Which statement best describes how GPS and INS work together?

• A. They operate completely independently.
• B. The INS provides continuous position updates to assist the GPS.
• C. The INS provides weather data to the GPS.
• D. GPS updates support the INS, and the INS performs dead reckoning.

Answer: (D)

Combining GPS updates with the INS is how integrated navigation stays accurate. The INS uses accelerometers and gyros to continuously estimate position, velocity, and attitude through dead reckoning, but it drifts over time due to sensor biases. GPS provides periodic, precise position and velocity fixes that anchor the INS solution and correct that drift. Between GPS updates, the INS still supplies motion information, while GPS updates continually refine the INS estimates. So, GPS updates support the INS, and the INS performs dead reckoning.