AHRS initialization time in MAG and DG is approximately?

• A. 70secs; 10 mins
• B. 5mins; 2mins
• C. 2mins; 5mins
• D. 30secs; 1min

Answer: (A)

AHRS initialization times depend on which reference sensors the system uses to establish attitude. Using the magnetometer as a reference gives a quick alignment because it uses Earth's magnetic field to lock in heading, so the system can settle in on the attitude in a relatively short period—about 70 seconds. In contrast, when relying on the directional gyro (DG) or inertial alignment, the estimator has to integrate sensor data and estimate biases without an external heading reference, which takes much longer to converge—often around 10 minutes for a stable alignment.

That’s why the best answer lists roughly 70 seconds for MAG and about 10 minutes for DG. The other options pair times that don’t align with how quickly a magnetometer-based alignment typically settles versus the much slower inertial-only alignment. In practice, factors like magnetic interference or movement can affect these times, but the general pattern remains: MAG is short, DG takes significantly longer.