Vehicular pulse-radar with very low false alarm rate by on-off pulse control and adaptive threshold

We present a method of suppressing mutual interference among pulse-type radars of an identical type. We separate the true self-reflection from the synchronous false reflection by controlling the pulse emission of a radar in an orthogonal on-off pattern. The interference signal is identified by observing the received signal in off-intervals. The identified interference signal can be easily removed from the received signal in the on-intervals. P/sub PA/ and P/sub M/ are derived with the I-Q demodulation scheme, where Gaussian noise alone is Rayleigh-distributed and reflected radar pulses with Gaussian noise are Rician-distributed. The threshold of detection is adaptively adjusted to prevent the increase of P/sub M/. We also present an algorithm for tracking the good region. In the experimental result, P/sub FA/ decreases by an order of 10/sup 4/ within the good region of threshold values, when compared with the conventional M of N method.