In order to extend the GNSS coverage to indoor environments, several systems have been proposed for indoor positioning. Among them, those using local GNSS-like signal transmitters are of specific interest since they could allow a single device, the GNSS receiver, to achieve the continuity of the positioning service from outdoors to indoors. Since these local antennas broadcast GNSS signals similar to those broadcasted by the satellites, the indoor signals may interfere with the outdoor ones. Thus, it increases the noise level at the outdoor receiver's end and the error on the computed positions. In this paper, we propose new codes that aim to reduce this interference for both the GPS and the GLONASS signals (considering one could evenly consider the two constellations).