Investigating munitions mobility in oscillatory flows with Inertial Measurement Units

Aiming at the problem that the guided projectile is difficult to implement in-flight alignment of roll angle with low-cost gyroscope, this paper proposes an in-flight alignment scheme based on the pitch angle velocity vector caused by gravity. The relationship between the rotation angular velocity measured by the gyroscope and the roll angle at the alignment time is established. In order to avoid the influence of uncalibrated MEMS gyroscope on alignment accuracy, the gyroscope error is modeled and included in the alignment equation. Then the gyroscope error is estimated and compensated by adaptive Adam algorithm. Consequently, the accuracy of alignment can be effectively improved. Mathematical simulations show that the alignment accuracy of the roll angle can be within 3 °, and the bias and installation error angle of the gyroscope can be effectively calibrated, which can improve the accuracy of inertial navigation.

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Momentum Balance Analysis of Spherical Objects and Long-Term Field Observations of Unexploded Ordnance (UXO) in the Swash Zone

Cristaudo¹,

Gross²,

Puleo

2023

JMSE

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Military activity has resulted in unexploded ordnance (UXO) existing in the nearshore. Understanding and predicting UXO behavior is important for object identification, and management. Here, two studies (laboratory and fieldwork) have been conducted to observe UXO surrogates in the swash zone and relate burial and migration to the underlying forcing conditions. A small-scale laboratory dam-break study was conducted to quantify migration of varying density spherical objects at different locations on a sloping, mobile, sandy bed. A moment balance was applied to derive two data-driven relationships to: (1) predict moments from the cross-shore flow velocity with predictions confined within a factor of two; (2) predict upslope or downslope migration from the moment. Fitting coefficients for the upslope and downslope relationships vary as a function of density, initial position, and burial. A field study was also conducted to investigate long-term behavior of eight varieties of UXO surrogates. Of the 129 observations, 56% were mobilized of which 76% were directed offshore. Burial/exposure was mostly related to far-field beach accretion/erosion (67%). However, scouring processes were also observed. Data showed that migration is likely a short-term process and most munitions will ultimately scour into a mobile bed.

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Investigating munitions mobility in oscillatory flows with Inertial Measurement Units

Cited by 4 publications

References 6 publications

Smart Surrogate Munitions for Nearshore Unexploded Ordnance Mobility/Burial Studies

Smart Surrogate Munitions for Nearshore Unexploded Ordnance Mobility/Burial Studies

In-flight alignment of roll angle and gyroscope calibration method for guided projectile based on adaptive Adam algorithm

Momentum Balance Analysis of Spherical Objects and Long-Term Field Observations of Unexploded Ordnance (UXO) in the Swash Zone

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