北斗星上多径对宽巷模糊度解算的影响分析

通过引入北斗星上多径参数,量化了北斗星上多径对宽巷模糊度解算的影响;从理论上分析了该影响量在非差、单差和双差条件下的特性,并采用零基线、短基线和长基线3组实测数据进行了分析与验证。结果表明:星上多径对非差宽巷模糊度估值的影响在三类卫星上表现出不同的特性,在MEO卫星上最大,可达1周;星间单差无法消除星上多径偏差影响,进而PPP宽巷模糊度的解算将受到影响;星上多径不会对零基线双差宽巷模糊度解算造成影响,对短基线双差宽巷模糊度解算的影响也可忽略,但长基线双差宽巷模糊度解算则受严重影响;星上多径会导致长基线双差宽巷模糊度平滑收敛缓慢,经改正后模糊度固定成功率能够显著提高,单历元取整成功率从52.7%提升到61.4%,平滑20个历元模糊度固定成功率即可从68.4%提升到95.5%。

Analysis of the Impact of BDS Satellite-Induced Multipath Errors on Wide-Lane Ambiguity Resolution

The parameter of satellite-induced multipath errors is first introduced to quantify the impact of the errors on wide-lane ambiguity resolution.And then the characteristics of the impact under un-differenced,single-differenced and double-differenced conditions are analyzed theoretically.Finally,zero-baseline,short-baseline and long-baseline measurement are used to analyze and verify the conclusion.The result shows that the influence of the satellite-induced multipath errors on un-differenced ambiguity resolution has different features on BDS three types of satellites,with the maximum up to one cycle on MEO satellites,and the between-satellite single-difference cannot eliminate the impact of the satellite-induced multipath errors,because of which the PPP wide-lane ambiguity resolution is also influenced.And the double-differenced wide-lane ambiguity resolution for zero and short baseline is free from the effects of the satellite-induced multipath errors,while the long-baseline double-differenced wide-lane ambiguity resolution is severely impacted.The satellite-induced multipath errors will lead to slow convergence of the smoothing of long-baseline double-differenced wide-lane ambiguity.And with the increase of fixed rate from 52.7% to 61.4% for single epoch resolution and 68.4% to 95.5% for 20 epoch's smoothing resolution,the fixed rate of long-baseline double-differenced wide-lane ambiguity is improved significantly when the errors are corrected.