Algorithm 1: Alonso and Shuster (TWOSTEP) [1]

Step 1: Calculate $z_k,L_k,\mathrm{for}k=1,2,\cdots ,N$         by using (4)–(6)   Step 2: Calculate the centered values ${\tilde{z}}_k,{\tilde{L}}_k\mathrm{for}k=1,2,\cdots ,N$ (7) Step 3: Calculate centered estimate ${\tilde{\theta }}^{\prime }$ and covariance matrix ${\tilde{P}}_{{\theta }^{\prime }{\theta }^{\prime }}$ (8) Step 4: Extract c and E from ${\theta }^{\prime }$ following (11) Step 5: Calculate $\varphi \left({\theta }^{\prime }\right)$ and $g\left({\theta }^{\prime }\right)$ from (10) Step 6: Update ${\theta }^{\prime }$ using (9) Step 7: Calculate $\eta$ following (12) Step 8: Repeat steps 4–7 until $\eta$ is sufficiently small   Step 9: Apply SVD on $E^{*}$ (13) and define matrix W Step 10: Calculate $D^{*},h^{*}$ (14) and $T,h$ (15)