Research on ranging method for linear frequency modulation radio fuze based on fractional fourier transform

To improve the ranging accuracy of the frequency modulation (FM) radio fuze under the limit of the little frequency deviation, two ranging methods, i.e. instantaneous initial frequency estimation method and fractional correlation method, for linear FM radio fuze based on fractional Fourier transform (FRFT) are proposed. The ranging principles of the two methods are described, their range resolutions and anti-noise performances are analyzed, and the simulations are carried out to validate these methods. The simulation results demonstrate that the ranging resolutions of the two methods which are affected by the modulation bandwidth rarely are much better than that of the ranging method based on the harmonic wave method. For the known frequency modulation rate, the complexity of the methods is reduced and acceptable for engineering realization. The fractional correlation method is better than the instantaneous initial frequency estimation method in anti-noise performance and can be used in the low signal-to-noise ratio circumstance.