| 摘要 |
PURPOSE:To measure the position of a receiving point, by converting a receiving point existing direction viewed from two transmission points to frequency. CONSTITUTION:Linear FM signals 3, 4 generated from a transmitter 2 are emitted from antennae 5, 6 and received by a receiver 1. The difference frequency F1 of two receiving signals, when the receiver 1 is present above planes 7, 8 constituted by the straight line 8 on the plane including the bisection point 7 of the line connecting the antennae 5, 6 and vertical to segments 5, 6, is larger than the difference frequency F2 when the receiver 1 is present on the planes 7, 8. Further, the difference frequency F3, when the receiver 1 is present below the planes 7, 8, becomes smaller than the difference frequency F2. Therefore, a difference frequency signal has the information of the receiver 1 in the direction looked from the antennae 5, 6 as frequency information and is the same to planes 20, 21 for vertically bisecting the line connecting antennae 6, 22. By this mechanism, three transmission waves are received on the basis of three of more of transmitting points emitting linear FM signals different in center frequency and two sets of receiving point directions are calculated from the frequency difference thereof and a receiving point can be calculated from the intersecting point of two directions. |
