论文部分内容阅读
本文讨论相关测速声纳的工作原理,分析系统主要参数的物理意义以及它们之间的相互关系,并讨论搜索、跟踪系统的工作过程。由接收换能器的指向性和Doppler公式可以导出接收信号带宽的表达式。这一带宽和船的航速成正比。为保持相关增益不变,系统主通道的等效积分时间和信号带宽的乘积应保持为常数,因而积分时间常数应随系统指示航速而变化。当系统处于搜索状态时,主通道的输出是零均值Gauss过程,求出其方差即可由误跟踪概率确定门限电压。系统所有时变参量的变化规律都可以用同一参数搜索速率α来描述。为使主通道输出电压能适时地超过给定的门限从而使系统由搜索状态转入跟踪状态,并收敛于平衡位置,α必须小于某一上限值αmo本文给出了使系统能正常工作的一个充分条件。除门限电压以外,α_m仅与最低的被测航速V_min、系统的[TW]值以及收发换能器的间距L有关。[TW]值愈大,允许的搜索速率愈低。当固定一个α值时,系统存在一个能够跟踪的最低航速。
This paper discusses the working principle of the related speed sonar, analyzes the physical meaning of the main parameters of the system and their interrelations, and discusses the search and tracking system work process. The expression of the received signal bandwidth can be derived from the directivity of the receiving transducer and the Doppler equation. This bandwidth is proportional to the speed of the ship. In order to maintain the relevant gain constant, the product of the equivalent integral time and the signal bandwidth of the main channel of the system should be kept constant. Therefore, the integral time constant should change with the system indicated speed. When the system is in the search state, the output of the main channel is a zero-mean Gauss process, and its variance can be obtained from the error tracking probability to determine the threshold voltage. The changing law of all the time-varying parameters of the system can be described by the same parameter search rate α. In order for the main channel output voltage can exceed a given threshold in time to make the system from the search state into the tracking state, and converge to the equilibrium position, α must be less than an upper limit αmo This article gives the system to work properly A sufficient condition. In addition to the threshold voltage, α_m is only related to the lowest measured speed V_min, the system [TW] value and the transceiver transducer spacing L. The larger the value of [TW], the lower the search rate allowed. When fixing an alpha value, the system has a minimum speed that can be tracked.