电离层延迟较大是基线较长情况下的模糊度解算需要解决的关键问题。当基线较长时,由于基准站和流动站的电离层相关性弱使得双差电离层残差较大,易导致模糊度解算所需时间长且成功率不高。本文提出了一种模糊度解算方法,该方法将北斗无线电测定业务(radio determination satellite system,RDSS)的下行S频段信号测量值与无线电导航业务(radio navigation satellite system,RNSS)信号测量值组合来削弱电离层的影响。首先,通过RDSS信号测量值与RNSS信号测量值一起进行频率组合研究,确定了几组电离层延迟系数小且总噪声波长比(total noise level,TNL)较小的组合。然后,利用这些组合形成几何无关和电离层无关模型解算GEO卫星的窄巷模糊度。最后利用已知窄巷模糊度的GEO卫星测量值辅助求解非GEO卫星的窄巷模糊度。利用实测北斗星历对提出的方法进行了仿真验证,结果表明,本文方法可以从整体上提高模糊度解算的速度和成功率。
Ionospheric delay is a major problem in the process of ambiguity resolution over medium and long baselines that the time consuming is barely satisfactory and the success rate is not high. This paper proposes a new ambiguity resolution method which combines the RNSS and RDSS observations of BeiDou to reduce the ionospheric delay. Firstly, two optical virtual observations with small total noise level and ionospheric delay coefficient are selected by analyzing the RNSS and RDSS combination signals. Then, the NL integers of GEO are solved using geometry-independent and ionosphere-free model which are formed by new virtual observations. Finally, the NL integers of non-GEO are solved with known GEO NL integers. This method is verified using simulated data. Test results show that, the new method has higher success rate and less consuming time compared with traditional method.
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