GNSS/LiDAR-Based Navigation of an Aerial Robot in Sparse Forests.

Autonomous navigation of unmanned vehicles in forests is a challenging task. In such environments, due to the canopies of the trees, information from Global Navigation Satellite Systems (GNSS) can be degraded or even unavailable. Also, because of the large number of obstacles, a previous detailed map of the environment is not practical.

Quaternion-Based Robust Attitude Estimation Using an Adaptive Unscented Kalman Filter.

This paper presents the Quaternion-based Robust Adaptive Unscented Kalman Filter (QRAUKF) for attitude estimation. The proposed methodology modifies and extends the standard UKF equations to consistently accommodate the non-Euclidean algebra of unit quaternions and to add robustness to fast and slow variations in the measurement uncertainty. To deal with slow time-varying perturbations in the sensors, an adaptive strategy based on covariance matching that tunes the measurement covariance matrix online is used.

Using data-driven discrete-time models and the unscented Kalman filter to estimate unobserved variables of nonlinear systems.

This paper addresses the problem of state estimation for nonlinear systems by means of the unscented Kalman filter (UKF). Compared to the traditional extended Kalman filter, the UKF does not require the local linearization of the system equations used in the propagation stage. Important results using the UKF have been reported recently but in every case the system equations used by the filter were considered known.

[Chronotropic-metabolic index in Chagas' disease].

Chronotropic incompetence is a common feature in Chagas' disease patients. New methodologies are now available to evaluate the chronotropic response in different subsets. The chronotropic-metabolic index (CMI) is one of these new indexes and quantifies the relationship between the increment of heart rate and the maximal oxygen consumption (VO2 max) during exercise testing.