| 摘要 |
<p>PROBLEM TO BE SOLVED: To elongate a detection distance of a pedestrian and to detect the position, by generating a transmission signal obtained by shifting a received radar signal frequency as much as a prescribed frequency and by transmitting the signal with a built-in power source, by a portable transmitter/receiver. SOLUTION: When a signal detecting circuit 24 of a portable transmitter/receiver 2 detects a radar signal of an on-vehicle transmitter/receiver, a CPU 25 controls a transmission signal generating circuit 23 to allow to generate a transmission signal obtained by shifting a radar signal frequency as much as a prescribed frequency, and transmits the signal with a transmission power of a built-in battery 29. The on- vehicle transmitter/receiver transmits and receives electromagnetic waves, and a filter circuit 7 executes filter processing of an intermediate frequency (IF) signal obtained by mixing transmitted and received signals. And a reflected signal S1 from an object in front of a vehicle is segregated from a transmission signal from the portable transmitter/receiver 2 (pedestrian signal) S2. A CPU 8 detects the positions of the object in front and the pedestrian carrying the portable transmitter/receiver 2 based on the reflected signal S1 and the pedestrian signal S2. In this case, a detection distance is elongated, because the potable transmitter/receiver 2 transmits the signal with the built-in power source.</p> |
