Suppressing masking effect in random signal radars by waveform design

In noise radars, measuring the cross-correlation between transmitted and received signals is a common method of signal processing. However, it brings a lot of unwelcome sidelobes that can mask weak echoes of far targets. There are many classical and modern methods of masking effect removal which are based on signal processing in the receiver side. In this study, a method of waveform design is presented and its ability to reduce masking effect is compared with that of radars using purely random waveforms. The method starts with choosing an arbitrary subsequence and continues with attaching new subsequences to the previous ones in a way that the sidelobe levels reduce. In addition, the performance of applying the well-known CLEAN algorithm to a purely random waveform and the presented waveform are considered in detail. Moreover, the waveform randomness is measured and compared with purely random waveforms. By means of computer simulations, it is illustrated that the proposed waveforms can produce smaller correlation sidelobes, while preserving their randomness characteristics.

[1]  Sune R. J. Axelsson.  Noise radar using random phase and frequency modulation , 2004, IEEE Transactions on Geoscience and Remote Sensing.

[2]  Ram M. Narayanan,et al.  FOPEN SAR imaging using UWB step-frequency and random noise waveforms , 2001 .

[3]  Jacek Misiurewicz,et al.  Stretch processing for masking effect removal in noise radar , 2008 .

[4]  Liu Guosui,et al.  The Development of Random Signal Radars , 1999 .

[5]  Elaine B. Barker,et al.  A Statistical Test Suite for Random and Pseudorandom Number Generators for Cryptographic Applications , 2000 .

[6]  Ram M. Narayanan,et al.  Doppler estimation using a coherent ultrawideband random noise radar , 1997, Optics & Photonics.

[7]  Ram M. Narayanan,et al.  Range sidelobe suppression technique for coherent ultra wide-band random noise radar imaging , 2001 .

[8]  Sune R. J. Axelsson,et al.  Noise Radar for range/Doppler processing and digital beamforming using low-bit ADC , 2003, IEEE Trans. Geosci. Remote. Sens..

[9]  K. Drouiche,et al.  A new test for whiteness , 2000, IEEE Trans. Signal Process..

[10]  Elaine B. Barker,et al.  A Statistical Test Suite for Random and Pseudorandom Number Generators for Cryptographic Applications , 2000 .

[11]  Ram M. Narayanan,et al.  Ultra-wideband continuous-wave random noise arc-SAR , 2002, IEEE Trans. Geosci. Remote. Sens..

[12]  Ram M. Narayanan,et al.  Design, performance, and applications of a coherent ultra-wideband random noise radar , 1998 .

[13]  Thomas L. Carroll,et al.  Adaptive chaotic maps for identification of complex targets , 2008 .

[14]  A. H. Gray.  Log spectra of Gaussian signals , 1974 .

[15]  A. Nelander.  Continuous coded waveforms for noise radar , 2007, 2007 International Waveform Diversity and Design Conference.

[16]  Jing Hu,et al.  Analysis of Biomedical Signals by the Lempel-Ziv Complexity: the Effect of Finite Data Size , 2006, IEEE Transactions on Biomedical Engineering.

[17]  R.D. Fry,et al.  CLEAN deconvolution for sidelobe suppression in random noise radar , 2008, 2008 International Conference on Radar.

[18]  A. Gray,et al.  A spectral-flatness measure for studying the autocorrelation method of linear prediction of speech analysis , 1974 .

[19]  B. D. Steinberg,et al.  Reduction of sidelobe and speckle artifacts in microwave imaging: the CLEAN technique , 1988 .

[20]  K. Kulpa,et al.  Masking effect and its removal in PCL radar , 2005 .

[21]  Duane W. Detemple.  75.11 The Noninteger Property of Sums of Reciprocals of Successive Integers , 1991 .

[22]  Shlomo Dubnov,et al.  Generalization of spectral flatness measure for non-Gaussian linear processes , 2004, IEEE Signal Processing Letters.

[23]  B. M. Horton.  Noise-Modulated Distance Measuring Systems , 1959, Proceedings of the IRE.

[24]  Ram M. Narayanan,et al.  Random noise radar interferometry , 1996, Optics & Photonics.

[25]  Gu Hong,et al.  The present and the future of random signal radars , 1997 .