北斗系统新民用导航电文历书参数算法与性能分析

Algorithm and performance analysis of the new almanac of BDS civil navigation message

研究新公布的北斗民用导航电文中的两类历书与北斗二号导航电文历书的差异,对比分析各类历书对接收机首次定位时间的影响。利用实际的历书数据,比较不同历书类型的用户算法,分析不同龄期数据对接收机首次定位性能的影响。结果表明,高精度历书在1周的数据龄期内性能较为稳定,中等精度历书精度稍逊于高精度历书,但由于简化了电文空间,能接近高精度历书性能。简约历书进一步简化了参数数目和电文空间,尽管位置误差达到了数百千米,但却能在数月之后保持相应精度,有利于缩短接收机首次定位时间。

The differences between the two kinds of almanac in the new BDS civil navigation message and the navigation message of BeiDou-2 were analyzed,and the influence of various almanacs on the initial positioning time of the receiver was analyzed. Based on the actual data of almanac,the user algorithms of different almanac types were compared,and the influence of different age data on the initial positioning performance of receivers was analyzed. The results show that the performance of the precise ephemeris with a week of data is more stable,and the accuracy of medium accuracy almanac is lower than the accuracy of the precise ephemeris,but the performance can close to that of the precise ephemeris as a result of simplifying the message space. The contracted almanac further simplifies the parameter number and message space,although the location error achieved hundreds of kilometers,but can keep the corresponding precision after a few months,and shorten the initial positioning time of the receiver.