基于伪随机序列自相关性的新型超声波测距系统

针对传统超声波传感器存在受环境因素影响大、抗干扰能力差等缺陷,提出了一种新型超声波测距系统的设计方法.该超声波测距系统基于伪随机序列自相关性原理,采用模块化设计,可准确地测量出超声波的传播速度和渡越时间,进而计算出障碍物的距离.采用低功耗,高性能的TMS320VC5509A DSP作为信息处理器,采用基于快速傅里叶变换(FFT)的相关判别算法,有效地提高了实时性.改进了超声波接收电路,采用高速绝对值电路代替传统的检波电路,可高效地从接收到的超声波信号中解调出伪随机序列.根据所设计的超声波测距系统的工作原理,提出了适用于该系统的误差校正方法.在干扰存在的情况下,进行了性能测试实验,实验结果表明,该超声波测距系统的测距误差在1.8%以内,具有良好的抗干扰性.

A Novel Ultrasonic Ranging System Based on the Self-correlation of Pseudo-random Sequence

A novel ultrasonic ranging system based on the self-correlation of pseudo-random sequence is designed in this paper.Modular design is applied in this ultrasonic ranging system,which can measure the ultrasonic propagation velocity and transit time accurately,and then calculate the obstacle's distance.The low power consumption and high performance of TMS320VC5509A DSP is used as the ultrasonic ranging system's signal processor.In order to improve the correlation calculation's real-time performance,the correlation judgment algorithm based on FFT is proposed.To improve the performance of the ultrasonic ranging system's receiving circuits; high speed absolute value circuit is used instead of the conventional detection circuit,which can demodulate the pseudo-random sequence from the ultrasonic signal.An error correction algorithm for this ultrasonic ranging system is proposed.The ultrasonic ranging system's performance test was conducted under the interference existed environment.The experimental results demonstrated that the ultrasonic ranging system has good anti-interference performance and its ranging errors are within 1.8%.