A real-time radar acquisition and imaging system for vector-network-analyzer (VNA) and ADC front-ends. It drives the radar through a frequency sweep, calibrates and preprocesses the measured S-parameters, runs a selectable imaging/detection processor, and presents the live result in a desktop GUI and an in-process web interface. The same application runs interactively on a workstation or unattended as a headless Raspberry Pi appliance.

Overview

The system is split into a C++ real-time pipeline and a Python application that supervises it and handles visualization and control.

The pipeline runs as three independent processes connected by lock-free POSIX shared-memory ring buffers. Each stage advances on its own, and a slow consumer never blocks a producer — the rings are latest-wins, so a reader that falls behind simply skips to the freshest frame:

Acquisition — sweep_orchestrator (or a hardware-specific producer) configures the radar, performs the frequency sweep, and publishes raw S11/S21 traces.
Preprocessing — data_preprocessor applies through/OSL calibration, reference subtraction, and optional frequency-domain notch filtering.
Processing — data_processor runs the selected processing mode and emits results (pass-through traces, B-scan images, or GPR images with detected objects). Detected objects are additionally broadcast to subscribers over a TCP locator server.

The Python application (python_app) starts and monitors the C++ binaries, reads the result rings, renders the live view with pyqtgraph, and exposes the same controls plus a pixel-identical live plot through an embedded web UI.

 radar hardware
       │
       ▼
 Acquisition ──[raw ring]──▶ Preprocessing ──[preprocessed ring]──▶ Processing ──[result ring]──▶ GUI / Web
                                                                          │
                                                                          └──▶ TCP locator (detected objects)

Supported hardware

librevna — single LibreVNA.
librevna_multi — synchronized multi-device LibreVNA.
compact_m_k209 — Compact-M K209 / S2VNA (including Raspberry Pi remote mode).
sn9000 — SNVNA SN9000 over VISA (pure-Python @py backend).
kamil_adc — external Kamil ADC acquisition process, with optional laser control.
mock / simulator — driver-less mode for development without hardware.

Processing modes

pass_through — magnitude and phase of the selected channel for each combo.
bscan — depth-versus-sweep B-scan heatmap.
gpr — coherent back-projection GPR imaging with object detection.
legacy_gpr — ellipse-intersection MIMO localization (point and extended/region modes).

Repository layout

Path	Contents
`data_acq_and_processing/`	C++ pipeline: `sweep_orchestrator/`, `preprocessing/`, `processing/` (including `locator/`), shared `common_cpp/` (config, IPC rings), and vendored `third_party/` (Eigen, nlohmann/json).
`python_app/`	Python application: `gui/`, `orchestration/` (process supervisor, shared-memory readers, config), `hardware_full/` (device drivers and services), `webui/`, `storage/`, `models/`, `workflows/`, `scripts/` (producers and tools), and `tests/`.
`run_config_examples/`	Ready-made configuration profiles, one per hardware setup.
`deploy/`	systemd daemon installer for Raspberry Pi appliances.
`build/bin/`	Compiled C++ binaries.
`device_firmware/`, `docs/`	Device firmware and vendor manuals.

Requirements

Linux (POSIX shared memory; GPIO on Raspberry Pi).
A C++20 compiler and make — Eigen and nlohmann/json are vendored, so no extra C++ dependencies are needed.
Python 3.12 with a virtual environment.

Build and run

From the repository root:

python3 -m venv .venv
.venv/bin/python -m pip install --upgrade pip
.venv/bin/python -m pip install -r requirements.txt
make                     # build the C++ binaries into build/bin/

Run the desktop GUI:

.venv/bin/python -m python_app.gui.main
# or, with the build step and single-instance handling:
./start.sh

start.sh supports --headless (offscreen, auto-start — for unattended Pi use), --profile PATH, --producer-only, --skip-build, and --clean-shm; see ./start.sh --help. The acquisition device (LibreVNA, Kamil ADC, …) is detected automatically from the active config's radar.model — there is no per-device flag.

The web interface is served in-process at http://<host>:8080. It mirrors the live plot and offers Start / Stop / Capture controls and the active processor settings.

Configuration

The active profile is run_config.json. It selects the radar model and sweep, the switch matrix and acquisition combos, the preprocessing calibration/reference assets, the GPR geometry, and the shared-memory ring sizes. Profiles for each hardware setup are provided in run_config_examples/ — copy one to run_config.json, or pass it with --profile, to use it.

Deployment

On a Raspberry Pi, deploy/install-daemon.sh installs a systemd service that runs the application headless and restarts it on failure. A single-instance lock ensures the interactive GUI and the daemon never run at the same time, since they share the radar, the shared-memory rings, and the locator port.

Tests

.venv/bin/python -m unittest discover -s python_app/tests