We propose to fix a high-precision GNSS antenna on the pulka during the 600km traverse of Nanok. The data will be processed using a state-of the-art scientific software to estimate the position of the GNSS antenna every 30s 24/24. The positions will be estimated at centimetres level accuracy on the vertical component and will allow us to improve the actual accuracy (~10-100m) of the ice sheet elevation. Another aspect of the experiment is to estimate the water vapor content in polar region. The water vapor is the main greenhouse gas but is also the most difficult component to estimate continuously especially in polar region. The data acquired during the bivouac periods of Nanok will allow the estimation of the variation of the water vapor across the Greenland continent. Finally, the GNSS data will be used to estimate the Total Electron Content in the Ionosphere-Plasmasphere system. The long traverse in the sub-auroral zone, will allow a better understanding of the coupling between the ionized layer and the geomagnetic field lines.   

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The GNSS receiver and antenna will be placed on one pulka. The GNSS antenna will be place on a fixed structure at the back of the pulka with on the top, to avoid any mask from the package in the pulka, and to assure a constant elevation of the antenna with respect to the ground (i.e. ice sheet elevation). The receiver will be place in the pulka itself, protected as much as possible from the cold. The receiver will be connected to a battery powered by solar panels.

The Nanok people will only need to verify regularly that the receiver is alimented in power, and that the receiver is registering data files by checking the lights on the receiver itself. The material will run 24/24h acquiring data every 30s.