Aftertreatment system NOx and ammonia control strategy

A system, comprising:

• a processing circuit comprising at least one processor coupled to a memory, the memory storing instructions therein that, when executed by the at least one processor, cause the processing circuit to:
• generate a spatially resolved model of a catalyst of an aftertreatment system, the spatially resolved model dividing the catalyst into one or more portions;
• and
• adjust the spatially resolved model based on one or more sensed values from at least one sensor upstream of the one or more portions and at least one sensor downstream of the one or more portions, wherein the catalyst is a first Selective Catalytic Reduction (SCR) catalyst, and wherein the aftertreatment system includes a second SCR catalyst positioned upstream of the first SCR catalyst.