IMUs are wildly expensive, and still have quite a lot of drift: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10752294" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10752294</a><p>Certainly the RQ-170 <i>has</i> an IMU, and I could believe it might use it as the primary means of navigation, but it&#x27;s almost certainly corrected by GPS, which gives you a means of altering the drone&#x27;s path by GPS spoofing.