Discrete Radon-Fourier Transform and Its Approximation Algorithm in Short Range Ubiquitous Radar

This paper studies long time coherent integration (LTCI) for low-observable target detection in short range ubiquitous radar (SRUR). Due to frequency modulated continuous wave (FMCW) technique in SRUR, traditional LTCI algorithms are not suitable for direct use. Discrete Radon-Fourier transform (DRFT) in SRUR (SRUR-DRFT) with uniform linear array is proposed, which not only eliminates across-range unit, across-Doppler unit and across-beam unit, but also corrects coupling and the error in digital system. In addition, an approximation algorithm for SRUR-DRFT with low computational complexity and good compatibility called two-stage coherent integration (2SCI) is introduced. In the first stage, the long observation time is divided into several subapertures and three-dimensional Fourier transform is carried out in each subaperture. In the second stage, short sequence DRFT is executed among subapertures. 2SCI achieves quasi-coherent integration in the whole aperture. Moreover, a dual-threshold detector named dual-threshold Radon-Fourier transform(DTRFT) is designed, which is a joint application of 2SCI and SRUR-DRFT. Then, the performances of the proposed algorithms are theoretically analyzed. The proposed algorithms are suitable for SRUR and FMCW radar, and can achieve a better compromise between detection performance and computational complexity than the existing algorithms. Finally, simulations and experiments with real data are provided to demonstrate the effectiveness of the proposed algorithms.