x_error: 0.442805081606 y_error: 0.368803560734 theta_error: 0.879850745201
x_error: 7.48365755499e-06 y_error: 0.00057053467026 theta_error: 0.494665533304
Note that the code no longer supports unknown data association, and the reason for the jittery performance was later discovered to be related to my wheel encoders update.
The below screenshot shows unknown data association but with the Gazebo-read landmarks for comparison.
x_error: 0.0280208941549 y_error: 0.291656583548 theta_error: 0.262606918812
x_error: 0.0360223278403 y_error: 0.00010442571894 theta_error: 0.280603200197