A Time Delay Estimation Method for Chirp Signal Based on Fractional Fourier Transform

Abstract

The invention discloses a time delay estimation method for linear frequency modulation signals based on fractional Fourier transform. Including the following steps: the reference signal r 1 (q) and the received signal r of the receiver 2 (q) respectively perform fractional Fourier transform with rotation angle α; according to the reference signal r 1 (q) and the received signal r 2 The magnitude information of the fractional Fourier transform of (q) obtains a preliminary estimate of the delay D According to the reference signal r 1 (q) and the received signal r 2 Phase information of the fractional Fourier transform of (q), and a preliminary estimate of the delay D Obtain a final delay estimate Based on the FRTDE estimator, the present invention further utilizes the phase difference information of two peaks to estimate the time delay, avoids the influence of quantization errors, and can obtain a higher-precision time delay estimation value.

Description

technical field [0001] The invention belongs to the field of signal time delay estimation, in particular to a high-precision linear frequency modulation signal time delay estimation method based on fractional Fourier transform. Background technique [0002] Delay estimation refers to the estimation of the time difference of signals received by different receivers. It is an important technology in signal detection and parameter estimation in the field of signal processing. Research hotspots in many fields such as storage and communication. [0003] Currently, there are many delay estimation methods. Among them, the generalized weighted correlation method is the most classic time-delay estimation algorithm, and its correlation time-delay estimation can reach CRLB. Later, various improvements and extension studies of this algorithm were carried out in the literature. In addition, there are adaptive delay estimation algorithms, Hilbert delay estimation algorithms, super-resolu...

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Problems solved by technology

[0005] In 2007, K.K.Sharma and S.D.Joshi proposed a variety of algorithms for delay estimation using FRFT. These algorithms are divided into two categories, one is based on the amplitude information of FRFT, and the other is based on the phase information of FRFT, such as the AMSFDF estimator (average magnitude squared fractional difference function); Tao R and Li X M proposed the FRTDE (fractional time-delay estimator) estimator based on the amplitude information of FRFT, which uses the deviation degree of the FRFT output peak value before and after the delay of the chirp signal to estimate the time delay. And the time delay estimation performance is studied from the two aspects of output signal-to-noise ratio and estimation accuracy, and it is proved that the estimator can reach the Cramer-Rao lower bound, but the estimator only uses the amplitude information, and the estimation accuracy is limited by the sampling frequency and sample The quantization error caused by the length; while the AMSFDF estimator uses phase information, the estimation accuracy is also limited by the quantization error caused by the sampling frequency and sample length

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