| 摘要 |
<p>A signal processing circuit (1) determines, at a plurality of different timings, distances (L1,L2) and radar-apparatus-direction components (Vmod1,Vmod2) of relative speed of a running-in-the-opposite-direction vehicle (102) approaching the local vehicle (101), on which the radar apparatus (100) is mounted, at a constant speed. The closest distance (r) between the local vehicle (101) and the running-in-the-opposite-direction vehicle (102) is established when they run side by side and cross each other. The signal processing circuit (1) utilizes both the constant relative speed and the Pythagorean theorem to calculate the closest distance (r) from an expression indicating that the relative speed represented by use of the distance (L1), the closest distance (r) and the radar-apparatus-direction component (Vmod1) of the relative speed is coincident with the relative speed represented by use of the distance (L2), the closest distance (r) and the radar-apparatus-direction component (Vmod2) of the relative speed.</p> |
