Planning as satisfiability is a principal approach to planning
with many eminent advantages. The existing planning
as satisfiability techniques usually use encodings
compiled from the STRIPS formalism. We introduce a
novel SAT encoding scheme based on the SAS+ formalism.
It exploits the structural information in the SAS+
formalism, resulting in more compact SAT instances
and reducing the number of clauses by up to 50 fold.
Our results show that this encoding scheme improves
upon the STRIPS-based encoding, in terms of both time
and memory efficiency.