| CPC G01S 13/42 (2013.01) [G01S 13/524 (2013.01)] | 19 Claims |
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1. 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;
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 the 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;
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 in the secondary echo or the primary echo determined as the weak 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 the frequency component of the strong echo;
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; and
weak echo strength correction circuitry to correct electric power of the weak echo with electric power of the topographic echo representing the weak echo parameter, wherein
electric power of the weak echo corrected by the weak echo strength correction circuitry, and the spectral width of the weak echo and the Doppler velocity of the weak echo estimated by the weak echo processor are provided as spectral parameters of the weak echo.
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