78484 - Monitoring and Positioning In Offshore Engineering

Learning outcomes

This course provides theoretical and operatives knowledges concerning the monitoring and positioning aspects in the offshore engineering. In particular, different techniques for an accurate positioning based on GNSS technology will introduced both for monitoring of off-shore structures and for geolocalization of off-shore infrastructures. Examples of real applications regarding the monitoring or the positioning of offshore structures will be discussed.

Course contents

Language: English

Preliminary required knowledges

For this course some basis on survey and geodesy are required. Typically these background will be given during the courses of geomatics or topography or survey at the bachelor degree level.

Monitoring and positioning in off-shore Engineering

• Module 1 (24 hours) – Prof. Luca Vittuari

Basic of Positioning

• Satellite-based positioning:
  • to support on-shore and off-shore geophysical prospecting and bathymetric single/multi-beam surveys;
  • to place at the design position offshore drilling rigs
  • for the laying of pipelines along the design tracks
• Positioning by means of integrated sensors and underwater positioning
  • Dynamic positioning of supply vessels;
  • SBL (Short Base Line), and LBL (Long Base Line) acoustic positioning systems;
  • Underwater control networks

• On-shore monitoring of vertical movements of the soil, by spirit levelling networks, DInSAR integrated by GNSS analysis

Module 2 (24 hours) – Prof. Luca Tavasci

Basic on geodetic reference frames (global reference frames, local geodetic reference frames)

Basic on GNSS technique:

• single point positioning using pseudorange measurements (how GNSS works for location aspects),
• GNSS for precise positioning (GNSS for monitoring and high precision positioning)
  • Relative positioning: phase differential GNSS approach
  • Precise Point Positioning approach
  • SBAS and Augmentation Systems
  • Geodetic Navigation Systems

Data Analysis:

• Post processing of time series: from measurements to data interpretation
  • Periodical signal detection
  • Discontinuity detection
  • Mean velocity detection
  • Noise characterization

Readings/Bibliography

Teachers upload the personal notes on the web site virtuale.unibo.it.

Teaching methods

The course is composed by frontal lessons and practice (outdoor and in laboratory.

In particular the course is generally composed by:

• 85% of frontal lessons
• 15% of practice (outdoor and in laboratory)

Assessment methods

The exam is mainly written and composed by 5/6 questions. Than, starting from the obtained grade is possible to have an oral section that can increase the final grade within 3 points.

The evaluation will be based on different aspect related to:

1) capability to identify the best methods and instrumentations for the case study

2) Knowledge of the methods and tecniques usefull for the case study

3) Capability to apply statistical tests for minimum movement detection.

4) Capability to estimate the real accuracy obtained by a topographical survey using the statistical law of the variance/covariance propagation in non linear multidimensional functions

Teaching tools

In order to support the classical frontal lessons in the classroom, some practical exercises will be performed both in outdoors and in the laboratory.

In particular:

Practices (outdoor)

• Survey of a small network using spirit leveling.
• Survey of a geodetic network using GPS static approach.
• RTK and NRTK survey practice
• TLS survey (if available)

Data analysis (laboratory)

Data Processing of the acquired data during the practices (in outdoor)

Office hours

See the website of Luca Vittuari

See the website of Alessandro Lambertini