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Position 2 > Positionnement Dynamique > Flashcards

Positionnement Dynamique Flashcards

1
Q

What are the advantages of a dynamic positioning system?

A
  • Excellente manoeuvrabilité
  • Pas dépendant de la profondeur d’eau
  • Rapide
  • Pas d’obstruction du fond de l’eau

These advantages make dynamic positioning systems suitable for various marine operations.

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2
Q

What are the disadvantages of a dynamic positioning system?

A
  • Système compliqué
  • Cher à l’installation
  • Cher d’essence
  • Beaucoup de maintenance

The complexity and cost can limit the use of dynamic positioning systems in certain scenarios.

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3
Q

List some applications of dynamic positioning systems.

A
  • Poseur de câble
  • Sea Launch
  • Navire foreur
  • Navire grues
  • Navire de croisière
  • Shuttle tanker

These applications highlight the versatility of dynamic positioning systems in the maritime industry.

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4
Q

What is an open-loop system?

A

Système où l’action contrôlée est indépendante du résultat obtenu.

Open-loop systems do not adjust based on feedback from the output.

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5
Q

What is a closed-loop system?

A

Système où l’action contrôlée est dépendante du résultat obtenu.

Closed-loop systems adjust their actions based on the feedback from the output to achieve desired results.

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6
Q

Qu’est-ce que le positionnement dynamique (DP) ?

A

Un système contrôlé par ordinateur permettant à un navire de maintenir sa position et son cap en utilisant ses propres moyens de propulsion.

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7
Q

Quels paramètres doivent être calculés pour contrôler le positionnement dynamique d’un navire ?

A

La position et le cap du navire, ainsi que, selon les systèmes, les mouvements du navire.

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8
Q

Combien de systèmes de référence de positionnement sont nécessaires pour le DP ?

A

Au moins deux systèmes de référence de positionnement.

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9
Q

Quel est le terme mieux connu pour désigner les systèmes de référence de positionnement ?

A

Position Reference System (PRS).

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10
Q

Listez quelques types de systèmes de référence de positionnement utilisés dans le DP.

A
  • Satellitaires
  • Laser
  • Ondes électromagnétiques
  • Hydroacoustique
  • Mécanique
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11
Q

What are the three main components of the system architecture?

A
  1. Capteurs ou instruments de mesure
  2. Console informatique
  3. Actionneurs

Each component plays a crucial role in the overall functioning of the system.

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12
Q

What types of sensors are included in the measurement instruments?

A

Anémomètres, girouettes, accéléromètres, PRS (Position Reference System), instruments de mesure du cap

These instruments help in collecting data necessary for system operation.

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13
Q

What is the role of the console informatique?

A

Effectue les calculs à l’aide du modèle mathématique et des données fournies par les capteurs

It also serves as an interface for the operator.

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14
Q

True or False: The operator can modify maneuver parameters in DP mode.

A

True

DP mode allows flexibility in operational parameters.

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15
Q

What are the actions performed by the actionneurs?

A

Agissent selon les commandes de l’ordinateur central

They include various propulsors, turbines, rudders, and/or propellers.

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16
Q

Fill in the blank: The _______ processes data using mathematical models and sensor inputs.

A

console informatique

This component is essential for decision-making in the system.

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17
Q

What is the absolute DP mode?

A

Maintenir une position géographique

This mode refers to maintaining a fixed geographic position.

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18
Q

What does relative DP mode maintain?

A

Maintenir sa position par rapport à un objet

This mode ensures the position is maintained relative to another object.

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19
Q

What is autotrack in DP modes?

A

Maintenir sa position, sa vitesse et son cap sur une route donnée

Autotrack helps in maintaining position, speed, and heading along a specified route.

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20
Q

What does the term ‘weathervane’ refer to in DP modes?

A

Maintenir son cap

This mode involves maintaining a specific heading.

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21
Q

What is the optimum heading facility in DP?

A

Weathervane ou optimum heading facility

This facility assists in determining the best heading based on environmental conditions.

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22
Q

What is the most commonly used positioning system?

A

DGPS

DGPS stands for Differential Global Positioning System.

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23
Q

What is a key advantage of DGPS?

A

La référence de positionnement est globale

The positioning reference is global and varies according to the GNSS.

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24
Q

How often is GPS available?

A

365/24

GPS is available 24 hours a day, 365 days a year.

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25
Q

What is a benefit of using DGPS equipment?

A

L’équipement est relativement bon marché et simple d’utilisation

DGPS equipment is relatively inexpensive and user-friendly.

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26
Q

What type of signals are DGPS signals?

A

Gratuits

The basic signals used in DGPS are free of charge.

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27
Q

What level of precision does DGPS offer for DP?

A

Assez précis

DGPS provides sufficient accuracy for dynamic positioning.

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28
Q

What is a feature of some DGPS receivers?

A

Bi-fréquences

Some receivers operate on dual frequencies.

