基于导航卫星伪距双差建立了相对导航模型,设计了基于伪距单差的最小二乘算法、基于伪距双差的最小二乘算法、基于伪距单差的EKF算法与基于伪距双差的EKF算法,并通过试验进行对比分析。研究结果表明:基于伪距双差的相对导航模型可以消除电离层、对流层、多路径误差、卫星钟差与接收机钟差;与最小二乘算法相比,EKF算法能够显著提高相对导航信息的解算精度;EKF算法下伪距双差的解算精度比伪距单差提高约10%;在几何精度因子最小的原则下,卫星个数增多,距离解算精度提高;基线为2m时,基于伪距双差的EKF算法所得距离解算精度可达到0.10m以内,方位角解算精度可达到4.0°,因此,EFK算法的精度和频率可满足大型舰船编队保持准动态的相对导航需求。
A relative navigation model based on the pseudo-range double-difference of navigation satellite was built.Pseudo-range single difference based least square algorithm,pseudo-range double-difference based least square algorithm,pseudo-range single difference based EKF algorithm and pseudo-range double-difference based EKF algorithm were designed and were compared by tests.Analysis result shows that pseudo-range double-difference based relative navigation model can eliminate ionosphere,troposphere,multi-path,satellite clock error and receive clock error.EKF algorithm can significantly improve the resolution accuracy of relative navigation information compared with least square algorithm. Under EKF algorithm,the resolution accuracy of pseudo-range double-difference is 10% better than pseudo-range single difference.Under the minimum GDOP value principle,when the number of satellites increases,the distance resolution accuracy becomes better. When baseline length is 2 m,the distance resolution accuracy of pseudo-range double-difference based EKF algorithm can reach within 0.10 m,azimuth resolution accuracy can reach 4.0°,so the test accuracy and frequency in this paper can satisfy the relative navigation demand of keeping quasi dynamic for large vessel formation.3tabs,27 figs,20refs.