Navigation Functionalities for an Autonomous UAV Helicopter
Navigation Functionalities for an Autonomous UAV Helicopter
Navigation Functionalities for an Autonomous UAV Helicopter
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66 CHAPTER 5. SENSOR FUSION FOR VISION BASED LANDING<br />
noisy. Early attempts have been made in applying a low-pass filter to this<br />
velocity to remove the noise but the increased delay made the tuning of the<br />
control system more difficult. The velocity data provided by the Kalm<strong>an</strong><br />
filter has low latency as c<strong>an</strong> be observed from the comparison with the GPS<br />
velocity. This is due to the fact that the Kalm<strong>an</strong> filter takes adv<strong>an</strong>tage of<br />
the high frequency <strong>an</strong>d low latency in<strong>for</strong>mation from the accelerometers.<br />
The use of low latency velocity in<strong>for</strong>mation allows <strong>for</strong> stable control during<br />
the l<strong>an</strong>ding approach.<br />
Figure 5.5: Comparison between velocity derived from raw vision position,<br />
sensor fusion <strong>an</strong>d GPS <strong>for</strong> the North component.<br />
Figures 5.8 <strong>an</strong>d 5.9, show a comparison between the attitude <strong>an</strong>gles<br />
provided by the vision system alone (see Paper III <strong>for</strong> details as to how the<br />
vision system calculates the attitude <strong>an</strong>gles), the attitude <strong>an</strong>gles calculated