Abstract
It is crucial for a ballistic missile defense system to discriminate the true warhead from decoys. Although a decoy has a similar shape to the warhead, it is believed that the true warhead can be separated by its micro-Doppler features introduced by the precession and nutation. As is well known, the accuracy of the phase-derived range method, to extract micro-Doppler curves, can reach sub-wavelength. However, it suffers from an inefficiency of energy integration and high computational costs. In this paper, a novel phase-derived range method, using high-order multi-frame track-before-detect is proposed for micro-Doppler curve extraction under a low signal-to-noise ratio (SNR). First, the sinusoidal micro-Doppler range sequence is treated as the state, and the dynamic model is described as a Markov chain to obtain the envelopes and then the ambiguous phases. Instead of processing the whole frames, the proposed method only processes the latest frame at an arbitrary given time, which reduces the computational costs. Then, the correlation of all pairs of adjacent pulses is calculated along the slow time dimension to find the number of cells that the point scatterer crosses, which can be further used in phase unwrapping. Finally, the phase-derived range method is employed to get the micro-Doppler curves. Simulation results show that the proposed method is capable of extracting the micro-Doppler curves with sub-wavelength accuracy, even if SNR = −15 dB, with a lower computational cost.
Highlights
Discriminating warheads from decoys is one of the most significant and challenging tasks in a ballistic missile defense system [1,2,3]
In the past few decades, various recognition methods have been proposed based on the micro-Doppler extraction, which can be roughly divided into five categories: radar cross-section (RCS) [4,9,10], high-resolution range profile (HRRP) [2,11], inverse synthetic aperture radar images [12,13,14], backscatter coefficient [15,16], and orbit information [17,18]
An improved phase-derived range method based on high-order multiframe TBD is proposed to conquer the difficulties in distinguishing the warheads from decoys
Summary
Discriminating warheads from decoys is one of the most significant and challenging tasks in a ballistic missile defense system [1,2,3]. Decoys have a similar shape to the true warhead and are released in the mid-course stage to deceive the missile defense system. When using radar to observe the warheads and decoys, the different micro-motions will introduce different micro-Doppler features in the received echoes. This makes it possible to separate them from each other [6,7,8]. In the past few decades, various recognition methods have been proposed based on the micro-Doppler extraction, which can be roughly divided into five categories: radar cross-section (RCS) [4,9,10], high-resolution range profile (HRRP) [2,11], inverse synthetic aperture radar images [12,13,14], backscatter coefficient [15,16], and orbit information [17,18]
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