Spatial RF.

The cheapest way to spoof a sensor is to attack one band, so sense across all of them. Spatial RF fuses the whole spectrum — mmWave vitals and fall detection, C-band through walls, authenticated UWB ranging, Wi-Fi CSI, BLE, mesh tomography, sub-GHz perimeter — weighted by how hard each band is to forge. Low-trust ambient bands corroborate but can never veto a real event; only a high-trust, keyed-coherent band can. Silence is a fault, not a gap: a dead or jammed node lowers the bar rather than blinding the system. Defeating the fabric means forging a jointly-consistent signature across the entire spectrum at once, which is physically incompatible. The research effort is Sentinel.