Locating a Coordinate System
All Coordinate Systems (CS) have inherently arbitrary origins and orientations
- In practice, there are many ways to tie a CS to measurements in the real world
- An Object Reference Model (ORM) provides the basis for developing such ties
Measurements contributing to ORMs are real, but such objects may not themselves be physically realized
- A canonical inertial spatial and coordinate frame may be defined which, taken as a whole, provides the basis for specifying the origin and orientation of a CS
- e.g., the J2000 inertial CS
- A local orthonormal CS may be defined for the purposes of describing the structure of a building within a computer design tool, without realizing the location and orientation of that CS with respect to any real-world body
- In general, however, objects that are physically realized are commonly used