空气中目标声场建模与软件实现

【作者】 马保宏；

【导师】 孙超；

【作者基本信息】 西北工业大学 ， 信号与信息处理， 2006， 硕士

【摘要】 在开发针对低空飞行及地面机动目标的声被动定位系统时，常常需要进行多次外场实验，以得到不同运动状态下以及不同声场环境中阵列接收到的数据，从而检测系统的准确性和可靠性。显然这将耗费大量的人力、物力，并且由于环境参数的变化，采集的数据很难满足系统的各种情况需求。本论文通过一套软硬件系统，实现了基阵接收到直升机辐射噪声的仿真。此仿真系统可以设定各种参数以模拟产生具有特定频率特性的直升机辐射噪声，按照直升机飞行参数的设定和环境参数的设定产生基阵接收到的数据。数据产生后，可以对仿真数据进行时频域分析，估计出各阵元接收数据间的相对时延，进而估计出目标的方位。仿真系统的环境参数涉及真实环境的各个方面，可以在最大程度上逼近各种真实坏境。软件用功能强大的Visual C++语言编程实现，界面友好，各种参数可以手动改写，方便用户构造各种特定的仿真环境。利用此仿真系统得到的数据在很大程度上可以替代外场实验的实测数据，在理论设计阶段对系统进行各种性能的评价，节约人力、物力资源。 本文的主要工作包括： 1、研究了直升机及地面装甲车的声场特征。结合实测数据，分析了这两种目标噪声的时域、频域特征。研究了影响目标噪声传播的因素：空气温度、湿度、风速、风向及大气中的雨雪等。建立了目标噪声信号传播和衰减的数学模型。 2、研究了用于接收目标噪声的阵列阵元特征，建立了阵列的位置误差模型，阵元幅度、相位误差模型，并基于这些模型接收目标噪声。结合用于估计各阵元上接收的噪声信号间相对时延的广义互相关算法的影响因素，给出了基于高采样率的各个阵元上精确时延信号的产生方法。 3、讨论了面向对象编程语言的优越性。结合软件工程，给出了在上述理论和数学模型基础上的软件设计方法，给出了仿真系统硬件部分的设计和使用方案。设计出目标运动状态仿真、目标时频域分析、阵元间时延估计、目标方位估计及数据D／A输出模块。 4、给出目标噪声的组成成分不同情况下，不同环境参数下的仿真实例。分析了仿真实例的时域通过特性和频域功率谱特性，估计出其他阵元上接收到数据相对于一号阵元的时延，并根据估计出来的时延，得出目标的水平方位角和俯仰角。更多还原

【Abstract】 When develop passive acoustic localization system directed mainly at targets flying low and maneuver targets on the ground, in order to gain data received by array elements under different motion states and acoustic field to demonstrate system reliability and accuracy, it needs large number of out-field experiments. Obviously, it will take up considerable of human and non-human sources. Moreover, the data received by array can hardly satisfy every requirement for varying environment parameters. The paper simulates the system of array receiving helicopter radiate noise is achieved by designing a system including hard ware and soft ware. By setting several parameters, the simulation system simulates the specific frequency helicopter radiate noise and data received by array elements according to specific environment and given flight route. After creating simulation data, it can analyze data in frequency field and estimate time-delay between every two elements data to gain orientation angles of target. The environment parameters of the simulation system include every aspect, therefore it can approximate real environment as far as possible. The system developed with Visual C++ language including powerful functions, provides a user- friendly interface and several parameters that can be changed at will, to facilitate simulating all kind of acoustic field environment. The data simulated by the simulation system can replace outfield experimentation data mostly, so it can economize large numbers of manpower and material resources, assess several system performances in theory design phase, and shorten research period.The main works are as follows:1. Study the acoustic field character of helicopter and armored car. Combining with measured data, analyze time-field and frequency-field characters of this two kinds acoustic signal. Study on several factors influent the targets acoustic signal’s transmission such as: air temperature, air humidity, wind velocity, wind direction, rain and snow. Build target acoustic signal’s transmission and attenuation math model.2. Study character of the array elements receiving target signal. Build locality error model, element scope and phase response model, moreover, receive target signal with these models. Then combining the factors that influent generalized cross correlation algorithm estimating the time delay between two element received data, a method basing on high sample, which is used to create element received high accuracy time delay between two elements data, is brought forward.3. Discuss object-oriented programming language’s merits, combining software更多还原