Fixed mmWave radar

Principles

Frequency-modulated continuous-wave radar compares transmitted and reflected chirps. Range processing and Doppler processing describe distance and radial velocity components. Angle estimation depends on the antenna arrangement.

Proposed signal chain

Acquisition → calibration → clutter suppression → range-Doppler representation → movement segmentation → feature extraction.

Design constraints

The proposed Hakilix Care system uses no optical cameras and requires no wearable device. Multipath, interference, sensor placement and multiple occupants remain evaluation questions.

Reading the processing stages

Acquisition: capture a documented sequence of radio chirps with timestamps and device configuration.

Calibration and quality checks: identify configuration changes, missing frames and conditions that make a segment unsuitable for analysis.

Range and Doppler processing: transform the sampled reflections into representations of distance and radial velocity. Processing choices affect resolution and interpretation.

Segmentation: identify a candidate movement interval without assuming its meaning. A short, fast transition could have several explanations.

Feature extraction: describe the interval with reproducible quantities that can be compared against reference observations.

Camera-free does not mean privacy-free

The proposed system does not collect optical video and requires no body-worn device. Nevertheless, activity patterns can reveal personal routines. A responsible protocol still needs consent, purpose limitation, retention rules, access control and an account of how visitors or other occupants are considered.

Hardware decisions remain open

Frequency band, antenna arrangement, mounting position, processing platform and sampling configuration should follow the research question and applicable operating requirements. No specific production device, installation coverage or detection accuracy is promised here.