Joint Doppler Frequency Research Articles

Joint Doppler Frequency and Direction of Arrival Estimation for TDM MIMO Automotive Radars

This paper considers a novel approach to joint estimation of the velocity (or Doppler frequency) and Direction of Arrival (DOA) of targets by time division multiplexing (TDM) multiple-input multiple-output (MIMO) radars in automotive applications. The TDM MIMO radars create orthogonal probing signals (in time domain) by allocating a transmitter to a separate time slot. In this paper, we consider a standard TDM MIMO radar to be the one where transmitters are activated sequentially according to their natural spatial order. The drawback of the standard TDM MIMO approach is the coupling of velocity and DOA information of the targets. The coupling reduces the unambiguous estimation interval of the Doppler frequencies of the targets by the number of transmit antennas being multiplexed. In this paper, we propose a novel cost function to jointly estimate both the Doppler frequency and the DOA of each target by reinstating the reduced unambiguous Doppler spectrum interval. Our approach is generally applicable to solve the Doppler ambiguity problems associated with any colocated standard TDM MIMO radar. To confirm this, we present the simulation results that evaluate the performances of two widely deployed TDM MIMO radar antenna configurations: non-overlapped and overlapped arrays. Moreover, we derive the analytical expressions to study the statistical performance of the proposed method. The simulation examples are presented to verify the performance of the proposed method as well as the accuracy of the analytical expressions.

Fast OMP algorithm for 3D parameters super‐resolution estimation in bistatic MIMO radar

A fast super-resolution method for joint Doppler frequency, direction of departure and direction of arrival estimation in bistatic MIMO radar is presented. First, the 3D echo signal model of bistatic MIMO radar with uniform linear transmit and uniform linear receive array is established. Then, the Kronecker compressive sensing (KCS) is introduced to improve the 3D parameters estimation performance. Moreover, a novel fast orthogonal matching pursuit (OMP) algorithm utilising 3D fast Fourier transformation is also presented to reduce the computation burden of KCS. Finally, the effectiveness of the method is validated by the simulation.

Joint Doppler frequency, 2D-DOD and 2D-DOA estimation for bistatic MIMO radar in spatial coloured noise

In this paper, we address the problem of four-dimensional angle and Doppler frequency estimation for L-shaped bistatic multiple input multiple output radar in spatial coloured noise. A novel method of joint estimation of Doppler frequency, two-dimensional direction of departure and two-dimensional direction of arrival based on the propagator method is discussed. Utilising the cross-correlation matrix which is formed by the adjacent outputs of matched filter in the time domain, the special matrix is constructed to eliminate the influence of spatial coloured noise. The proposed algorithm provides lower computational complexity and has very close parameter estimation to the estimation of signal parameters via rotational invariance techniques algorithm and DOA-matrix algorithm in high signal-to-noise ratio and Cramér–Rao bound is given. Furthermore, multidimensional parameters can be automatically paired by this algorithm to avoid the performance degradation resulting from wrong pairing. Numerical simulation results demonstrate the effectiveness of the proposed method.

A Joint Doppler Frequency Shift and DOA Estimation Algorithm Based on Sparse Representations for Colocated TDM-MIMO Radar

We address the problem of a new joint Doppler frequency shift (DFS) and direction of arrival (DOA) estimation for colocated TDM-MIMO radar that is a novel technology applied to autocruise and safety driving system in recent years. The signal model of colocated TDM-MIMO radar with few transmitter or receiver channels is depicted and “time varying steering vector” model is proved. Inspired by sparse representations theory, we present a new processing scheme for joint DFS and DOA estimation based on the new input signal model of colocated TDM-MIMO radar. An ultracomplete redundancy dictionary for angle-frequency space is founded in order to complete sparse representations of the input signal. The SVD-SR algorithm which stands for joint estimation based on sparse representations using SVD decomposition with OMP algorithm and the improved M-FOCUSS algorithm which combines the classical M-FOCUSS with joint sparse recovery spectrum are applied to the new signal model’s calculation to solve the multiple measurement vectors (MMV) problem. The improved M-FOCUSS algorithm can work more robust than SVD-SR and JS-SR algorithms in the aspects of coherent signals resolution and estimation accuracy. Finally, simulation experiments have shown that the proposed algorithms and schemes are feasible and can be further applied to practical application.

Joint Doppler-Frequency Diversity for OFDM Systems Using Hybrid Interference Cancellation in Time-Varying Multipath Fading Channels

In time-varying fading channels, orthogonal frequency division multiplexing systems suffer severe performance degradation caused by interchannel interference (ICI). We utilize this ICI as a source of diversity by using a new ICI-cancellation algorithm and Wiener filter. The proposed algorithm can support joint Doppler-frequency diversity gain. In addition, both the computational complexity and total detection time are reduced.