罗兰C脉冲色散的理论预测

Theoretical Prediction of Dispersion of Loran C Pulse

本文简要介绍了罗兰 C 脉冲色散的一种理论预测方法。对最具代表性的四种典型地面计算了以下各种色散效应:脉冲频谱的畸变,载波过零时刻的超前,载波周期的展宽和载波正向过零点后前峰值幅度比的变化等。这些效应对导航精度的影响在文中也进行了讨论。计算结果表明,海水在2000km 以内,良导电地在1500km 以内,中等导电地在720km 以内和差导电地在250km 以内可以忽略色散效应。

This paper presents a method for calculation of the propagation dispersion of Loran C pulse besed on Fourier annalysis and calculation of grotmdwave transmission function W.The paper gives some results of calculation for Loran C pulse propagation dispersion along four typical pathes with the different conductivity paramenters.Some effects on navigation precision by the disper- sion is also discussed here. The calculated results show that the dispertion effects can be negligible over the following transmission path ranges:sea 2000 km,fine conductivity earth 1500 km,middle conductivity earth 720 km and bad conductivity earth 250 km.