Passive Radar - KrakenSDR Multi-Beam System
Phase 7/10 (60%)
Concept
Ambient RF signals reflect off objects in the environment. By processing these reflections with coherent multi-channel receivers, we can extract bistatic range and Doppler shift information — an interesting signal processing challenge.
Quick Facts
| Status | Phase 7/10 (60%) |
| Language | N/A |
| Started | 2026 |
What This Is
An experimental signal processing project exploring how to analyze reflections of ambient radio signals. The system uses coherent multi-channel RF data to study bistatic geometry and Doppler effects.
Core Principles
Signal Reflection and Processing:
- Ambient Transmitters: FM radio, DVB-T, or cellular signals serve as convenient RF sources
- Bistatic Geometry: Separates transmitter and receiver — objects reflect signals toward the receiver
- Cross-Correlation Processing: Correlates reference channel (direct signal) with surveillance channels (reflections)
- Range-Doppler Mapping: Extracts time-delay and frequency-shift information from reflections
Signal Processing Chain:
- Reference Signal Capture: Acquire clean direct signal from transmitter
- Reflection Channel Processing: Receive signals containing reflections
- Adaptive Interference Cancellation: Remove direct signal and static multipath
- Cross-Correlation: Extract reflection signatures via time-delay analysis
- Doppler Analysis: Apply FFT to study frequency shifts from motion
- Detection Processing: Threshold analysis and signal extraction
Why This Approach:
- Cost-Effective: Uses existing RF infrastructure for experiments
- Educational: Practical exploration of bistatic geometry and signal processing techniques
Architecture
v1.0 Foundation (Phases 1-4, Complete): Established distributed multi-beam architecture using ProcessPoolExecutor for parallel surveillance channels. CFAR detection (Phase 5) implemented and verified.
v2.0 Real-Time Tracking (Phases 5-10, In Progress):
Currently implementing track management and association logic (Phase 6). The system now maintains tracks across multiple beams with detection-level recording for storage efficiency.
Key Features:
- Multi-Beam Processing: Parallel surveillance channels across 5-channel coherent array
- CFAR Detection: Constant False Alarm Rate detection complete
- Track Management: Per-beam tracking with cross-beam fusion planned for v3
- Real-Time Operation: Aircraft tracking with sub-second latency
Current Status
Phase 6 in progress. Clean, understandable, stable codebase that reliably tracks aircraft in real-time. Phase 5 (CFAR Detection) complete and verified.