中文摘要：

基于三层高度谱,研究了弱湍流环境下斜程大气激光通信系统的误码率.推导出采用开关键控和脉冲位置调制方式时的误码率表达式;对天顶角、光波长、三层高度谱的幂律谱指数以及调制方式等因素对误码率的影响进行了分析.研究结果表明,三层高度谱模型湍流强度分布与实际斜程大气一致,误码率随光波长的减小和天顶角的增大而增加,脉冲位置调制方式比开关键控更节省系统的平均发射功率.

英文摘要：

Based on the three-layer altitude spectrum,this paper analytically investigates the bit error rate（BER）performance of the slanted laser communication system under the weak turbulence condition.The expressions for BER using on-off keying（OOK）and pulse position modulation（PPM）are derived.An analysis of impacts of the zenith angle,wavelength,power-law index and modulations on BER is made.Theoretical results show that the descriptions of turbulence given by the three-layer altitude spectrum is consistent with the actual situation.With the wavelength decreasing and zenith angle increasing,BER increases.Furthermore,PPM requires less average transmitted power than OOK,which may achieve the aim of saving cost without increasing the error rate in system design.