Patent ID: 11927666
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Measurement (Instruments)
Classification: CPC G  Y | IPC G

Claim 10:
11. A signal processing apparatus that performs signal processing on a reception signal of a reflected wave of pulsed undulation repeatedly transmitted into a space, the signal processing apparatus comprising:
secondary echo phase correction circuitry to generate a reception signal in a secondary echo region by phase correction of the reception signal of the reflected wave;
a secondary echo processor to remove a topographic echo from the reception signal in the secondary echo region and estimate electric power of a topographic-echo-processed secondary echo, a spectral width of the topographic-echo-processed secondary echo, and a Doppler velocity of the topographic-echo-processed secondary echo;
a secondary topographic echo processor to estimate electric power of a topographic-echo-unprocessed secondary echo from the reception signal in the secondary echo region and calculate electric power of a secondary topographic echo based on a difference between electric power of the topographic-echo-unprocessed secondary echo and electric power of the topographic-echo-processed secondary echo;
secondary topographic echo presence determination circuitry to determine whether the secondary topographic echo is present based on electric power of the secondary topographic echo calculated by the secondary topographic echo processor;
primary echo phase correction circuitry to generate a reception signal in a primary echo region by phase correction of the reception signal of the reflected wave;
a primary echo processor to remove a topographic echo from the reception signal in the primary echo region and estimate electric power of a topographic-echo-processed primary echo, a spectral width of the topographic-echo-processed primary echo, and a Doppler velocity of the topographic-echo-processed primary echo;
a primary topographic echo processor to estimate electric power of a topographic-echo-unprocessed primary echo from the reception signal in the primary echo region and calculate electric power of a primary topographic echo based on a difference between electric power of the topographic-echo-unprocessed primary echo and electric power of the topographic-echo-processed primary echo;
primary topographic echo presence determination circuitry to determine whether the primary topographic echo is present based on electric power of the primary topographic echo calculated by the primary topographic echo processor;
strong-and-weak-echo distinction and output circuitry to compare the topographic-echo-processed secondary echo with the topographic-echo-processed primary echo, make categorization into a strong echo and a weak echo, and provide as weak echo parameters, (i) a strong-topographic-echo-removed reception signal resulting from removal of the topographic echo in the primary echo or the secondary echo determined as the strong echo and (ii) electric power of the topographic echo;
a strong echo remover to generate 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;
weak echo phase correction circuitry to generate a reception signal in a weak echo region by phase correction of the reception signal resulting from removal of a frequency component of the strong echo; and
a weak echo processor to estimate from the reception signal in the weak echo region, electric power of the weak echo, a spectral width of the weak echo, and a Doppler velocity of the weak echo, wherein
when the secondary topographic echo presence determination circuitry determines the secondary topographic echo as being absent, the secondary echo processor (i) sets electric power of the topographic-echo-unprocessed secondary echo estimated from the reception signal in the secondary echo region as electric power of the topographic-echo-processed secondary echo and (ii) estimates the spectral width of the topographic-echo-unprocessed secondary echo and the Doppler velocity of the topographic-echo-unprocessed secondary echo as the spectral width of the topographic-echo-processed secondary echo and the Doppler velocity of the topographic-echo-processed secondary echo, respectively,
when the primary topographic echo presence determination circuitry determines the primary topographic echo as being absent, the primary echo processor (i) sets electric power of the topographic-echo-unprocessed primary echo estimated from the reception signal in the primary echo region as electric power of the topographic-echo-processed primary echo and (ii) estimates the spectral width of the topographic-echo-unprocessed primary echo and the Doppler velocity of the topographic-echo-unprocessed primary echo as the spectral width of the topographic-echo-processed primary echo and the Doppler velocity of the topographic-echo-processed primary echo, respectively,
when an echo determined as the weak echo by the strong-and-weak-echo distinction and output circuitry is the secondary echo and when the secondary topographic echo presence determination circuitry determines the secondary topographic echo as being absent, or
when an echo determined as the weak echo by the strong-and-weak-echo distinction and output circuitry is the primary echo and when the primary topographic echo presence determination circuitry determines the primary topographic echo as being absent,
the weak echo processor estimates from the reception signal in the weak echo region, electric power of the weak echo, the spectral width of the weak echo, and the Doppler velocity of the weak echo,

in addition, when an echo determined as the strong echo by the strong-and-weak-echo distinction and output circuitry is determined by the secondary topographic echo presence determination circuitry or the primary topographic echo presence determination circuitry as being free from the secondary topographic echo or the primary topographic echo,
the strong-and-weak-echo distinction and output circuitry provides as the weak echo parameter, the reception signal of the secondary echo or the primary echo determined as the strong echo instead of the strong-topographic-echo-removed reception signal, and
the strong echo remover generates a reception signal resulting from removal of a frequency component of the strong echo from the reception signal of the secondary echo or the primary echo determined as the strong echo that represents the weak echo parameter.