Elder M. Hemerly, Benedito C.O. Maciel, Anderson de P. Milhan and Valter R. Schad
The purpose of this paper is to employ an extended Kalman filter for implementing an AHRS (attitude and heading reference system) with acceleration compensation, thereby improving…
Abstract
Purpose
The purpose of this paper is to employ an extended Kalman filter for implementing an AHRS (attitude and heading reference system) with acceleration compensation, thereby improving the reliability of such systems, since this removes the usual restrictive assumption that the vehicle is undergoing a non‐accelerated maneuver.
Design/methodology/approach
MARG (magnetic, acceleration and rate gyros) sensors constitute the basic hardware, which are integrated by the Kalman filter. The error dynamics for attitude and gyro biases is obtained in the navigation frame, providing a much simpler approach than usually taken in the literature, since it relies on direct quaternion differentiation. The state vector associated to the error dynamics possesses six components: three are associated to the quaternion error and three concern gyro bias estimates.
Findings
The AHRS is implemented in an ARM (Advanced RISC Machine) processor and tested with experimental data. The accelerated case is treated by two complementary approaches: by changing the noise variance in the Kalman filter, and by obtaining an acceleration information from GPS (global positioning system) velocity measurements. Experimental results are presented and the performance is compared with commercial ARHS systems.
Practical implications
The proposed AHRS can be implemented with low cost MARG sensors, and GPS aiding, with use for instance in UAV (unmanned aerial vehicle) and small aircrafts' attitude estimation, for navigation and control applications.
Originality/value
Usually the AHRS designs employ as states total gyro bias and Euler angles, or quaternion, and do not consider the accelerated case. Here the state is comprised by gyro bias and quaternion error variables, which attenuates the effect of nonlinearities, and two complementary procedures tackle the accelerated case: acceleration correction by using a GPS derived acceleration signal and change in the output noise covariance used by the Kalman filter.
Details
Keywords
This paper aims to look at how organisational partnerships balance knowledge exploration and exploitation in contexts that are rife with paradoxes. It draws on paradox theory to…
Abstract
Purpose
This paper aims to look at how organisational partnerships balance knowledge exploration and exploitation in contexts that are rife with paradoxes. It draws on paradox theory to examine the partnership’s response to the explore-exploit relationship.
Design/methodology/approach
A multiple interpretive case study was used to examine international partnerships in three African countries. These partnerships were between international (Northern-based) non-governmental organisations and local African non-governmental organisations.
Findings
The research finds that within the partnership, knowledge exploration and exploitation exist as a duality rather than a dualism. This is supported by the acceptance and confrontation of paradoxes of performing and belonging. However, macro-level paradoxes of organising linked to power, culture and epistemologies inhibit further effective confrontation of the explore-exploit paradox.
Practical implications
The findings can help managers working in international development organisations to understand how learning is enabled and constrained in partnership-based programmes.
Originality/value
The study provides a novel contribution to knowledge management by applying the paradox perspective to the explore-exploit relationship. This paper extends previous work by drawing on the levels and repertoires present in the paradox perspective to understand how knowledge exploration and exploitation can be mutually reinforcing and can exist as a duality.