A Channelization-Based DOA Estimation Method for Wideband Signals

Abstract

Abstract:In this paper, we propose a novel direction of arrival (DOA) estimation method for wideband signals with sensor arrays. The proposed method splits the wideband array output into multiple frequency sub-channels and estimates the signal parameters using a digital channelization receiver. Based on the output sub-channels, a channelization-based incoherent signal subspace method (Channelization-ISM) and a channelization-based test of orthogonality of projected subspaces method (Channelization-TOPS) are proposed. Channelization-ISM applies narrowband signal subspace methods on each sub-channel independently. Then the arithmetic mean or geometric mean of the estimated DOAs from each sub-channel gives the final result. Channelization-TOPS measures the orthogonality between the signal and the noise subspaces of the output sub-channels to estimate DOAs. The proposed channelization-based method isolates signals in different bandwidths reasonably and improves the output SNR. It outperforms the conventional ISM and TOPS methods on estimation accuracy and dynamic range, especially in real environments. Besides, the parallel processing architecture makes it easy to implement on hardware. A wideband digital array radar (DAR) using direct wideband radio frequency (RF) digitization is presented. Experiments carried out in a microwave anechoic chamber with the wideband DAR are presented to demonstrate the performance. The results verify the effectiveness of the proposed method.

Experimental validation of direction of arrival estimation for high chirp‐rate linear frequency modulated radar signals

“…where aðf i ; θ p Þ ¼ ½1; e −j2πf i τ 2 ðθ p Þ ; …; e −j2πf i τ M ðθ p Þ � T , is the array steering vector towards the direction of the p th source signal [32]. For brevity, let a i (θ p ) denote a(f i , θ p ), A i (θ) denote A(f i , θ),…”

“…Different narrowband DOA estimation techniques may be applied in the channelised framework. Application of the well‐known narrowband MUSIC DOA estimation approach in [21] to the channelised framework yields the channelised MUSIC technique [32]. Note that ISSM can be considered as an extreme case of channelisation with J = K , that is, the DFT size is the number of frequency bins.…”

“…This article considers a version of channelised MUSIC which is a fast Fourier transform (FFT)-based technique. FFT-based channelisation decomposes the received signal into frequency bins (sub bands) to achieve an acceptable trade-off between the high DOA estimation performance associated with bilinear techniques [29][30][31] which are derived from quadratic timefrequency distributions (QTFDs), and a lower computational complexity, to enable real-time implementation [32][33][34][35]. FFTbased channelisation also has a lower computational complexity compared to the techniques based on ambiguity functions [6,36].…”

“…In addition, MUSIC provides high resolution DOA estimation even with a relatively limited number of antenna array elements. While channelised MUSIC has been applied previously for DOA estimation of wideband stationary signals [32,33], we apply it without the preprocessing steps, to high chirp-rate nonstationary signals so as to localise the signal power while reducing the noise bandwidth in the frequency domain, thereby improving the SNR. Furthermore, we exploit the gain achieved from incoherently combining the spatial pseudospectra generated from different frequency bins.…”

Sparse Reconstruction Based Robust Near-Field Source Localization Algorithm

“…The source localization problem in array signal processing is an important problem which has a wide range of applications. For example: related topics in radar, sonar, wireless communications, and seismology is to determine the location of the radiation (or reflection) sources by passive sensor array [ 1 , 2 , 3 , 4 ]. According to the distance of the source from the array, the localization problem is divided into far-field source localization problem and near-field source localization problem.…”