Gyroscope (gyro)
The gyroscope is the sensor that measures the quad's rotation rate per axis — the basis of all control and all blackbox analysis.
Every PID decision and every FFT is based on the gyro signal. The gyro's quality (noise behaviour, e.g. MPU6000 vs. ICM-42688) determines how much filtering is needed. PIDoctor reads the filtered and — in debug mode — the unfiltered gyro.