A Constant-Envelope Pseudo-Random Phase-Coded Noise Radar Architecture for Micro-Motion Sensing Under Strong Clutter and Same-Slope Interference

The waveform architecture, not the downstream detector, determines whether a weak micro-motion target remains representable in the range profile under strong clutter and same-slope interference. This work quantifies that claim for a noise radar architecture built on a constant-envelope pseudo-random phase-coded waveform with deterministic linear-feedback-shift-register (LFSR) regeneration, compared against an identically parameterized frequency-modulated continuous-wave (FMCW) baseline. Using a physics-constrained simulation assembled exclusively from industry-standard radar primitives with datasheet-level front-end impairments, each failure mechanism is isolated as it cannot be in coupled measurements, and every headline metric is evaluated over 100 independent code realizations. A weak target adjacent to a 23-dB-stronger scatterer is masked by the FMCW baseline in 100/100 evaluations and preserved as a detectable local peak in 100/100 realizations; under same-slope mutual interference, the FMCW chain collapses (0.6±0.2 dB suppression, coherent ghosts in all realizations) while the pseudo-random architecture retains 33.9±0.6 dB; cabin multipath visibility headroom improves by 22.9 dB. The boundary is stated with equal precision: clean-scene sensitivity and cross-slope interference favor or match FMCW, and phase-domain vibration extraction is waveform-insensitive even under impairments. Among five pseudo-random candidates, constant envelope (0 dB PAPR) and deterministic regenerability—not randomness itself—are the attributes mandatory for single-chip integration. The contribution is a mechanism-level attribution of waveform-dependent transduction loss, not an absolute detection-performance claim. A related Chinese patent application (No. 202610040851.1) is published and cited in the manuscript; experimental validation with a radar evaluation module is planned as follow-up work.