In the Domain Engineering (DE) discipline, different approaches are used for one purpose, the treatment of non-functional requirements (NFR) to build a reference architecture (RA), or generic architecture from which all product members of a family of a domain, are generated. Consequently, the same process is adapted to different contexts and abstraction levels. This paper proposes a Unified Domain Analysis Process (UDAP) of DE, which uses Aspect and Goal orientations and the specification of NFR by quality standards. This process integrates the following specific techniques: - extended process of Chung and others, based on the NFR Framework with treatment of crosscutting concerns of Losavio and others - ISO/ IEC 25010 quality standard to specify NFR. The proposed process obtains the RA as the main artifact and can be reused as an asset in the context of software product lines.