基于TDOA的超声波测距误差分析与改进

Error Analysis and Improvement of Ultrasonic Distance Measuring Based on TDOA

基于TDOA的超声波测距模型认为距离为声波的速度与时间差之积,忽略了温度等因素对速度的影响,此外,系统计时的误差影响了时间差测量,导致测距精度不高.分析了基于TDOA原理的超声波测距系统误差的主要来源,建立模型,通过实验对温度、距离衰减及时间差测量进行补偿,利用超声波反射特性对障碍物进行测距,并利用多探头在一定程度上削弱了方向性带来的影响.实验结果表明:系统性能稳定,测距精度高,环境适应性更强.在超声波测距范围内,最大误差不超过4 cm.

It＇s considered that the distance equals the square of sound velocity and time difference in TDOA（time difference of arrival） based distance measuring models which ignore the affect of temperature and other factors.Furthermore,the system timing error has impact on the measurement of time difference.The sources of the inference are analyzed,and the mathematic model is established.According to the experiment,the compensations of temperature,distance attenuation and time difference measurement are achieved.Using the reflection characteristic of ultrasonic,the impact of obstacle on distance measuring is weakened.And through multiple probes,the problem of directivity is solved to some degree.As shown in the experimental results,the proposed system can operate with high stability;its precision of distance measurement and the environmental adaptability are high.Within the measurement region,the error is less than 4 cm.