| As the simple structure, low price and steady performance which would not be influenced by the environment, the Ultrasonic ranging technology is widely used in the field of car-revering radars. The current car-revering radar normally employed the large- beamwidth design to expend the detecting range, but such performance leds to big probability of fake alert, and made the measurement easily be disturbed. Aiming at the problem, a method of small-beamwidth for ultrasonic range-finding system is given in the paper, this method can strengthen directivity effectively and improved the anti-jamming ability. To narrow the ultrasonic beamwidth, The follow are the major study results of the paper:1. The directivity of transducer array is studied. Choose uniform linear array to be the transducer and its directivity parameter is analyzed. The 3-element linear array suit for the vehicle was designed And the test to the resonance frequency and resonance impedance are done.2. A novel driving circuit of ultrasonic transducer array and high-precision echo receiving circuit are designed. Single chip processor circuit is adopted to do the A/D conversion and correlate calculation, and the experiment is given.3. The performance test about measuring distance and beamwidth is made by the single chip processing circuit.Experimental results show that the beamwidth of the small-beam width ultrasonic range-finding system isθ-3dB≈2.2 and the range of ultrasonic measuring system is greater than 2.5 meters, which satisfies the designing demand. |
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