10/09/2026
Let’s learn about RADAR! 📡
Did you know that your hometown airport hosts a critical piece of the air traffic surveillance infrastructure serving Michigan and the surrounding Great Lakes region?
MKG’s radar is an ASR-9 (Airport Surveillance Radar), and the technology behind it is fascinating!
Located about a hundred feet up on top of a large tower, near the terminal parking lot, the giant rotating antenna does far more than monitor aircraft arriving and departing Muskegon’s airspace. It’s part of an interconnected surveillance network called “Fusion” that helps air traffic controllers safely manage aircraft movements across the entire region.
The ASR-9 installation uses two primary methods to track aircraft:
📡 Primary Radar: The antenna transmits powerful pulses of radio energy that reflect off aircraft and return to the receiver. By measuring how long those signals take to return and the direction they came from, the system calculates an aircraft’s distance and bearing. This allows radar to detect aircraft even if they aren’t equipped with a functioning transponder.
✈️ Secondary Surveillance Radar: A separate antenna interrogates aircraft transponders, which respond with their assigned four-digit “squawk code” and pressure altitude. Squawk codes help controllers identify individual aircraft on radar displays. There are 4,096 possible combinations, including special codes like 7500 (hijacking), 7600 (radio failure), and 7700 (emergency).
Our ASR-9 has a surveillance range of approximately 60 nautical miles, and its antenna completes a full rotation about every 5 seconds. It also has weather detection capabilities that help controllers identify precipitation.
But here’s where things get really interesting.
The FAA’s Fusion network combines information from multiple radar installations across Michigan to support ATC operations at Great Lakes Approach in Kalamazoo and Chicago Center.
Here’s a great example of how that works right here in West Michigan: MKG and GRR in Grand Rapids both have ASR-9 radar installations, located exaclty 41 miles apart.
With each radar capable of detecting aircraft up to approximately 69 miles away, their surveillance areas overlap considerably. That provides valuable redundancy, allowing both installations to contribute coverage of the airspace surrounding Muskegon and Grand Rapids. If one radar becomes unavailable, the other can continue providing surveillance information across much of the shared coverage area.
And there’s another significant advantage to this teamwork! While an individual ASR-9 takes roughly 5 seconds to complete a rotation, the fused surveillance system can update an aircraft’s displayed position approximately every 3-4 seconds. If an aircraft is traveling at 400 mph or more, every second matters.
So the next time you drive past that spinning antenna at MKG, remember that it’s doing far more than watching our little corner of West Michigan.
It’s an important piece of a massive, interconnected nationwide system helping keep aircraft moving safely through the skies across Michigan and beyond, 24/7/365. ✈️
