光电跟踪仪电视系统的作用距离是其重要指标之一，在系统设计过程中，应进行必要的计算、分析和研究.详细探讨了影响电视跟踪系统作用距离的主要因素，分析了目标成像尺寸、目标和天空背景在电视像面的照度和对比度，建立了标准大气条件下，电视系统作用距离的数学模型，提出采用光学和信号处理手段相结合的方法可有效提高电视系统的作用距离，利用计算探测距离的公式可估计系统的作用距离，进而为设计提供参考.

The effective distance of TV system in electro-optic tracker is one of the key performances, which must be calculated, analyzed and studied when the system is designed. The factors affecting the effective distance of the system are discussed, the target imaging size on TV，the luminance and contrast of targets and sky background on the imaging surface of TV are analyzed. A mathematic model of effective distance of TV under the standard atmosphere condition is established. The approach of combining the optics and signal process is capable of increasing the effective distance of TV system, the calculation formula of detection distance can be used to estimate the effective distance of the system and provide references for design.