Design of a fast echo matching algorithm to reduce crosstalk with Doppler shifts in ultrasonic ranging

• Published in: Measurement science & technology Vol. 28; no. 2; pp. 25103 - 25111
• Main Authors: Liu, Lei, Guo, Rui, Wu, Jun-an
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.02.2017
• Subjects: chaotic sequences; crosstalk; Doppler shifts; echo matching; pulse coding; ultrasonic sensor
• ISSN: 0957-0233; 1361-6501; 1361-6501
• DOI: 10.1088/1361-6501/aa512c

Crosstalk is a main factor for wrong distance measurement by ultrasonic sensors, and this problem becomes more difficult to deal with under Doppler effects. In this paper, crosstalk reduction with Doppler shifts on small platforms is focused on, and a fast echo matching algorithm (FEMA) is proposed on the basis of chaotic sequences and pulse coding technology, then verified through applying it to match practical echoes. Finally, we introduce how to select both better mapping methods for chaotic sequences, and algorithm parameters for higher achievable maximum of cross-correlation peaks. The results indicate the following: logistic mapping is preferred to generate good chaotic sequences, with high autocorrelation even when the length is very limited; FEMA can not only match echoes and calculate distance accurately with an error degree mostly below 5%, but also generates nearly the same calculation cost level for static or kinematic ranging, much lower than that by direct Doppler compensation (DDC) with the same frequency compensation step; The sensitivity to threshold value selection and performance of FEMA depend significantly on the achievable maximum of cross-correlation peaks, and a higher peak is preferred, which can be considered as a criterion for algorithm parameter optimization under practical conditions.