rigpa is a buddist term, i think for the state of meditation or samadi but i am not too sure maybe other practictioners can help with a more detailed exsplanation.
Rigpa is a state in which one can reside. Rigpa is a state most often associated with Dzogchen a direct transmission guru based Buddhist practice.
There are kind of two "levels" of emptiness in Buddhism, emptiness of self and then beyond, the emptiness of ultimate reality. The realization of of emptiness of self is the stepping beyond the dualistic self at the local body mind level/layer. Rigpa is beyond that and is the residing in the base of ultimate reality (or the integration of all existence).
Rigpa is not "noticing" in an intellectual way, but is the "experience" of instantaneous pure presence. A realization of primordial bodhicitta where one "knows" that it is the source of all manifestations of energy/form. Where one is not a wave in the ocean, but the "transmission" of the ocean itself.
This is a non Yoga and AYP topic. You can check out some of the other discussions of Rigpa at the LivingUnbound site.