Alignment methods for strapdown inertial systems.

Farrell, James L.; Knight, J. W.; Thompson, Edward H.

doi:10.2514/3.28671

Cited by 7 publications

(1 citation statement)

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“…The very purpose of the alignment is to roughly estimate the attitude of the vehicle (or body) frame relative to the navigation frame, so that it can be used, and posteriorly corrected, by any filtering-based navigation/guidance stage deployed afterwards [4]. As explained by Thompson, Farrell, and Knight [5], the alignment requires the observation of, at least, two noncollinear vectors, whose components should be known in both body and navigation frames. Traditionally, the local gravity and Earth rate vectors, measured by stationary accelerometers and gyros, respectively, provided by an Inertial Measurement Unit (IMU), have been chosen for INS alignment purposes [6].…”

Section: Introductionmentioning

confidence: 99%

Error Analysis of Accelerometer- and Magnetometer-Based Stationary Alignment

Silva

Paiva

Carvalho

2021

Sensors

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This paper revisits the stationary attitude initialization problem, i.e., the stationary alignment, of Attitude and Heading Reference Systems (AHRSs). A detailed and comprehensive error analysis is proposed for four of the most representative accelerometer- and magnetometer-based stationary attitude determination methods, namely, the Three-Axis Attitude Determination (TRIAD), the QUaternion ESTimator (QUEST), the Factored Quaternion Algorithm (FQA), and the Arc-TANgent (ATAN). For the purpose of the error analysis, constant biases in the accelerometer and magnetometer measurements are considered (encompassing, hence, the effect of hard-iron magnetism), in addition to systematic errors in the local gravity and Earth magnetic field models (flux density magnitude, declination angle, and inclination angle). The contributions of this paper are novel closed-form formulae for the residual errors (normality, orthogonality, and alignment errors) developed in the computed Direction Cosine Matrices (DCM). As a consequence, analytical insight is provided into the problem, allowing us to properly compare the performance of the investigated alignment formulations (in terms of ultimate accuracy), as well as to remove some misleading conclusions reported in previous works. The adequacy of the proposed error analysis is validated through simulation and experimental results.

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Section: Introductionmentioning

confidence: 99%