Abstract: A radar system, a radar device, and an interference avoidance method are obtained that can utilize frequency effectively even in three or more radar devices. A radar system includes three or more radar devices and a schedule management controller. Schedule management controller predicts an interference time period that is a time period during which the overlapping scanning/radiation range is generated, determines a first interference avoidance measure that is a measure to cause radar devices to use respective different use frequencies while keeping a restriction on the number of frequency channels, in the predicted interference time period, and determines a second interference avoidance measure to be performed by a radar device that is unable to avoid interference by the first interference avoidance measure.

Abstract: A secondary echo and a primary echo subjected to topographic echo processing are compared with each other. When there is a topographic echo in the primary echo or the secondary echo determined as a strong echo, an echo resulting from removal of the topographic echo is defined as a strong-topographic-echo-removed reception signal. Electric power of the topographic echo in the secondary echo or the primary echo determined as a weak echo and the strong-topographic-echo-removed reception signal are defined as weak echo parameters. Electric power of the weak echo estimated from a reception signal in a weak echo region resulting from phase correction of a reception signal resulting from removal of a frequency component of the strong echo from the strong-topographic-echo-removed reception signal representing the weak echo parameter, a spectral width of the weak echo representing the weak echo parameter, and a Doppler velocity of the weak echo are provided as spectral parameters.

Abstract: 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.

Abstract: Based on a reception signal of a reflected wave of pulsed undulation repeatedly transmitted into a space, a Doppler spectrum derived from the reception signal, and a topographic-echo-removed spectrum resulting from removal of a topographic echo from the Doppler spectrum, a first weather echo region is found by using a weather parameter among weather parameters that is different in behavior between a weather echo and the topographic echo, and a second weather echo region is found by using a weather parameter among the weather parameters a behavior of which is not dependent on a Doppler velocity. The weather echo region is determined based on the first weather echo region and the second weather echo region. A signal processing apparatus and a signal processing method with which a zero-Doppler weather echo attenuated, that is, erroneously suppressed, by topographic echo removal processing is readily reconstructed are thus obtained.

Abstract: A secondary echo and a primary echo subjected to topographic echo processing are compared with each other. When there is a topographic echo in the primary echo or the secondary echo determined as a strong echo, an echo resulting from removal of the topographic echo is defined as a strong-topographic-echo-removed reception signal. Electric power of the topographic echo in the secondary echo or the primary echo determined as a weak echo and the strong-topographic-echo-removed reception signal are defined as weak echo parameters. Electric power of the weak echo estimated from a reception signal in a weak echo region resulting from phase correction of a reception signal resulting from removal of a frequency component of the strong echo from the strong-topographic-echo-removed reception signal representing the weak echo parameter, a spectral width of the weak echo representing the weak echo parameter, and a Doppler velocity of the weak echo are provided as spectral parameters.

Abstract: Based on a reception signal of a reflected wave of pulsed undulation repeatedly transmitted into a space, a Doppler spectrum derived from the reception signal, and a topographic-echo-removed spectrum resulting from removal of a topographic echo from the Doppler spectrum, a first weather echo region is found by using a weather parameter among weather parameters that is different in behavior between a weather echo and the topographic echo, and a second weather echo region is found by using a weather parameter among the weather parameters a behavior of which is not dependent on a Doppler velocity. The weather echo region is determined based on the first weather echo region and the second weather echo region. A signal processing apparatus and a signal processing method with which a zero-Doppler weather echo attenuated, that is, erroneously suppressed, by topographic echo removal processing is readily reconstructed are thus obtained.

Abstract: 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.

Abstract: In a weather radar apparatus, an array antenna includes antenna elements arranged in a horizontal direction and an elevation angle direction. An antenna driver rotates the array antenna in an azimuth direction. A transmitter controls the antenna elements to radiate the transmission waves with controlled amplitudes and phases respectively. A reception beam former processes reception signals to form a plurality of reception beams in the azimuth direction. A reception beam allocator receives an azimuth at which the array antenna is oriented, and allocates the reception beams to respective azimuth ranges. A weather observer obtains information about a result of weather observation for each of the azimuth ranges, from the reception beams allocated to the respective azimuth ranges by the reception beam allocator.