What is the purpose of a bias in sensor readings and how is it corrected?

• A. A bias is a random noise; correct by filtering
• B. A bias is the maximum sensor output; correct by scaling
• C. A bias is a consistent offset; correct via calibration or offset adjustment
• D. A bias is the sampling rate; correct by increasing sample rate

Answer: (C)

Bias is a consistent offset between what the sensor outputs and the true value. It stays the same (or drifts slowly) regardless of the actual input, due to sensor imperfections, temperature effects, or electronics aging. Because this offset is systematic, you can remove it by calibration: compare the sensor reading to a known reference, determine the offset amount, and subtract that offset from all future measurements (either in software or by adjusting the sensor hardware). For example, an accelerometer at rest should read zero; if it shows a constant 0.05 g, that 0.05 g is the bias and subtracting it yields accurate readings. This approach is different from addressing random noise, which is handled with filtering; it’s also not about the sensor’s range or how often you sample.