Estimating device, estimating method, and recording medium

An estimating device that estimates a distance to a living body, the estimating device comprising:

• a transmission signal generator that generates a multicarrier signal obtained by modulating a plurality of subcarrier signals;
• a transmission antenna including M transmission antenna elements, where M is a natural number greater than or equal to 1;
• a transmitter that causes the transmission antenna to transmit the multicarrier signal, by processing and outputting the multicarrier signal to the transmission antenna;
• a reception antenna including N reception antenna elements, where N is a natural number greater than or equal to 1;
• a receiver that measures, for a first period equivalent to a cycle derived from an activity of the living body, a plurality of reception signals which are received by each of the N reception antenna elements and include a reflected signal which is the multicarrier signal transmitted from each of the M transmission antenna elements that has been reflected or dispersed by the living body;
• a complex transfer function calculator that calculates a plurality of complex transfer functions for each of a plurality of subcarriers to which the plurality of subcarrier signals correspond, using the plurality of reception signals measured by the receiver in the first period, the plurality of complex transfer functions indicating a propagation characteristic between a transmission antenna element and a reception antenna element in each of M×N combinations which are combinations of each of the M transmission antenna elements and each of the N reception antenna elements;
• a living body correlation matrix calculator that calculates, for each of the plurality of subcarriers, a living body correlation matrix having M rows×N columns by (i) recording sequentially in time series, which is an order in which the plurality of reception signals are measured, the plurality of complex transfer functions calculated by the complex transfer function calculator and (ii) extracting components relating to the living body from the plurality of complex transfer functions recorded sequentially in time series, the (i) recording and the (ii) extracting being performed for each of the plurality of subcarriers and each of the M×N combinations;
• and
• an estimator that estimates, using the living body correlation matrix calculated for each of the plurality of subcarriers, a third distance which is a sum of a first distance between the transmission antenna and the living body and a second distance between the reception antenna and the living body.