深海走航投弃式剖面仪传输信道特点的分析

Analysis of Transmission Characteristic of Deep-sea Abandoned Measuring Instrument Channel

走航投弃式剖面仪是海洋环境数据获取的重要仪器,主要应用于海洋环境观测中海洋参数的大面积快速测量,但传输信道特点一直并不明确,对信道传输性能的提高缺乏一定的理论基础。以XCTD信道为研究对象,优化了信道的模型和传递方程,计算得到信道阻抗参数值;采用时频法研究投弃式剖面仪信道基带传输信号的时变性,分析不同频率下的信号带宽的变化特性,分析随机噪声对传输信号和误码率的影响规律,结果表明,深海走航投弃式剖面仪传输信道在不同深度和传输速率下具有的"时变/窄带/低信噪比"规律特性,该信道特点与水声信道具有更多的相似性,该结论为提高XCTD信道传输性能拓宽了研究思路,为深海投弃式观测技术发展的信道传输技术共性问题提供了理论支持。

The expendable conductivity-temperature-depth （XCTD） profiler is an important instrument for acquiring data of marine environment, which mainly applied in measuring large area of ocean parameters rapidly in marine environment ob- servation, but the transmission channel is always not clear, and there is lack of certain theoretical basis to improve the perfor- mance of the channel transmission. This paper takes XCTD as the research object, and optimizes the circuit model and trans- fer equation of the channel, and calculates the channel impedance parameters; this paper studies on the time -varying of channel baseband transmission signals of expendable profiler by time frequency method, and analyzes the variation charac- teristics of signal bandwidth in different frequency, and analyzes the influence of random noise on transmission signal and er- ror rate. The results show the characteristics of ＂ time-varying/narrowband/low signal-to-noise ratio ＂ of the transmission channel of the expendable conductivity-temperature-depth （XCTD） profiler in different depth and transmission rate, and there is more similarity between characteristics of the channel and underwater acoustic channel. The conclusion expands the research ideas in improving the transmission performance of XCTD channel, and provides theoretical support for the common problems of channel transmission technology in the development of deep-sea expendable observation technology.