Deep space reception by AMSAT-DL
summary
AMSAT-DL uses a 20 m Bochum dish and GNU Radio to decode Tianwen‑1 telemetry at ranges beyond 393 million kilometers, collecting about 6 GB of decoded frames over ~230 hours. Low‑rate beacon runs ~7 kbps after FEC (convolutional + Reed‑Solomon) with a residual carrier and BPSK subcarriers; high‑speed downlink uses suppressed‑carrier QPSK and four‑word interleaved RS blocks. GNU Radio flowgraphs perform PLL, symbol‑sync, CCSDS framing and FEC, and decoded state vectors feed GMAT for orbit propagation and precise antenna pointing during relay and landing events.
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