Subject: Obstacles

> what is the identity of an obstacle? an obstacle gives out its own identity

The obstacle identifies itself.

> or our system(i.e the sensor subsystem) assigns an identity for an obstacle?

It does need to assign an object identity, but that is not the same as
identification.  Object identity is an internal, implementation notion.

> Do the intelligent obstacles and the dumb obstacles both have identities or
> only the intelligent ones have identities?

Only the intelligent ones.

> what kind information will be requested? Can I assume that the required
> information is about the location of an obstacle, or the local environment?
> nothing else?

Obstacles have locations but they also move.  The motion of an obstacle is its
track.  You need to know the track to prevent collisions.