Improved Inertial/Odometry/GPS Positioning of Wheeled Robots Even in GPS-Denied Environments - Global Navigation Satellite Systems: Signal,Theory and Applications - page 275

789.2 meters the latter shows an error of 68.29 meters. The reason for this huge enhancement
of performance is the use of accelerometers vice the two gyroscopes used to get pitch and roll
from the RISS.
As seen in the first trajectory the benefit of using velocity updates during GPS outages derived
from the wheel encoders is seen by two comparisons. The first comparison uses KF with full
IMU and considers two sets of results, one with and the second without velocity updates.
With velocity updates the solution has an average of the maximum positional error for the
seven GPS outages equal to 11.44 meters while the case without updates has 789.2 meters of
error.
Fig. 9. Three solutions and reference for second trajectory: Red for reference, Yellow for KF
using full IMU with velocity updates, Green for KF using RISS without updates, Blue for KF
using RISS with velocity updates.
Fig. 10. RMS errors for altitude and 2D position for the seven outages in second trajectory.
The second comparison uses KF with RISS and considers two sets of results, one with and
the second without velocity updates. With velocity updates the solution has an average of