M.Lintz, Télémétrie Laser Atelier Télescopes NG 27-28/03/ Laser ranging at the nm precision level: The two mode interference measurement in the Iliade rangemeter Duy-Hà Phung, Clément Courde, Michel Lintz Laboratoire ARTEMIS, OCA Nice Christophe Alexandre Laboratoire CEDRIC-LETITIA, CNAM, Paris

M.Lintz, Télémétrie Laser Atelier Télescopes NG 27-28/03/ Three measurements: Optical wavelength (  L mod opt ) phase measurement (highest resolution, < nm) + Synthetic wavelength (  L mod  ) phase measurement at µ-wave frequencies: interm. length scale, to <<10 -4 cycle + Time-of-flight measurement Iliade: combination of three length scales   long-term phase drifts in microwave components >> cycle! same signal collab. Etienne Samain, GéoAzur, OCA Stéphane Pitois, ICB, Univ. Dijon

M.Lintz, Télémétrie Laser Atelier Télescopes NG 27-28/03/ Iliade: optical- and synthetic-length scales in one signal phase meas. ² ² 44 interf. complex signal (helps identification of systematics) rather complex set-up rather complex procedure difficulties related with AM-to-PM coupling (thermal transients in the measurement photodiode) due to amplitude variations resolution improves as 1/   expected accuracy: nm L - scan complex plane plot of the signal microwave opt.-beat-note