PROBLEM TO BE SOLVED: To highly accurately estimate the location of a signal transmission source even in the case of the presence of the signal transmission source in the vicinity of a signal reception device.
SOLUTION: Reception sensors 10a-m receive a signal incoming from a prescribed direction. Signal conversion parts 12a-m convert the reception signal from analog mode into digital mode. A correlation matrix computing part 14 computes a correlation matrix of the reception signal. An integration part 16 integrates the correlation matrix. A characteristic value computing part 18 computes characteristic values etc. from the correlation matrix. A function processing part 20 estimates the location of the signal transmission source from a performance function with coordinates as a parameter. An intensity determining part 22 computes the intensity of the signal incoming from the signal transmission source estimated by the function processing part 20. In the case that its value is smaller than a threshold value, a defect location corresponding to the signal is removed from defect location candidates. A display unit 24 displays the above-mentioned estimation result in prescribed form.