Higher order spectral analysis of weather signals

Abstract

Higher Order Spectral Analysis (HOSA) is very useful technic for analysing the statistical relationships between spectral components and their distribution. HOSA can be defined in terms of bispectrum as a third order spectrum. One of the main reasons to consider HOSA on weather signals is that to characterise the Doppler spectrum obtained through the backscattered echoes which are generally skewed and having multiple peaks. The analysis also brings out any deviations from gaussianity and the performance under noisy environment. This will help in identifying and detecting the signals and their by better estimation of moments for further processing The bispectrum estimation technique has been applied to a complex time series data derived from a Polarimetric X-band Doppler Weather Radar (DWR). The results of this analysis are compared with the conventional techniques like Fourier method and pulse pair technique. It is observed that through bispectrum approach the gaussian noise components are significantly removed from the back scattered signals and improves the detectability of the weather signals under noisy condition.

KEYWORDS:

• Higher Order Spectral Analysis (HOSA)
• cumulants
• bispectrum
• X-band polarimetric Doppler weather radar

Acknowledgements

The authors would like to thank T. Subramanya Ganesh, ISTRAC, Bangalore for their careful reading of the manuscript and useful discussions on the results of this paper. The authors would also like to thank all their colleagues from the Radar Development Area of ISTRAC/ISRO.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Ramyakrishna Enugonda

Ramyakrishna Enugonda received B.tech in Electronics and Communications and M.tech in Space Technology and Applications from Chadalawada Ramnamma Engineering College and from the SV University, Tirupati, India respectively. She joined as a Research fellow in ISTRAC-ISRO in 2018. She is currently pursuing PhD in the department of Avionics, Indian Institute of Space Science and Technology (IIST), Trivandrum. Her main research area includes in the field of weather and atmospheric radar signal processing and Turbulence studies.

V. K. Anandan

V. K. Anandan received his M.Sc. and M.Tech degree from Cochin University of Science and Technology, Cochin and PhD in Electronics & Communication Engineering and Physics from Sri Venkateswara University, Tirupati, India. He has done his post-doctoral research at National Central University, Taiwan. Joined Indian Space Research Organisation (ISRO) in 1991 and presently working as Deputy Director. Involved in system design and development of Phased array atmospheric radars and Polarimetric Doppler Weather radar systems, Tracking radars, sodars, multi-channel receiver developments and post beam steering techniques employed to radar systems. His area of interest includes Phased array radar system developments, multiple satellite tracking and commanding system, signal processing algorithm developments, scientific studies related to remote sensing of the atmosphere and weather using different observational systems.

Basudeb Ghosh

Basudeb Ghosh received Bachelor's degree in Electronic Sciences and Master's degree in Electronics from University of Calcutta in 1999 and 2001, respectively, and Ph.D. degree with specialization in Microwave engineering from Indian Institute of Technology (IIT), Roorkee in 2009. Presently, he is working as Associate professor in Dept. of Avionics, Indian Institute of Space Science and Technology (IIST). Before joining IIST, he worked in Chang Gung University, Taiwan as a post-doctoral research associate. His main area of research work includes computational electromagnetic techniques, passive microwave devices, Metasurface antennas and wireless power transfer.