In practical situations such as hostage rescue. earthquake and other similar events. the ultra-wideband (UWB) life-detection radar echo response from the respiration motion of the trapped person is always quasi-/non-periodic in respiration frequency or very weak in respiration amplitude. which can be called quasi-static vital sign. https://www.vacuumdoctores.shop/product-category/floor-scrubbing-machinery-rider-and-walk-behind/