Doppler estimation method based on joint waveform design

Abstract

The invention discloses a Doppler estimation method based on joint waveform design. The method comprises the following steps: constructing a receiving data frame; performing coarse Doppler range estimation on the CW signal of the received data frame by using FFT frequency measurement; solving a fuzzy function according to the PN sequence of the received data frame to carry out fine Doppler range estimation; according to the chirp signal of the received data frame, carrying out secondary solution on the fuzzy function and the Doppler factor, combining with the fine Doppler range estimation in the previous step to obtain the optimal fine Doppler, and compensating the received data frame according to the optimal fine Doppler; and carrying out carrier tracking on the compensated received data frame through a Costas ring so as to correctly demodulate information. According to the method, a plurality of special waveforms are used for estimating Doppler degrees in a combined mode, accurate estimation of underwater Doppler is integrally achieved, complexity is not changed, and Doppler estimation accuracy can be improved.

Description

technical field [0001] The invention relates to the technical field of underwater acoustic communication, in particular to a Doppler estimation method based on joint waveform design. Background technique [0002] Underwater acoustic communication is an important way of information transmission in the marine environment, and with the further development of the marine economy, people have higher and higher requirements for underwater acoustic communication technology. In the air, because the propagation speed of electromagnetic waves is close to the speed of light, the relative speed between the transmitter and receiver is much smaller than the propagation speed of electromagnetic waves, so the Doppler effect has little influence and can be regarded as frequency shift. Compared with terrestrial radio communication, the development of underwater acoustic communication technology lags behind seriously. The key is that underwater acoustic channel has more serious multipath effect...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problem that the Doppler effect is easy to cause the compression or expansion of the time domain of the signal in broadband communication, the block-based Doppler estimation algorithm has the advantages of simple frame structure, low computational complexity and easy implementation, but this method has two The disadvantages restrict its application in high-speed mobile underwater acoustic communication: 1. Since this method adds a linear frequency modulation (Linear Frequency Modulation, LFM) signal at the beginning and end of the signal frame to estimate the signal frame length, it needs to buffer a data frame, which is not conducive to information 2. The estimation accuracy of this method depends on the time-bandwidth product (BT) of the LFM signal, and with the increase of BT, the Doppler tolerance of the LFM signal will decrease. Therefore, under the condition of high-speed relative motion Unable to accurately estimate Doppler shift factor

Although some improved methods based on the above two methods were proposed after this method, they still did not deal well with the relationship between computational complexity and estimation accuracy in the case of high relative motion.

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