In an embodiment, a method includes: generating a target displacement signal indicative of a movement of a human target based on raw digital data generated by a millimeter-wave radar sensor; and estimating a vital sign of the human target based on the target displacement signal, where generating the target displacement signal includes: generating target in-phase (I) and quadrature (Q) (I/Q) data associated with the human target based on the raw digital data, classifying the target I/Q data as high quality data or as low quality data using a first neural network, when the target I/Q data is classified as low quality data, discarding the target I/Q data, when the target I/Q data is classified as high quality data, performing ellipse fitting on the target I/Q data to generate compensated I/Q data, and generating the target displacement signal based on the compensated I/Q data.

A radar apparatus includes a plurality of transmit antennas that transmits a plurality of transmission signals using a multiplexing transmission, and a transmission circuit that applies phase rotation amounts corresponding to combinations of Doppler shift amounts and code sequences to the plurality of transmission signals. Each of the plurality of transmission signals is assigned a different combination among the combinations. The combinations include at least two combinations of a same number of multiplexing by the code sequences.

A radar apparatus includes a plurality of transmit antennas that transmits a plurality of transmission signals using a multiplexing transmission, and a transmission circuit that applies phase rotation amounts corresponding to combinations of Doppler shift amounts and code sequences to the plurality of transmission signals. Each of the plurality of transmission signals is assigned a different combination among the combinations. The combinations include at least two combinations of a same number of multiplexing by the code sequences.

A signal processing apparatus that performs signal processing on a Doppler spectrum derived from a reception signal of a reflected wave of pulsed undulation repeatedly transmitted into a space removes a topographic echo spectrum from the Doppler spectrum and extracts a plurality of candidate points of a target echo spectrum from the Doppler spectrum from which the topographic echo spectrum has been removed. Furthermore, the signal processing apparatus determines positional relation between the candidate points and a plurality of removed points of the topographic echo spectrum removed from the Doppler spectrum and extracts as an interpolation point, a point where the target echo spectrum is missing by removal of the topographic echo spectrum based on positional relation between the candidate points and the removed points in a direction of a frequency axis.

A signal processing apparatus that performs signal processing on a Doppler spectrum derived from a reception signal of a reflected wave of pulsed undulation repeatedly transmitted into a space removes a topographic echo spectrum from the Doppler spectrum and extracts a plurality of candidate points of a target echo spectrum from the Doppler spectrum from which the topographic echo spectrum has been removed. Furthermore, the signal processing apparatus determines positional relation between the candidate points and a plurality of removed points of the topographic echo spectrum removed from the Doppler spectrum and extracts as an interpolation point, a point where the target echo spectrum is missing by removal of the topographic echo spectrum based on positional relation between the candidate points and the removed points in a direction of a frequency axis.

A method, system and apparatus are provided for estimating characteristics of a wireless communication channel between at least two passive radio frequency (RF) nodes. Backscatter channel state information (BCSI) is measured during communication between the at least two passive RF nodes using the wireless communication channel. An RF node aggregates the measured BCSI and the aggregated BSCI is analyzed to detect at least one activity of a plurality of activities.

A detection area determining unit (6) determines a detection area where there is a possibility that a tsunami occurs. A current velocity estimating unit (7) estimates, as a sea-surface velocity of current in the detection area, a value obtained by smoothing sea-surface velocity of currents corresponding to cells included in the detection area. A tsunami detecting unit (8) detects occurrence of the tsunami in the detection area, based on the sea-surface velocity of current estimated by the current velocity estimating unit (7).

A detection area determining unit (6) determines a detection area where there is a possibility that a tsunami occurs. A current velocity estimating unit (7) estimates, as a sea-surface velocity of current in the detection area, a value obtained by smoothing sea-surface velocity of currents corresponding to cells included in the detection area. A tsunami detecting unit (8) detects occurrence of the tsunami in the detection area, based on the sea-surface velocity of current estimated by the current velocity estimating unit (7).

According to an example aspect of the present invention, there is provided monitoring living facilities by a multichannel radar. A field of view within a frequency range from 1 to 1000 GHz, for example between 1 to 30 GHz, 10 to 30 GHz, 30 to 300 GHz or 300 to 1000 GHz, is scanned using a plurality of radar channels of the radar. Image units comprising at least amplitude and phase information are generated for a radar image on the basis of results of the scanning. Information indicating at least one error source of a physical movement of the radar and interrelated movements of targets within the field of view are determined on the basis of the image units. Results of the scanning are compensated on the basis of the determined error source. A radar image is generated on the basis of the compensated results.

According to an example aspect of the present invention, there is provided monitoring living facilities by a multichannel radar. A field of view within a frequency range from 1 to 1000 GHz, for example between 1 to 30 GHz, 10 to 30 GHz, 30 to 300 GHz or 300 to 1000 GHz, is scanned using a plurality of radar channels of the radar. Image units comprising at least amplitude and phase information are generated for a radar image on the basis of results of the scanning. Information indicating at least one error source of a physical movement of the radar and interrelated movements of targets within the field of view are determined on the basis of the image units. Results of the scanning are compensated on the basis of the determined error source. A radar image is generated on the basis of the compensated results.