Explain the principle of Data Association in context of Simultaneous Localization and Mapping $($SLAM$).$

$$ Explain how the state variable of the filter is composed?

$$ Draw an example and explain the estimation of the parameters used for decision in the data association step.

$$ How is the result of the Data Association used in the update step of the Kalman processing. Which matrix gets modified with this result and how?

$$ which distance is compared for association $($equation$).$