I think a Government of Canada official could answer your second question better than I could.
The detection system used by the Department of National Defence may or may not be NAV CANADA's.
To answer your first question, I would say that there are different types of flights. Normally, passenger carrying airplanes are operated in accordance with instrument flight rules, or IFR. In that case, ICAO international standards apply. Pilots have to have a flight plan, and very seldom does an aircraft enter Canadian airspace without having previously filed a flight plan.