To provide a time difference orientation detection device for calculating the arrival orientation of a radio wave from difference in receiving time using a plurality of antenna elements, of which accuracy in orientation detection depends on the measurement accuracy of time difference and is conventionally poor in the case of an incoming radio wave with a narrow frequency band because the measurement accuracy is in reverse proportion to the frequency band of the incoming radio wave.
In a model, it is assumed that an incoming radio waveform is narrow-banded from an ideal pulse waveform to a blunted trapezoid form. Using Wiener filter theory, the incoming radio waveform is virtually wide-banded to estimate the original transmitting signal. For this purpose, in addition to conventional orientation detection system, a dimension detection system is provided to calculate a S/N ratio of the incoming radio wave and a band limit filter from a detected rise time and a fall time. The orientation detection system obtains the S/N ratio and the band limit filter, performs Wiener filter calculation, and measures the difference in the incoming time of a receiving signal so as to calculate the arrival orientation. The accuracy in orientation detection is thus improved.
MATSUNAGA KAZUYUKI
HAYAMA KATSUHIRO
Tadahiko Inaba
Kanako Murakami
Nakatsuru Kazutaka
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