雷达回波视频信号模拟技术研究
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摘要
研究了雷达回波视频信号的实时模拟方法。目的在于能够模拟产生出符合导航雷达实际工作环境的雷达回波视频信号。其主要用途是为ARPA和VTS系统研究、实验、教学和专业人员培训提供雷达回波信号源。
对雷达目标(即船舶)和雷达工作环境建立了数学模型。目标模型包括船舶的距离、方位、速度和回波幅度、幅度起伏。距离、方位、速度是用矢量方法来确定的。回波幅度主要由船舶的雷达截面积来决定。回波幅度起伏是用斯威尔林统计模型来描述。环境模型包括机内噪声、海浪杂波、雨雪杂波、同频干扰、虚假目标等杂波模型。机内噪声是高斯白噪声。海浪杂波和雨雪杂波属于平稳随机过程：其幅度分布服从特定的统计规律；其具有特定的功率谱。本文提出了一种将随机序列通过数字功率谱处理滤波器，从而产生雷达杂波的方法。其中，功率谱处理滤波器是运用谱估计手段来设计的。本文还提出一种通过对截短的高斯白噪声序列进行二维FFT，结果产生具有很强的二维相关性的雷达杂波的方法。这种方法可以用来模拟雷达虚假目标回波。
根据确定的数学模型，设计了计算机模拟生成各种回波数据的算法。在Windows平台上使用VC++6.0语言作为开发工具编写了名为《雷达回波视频信号数据生成系统》的计算机软件。该软件实现了上述算法，能够运算生成雷达回波视频信号数据。同时，该软件应用了计算机图像处理技术和多线程编程技术，能够根据所产生的数据动态地仿真生成雷达接收机视频图像。
The purpose of the research is to simulate the radar echo signal in real-time, which is in agreement with the actual navigation radar operating-environment characteristic and provided for ARP7A&VTS systems.
The mathematical model of radar target and operating-environment is presented. The model of radar target is composed of distance, bearing, speed, heading and amplitude of echo, fluctuation. The distance, bearing, speed and heading are defined by the method of vector. The radar echo amplitude is mainly determined on the radar cross section. The fluctuation of the radar echo is illustrated by the Swelling' model I. The mathematical model of the radar operating-environment is composed of sea-clutter, rain-clutter, thermal noise, false target and interference signal from another radar operating at the same band etc. The thermal noise is generally modeled as a white Gaussian noise (WGN). The sea-clutter and rain-clutter are modeled as a stable stochastic process with a certain amplitude distribution and a kind of power spectral type. A method has been proposed to make the stochastic sequence correlated by passing it into a low-pass filter, which is based on an estimation of spectrum. It has been realized to simulate the correlated radar clutter by applying the above method. In addition, another method has been given to simulate the false target, which is based on the two-dimensional FFT. The correctness and practicality of this method are proved by the simulation result.
According to the mathematical model, some algorithms have been designed for simulating the radar echo data. The software of simulation has been realized with Visual C++, the function of which is to produce the radar echo data and create the simulated image of radar video in real-time. The multi-thread program technique and computer-image processing have been involved in the software. The results of simulation show the applicability and effectiveness of the mathematical model and the software.
对雷达目标(即船舶)和雷达工作环境建立了数学模型。目标模型包括船舶的距离、方位、速度和回波幅度、幅度起伏。距离、方位、速度是用矢量方法来确定的。回波幅度主要由船舶的雷达截面积来决定。回波幅度起伏是用斯威尔林统计模型来描述。环境模型包括机内噪声、海浪杂波、雨雪杂波、同频干扰、虚假目标等杂波模型。机内噪声是高斯白噪声。海浪杂波和雨雪杂波属于平稳随机过程：其幅度分布服从特定的统计规律；其具有特定的功率谱。本文提出了一种将随机序列通过数字功率谱处理滤波器，从而产生雷达杂波的方法。其中，功率谱处理滤波器是运用谱估计手段来设计的。本文还提出一种通过对截短的高斯白噪声序列进行二维FFT，结果产生具有很强的二维相关性的雷达杂波的方法。这种方法可以用来模拟雷达虚假目标回波。
根据确定的数学模型，设计了计算机模拟生成各种回波数据的算法。在Windows平台上使用VC++6.0语言作为开发工具编写了名为《雷达回波视频信号数据生成系统》的计算机软件。该软件实现了上述算法，能够运算生成雷达回波视频信号数据。同时，该软件应用了计算机图像处理技术和多线程编程技术，能够根据所产生的数据动态地仿真生成雷达接收机视频图像。
The purpose of the research is to simulate the radar echo signal in real-time, which is in agreement with the actual navigation radar operating-environment characteristic and provided for ARP7A&VTS systems.
