Using a novel mobile phase-sensitive radio echo sounder (pRES) system, radar profiling was conducted at Colle Gnifetti, Monte Rosa massif (Swiss–Italian Alps) in September 2021 to detect its deep englacial radiostratigraphy. The pRES (also denoted as autonomous pRES (ApRES) for stationary operations) is a frequency-modulated continuous wave (FMCW) radar operating at 200 to 400 MHz (Brennan et al., 2014). It provides phase-coherent radar data, which enables the application of Layer-optimized Synthetic Aperture Radar (LO-SAR) processing to improve the detectability of internal reflection horizons. We mobilized the pRES by placing its skeleton antennas in inflated tractor inner tubes and connecting them with a wooden frame. The antennas were separated by 2.7 m (center-to-center), elevated a few centimeters above the snow surface and their dipole axes were oriented perpendicular to the profiling direction. The data were acquired in stop-and-go mode with a median trace spacing of approximately 13 cm. Positioning was controlled by the Trimble® R9s GNSS system, operated in RTK mode. A profile with a total length of 285 m was acquired. It is split into two transects, a 166 m long transect across the glacier saddle that passes the drill location of the CG03 ice core (Sigl et al., 2018), and an intersecting 119 m long transect upstream towards south/the KCC ice core (Kerch et al., 2018).