北斗三频电离层延迟及码硬件延迟解算方法

BDS Triple-frequency Ionospheric Delay and Code Hardware Delay Estimation Method

准确固定非差模糊度是利用相位观测量获取高精度电离层延迟的关键。三频观测条件下常规的处理策略需依次固定超宽巷、宽巷以及窄巷模糊度,通常利用MW(melbourne-wubbena)组合解算宽巷模糊度时易受到码硬件延迟和观测噪声的影响而固定错误。利用北斗三频数据和GIM(grid ionosphenimap)产品,通过固定的超宽巷模糊度以及构造相位无几何组合解算宽巷模糊度,进而重构得到高精度电离层延迟,并且分离了码硬件延迟总量。结果表明,GIM模型辅助条件下宽巷模糊度固定成功率能达到100%,且消除了系统性偏差;电离层重构值与GIM模型改正值存在约1 m的差异,等效精度约6TECU;分离的码硬件延迟变化平稳,标准偏差不超过0.3 m。

Getting precise undifferenced ambiguity resolution is the key issue when obtaining high-precise ionospheric delay with phase observations.Generally,extreme wide-lane （EWL）,wide-lane （WL） and narrowlane ambiguities are needed in the process under triple-frequency conditions.The MW combination wide-lane ambiguity may be fixed into a wrong integer because of the influence of code hardware delay and observation noise.In this paper BDS triple-frequency observation and GIM production are applied to resolve wide-lane ambiguity with a fixed EWL ambiguity and phase geometry-free （GF） combination.In addition,high-precise ionospheric delay is reconstructed and code hardware delay is separated.Test results show that the wide-lane ambiguity fixing success rate rises to 100% when assisted with GIM information,while the ambiguity is free of systemic bias.There is a difference of about 1.0m between the reconstructed ionospheric delay and GIM corrections,meaning an equivalent precision of 6 TECU.The standard deviation of the separated code hardware delay is less than 0.3 m.