RADAR DEVICE

PURPOSE:To easily calculate a target distance in a short time by detecting a higher Doppler frequency by a frequency judging circuit after signal detection and calculation the distance from frequency differences in two frequency modulation phases in order. CONSTITUTION:A signal detector 6 detects Doppler frequency signals in FM phase C of constant frequency and in FM phase B of linear frequency modulation shifted in frequency by a value corresponding to the distance of the target by a target frame and a je engine modulation. Then a frequency discriminating circuit 7 selects a signal of higher frequency between the phases C and B to calculate the difference between the both, and when the difference is positive, the frequency difference to a distance measuring circuit 8. The circuit 8 multiplies the frequency difference by C0/2F (C0: light velocity, F: frequency modulation degree in phase B). Then a distance decision circuit 9 determines the distance found by the circuit 8 as the real distance when the distance determined by a distance decision circuit 8 is smaller than fJEMC0/2F (fJEM) (fJEM: frequency shift).