Data acquisition for the project is based on the following hardware (unmanned platforms and sensors) that is owned by the Laboratory of Geophysical – Satellite Remote Sensing and Archaeoenvironment, Institute for Mediterranean Studies, Foundation for Researcher and Technology Hellas (FORTH).
![](http://actys.ims.forth.gr/wp-content/uploads/GPS.jpg)
GPS receiver
This GPS antenna is used in Real-Time Kinematics (RTK) mode for collecting ground control points with high accurracy (<20cm). RTK measurements are provided via a HEPOS connection. Accurate ground control points are required for georeferencing centimeter-resolution drone imagery.
![](http://actys.ims.forth.gr/wp-content/uploads/drone.jpg)
Unmanned aerial vehicle (UAV) platform
The DJI Phantom 4 Pro drone is used for collecting aerial imagery. It has a default camera which acquires 16 megapixels RGB imagery in interval mode. In addition, the multispectral camera below is mounted on the drone for acquiring images with calibrated reflectance values.
![](http://actys.ims.forth.gr/wp-content/uploads/mica.jpg)
Multi-spectral sensor
This is a Mica Sense Red-edge model. It is mounted on the UAV and it is connected with its own GPS antenna which is also a down-welling irradiance sensor. This camera collects spectrally-calibrated imagery at four bands in the visible spectrum (red, green, blue, red-edge) and one band at the near infrared spectrum. The near infrared is completely absorbed by the water,thus it is only used for masking the land surface from the sea.
![](http://actys.ims.forth.gr/wp-content/uploads/boat.jpg)
Unmanned surface vehicle (USV) platform
This is an 1-meter long polyester boat for acquiring single-beam sonar bathymetry. It is remotely-controlled and it is mounted with the GPS receiver and the sonar sensor shown below. The USV is ideal for operating in very shallow water depths.
![](http://actys.ims.forth.gr/wp-content/uploads/sonar.jpg)
Sonar sensor
This is a single-beam sonar transmitter/receiver. It is battery-powered and it is mounted on the USV side. It is integrated with the GPS via a bluetooth connection and it operates at high frequency (235 kHz) collecting high resolution bathymetric profiles. Sonar measurements are vital for calibrating the drone imagery and producing wide-scale bathymetry.