Leapfrog vs Pre-defined targets
Move Device Position, or “Leapfrog,” is a technique used with portable measuring devices to extend their working volume. Reference points are measured with the device in one position, and then remeasured after the device has been relocated to a new position. The reference points link the new device position with the original coordinate system, allowing for measurements to be taken and reported in the same reference frame.
A pre-defined target reference system consists of a calibrated artifact or set of references that are used for relocation. The position of these targets is established by a separate device capable of large volume measurements, we’ll call this the “referencing” device (i.e., a laser tracker). Another measurement device, which we’ll refer to as the “inspection” device (i.e., a measurement arm, etc), can be placed anywhere within reach or line of sight of the pre-defined targets and can locate itself inside the larger reference frame by simply measuring any set of reference points.