Sensor and estimating method

An estimating method for a sensor using a transmit antenna having N transmit antenna elements, N being a natural number of two or greater, a receive antenna including M receive antenna elements, M being a natural number of two or greater, circuitry, and a memory, the estimating method comprising:

• acquiring an N×M first matrix having complex-number transfer function components, each of the complex-number transfer function components representing propagation characteristics between a transmit antenna element and a receive antenna element, from the N receive signals received by each of the M receive antenna elements for a predetermined period, the N receive signals include reflection signals generated as a result of some of N transmit signals transmitted from the N transmit antenna elements being reflected by the organism;
• extracting a second matrix corresponding to a predetermined frequency range from the first matrix, the second matrix representing components influenced by a vital sign including at least one of respiration, pulse, and motion of the organism;
• estimating a position of the organism with respect to the sensor by using the second matrix;
• calculating a first distance indicating a distance between the organism and the transmit antenna and a second distance indicating a distance between the organism and the receive antenna, based on the estimated position of the organism, a position of the transmit antenna, and a position of the receive antenna;
• calculating a radar cross-section value with respect to the organism by using the first and second distances;
• and
• estimating a posture of the organism by using the calculated radar cross-section value and information indicating associations between radar cross-section values and postures of the organism stored in the memory.

An estimating method for a sensor system using a transmit antenna having N transmit antenna elements, N being a natural number of two or greater, and a receive antenna including M receive antenna elements, M being a natural number of two or greater, circuitry, and a memory, the estimating method comprising:

• acquiring propagation data corresponding to propagation characteristics from the transmit antenna to the receive antenna;
• extracting organism components, which represent a vital sign of a organism, from the propagation data;
• estimating a relative position of the organism with respect to the sensor based on the organism components;
• calculating a radar cross-section value with respect to the organism based on (i) the relative position of the organism, and (ii) the organism components;
• acquiring association information for determining posture based on radar cross-section values;
• and
• determining a posture of the organism by using the calculated radar cross-section value and the association information.