Use of fractional autocorrelation for efficient detection and parameter estimation of polyphase-coded radar signals

The relationship between the recently developed fractional autocorrelation and the fractional Fourier transform parallels the connection between conventional autocorrelation and the classical Fourier transform. Additionally, fractional autocorrelation that is defined at an arbitrary angle of the time-frequency plane corresponds to the radial slice of the ambiguity function at that angle. Thus, any desired radial slice of the ambiguity function, that is commonly used in radar signal processing as a two-dimensional correlation function, can be obtained via fractional autocorrelation which is itself a one-dimensional correlation. In this article, we propose a fast detection statistic based on fractional autocorrelation for detection and sweep rate parameter estimation of polyphase-coded radar signals. Performance of the proposed statistic is tested using various simulations.