基于辐射传输特性的目标距离估计作为一项典型的被动测距技术, 是目前光电对抗领域的一个研究热点。 在测距过程中无需向外界发射能量, 使得这种探测方式极大地增强了导弹或无人机的隐身能力和突防能力。 针对现有被动测距系统不适用于对迎面而来目标物体实施被动距离估计的不足, 提出了一种改进的小温差目标距离估计方法。 在引入了信号传递函数概念的基础上, 明确了当前算法的工作曲线, 指出这种方法的非线性会导致目标距离估值不唯一的风险。 本文应用非线性校正技术, 构造了新的距离估计算法。 得到了一个利用3~5和8~12 μm双波段红外传感信息, 目标背景温度和气象条件的测距公式。 研究表明, 当目标与背景表观温差等于5 K、 而背景温度估计偏差不超过±5 K时, 目标距离估计误差可控制在10%左右。

It is a typical passive ranging technology that estimation of distance of an object is based on transmission characteristic of infrared radiation, it is also a hotspot in electro-optic countermeasures. Because of avoiding transmitting energy in the detection, this ranging technology will significantly enhance the penetration capability and infrared conceal capability of the missiles or unmanned aerial vehicles. With the current situation in existing passive ranging system, for overcoming the shortage in ranging an oncoming target object with small temperature difference from background, an improved distance estimation scheme was proposed. This article begins with introducing the concept of signal transfer function, makes clear the working curve of current algorithm, and points out that the estimated distance is not unique due to inherent nonlinearity of the working curve. A new distance calculation algorithm was obtained through nonlinear correction technique. It is a ranging formula by using sensing information at 3~5 and 8~12 μm combined with background temperature and field meteorological conditions. The authors’ study has shown that the ranging error could be mainly kept around the level of 10% under the condition of the target and background apparent temperature difference equal to ±5 K, and the error in estimating background temperature is no more than ±5 K.