“…In 2008, weighted total least-squares (WTLS) solution has also been proposed by Schaffrin and Wieser (2008) using Lagrange multipliers (LM) for an errors-in-variables (EIV) model with fairly general variance-covariance matrices. Since then, a number of WTLS solutions have been developed by Schaffrin and Wieser (2009), Markovsky et al (2010), Neitzel (2010), Shen et al (2011), Tong et al (2011), Amiri-Simkooei and Jazaeri (2012), Mahboub (2012), Amiri-Simkooei and Jazaeri (2013), Fang (2013), , Fang (2014cFang ( , 2015, Jazaeri et al (2014). In particular, Neitzel (2010) implemented a WTLS solution by using iteratively linearised GaussHelmert (GH) model (Pope, 1972), and Mahboub (2012) improved the WTLS solution of Schaffrin and Wieser (2008).…”