**Preface to "UAV or Drones for Remote Sensing Applications in GPS/GNSS Enabled and GPS/GNSS Denied Environments"**

Dear Colleagues,

The design of novel UAV systems and the use of UAV platforms integrated with robotic sensing and imaging techniques, as well as the development of processing workflows and the capacity of ultra-high temporal and spatial resolution data have enabled a rapid uptake of UAVs and drones across several industries and application domains.

The scope of this book provides a forum for high-quality peer-reviewed papers that broaden awareness and understanding of single and multiple UAV developments for remote sensing applications, and associated developments in sensor technology, data processing and communications, and UAV system design and sensing capabilities in GPS enabled and more broadly Global Navigation Satellite System (GNSS) enabled and GPS /GNSS denied environments.

Contributions include:

UAV-based photogrammetry, laser scanning, multispectral imaging, hyperspectral imaging, and thermal imaging;

UAV sensor applications, spatial ecology, pest detection, reef, forestry, volcanology, precision agriculture wildlife species tracking, search and rescue, target tracking, the monitoring of the atmosphere, chemical, biological, and natural disaster phenomena, fire prevention, flood prevention, volcanic monitoring, pollution monitoring, microclimates, and land use;

Wildlife and target detection and recognition from UAV imagery using deep learning and machine learning techniques;

UAV-based change detection;

Sense and avoid;

UAV navigation in cluttered environments;

Single and multiple UAVs or swarms in GPS /GNSS denied environments;

On-board decision making;

Real-time georeferencing for UAV-based imaging;

Radiometric and spectral calibration of UAV-based sensors;

UAV onboard data storage, transmission, and retrieval;

Collaborative strategies and architectures to control multiple UAVs and sensor networks for the purpose of remote sensing.

#### **Felipe Gonzalez Toro, Antonios Tsourdos**

*Editors*
