Undersampled signal arrival time difference measuring method

Abstract

The invention discloses an undersampled signal arrival time difference measuring method. The method includes adopting at least 4 radio receivers to receive signals emitted by one target, and determining the time domain sampling sequence of each radio receiver for signal receive by undersampling; performing discrete time Fourier conversion on the time domain sampling sequence of each radio receiver for signal receive to determine the frequency domain sampling sequence of each radio receiver for signal receive; establishing signal arrival time difference constraints of spectrum aliasing among the frequency domain sampling sequences of all the radio receivers for signal receive; performing alternate two-step iterative data processing through the signal arrival time difference constraints of the spectrum aliasing, determining the minimum fitting error corresponding to a time difference of searching, and measuring the time difference of searching corresponding to the minimum value of the minimum fitting error of the signal arrival time difference. The method has the advantages that the error of signal arrival time difference measuring is small, and the quantity of signal data to be transmitted and processed is small.

Description

1. Technical field [0001] The invention belongs to the technical field of electronic information, and relates to a method for measuring the time difference of arrival of radio signals, in particular to a method for measuring the time difference of arrival of signals by using signals received by a radio receiver when there is spectrum aliasing under the condition of undersampling. 2. Background technology [0002] Determining signal time difference of arrival (TDOA) has extensive and important applications in communication, radar, sonar, telemetry and other fields. [0003] Common methods for measuring signal TDOA include time-domain measurement methods and frequency-domain measurement methods. The former first determines the cross-correlation sequence of the time-domain sampling sequence of signals received by two radio receivers, and then measures the signal TDOA as the peak value corresponding to the amplitude of the cross-correlation sequence. , the amount of calculation ...

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Problems solved by technology

[0006] Reducing the time-domain sampling rate of the signal can reduce the amount of signal data that needs to be transmitted and processed to determine the signal TDOA. However, when the time-domain sampling rate of the signal received by the radio receiver is lower than the Nyquist sampling frequency, that is, under-sampling , there will be spectrum aliasing phenomenon: in the frequency domain sampling sequence determined by the discrete time Fourier transform of the undersampled time domain sampling sequence, the frequency domain sampling sequence corresponding to the bandwidth of the signal transmitted by the target will appear aliasing, if Failure to deal effectively with the spectral aliasing phenomenon that occurs in the case of undersampling will cause the signal TDOA measured by the commonly used time domain measurement method and frequency domain measurement method to deviate from the true value or even fail

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