Passive radar measurements using synchronized RTL-SDR DVB-T receivers
Two DVB-T receivers were clocked from the same reference and data collected at 2.048 MS/s with one antenna facing the reference signal of a DVB-T emitter in Sendai, Japan, and the other Yagi-Uda antenna facing the target. The samples are collected as interleaved 8-bit integers (char) for saving space. The data are made available at https://www.iqengine.org under GNU Radio SigMF Repo -> Passive Radar (both channels split in two files during post-processing although initially saved as a single interleaved file).
See the 2018 FOSDEM presentation for a description of the experiment
The GNU Radio flowchart is limited to two RTL-SDR sources provided by the OsmoSDR Source
(gr-osmosdr package in Debian GNU/Linux) whose output is interleaved and stored in a
file. Be aware of the huge file size resulting from running this flowchart: at 2.4 MS/s, 32-bit
float, two complex channels the datarate is 38.4 MB/s or 2.3 GB/minute. Post-processing involves
running the cross-correlation between both channels for all possible frequency offsets introduced
by moving targets.
In case multiple azimuths are considered, the dataflow must never between acquisitions or a random delay from the USB bus will be introduced from one acquisition to the next. The 0MQ Publish/Subscribe mechanism allows for continuously running the RTL-SDR stream while connecting the subscribe source to a file only when the new azimuth has stabilized.
See W. Feng, J.-M Friedt, G. Cherniak, M. Sato, Passive bistatic radar using DVB-T receivers as general-purpose software-defined radio receivers , Rev. Sci. Instrum. vol.89, 104701 (Sept. 2018) at http://jmfriedt.free.fr/dvbt_hardware.pdf for a detailed description of the setup.