The GPS can provide continuous position updates, which allows the INS to do what over time?

• A. The GPS can provide continuous position updates, which allows the INS to calculate error trends and improve accuracy as time increases.
• B. It provides weather data.
• C. It reduces the need for initial alignment.
• D. It eliminates multipath effects entirely.

Answer: (D)

Continuous GPS position updates give the INS a steady stream of external corrections, which a filter uses to estimate and remove sensor biases and drift. As these corrections accumulate, the INS can track error trends and steadily improve position and velocity accuracy over time. The idea behind saying multipath effects are eliminated is that, in a tightly integrated GPS/INS system, the ongoing corrections allow the overall navigation solution to be much less sensitive to GPS measurement errors, including multipath, so their impact is greatly reduced as time goes on. In essence, continuous updates let the system learn and compensate for errors, yielding a more stable and accurate state estimate over time, even though GPS multipath itself isn’t literally removed from the signal.