Methodology for Verifying the Indication Correctness of a Vessel Compass Based on the Spectral Analysis of Heading Errors and Reliability Theory

Jaskólski, Krzysztof

doi:10.3390/s22072530

Cited by 6 publications

(7 citation statements)

References 20 publications

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“…All the surveys were carried out in the course of these vessels performing their statutory tasks. The data recorded on the ORP Arctowski survey ship are very similar to those previously used in an earlier publication [ 17 ], although, at that time, the recordings were made on a different vessel.…”

Section: Resultsmentioning

confidence: 80%

The Properties of a Ship’s Compass in the Context of Ship Manoeuvrability

Felski

Jaskólski

2023

Sensors

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In evaluating the accuracy of most navigation measuring systems, it is accepted, as a rule, that measurement errors are characterised by a normal distribution. With reference to the compass, the approach of most producers is similar. However, in the case of this measuring device, the dynamics of the ship should also be taken into account. The problem is that any changes in the ship’s heading can be measured exclusively with the use of a compass. Until quite recently, this device was built based on mechanical elements, so it possessed its own dynamic properties. This means the appearance of specific, positive feedback (self-reinforcing feedback) because if the compass did not point to the correct heading, it could lead the ship to stray from the correct heading. On the other hand, it could mean an incorrect compass setup, even though the ship had the correct heading. Any incorrect indications of the compass were then interpreted as a ship’s departure from the correct heading. This problem was not essential in the era of magnetic compasses because the errors in these compasses are relatively constant, unlike the errors in gyrocompasses, which have an oscillatory and random character and, thus, it is not possible to describe them accurately with mathematical relations. This issue was already perceived before WWII, when the Anschutz Company proposed, among other solutions, using the so-called Schuler period in the construction of gyrocompasses. Fibre optic gyrocompasses do not possess mechanical sensors, so the variability of their indications is of a different character. However, computational processes, as well as applied inertial sensors, also cause certain errors of an oscillatory nature. This raises the following questions: what is the spectrum of the error frequency of such compasses, and what is the influence of the ship’s movement on them? The authors attempted to evaluate this phenomenon by performing measurements made on board three hydrographic platforms and comparing them with the headings indicated by other compasses.

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Section: Resultsmentioning

confidence: 80%

The Properties of a Ship’s Compass in the Context of Ship Manoeuvrability

Felski

Jaskólski

2023

Sensors

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“…The maximum MTTR exceeds 1100; 1300 s, respectively. Outlying values for the main harmonics can be filtered out with a low-cut filter with a finite impulse response (FIR) [21].…”

Section: Resultsmentioning

confidence: 99%

Availability of Automatic Identification System (AIS) Based on Spectral Analysis of Mean Time to Repair (MTTR) Determined from Dynamic Data Age

Jaskólski

2022

Remote Sensing

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Good marine practice and proper operation of navigation, radio navigation, and radio communication systems are nowadays of key importance for marine navigation safety. This applies to merchant vessels and navy ships and effectively monitoring unmanned vehicles along a set route. Technological progress has contributed to developing equipment for ships and unmanned vehicles, which are fitted out with devices of the automatic identification system (AIS). One of the issues in AIS operation is limited-service availability, which manifests itself in the presence of incomplete data for the navigation parameters sent by radio, compressed in dynamic data messages. This results in the unusability of the system information for ships equipped with an AIS transponder. This paper aims to develop an AIS service availability model based on the mean time of incomplete navigation parameter occurrence in AIS data messages and to present the test results in the time and frequency domain using a mathematical method—Fast Fourier Transform. The study results refer to five basic navigation parameters and are indicative of a high service availability index—over 0.99 for three out of the five navigation parameters tested. Data recorded by a ship’s system receiver were the key source of practical knowledge concerning the limitations of AIS service availability. The experiment revealed interruptions in regular data inflow from navigation devices. In effect, a description was provided of a functional relationship based on a spectral analysis of the frequencies of the times occurring between service repair (time to repair—TTR), and the use of the model to analyze other variables was proposed.

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“…Plotting the compass course is a basic task executed by an electronic compass. The measured resultant vector of the magnetic field is corrected automatically (auto-compensation) by the deviation value, so it equals the magnetic course value [ 50 , 51 , 52 , 53 , 54 , 55 ]. An INI-200 ATC compass was used in the measurements.…”

Section: Methodsmentioning

confidence: 99%

Determination of USV’s Direction Using Satellite and Fluxgate Compasses and GNSS-RTK

Makar

2022

Sensors

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The measurement of a mobile object’s movement direction is performed by means of various analogue and digital devices, including both autonomous and non-autonomous ones. They represent different measuring qualities, dimensions, weights and tolerance to ambient disturbances. They allow measuring the course of heading and course over ground (COG) in sea navigation. They are used for the determination of motion vectors on the water’s surface and with respect to the sea bed, in integrated systems, DP and autopilots. Results of dynamic tests of three heading meters: electronic and satellite compasses, and Global Navigation Satellite Systems (GNSS) determining COG are presented in this paper. The measurements were conducted in good measuring conditions, in an open upper hemisphere for satellite receivers and at no or minimal disturbances of the magnetic field. Sensors were mounted on an unmanned survey vessel (USV) that was moving straight, performing quick turns and circulations. Each of them has some limitations with respect to its use in the water area in which a hydrographic sounding is to be performed; attention was paid to the possibility of using a given compass on board a small autonomous ship navigating automatically.

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Methodology for Verifying the Indication Correctness of a Vessel Compass Based on the Spectral Analysis of Heading Errors and Reliability Theory

Cited by 6 publications

References 20 publications

The Properties of a Ship’s Compass in the Context of Ship Manoeuvrability

The Properties of a Ship’s Compass in the Context of Ship Manoeuvrability

Availability of Automatic Identification System (AIS) Based on Spectral Analysis of Mean Time to Repair (MTTR) Determined from Dynamic Data Age

Determination of USV’s Direction Using Satellite and Fluxgate Compasses and GNSS-RTK

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