Correlated peak position information-based time synchronization method for underwater acoustic spread spectrum communication

Abstract

The invention discloses a correlated peak position information-based time synchronization method for underwater acoustic spread spectrum communication. The method comprises the following steps: 1, initializing parameters of a receiving terminal; 2, acquiring a signal by using the receiving terminal; 3, performing correlation operation on a second processed signal block variable and a local synchronization reference signal; 4, calculating the peak position of a correlation operation result of the second processed signal block variable and the local synchronization reference signal; 5, judging whether a difference value between pos_1 and pos_2 is less than a certain permissible deviation range or not; 6, extracting a section of the signal s1(k) from the first processed signal block variable; 7, performing circular convolution calculation on the s1(k) and an inverted sequence sflip1r(k) of a local demodulation reference signal; 8, judging whether the deviation of the peak position from the starting or ending position of the signal is within a certain permissible deviation range or not. According to the method, the addition of a signal head is avoided, the easiness in networking is ensured, the requirements on the calculation capability of a platform are low, the method is convenient to operate, and the pseudo triggering or triggering omission rate is reduced.

Description

technical field [0001] The invention relates to a time synchronization method, in particular to a time synchronization method based on correlation peak position information in underwater acoustic spread spectrum communication. Background technique [0002] Spread spectrum communication has the characteristics of anti-multipath, anti-interference, and easy networking, and has been widely used in shallow sea channel conditions. At the same time, due to the spread spectrum gain of spread spectrum communication, it has also been used in remote underwater acoustic remote control with low signal-to-noise ratio. application. Time synchronization is the prerequisite for correct decoding at the receiving end of a communication system including spread spectrum communication. Like other underwater acoustic communication systems, the current time synchronization method of spread spectrum communication is to use the external synchronization method, that is, an auxiliary synchronization ...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: first, the use of auxiliary synchronization head reduces the transmission speed, and at the same time, it is difficult to find a large number of orthogonal synchronization head signals in networking occasions; second, using point-by-point shift, each sampling period A matching filtering operation is required, which puts higher demands on the computing power of the platform to meet real-time performance; third, using the amplitude threshold judgment, it is necessary to send a training synchronization header signal in advance to obtain the threshold. When changing the sea area, sending and receiving In the case of location, distance or other conditions, it is necessary to re-acquire the threshold, which brings operational complexity. At the same time, due to the existence of interference signals and the time-varying nature of underwater acoustic channels, it is easy to generate time-synchronized virtual triggers or missing triggers.

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