State-of-the-art equipment will be deployed during the test weeks including:
- Automated boats (USV)
- Underwater vehicles (AUV & ROV)
- Hydrographic boats and Zodiac
- Amphibious vehicle (Argo)
DTM of Guerledan Lake
This project aims to provide the bathymetry of lakeGuerlédan. Emphasis will be placed on survey design to ensure, as far as possible, full coverageof this geographical area. The resulting bathymetric model will be used by others students as a basis for their oceanographic studies. This Digital TerrainModel (DTM) will then be compared to previous ones.The results will be provided to EDF to support their environmental projects. For these purposes, hydrographic data will be collected to achieve S-44 IHO special order. Requested work: As a first step, the students have to install and configure their mobile mapping system. They will be responsible for ensuring the effective functioning of the system using the patch test and QC procedures. The extends of lake Guerlédan makes it necessary toset priority areas. The latter will be defined by the teacher team together with bathymetric data users. The students will be in charge of the design and conduct of the bathymetric surveys. An initial Quality Check procedure will be systematically applied after each survey to guarantee the data quality. The post processing as well as the DTM comparisons will be finalized at ENSTA Bretagne.
Reference network setup around Lake Guerlédan
The aim of this project is to realize a reference network along Lake Guerlédan. This network will allow the georeferencing of surveys in national 3D (RGF93) and height (IGN69) reference frames. Works to lead:
- Listing of nearby existing markers from French 3D and vertical networks.
- Choice of new markers
- Observation by static GNSS or terrestrial measurements (total station) of markers
- Vertical referencing of new markers to IGN69by direct and/or trigonometric leveling
Low-cost and autonomous hydrographic system
This project aims at designing a low-cost and autonomous hydrographic system. This robotized approach will lead to the acquisition of a digital elevation model (DEM) of the Guerlédan Lake. The project includes the software development of the platform, the installation of several sensors, data processing, and control quality check. The final goal is to obtain a real-time data process including acquisition, processing and quality-check.
Seamless mapping of the shore
This subject intends to construct a seamless digital elevation model (DEM) from land to shallow water. To accomplish this objective, an amphibious off-road vehicule is equipped with a laser scanner and with a single-beam scanning sonar. The challenging part of this project is to merge the data from these two sensors into a single DEM and to analyze the relevancy of data near the water surface.
Using robots for bed-sediment grain size analysis
Bed-sediment grain size is usually studied using high resolution cameras mounted on ROVs (Remotely Operated Vehicles). However, in shallow water or in rivers with varying currents, it might not be possible to use submarines. This project proposes to study the use of 2 types of robots to try to overcome this issue: surface robots and aerial robots. The idea is to build/use robots such as a hovercraft and a multirotor, able to deploy an underwater camera, and process the resulting data to get information on the sediment.
3D reconstruction of immerged objects
The French hydrographic service (SHOM) is interested in testing different bathymetric functionalities of the Kongsberg E M2040C Multibeam echosounder, inorder to detect specific objects such as trees. The aim of this study is to reconstruct 3D underwater objects, comparing the results obtained either with the classic bathymetric method, the extra-detection, and the water column data. These last two methods are supposed to improve the reconstruction of 3D objects. The main results of this study will be discussed and analyzed.
Localization of a plane black box
A plane black box lost on the sea floor should emit a specific acoustic signal that it is possible to detect using hydrophones installed on an autonomous robot. Depending on the signal received, the robot could move and try to localize it, and get asclose as possible. To simplify tests, the acoustic signal of the black box will be considered as the same as the one specified in the corresponding task of the SAUC-E 2016 competition: a 15 KHz sinusoid emitting during 10 ms every second, see http://sauc-europe.org/. Thus, it should be possible to easily generate/record this signal from a standard PC sound card. To set up this experiment, a waterproof box with aniXBlue hydrophone and the corresponding audio amplifier (powered by a 12 V battery) that can be directly connected to the audio output of a PC will be available. This will be used as the black box. The robot used (boat and/or submarine) to localize the black box will be equipped with 2 Aquarian Audio H2a-XLR hydrophones directly connected to the stereo microphone input of the embedded computer (enable Phantom power supply of the microphone input if necessary). The final goal of the project will be to make a demo where the robot can automatically and as accurately as possible go in the direction of the black box by localizing it thanks to its acoustic signal.
Acoustic and oceanographic study of water column
- Acoustic part: The aim of this part is to study water column in order to define if different water masses exist. For this, some acoustic surveys will be lead thanks to single beams at several frequencies. The advantage of multi-frequency is linked to the fact the reflectors don’t have the same behaviour according to its nature (rigid, gaseous, fluid-like…). The recordings of echograms at different frequencies allow us in some cases to distinguish the different reflectors. These surveys can be repeated on several days to put in evidence an eventual temporal evolution.
- Oceanographic part: Surveys of temperature and chlorophyll concentration will be lead at fixed point (temporal sampling) and/or on radiales (spatial sampling). These surveys will be integrated in an oceanographic model at Guerledan Lake in order to put in evidence the water masses and their temporal and spatial variability. A comparison will be done with acoustic data to see if a stratification on temperature would be the explanation of the presence of different water masses at acoustic level.
The first aim of this study is to develop an oceanographic model of Guerledan Lake to simulate pollution cases. Some environmental parameters will be used for model parametrisation and for lake characterization: temperature, chlorophyll, turbidity. Different pollution scenarii will be simulated and these simulations will be used to try to develop anoperational tool that shows how the pollution will be propagated in function of meteorological conditions, pollutant characteristics,… The second aim of this study is to use the oceanographic model of Guerledan to put in evidence the possible presence of seiches.
Dam inspection with a forward looking sonar
Dam inspection can be performed underwater by acoustic means. We will first use a mechanical scanning sonar carried by an in-house rolling carrier and then a forward looking sonar (FLS) carried by a ROV (Remotely Operated Vehicle). This project aims to find the best strategy to inspect the dam of the Guerledan lake given systems capabilities and dam characteristics.