Sea state estimation using vessel response in dynamic positioning

Abstract

This paper presents a novel method for estimating the sea state parameters based on the heave, roll and pitch response of a vessel in dynamic positioning (DP), i.e., without forward speed. The algorithm finds the wave spectrum estimate from the response measurements by directly solving a set of linear equations, and as a result it is computationally efficient. The main vessel parameters are required as input. Apart from this the method is signal-based, with no assumptions on the wave spectrum shape. Performance of the proposed algorithm is demonstrated on full-scale experimental DP data of a vessel in three different sea states at head, bow, beam, quartering and following sea waves, respectively.

Modeling and Analysis of Motion Data from Dynamically Positioned Vessels for Sea State Estimation

“…Most of the research for sea state estimation recently is combining the wave-induced response measurements, which are collected by wave buoys or directly from the ship motion, and a mathematical model. The previous work focused on the field of frequency domain analysis where the wave (energy) spectrum would be given [7], [8], [9], [10], [11], [2]. Pascoal and Soares [12] proposed a Kalman filtering based method which relies on the accurate RAOs in time domain only.…”

“…As the complex marine operations have been moving towards the ultra-deep sea, the demanding of new technologies and equipment is increasing to make the operations more safe for the harsh environment [1]. The working window of vessels is weather-dependent, which requires adequate understanding of the weather condition to reduce cost and improve safety [2]. Recently, there is a trend to consider developing more advanced vessels that have intelligence and are capable of executing different levels of autonomy for maritime operations.…”

“…A *Corrosponding author Xu Cheng and Robert Skulstad have equal contribution. 1 ship can be considered as a big wave buoy, thus, inherently equipped with a sea state estimation system [2].…”

Estimation of on-site directional wave spectra using measured hull stresses on 14,000 TEU large container ships

“…Brodtkorb et al developed a simple method to solve the wave spectrum by using the iteration method. Under the condition of zero velocity and long-crested waves, the wave spectrum is estimated by the experimental ship, and a good result is obtained [18]. After that, considering the influence of ship speed and short-crested waves, Nielsen et al extended the method and verified the effectiveness of the method [19].…”

Ship Motion-Based Wave Estimation Using a Spectral Residual-Calculation

“…Nonetheless, the underlying computational/mathematical methods have been found to suffer in many cases of being too slow or inefficient (although being fairly accurate). Recently, however, a novel procedure has been developed by Brodtkorb et al [10] and Nielsen et al [11], where the former study considers stationkept, dynamically positioned ships exclusively, while the latter [11] focuses on ships with a non-zero forward speed, and to some extent represents a generalisation of the former. Regardless of forward speed, the procedure relies on a bruteforce, residual calculation formulated in the frequency domain through spectral analysis and, indeed, this solution-strategy is what makes the particular procedure computationally very efficient with computational times in the order of a few seconds.…”