Exactly. It was tracked with radar reflectors to make it visible, and from a position they knew the jets would be close, while also tracking their transponders

Exactly. It was tracked with radar reflectors to make it visible, and from a position they knew the jets would be close, while also tracking their transponders to correlate with the reflection data. This is the equivalent of saying they successfully completed the Daytona 500 by driving a Honda around the track a few times at 45 miles an hour with the track closed to everyone else.