNU Radio >>> >>> GNU radio has been one of the best simulation software platform for >>> designing almost any communication system. In particular, our research >>> expertise exists in the field of software defined radio (cognitive radio). >>> The major utility of cognitive radios (CR) lies in developing a protocol >>> for efficient dynamic spectrum access. As of now, there are various blocks >>> available in the GNU radio companion which help in building different >>> cognitive radio specific systems but our interest is mainly focused over >>> the enhancement of Quality of Experience of CR users (secondary or >>> unlicensed users) through Machine Learning based efficient dynamic spectrum >>> access (DSA). >>> >>> In GNU radio, we intend to develop a comprehensive Learning based >>> (supervised learning like Artificial Neural Networks, Support Vector >>> Machines, Recurrent Neural Networks, and unsupervised learning like K-means >>> clustering) DSA library which would help the CR research community to >>> immediately design gamut of systems simply by utilizing the blocks present >>> in our library, viz. spectrum prediction, spectrum modeling, spectrum >>> characterization and many more. >>> >>> We have already published the efficiency of applied machine learning in the >>> context of cognitive radio scenarios thereby providing better and enhanced >>> QoE of CR users and our idea is to extend this horizon towards GNU radio >>> companion so as to better appreciate and qualify the CR research with >>> simplicity, robustness and efficiency. >>> >>> We would love to be a part of this program and contribute vitally towards >>> the community. >>> >>> Yours Sincerely >>> Sushil Iyer >>> B.Tech Third Year >>> LNMIIT, Jaipur >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> Discuss-gnuradio@gnu.org >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
