Bistatic range rate

Bistatic range rate is when two things are measuring how fast something is moving away from them, but they are not near each other. It's like when you and your friend are standing far apart and you each have a stopwatch. When someone runs past you, you start your stopwatch and your friend starts theirs. You both stop your stopwatch when the person is far away. Then you can compare your times to see how fast the person was running. Bistatic range rate is important because it helps us understand how things move and how they are changing over time. It's used in things like radar, where we need to know how fast planes, ships, or cars are moving.