“…Although pPCA has previously been employed in various areas of research, e.g. estimation of the EOF's for satellite-derived sea surface temperature (SST) data (Houseago-Stokes and Challenor 2004), a study on the precipitation and absorption squeeze (Andrei and Malandrino 2003), generation of the video textures (Fan and Bouguila 2009), detection of a small target (Cao et al 2008), investigation of traffic flow volume (Qu et al 2009), managing self-organizing maps (Lopez-Rubio et al 2009), detection of outliers (Chen et al 2009), tracking of the objects (Xiang et al 2012), speaker recognition (Madikeri 2014), investigation of the nonlinear distributed parameter processes (Qi et al 2012), nonlinear sensor fault diagnosis (Sharifi and Langari 2017), studying trends of mean temperatures and warm extremes (Moron et al 2016), denoising of images (Mredhula and Dorairangaswamy 2016) or detection of the rolling element bearing fault (Xiang et al 2015), according to the best of our knowledge, the pPCA filtering that is readily adapted to the position time series with missing data, has been presented for GNSS residuals (either position or ZTD) for the first time.…”