多系统混频非差非组合精密单点定位方法研究

多系统多频精密单点定位(PPP)因具有增加观测冗余信息、提高系统性能可靠性和提升导航性能指标等优势而被广泛研究.非差非组合PPP模型直接使用原始伪距和载波相位观测值,不做任何线性组合,适合多系统多频率的PPP数据解算.目前,各个系统虽已提供3个或更多频率,但除北斗系统外,其余系统无法保证全星座都提供三频信号,使得多系统多频PPP的性能分析多采用多系统双频或单系统三频模型,没有充分利用多系统多频的观测信息.因此,采用多系统混频模型进行非差非组合PPP,该模型的具体表述为北斗三频+GPS双频+GLONASS双频PPP模型,充分利用可用的观测信息,提升了冗余度.利用CUT0、JFNG、NNOR、SIN1这4个测站的观测数据以及MGEX的精密轨道和钟差产品进行仿真实验,实验结果表明,多系统混频非差非组合PPP相较多系统双频非差非组合PPP的平均静态解RMS在东向提高了9.6％,北向相当,天向提高了11％;平均动态解RMS在东向提高了7.3％,北向相当,天向提高了5.7％.

Research on Undifferenced and Uncombined Precise Point Positioning Method of Multi-system and Mixing-frequency

Precision point positioning(PPP) has been widely studied for its advantages of increasing redundant observation information, improving system performance reliability and improving navigation performance indicators. The undifferenced and uncombined PPP model directly uses the original pseudo range and carrier phase observations without any linear combination, which is suitable for PPP data calculation of multi-system and multi-frequency. At present, although each system has provided three or more frequency, no system except the BeiDou system can guarantee that all the constellations can provide three frequency signals. The performance analysis of multi-frequency and multi-system PPP model mostly adopt multi-system dual-frequency or single system triple-frequency model, while the observation information of multi-system and multi-frequency is not fully utilized. Therefore, this paper uses the multi-system mixing frequency model for undifference and uncombination PPP. The specific expression of the model is BeiDou triple frequency + GPS dual frequency + GLONASS dual frequency PPP model, which makes full use of available observation information and improves the redundancy. Based on the observation data of CUT0, JFNG, NNOR and SIN1, as well as the precise orbit and clock offset products of MGEX, the experimental results show that the average static solution RMS of dual frequency undifferenced and uncombined PPP can be increased by 9.6% eastwards, equivalent northwards, and increased by 11% upwards; the RMS of the average dynamic solution can be increased by 7.3% eastwards, equivalent northwards, and increased by 5.7% upwards.