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29
Q

Fill in the blank: Les corrections différentielles sont ______.

A

payantes

Differential corrections often come at a cost.

30
Q

What issue can occur near platforms and structures?

A

Problèmes récurrents de multi-trajet

Multipath issues can affect signal reception near structures.

31
Q

What can lead to loss of differential signals?

A

Présence des plateformes et autres structures

The presence of platforms can obstruct or degrade signal quality.

32
Q

What is a limitation related to GNSS?

A

Âge des corrections

The age of corrections can affect their accuracy and reliability.

33
Q

What is a fundamental principle of hydroacoustic reference?

A

Un transducteur est installé sous la coque du navire

A transducer is installed under the hull of the ship, similar to an echo sounder.

34
Q

What does the transducer emit?

A

Signaux sous formes d’impulsions

The transducer sends out signals in the form of mechanical waves.

35
Q

What is the purpose of the transponder in hydroacoustic positioning?

A

Déposés sur le fond marin à un endroit connu

The transponder is placed on the seabed at a precisely known location.

36
Q

What does the reception of signals allow in hydroacoustic systems?

A

Générer des données de positionnement

The received signal is used to produce positioning data.

37
Q

What are the two main types of HPR systems?

A

• Ultra-short Baseline HPR (USBL)
• Long Baseline HPR (LBL)

38
Q

What is a characteristic feature of the Ultra-short Baseline HPR (USBL)?

A

Un seul transpondeur est utilisé

39
Q

What does the transpondeur in USBL do?

A

Il répond aux impulsions codées du transducteur

40
Q

Where is the transpondeur installed in a USBL system?

A

À l’extrémité d’une tige de 4 à 5 mètres sous la coque du navire

41
Q

How is the distance separating the navire from the transpondeur determined in USBL?

A

Le signal reçu par le transducteur est traité

42
Q

What type of measurements does the transducteur in USBL allow?

A

Mesurer la direction du signal de retour en 3D

43
Q

What additional inputs are used in USBL to enhance measurement accuracy?

A

GYRO et MRU

44
Q

What is the precision range of the USBL system?

A

Précision de l’ordre de 1 à 2% de la profondeur

45
Q

What is one advantage of the USBL system?

A

Indépendant des autres parties, par exemple, DGPS relatif

46
Q

What is a disadvantage of the USBL system?

A

Complexe et dispendieux

47
Q

What factors can affect the precision of the USBL system?

A

• Présence de larges structures sous-marines
• Bruits, à l’aération, couches d’eau, turbulences et impuretés de l’eau

48
Q

In what types of water is USBL considered ineffective?

A

Eaux peu profondes et très profondes

49
Q

What problem can arise with USBL concerning other HPR systems?

A

Interférence possible avec d’autres HPR

50
Q

What does the precision of the USBL system depend on?

A

Le gyrocompas

51
Q

Fill in the blank: The USBL system can track _______ in motion.

A

des cibles

52
Q

What is a key limitation of the USBL system in deep waters?

A

Loses precision due to limitations in angular calculation at the transducer

53
Q

How does the LBL system differ from the USBL system regarding angle calculation?

A

No need to calculate angle at the transducer

54
Q

How are transducers installed in the LBL system?

A

Installed the same way as with USBL

55
Q

How many transponders are typically placed on the seabed in the LBL system?

A

4 or 5 transponders

56
Q

What is the purpose of the transducer emitting a signal towards the seabed?

A

To measure distance between each transducer/transponder pair

57
Q

What method is used to determine the position of the vessel in the LBL system?

A

Trilatération

58
Q

What effect do ship movements have on positioning in the LBL system?

A

No effect on positioning since no angular measurement is made

59
Q

What is the precision range of the LBL system?

A

0.2 to 0.4% of the depth

60
Q

What is one advantage of the LBL system regarding independence?

A

Independent of other parts, e.g., relative DGPS

61
Q

Can the LBL system be referenced globally?

A

Yes

62
Q

What are some disadvantages of the LBL system?

A

Complex and expensive; issues with noise, aeration, water layers, turbulence, and impurities

63
Q

How can the presence of large underwater structures affect the LBL system?

A

It can affect precision

64
Q

In which water conditions is the LBL system ineffective?

A

Shallow and very deep waters

65
Q

What does the precision of the LBL system depend on?

A

Gyrocompass

66
Q

Is there a possibility of interference with other HPR systems in LBL?

A

Yes, but this issue is resolved with multi-user systems

67
Q

What calibration possibility exists for the LBL system?

A

Calibrate for the actual density of the water column with specific transponders

68
Q

What is the average frequency range for hydroacoustic reference systems?

A

Between 18 and 32 kHz

69
Q

What is a feature of multi-user systems in the LBL context?

A

Hydrophone on the vessel to limit acoustic saturation possibilities

70
Q

Can some LBL systems be used as USBL?

A

Yes

Position 2 (1 decks)

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