One reason NORAD has detected more “objects” in recent days may be that the command recently retuned its filters to better spot slow-moving targets operating above a certain altitude, A source briefing on the matter told CNN.
The filters were only retuned and expanded in the past week, the sources said, after a high-altitude balloon suspected of being a Chinese spy flew over the United States and sparked a debate over the country’s ability to detect and defend against any potentially threatening objects entering its territory airspace.
The Washington Post first reported the NORAD shakeup.
The U.S. was able to track the path of the spy balloon before it entered U.S. airspace — and eventually shot it down off the coast of South Carolina — in large part because the U.S. intelligence community has developed a tracker over the past year. The balloon approach, using a specific set of signals they send out, as CNN previously reported.
In general, however, NORAD tends to prioritize detection of fast-moving targets below a certain altitude—threat aircraft or certain missiles, for example, might fly at that altitude.
The narrower filter is designed to give NORAD and defense officials a better understanding of the vast amounts of data collected on any given date, the sources said. AWACS pick up a lot of noise if they don’t filter out slow-moving objects, such as weather balloons and birds.
Two of the three objects shot down in the past three days were flying near Alaska and over northern Canada at altitudes of about 40,000 feet, posing a potential threat to civilian aircraft, U.S. and Canadian officials said. Both objects appear to have a balloon with a small metal cylinder underneath, officials said.
So far, little is known about the third object that was shot down near Lake Huron on Sunday.