The mathematical model of radar target and operating-environment is presented. The model of radar target is composed of distance, bearing, speed, heading and amplitude of echo, fluctuation. The distance, bearing, speed and heading are defined by the method of vector. The radar echo amplitude is mainly determined on the radar cross section. The fluctuation of the radar echo is illustrated by the Swelling' model I. The mathematical model of the radar operating-environment is composed of sea-clutter, rain-clutter, thermal noise, false target and interference signal from another radar operating at the same band etc. The thermal noise is generally modeled as a white Gaussian noise (WGN). The sea-clutter and rain-clutter are modeled as a stable stochastic process with a certain amplitude distribution and a kind of power spectral type. A method has been proposed to make the stochastic sequence correlated by passing it into a low-pass filter, which is based on an estimation of spectrum. It has been realized to simulate the correlated radar clutter by applying the above method. In addition, another method has been given to simulate the false target, which is based on the two-dimensional FFT. The correctness and practicality of this method are proved by the simulation result.
According to the mathematical model, some algorithms have been designed for simulating the radar echo data. The software of simulation has been realized with Visual C++, the function of which is to produce the radar echo data and create the simulated image of radar video in real-time. The multi-thread program technique and computer-image processing have been involved in the software. The results of simulation show the applicability and effectiveness of the mathematical model and the software.
引文
1 R L米切尔，雷达系统模拟，科学出版社，1986
2 程佩青，数字信号处理教程，清华大学出版社，1998
3 复旦大学，概率论，人民教育出版社，1979
4 张建中，常用时间序列分析软件包，气象出版社，1986
5 王立宁、乐光新，MATLAB与通信仿真，人民邮电出版社，2000
6 缪德刚、方乃正，航海雷达，大连海事大学出版社，1990
7 丁鹭飞，雷达原理，西北电讯工程学院出版社，1984
8 王世远、缪德刚，航海雷达与ARPA，大连海事大学出版社，1999
9 张润泽，船舶导航雷达，第一册，人民交通出版社，1990
10 张润泽，船舶导航雷达，第三册，人民交通出版社，1990
11 宋海娜等，低入射角下雷达海杂波的建模与仿真，国防科技大学学报，2000，第22卷第3期
12 张兴敢，朱兆达，用高速数字信号处理器实现雷达视频杂波模拟，南京航空航天大学学报，1995，第27卷第2期
13 朱灿焰，雷达杂波相关功率谱特性的 AR 模型及其模拟，北京理工大学学报，1998，第15卷第3期
14 方再根，计算机模拟与蒙特卡洛方法，北京工业出版社，1998
15 齐国清，FMCW 液位测量雷达系统设计及信号处理方法，大连海事大学，2001
16 蔡颖，应用随机过程论，大连海事大学出版社，1998
17 David J．Kruglinski and Scot Wingo，George Shepherd，Visual C++6．0技术内幕，北京希望电子出版社，2001
18 Ward K. D and Watts S, Radar sea clutter[J], Microwave Journal, 1985
19 Oliver C. J, Correlated K-distributed clutter Models[J], Optical Acta, 1985, 32(12)
20 Cole S N, Environment and radar operation simulator, AD-A008051,1985
21 A. V. Oppenbeim and R. W. Schafer, Digital signal Processing[M], New Jersey: prentice-hall, inc, 1975
2 程佩青，数字信号处理教程，清华大学出版社，1998
3 复旦大学，概率论，人民教育出版社，1979
4 张建中，常用时间序列分析软件包，气象出版社，1986
5 王立宁、乐光新，MATLAB与通信仿真，人民邮电出版社，2000
6 缪德刚、方乃正，航海雷达，大连海事大学出版社，1990
7 丁鹭飞，雷达原理，西北电讯工程学院出版社，1984
8 王世远、缪德刚，航海雷达与ARPA，大连海事大学出版社，1999
9 张润泽，船舶导航雷达，第一册，人民交通出版社，1990
10 张润泽，船舶导航雷达，第三册，人民交通出版社，1990
11 宋海娜等，低入射角下雷达海杂波的建模与仿真，国防科技大学学报，2000，第22卷第3期
12 张兴敢，朱兆达，用高速数字信号处理器实现雷达视频杂波模拟，南京航空航天大学学报，1995，第27卷第2期
13 朱灿焰，雷达杂波相关功率谱特性的 AR 模型及其模拟，北京理工大学学报，1998，第15卷第3期
14 方再根，计算机模拟与蒙特卡洛方法，北京工业出版社，1998
15 齐国清，FMCW 液位测量雷达系统设计及信号处理方法，大连海事大学，2001
16 蔡颖，应用随机过程论，大连海事大学出版社，1998
17 David J．Kruglinski and Scot Wingo，George Shepherd，Visual C++6．0技术内幕，北京希望电子出版社，2001
18 Ward K. D and Watts S, Radar sea clutter[J], Microwave Journal, 1985
19 Oliver C. J, Correlated K-distributed clutter Models[J], Optical Acta, 1985, 32(12)
20 Cole S N, Environment and radar operation simulator, AD-A008051,1985
21 A. V. Oppenbeim and R. W. Schafer, Digital signal Processing[M], New Jersey: prentice-hall, inc, 1975