On 07/28/2010 05:39 PM, Juha Vierinen wrote: > Hi, > > I recently wrote some preliminary code to see if a USRP2 could be used > as a wide band ionosonde receiver (FM CW ionospheric chirp sounder). > Sure enough, after a morning of programming I managed to create a > simple ionosonde receiver using the following set of hardware: USRP2, > GPSDO, LFRX and a wide band magnetic loop antenna. I'm listening to > ionospheric echos to a transmitter located about 1 km away from the > receiver, which is transmitting a 0.5 MHz/s sweep from 0.5 MHz to 16 > MHz every minute. I simply request the USRP2 to start sampling with a > 20 MHz bandwidth at the correct time (we have written a sampler that > allows you to specify in unix time when to start sampling). These > files are then analyzed using a simple R script that produces the > following type of an ionogram (see attached file). > > The next step would be to program the analysis part in C so that it > would be possible to track multiple ionospheric chirp sounders > simultaneously. I can release the code if somebody is interested > building their own wide band ionosonde receiver. > > I also recently finished work on a beacon satellite receiver similar > to the GNU digital beacon receiver that Mamoru Yamamoto has done. The > program allows you to measure relative total electron content (line > integrals of electron density) between a satellite and a receiving > station. We are planning to build a ionosopheric tomography receiver > chain using USRP hardware and the software is written wit h this in > mind. The program is C++ and allows tracking of multiple simultaneous > beacon satellites. If there is interest, I can also release this code > too. The software should work with a generic USRP and two WBX > daughterboards. > > BR, > juha > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > Juha:
That's very interesting work. Several months ago, I used Gnu Radio to build a Sudden Ionospheric Disturbance receiver, based on a magnetic loop, a commercial audio amplifier for microphones, and a 96KHz sampled sound subsystem. The SID receiver can tune up to 6 different VLF stations, and measure the received power throughout the day. The receiver software is easily able to see the standard diurnal variation in ionospheric reflectivity, as well as see sudden enhancements due to solar X-ray flares. My software has captured several solar X-ray events in the last few months. The code is available for anyone who wants it. -- Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
