What is the minimum number of legs that must be flown to complete sensor registration?

What is the minimum number of legs that must be flown to complete sensor registration?

• A. One
• B. Four
• C. Two
• D. Three

Answer: (C)

The key idea is that you need observations from more than one viewpoint to determine how the sensor is positioned and oriented relative to the vehicle. With a single leg (one flight), all measurements come from the same pose, so you can’t uniquely solve for the six parameters that describe the sensor’s pose (three for translation, three for rotation). You wouldn’t know how much of what you see is due to the sensor’s tilt versus its position. When you fly a second leg, you get a different viewpoint. Those two sets of observations provide enough independent information to constrain and solve for the relative pose between the sensor and the vehicle, especially if you’re using a known calibration target or reference features in both legs. Two legs give you the minimum data needed to register the sensor accurately; more legs can improve robustness and accuracy, but two is the smallest number that makes the problem solvable.

The key idea is that you need observations from more than one viewpoint to determine how the sensor is positioned and oriented relative to the vehicle. With a single leg (one flight), all measurements come from the same pose, so you can’t uniquely solve for the six parameters that describe the sensor’s pose (three for translation, three for rotation). You wouldn’t know how much of what you see is due to the sensor’s tilt versus its position.

When you fly a second leg, you get a different viewpoint. Those two sets of observations provide enough independent information to constrain and solve for the relative pose between the sensor and the vehicle, especially if you’re using a known calibration target or reference features in both legs. Two legs give you the minimum data needed to register the sensor accurately; more legs can improve robustness and accuracy, but two is the smallest number that makes the problem solvable.