Most likely GLS. Pretty cool and virtually transparent to the operating pilots. We're encountering more and more in the international realm. Uses a highly accurate GPS ground station at the airport to tell the airplane exactly where it is. Same freqs as ILS without the transmitter sidelobes, so no false glideslopes. RUMINT has it that Russia started using a several of these because they are easier to install and maintain in remote locations...but long-haul pilot RUMINT worth the price you pay to get it.
As to Trump's comment, it seems like he doesn't make stuff up completely out of thin air. He simply overhears a conversation that he knows nothing about, then turns around and talks like he knows everything on the topic. So basically the same 10% rule surrounding every pilot story ever told.