Very Short Baseline Measurement System.

Short range distance measurement techniques and instruments are reviewed to assess the practical accuracy limits achievable, especially over a short range of approx. 50 m. Surveying instruments typically exhibit accuracies of several mm over this range and are limited by modulation and phase measurement techniques. More elaborate research instruments have demonstrated a resolution of better than 0.1mm, but are still limited to overall accuracies of 0.5 to 1mm by instrument placement and system calibration errors. Keywords: Distance measurement; Rangefinders; Surveying.