动态环境下PPP的GNSS大气水汽反演

Precipitable water vapor retrieving using precise point positioning in dynamic scenario

利用静态PPP(精密单点定位)处理稳定的GNSS地面站可以高精度反演大气中的水汽含量.对于运动的载体,静态PPP无法正确地估计待估参数.利用动态PPP数据处理方法,在解算载体动态位置的同时,可以估计动态载体GNSS的天顶总延迟,并在此基础上计算水汽含量.分别利用PPP动态和静态模型解算3.5 h的稳定可靠GNSS参考站数据,结果表明,动态PPP与静态PPP利用稳定CORS站解算大气可降水量(PWV)时,最大差别为6.6 mm,且水汽的变化趋势基本一致.在快速运动平台下,旋转平台解算的PWV与相同环境下的CORS站解算的水汽结果在量级上一致,但并不能像CORS站结果一样可以反映出水汽的变化趋势.针对地震等GNSS台站失稳问题,分别利用动态、静态PPP进行水汽的提取,结果表明,地震的短期形变对PPP水汽的提取无明显影响.建议使用静态PPP对失稳GNSS台站进行水汽提取.

Precise point positioning(PPP)has been well established for retrieving the precipitable water vapor(PWV)in the static model.Yet it is not always suitable for static PPP PWV retrieving,for an instance,the GNSS antenna keeps moving.Position and zenith total delay(ZTD)are coinstantaneously estimated in dynamic PPP mod-el,which is an option for the PWV retrieving in dynamic scenario.GNSS data over 3.5 hours have been gathered from the Continuously Operating Reference Stations(CORS).Both static and dynamic PPPs have been applied for the CORS data processing.The result reveals that the maximum difference is 6.6 mm,and dynamic PPP PWV grad-uate movement agrees in magnitude with that from static PPP PWV.A rotation arm has been designed for GNSS re-ceiver gathering data in dynamic scenario.PPP in dynamic model can retrieve the rotation arm PWV,which makes sense to the one from CORS PWV,but lose the capacity of detecting the PWV changes.GNSS station can have dis-placement in a short term in the earthquake event.Both static PPP and dynamic PPP have been assessed for this scenario.The result reveals that displacement due to the earthquake does not make an evident effect on the PWV re-trieving both in static PPP and dynamic PPP.The static PPP is still recommended for the PWV retrieving over the earthquake period.