Range Resolution Enhancement using Root-MUSIC Analysis in CTFM Sonar for Bandwidth-limited Applications

ABSTRACT

This paper presents a detailed study of the application of Root-MUSIC algorithm in the continuous-time frequency modulation (CTFM) system. Classically, CTFM-based sonars and radars use the Discrete Fourier transform (DFT) magnitude peaks to find the range of the received echoes. In applications where the medium does not support large signal bandwidth over the ranges of interest, the DFT technique cannot provide the required range resolution. A technique called dual demodulator continuous-time frequency modulation (DDCTFM) was proposed to overcome this limitation and provides greater range resolution. But we observe that there is a problem of phase mismatch in DDCTFM that does not increase the range resolution. This problem is explained in the paper. The super resolution Root-MUSIC algorithm is studied in this context to evaluate its efficacy in providing higher frequency resolution and corresponding range resolution in CTFM. Several detailed simulation experiments done in MATLAB to provide insight into its performance are reported in the paper. Also, lab experiments have been done to practically demonstrate the efficacy of using Root-MUSIC technique in CTFM. Based on the results obtained from the simulation experiments, it is concluded that there is an improvement by a factor of 2.8 in the range resolution estimation by the use of Root-MUSIC algorithm over DFT-based analysis in CTFM. In practical experiments, the improvement factor obtained in the range resolution estimation is 2.35.

KEYWORDS:

• CTFM
• DDCTFM
• Root-MUSIC

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Notes on contributors

Kapil Dev Tyagi

Kapil Dev Tyagi did his BE degree in Electronics and Communication Engineering from Rajasthan University (2003) and MTech degree from IIT Delhi (2010). He worked as a lecturer in UP technical university during 2003–2006. He also served as a scientist in Indian Space Research Organization during 2007–2008. He did his PhD degree from IIT Delhi in 2016. Presently, he is working as an assistant professor at Jaypee University, Noida.

E-mail: [email protected]

Arun Kumar

Arun Kumar received the BTech, MTech, and PhD degrees in Electrical Engineering from IIT, Kanpur, in 1988, 1990, and 1995, respectively. He was a visiting researcher at the ECE Department, University of California, Santa Barbara, from 1994 to 1996. Since December 1996, he has been with the Centre for Applied Research in Electronics (CARE), IIT Delhi, where he is currently a professor. He was the head of CARE from April 2012 to August 2016. He was also head of the Instrument Design and Development Centre of IIT Delhi from May 2015 to August 2016. His research interests span the areas of digital signal processing, underwater and air acoustics, speech processing for human and machine communication, and multisensor data fusion for mobile and wearable devices. He is an inventor on five US patents (two granted and three applications published). He has published over 100 papers in refereed journals and conferences and has supervised 50 funded R&D projects from government organizations and Indian and foreign industries. These have led to about 20 Technology/Know-how transfers to industry and government organizations. Many technologies developed by him are deployed in the field and are in practical use. He is an editor of the IETE Journal of Research since 2009 and a member of the Executive Committee of the India Chapter of IEEE Oceanic Engineering Society.

E-mail: [email protected]

Rajendar Bahl

Rajendar Bahl has a BTech (Honours) degree in Electronics and Electrical Communication Engineering from IIT Kharagpur (1974) and PhD (EE) degree from IIT Delhi (1982). He has been a past head of the Centre during 1996–1999. He has participated in various national bodies of the Department of Electronics, Ministry of Information Technology, and the Defence Research & Development Organisation. He was jointly awarded the 1982 Invention Award of the National Research & Development Corporation for the indigenous development of a digital control system. He won a Senior Fellowship award of the US National Research Council during 1989–1990 at the Naval Postgraduate School, Monterey. He has also been a visiting professor in the field of bio-acoustics at the Institute of Industrial Science, University of Tokyo, Japan, during 2002–2004. His major expertise is in sonar design and he has implemented a number of projects in this area.

E-mail: [email protected]