As is well known, the phase-shifting interferometry techniques allow to reach longitudinal resolution to ~ 0.1 nm, but the value of lateral resolution remains at the level of ~ 1 mm. For providing of high lateral resolution of linear measurements in the interference microscope profilometer it was proposed to use a position detection sensor of sharp edge. Principle of sensor’s measurement is based on registration of laser spot intensity scattered by the measurement sample surface under displacement of sample in the lateral direction. The paper shows the prototype scheme of measurement system containing the Linnik interferometer used for surface nanorelief measurement and a position detection module of sharp edge. Measurement process and experimental results are presented. The combining of measurement results performed by the Linnik interferometer and a position detection sensor of sharp edge can allow us to precisely (better then diffraction limit) define the position of sharp edge on the reconstructed surface nanorelief.