Abstract. We present a simple two-mode telemetry procedure which eliminates cyclic errors, to allow accurate absolute distance measurements. We show that phase drifts and cyclic errors are suppressed using a fast polarization switch that exchanges the roles of the reference and measurement paths. Preliminary measurements obtained using this novel design show a measurement stability better than 1 µm. Sources of residual noise and systematic errors are identified, and we expect that an improved but still simple version of the apparatus will allow accuracies in the nanometre range for absolute measurements of kilometre-scale distances.

Keywords: electronic distance measurement, metrology, cyclic error, polarization switching, phase-lock loop

Print publication: Issue 12 (December 2009)
Received 29 July 2009, in final form 10 September 2009
Published 29 October 2009