Pilot:
J-TRUE FPV
utilities
Filter calc tool
Your quadcopter’s brain is the Flight Controller (FC). The FC has an on-board gyro chip that has a built-in filter (the “Digital Lowpass Filter” [DLPF]) and also the software (firmware) on the FC has additional filters. These filters are needed to reduce the vibration the gyro detects from the motors spinning; the “noise” you hear from the motors. In the quadcopter industry, we call it “gyro noise”. The downside of filters is they delay the gyro readings going into the P.I.D. loop; the main control loop that flys the quad. Like steering a boat at low throttle, the delay can cause over-correcting when the FC needs to make fast auto-corrections in flight; leading to poor flight performance. However, too much “noise” (motor vibrations) in the gyro signal can be amplified by the PID loop and cause the motors to get hot and burn out. So the ideal amount of filtering is “just enough”.
My filter calc tool calculates the amount of filtering delay your filter setup is adding to the gyro signal. A reasonable amount of filter delay is 4ms to 5ms for a 5″ quad to have decent flight handling characteristics. For more details on filters and how they work see the Fundamentals page.