A navigation system for tracking the position of an object includes a GPS receiver responsive to GPS signals for periodically providing navigation state measurement updates to a navigation processor. When the sign assembly is expanded, or in its deployed state, the fabric covering and support frame possess a connective tension relationship with respect to one another which creates and supports both the sign assembly display sign and base in a stable manner. A single or multiple such treatments may be employed. The vertical displacement device may also be included in optical coherence and confocal imaging systems. The pipe connection may be used in conjunction with a clamp.