First of all, the North Warning System, as is, is very limited in its ability to actually detect the current threat represented by Russia right now, and China in the future—especially given that the threat from China may be coming from the west coast, and the North Warning System is geared towards a threat coming from the Arctic, which is what it was designed for back in the early 1980s.
We're talking about modernization of the layered sensor systems, and that includes the arrival of over-the-horizon radar, which are not going to be co-located with the current North Warning System, but will be optimized in order to actually provide North America, i.e., Canada and the U.S. specifically, with a long-range detection of air and space threats. That is expected to be available in the later part of this decade.