Research Of Anti-Coating-Stealth Objective With A Passive Millimeter Wave Seeker

Stealth technology or low observables technology is a sub-discipline of electronic countermeasures, and it is a combination of technologies that attempt to make the military weapons less visible to radar, infrared and other detection methods.Stealth technology will be one of the decisive factors in a war. It changes the methods of the war and the strategic equilibrium. Now, stealth technology will not only be incorporated in fighters and bombers but also in ships, tanks, missiles, and other military weapons.As the rapid developments of stealth technology, it reminds us that our national defensive system has to seriously consider the likelihood of facing stealth threats in the future. Because of this, in our national defense, it is urgent and important to develop the new methods that can counter the low observables of the new generation stealth weapons.This thesis consists of eight chapters. In view of the characteristics of the coating-stealth objective, we mainly deal with a new method for anti-coating-stealth objective with the passive millimeter wave seeker system. The basic principles of this method are totally different from those of the passive detective techniques for stealth technology in the United States, Russia, England, France, and Germany.In this thesis, as concerns the technologies of anti-stealth, makes a comprehensive discussion with important attention paid to their basic principles, their technological capabilities, etc.In Chapter 1, we mainly introduce the recent researches and developments of stealth technology and anti-stealth technology.In Chapter 2, firstly, we review characters of millimeter wave seeker system. Then, we give the electromagnetic radiometric equation of the coating stealth objective and the generally solution of the electromagnetic radiometric equation. The possibilities which the radiation character of the stealth objective measured by the passive millimeter wave radiometer are analyzed.A new calibration technique is presented in millimeter wave measurement. The experiments of technological capabiliies are offered. Final, the way which checked in the experiments of the passive millimeter wave seeker system is given. In Chapter 3, there is no explicit signal interference problem, since the millimeter wave radiometric signal is incoherent. In addition, the millimeter wave radiometric signal is likelihood. The information of the probability after effect density function of the coating stealth targets'model parameter is introduced. According to data of antenna temperatures resulted from the coating stealth targets, a method to calculate the minimum variance and the best value of the coating-stealth target's radiation temperatures with passive millimeter wave seeker was introduced.In Chapter 4, the signal that received by the radiometer depends on the objects' physical temperature and emissivity (or reflectivity), the surrounding medium temperature, and the ratio of the object area to the radiometer beam spot area.The model of the interaction between the electromagnetic radiations properties of the antenna and the incident radiation from the environment is set up. Then, the interpolation solutions of armored target's brightness temperatures are obtained and are used in 3mm wave directness radiometer.In Chapter 5, the radiometer does not measure the brightness temperature directly. Instead, it measures the antenna temperature, which is the brightness temperature "smoothed" by the system antenna pattern weighting function.In order to obtain the radiometric brightness temperatures of the coating-stealth targets, a Fredholm type integral equation of the first kind must be solved. This equation is ill-posed and its solutions are extremely unstable.The method of optimal and control has been explored and was then applied to retrieve armored target's brightness temperature in 8mm wave alternating radiometer. And the technique is checked in the experiment.In Chapter 6, the passive detective techniques of the millimeter wave radiometer play important role in anti-stealth and in homing guidance for anti-armor missile. Passive locating is one of the important steps in the research of the anti-stealth technology. We discuss systematically the basic principles and techniques related with passive locating, offer the algorithms for measurement and locating.In Chapter 7, in view of coating-stealth, we provided a method to test the radiation character of our stealth objective with the passive millimeter wave radiometer. And the formulas are presented to calculate the main parameters (the reflective coefficient and the radiation coefficient) of the millimeter-wave absorbers. And the errors are analyzed. It will be of great value to us in the research work of stealth technology.In Chapter 8, In view of the image of passive millimeter wave targets is gray image, and the image blur is still severe problem. To solve the problem, the gray morphology which is one of the nonlinear geometry-analysis was introduced. The gray structuring element was taken, the peak operator and the valley operator of the image with the millimeter wave radiometer were studied, and enhanced images of passive millimeter wave target were given based on morphological gradient. And the multiscale edge detection of images was presented. The main factors about coating stealth armored targets be detected with passive millimeter wave seeker were analyzed.