Hey all,
I’ve been working on an FMCW radar using GNU Radio with a LimeSDR Mini v2.4. Right now Doppler/velocity seems to work (I can see peaks shift when something moves). Range is not working
Flowgraph:
TX chirp → RX
Dechirp (conjugate multiply)
DC blocker
Stream to Vector → Range FFT → Mag/Log display
Issue:
- I don’t see any clear peaks for targets within ~0–10 meters
- Occasionally I see faint lines around ~200–300 m, but they seem static and not tied to movement
Parameters:
- Sample rate: 2e6
- Chirp samples: 1024
- Bandwidth: ~8 MHz
→ Range resolution ≈ 18.75 m
I understand that short-range targets may collapse near DC with this resolution, but even after adjusting parameters for finer resolution, I still don’t see meaningful range peaks. Am I just displaying it incorrectly, or is this likely an issue in the processing chain?
Thanks
.grc file:
