A preliminaryestimate or conceptual estimate is based on the conceptual design of the facility at the state when the basic technologies for the design are known.
初步估算或者称为概念方案阶段估价主要基于概念设计方案进行估算，此时只明确了最基本的技术方案。
2
Moreover, this is a preliminaryestimate and past revisions have sometimes been quite large; barely perceptible growth of 0.1% in late 2009 was subsequently pushed up to 0.5%.
In flight vehicle preliminary design it is necessary to quickly and economically estimate the aerodynamics of a wide variety of flight vehicle configuration designs.