Enhancing the Orthogonality of Polyphase Signal with Multi-Pulse Joint Processing

In this paper, the problem that the polyphase signal may not satisfy the orthogonality requirement in the condition of limited bandwidth is investigated. The use of waveforms that lack orthogonality leads to possible harmful effects in multiple-input and multiple-output (MIMO) radar and distributed coherent aperture radar (DCAR). For the purpose of enhancing the orthogonality of the signal, a multi-pulse joint transmission strategy of polyphase signal and the corresponding echo signal processing algorithm based on sliding window are proposed. We further analyze the relationship between the degradation of detection performance and the step size of the sliding window. In addition, the Doppler tolerance of the signal is also derived. Finally, the enhancement of the orthogonality by using the multi-pulse joint processing strategy and the relationship between Doppler tolerance and coherent time are verified via numerical simulations.