In https://github.com/BagaskaraPutra/PyNOA/blob/master/martinelli_2010_simple_localization_mobileRobot2D.ipynb, only 1 observable mode ($D$) is detected. There should be 2 detected observable modes: $D$ and $\theta_R - \phi_R$ 
In https://github.com/BagaskaraPutra/PyNOA/blob/master/martinelli_2010_simple_localization_mobileRobot2D.ipynb, only 1 observable mode ($D$ ) is detected. There should be 2 detected observable modes: $D$ and $\theta_R - \phi_R$
