A Joint Estimation Method of Delay and Doppler Frequency Shift

Abstract

The invention belongs to the technical field of radio signal parameter estimation and provides an estimating method in combination with time delay and Doppler frequency shift. The method is characterized by firstly acquiring two signals one of which is a to-be-tested signal and the other one of which is a reference signal; solving the Sigmoid cyclic autocorrelation of the reference signal and the Sigmoid cyclic cross correlation between the to-be-tested signal and the reference signal; solving a Sigmoid cyclical fuzzy function; and determining an estimated value of the time delay and Doppler frequency shift according to a position corresponding to a Sigmoid cyclical fuzzy function maximum value where the Sigmoid cyclical fuzzy function to-be-tested signal cyclic frequency is located. An experiment shows that the method may obtain effective estimation of the time delay and Doppler frequency shift when noise has hard pulses and an interference signal with the same carrier frequency of the to-be-tested signal exists.

Description

Technical field [0001] The invention belongs to the technical field of radio signal parameter estimation, and relates to a method for joint estimation of time delay and Doppler frequency shift, and in particular to a method for joint estimation of time delay and Doppler frequency shift using a Sigmoid transform cyclic ambiguity function. Background technique [0002] In satellite interference source positioning or radar positioning, the time delay change caused by the relative motion between the target and the receiver is usually equivalent to Doppler frequency shift, which involves the time delay and Doppler frequency shift. Joint estimation problem. Since two parameters are estimated at the same time, the estimation method is more susceptible to noise or interference, especially when the signal is affected by impulse noise and co-frequency interference at the same time, many classic methods will fail, such as: based on second-order statistics Ambiguity function and cyclic ambi...

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Problems solved by technology

Since two parameters are estimated at the same time, the estimation method is more susceptible to noise or interference, especially when the signal is affected by impulse noise and co-channel interference at the same time, many classic methods will fail, such as: based on second-order statistics Fuzzy functions and circular fuzzy functions can work normally under Gaussian noise, but they cannot resist impulsive noise; fractional low-order fuzzy functions based on fractional low-order statistics can resist impulsive noise, but cannot resist the influence of co-channel interference; The fractional low-order circular ambiguity function and the generalized fractional low-order circular ambiguity function that resist both impulse noise and co-channel interference also have their inherent disadvantages: the order of the fractional low order requires prior knowledge of the noise, otherwise the improper selection of the order It will affect the estimation effect of the method. In addition, when the fractional low-order statistics are impulsive, they have insufficient ability to suppress impulsive noise, and the peak value is not obvious, which may lead to estimation errors.

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