Patent ID: 7496157

Claim:
An apparatus for detecting a body, comprising: transmission signal-generating means for generating transmission signals; modulation means for producing modulated signals by modulating the transmission signals generated by the transmission signal-generating means; transmitter/receiver means for transmitting the modulated signals produced by the modulation means as transmission waves and for receiving the reflected waves thereof; pulse compressing means for finding a correlation between received signals of the reflected waves received by the transmitter/receiver means and the modulated signals, and for compressing the received signals; and body detecting means for detecting a body based on the transmitted signals and the received signals that are compressed; wherein, in finding a correlation, the pulse compressing means multiplies the received signals by a conjugated complex signal of the modulated signals a plurality of number of times at timings that differ in time relative to the received signals, operates a differential vector between the multiplied result and the preceding multiplied result for each unit of modulation, adds up the calculated differential vectors for each unit of modulation, and averages the added results to find the correlation; wherein the pulse compressing means includes Doppler shift correction means for correcting the Doppler shift in the received signals of the reflected waves by using correction signals for correcting the Doppler shift in the received signals; wherein the pulse compressing means determines a correlation between the demodulated signals and the received signals after the Doppler shift has been corrected by the Doppler shift correction means, and compresses the pulses thereof relying upon the result thereof; wherein the Doppler shift correction means have different frequencies of correction signals, wherein the body detecting means detects the body based on the received signals from the Doppler shift correction means; wherein the pulse compressing means find a correlated value that represents a degree of correlation between the received signals after the Doppler correction and the modulated signals, and compress the received signals relying on the correlated value; and wherein body detecting means adds up the received signals compressed by the pulse compressing means, executes the threshold value determination to determine the magnitude of amplitude of the received signals that are added up relative to a preset level of amplitude to detect the body based on the result of determination.